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Thread: Decent Espresso Machines (DE1) - Any thoughts?

  1. #951
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    High Voltage Tests and Tethering Experiments

    locksandmore.jpg

    According to the UL safety standard, every machine assembled needs to be tested to make sure there is virtually no electrical leakage that could cause a shock. Wikipedia has an easy to read explanation https://en.wikipedia.org/wiki/Hipot of this. A piece of specialized test equipment known as a "high pot tester" arrived this week Products - SHENZHEN MEIRUIKE TECHNOLOGY CO.,LTD.
    dial.jpg

    My three electrical engineers reading through UL's excellent essay on the theory and practice of this "dielectric voltage withstand test" https://library.ul.com/wp-content/up...Test_v5_HR.pdf

    You can see Parry in the bottom right photo, with an absolutely enormous red plastic probe, gingerly approaching a DE1 to do the first test while Stanley stands safely back.


    CATERING KIT & DE1PRO
    On the top right photo, you can see Alex testing pumps for the "catering kit" that plugs into the DE1PRO models. I wanted to make sure that the pump was strong enough to lift was 2 meters up into DE1PRO to refill it. We use the Basecamp forum software to record all this, and Alex is making a video and timing the flow. In the end, this pump (that we'll likely use) lifted water 2 meters high, at a flow rate of 1 liter per minute.


    WATER MIXING ASSEMBLY
    On the bottom left photo, you can see us starting to put together the water mixing assembly. This is the most complicated part of the machine, with 4 valves, 9 temperature probes, and a pressure sensor. You can see a few of our color-coded temperature sensors on the left side of the photo. I'm not entirely happy with how the color-coded sheath is looking after cutting + melting with a heat gun. The ends are a bit messy looking. Yesterday I ordered a "hot wire knife" https://www.aliexpress.com/item/220V...21860906.html? which I believe is the correct tool for cutting the mesh, and hopefully will give us a cleaner result.
    knife.jpg

    ANTI-THEFT CABLE
    I received the "anti-theft cable" yesterday (middle right photo), and today wired it up in various ways. Just a reminder about this: it's both for cafes who don't want to have their tablet stolen, and as a backup solution if Intertek requires us to prevent removal of the Bluetooth tablet for safety compliance reasons.

    This cable has a bit that fits into the headphone jack. It's tightened and removed with an included screwdriver with a square "inverse Allen wrench" end to it. I like that it's nondestructive, but I didn't like that it doesn't fit tightly. If you overtighten, the screen starts to push away from the chassis.

    I like that the other end can be secured with a 3M glue pad or with bolts. The advantage of the bolts is that this could be secured non-destructively to the back panel (middle top photo). If you didn't want the cable, you'd take the chassis cover off and remove the bolt, with no lasting damage. However, there is a dangling cable with this approach.

    If the 3M glue pad is used, a very short lock cable could be specified, and the lock becomes almost invisible (top left and middle bottom photos).

    Since the tablet has a stand glued to the back of it, I'm thinking that this would be a more invisible place to tether a locking cable, instead of on the headphone jack, which is both visible and not tight fitting or all that secure.

    That brings us back to the original tethering proposal I made a few days ago, but with the cable going straight back and into the chassis at the back left (where it is on the top row, middle photo). The advantage of this approach is that the cable is not mostly invisible from the user's stance in front of the machine. Also, the security cable can be completely removed with a pair of wire cutters (off the tablet stand) and from the inside of the chassis (with a Torx screwdriver to remove the cover).
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    chained to the idea

    I've just now ordered 5 different styles of black chains to see which style we prefer. To comply with Intertek's request for a tether for safety compliance reasons, we could simply run the chain from the tablet stand to a torx screw on the back panel. It's my belief that a locking cable tie on the tablet stand would likely comply, as it's only removable with wire cutters.

    Here's a photo of the concept, put together now.

    IMG_7917.jpg

    We have a slight concern that taps on the tablet could cause metal-moving noise, but that didn't happen on the mockup we just did. But we'll watch for that.

    https://www.aliexpress.com/store/product/Free-shipping-bracelet-necklace-material-DIY-accessories-Jewelry-parts-iron-chain-3-5-5MM-SMM1066/1016256_32463314658.html

    https://www.aliexpress.com/store/product/Free-shipping-bracelet-necklace-material-DIY-steel-chain-accessories-Jewelry-parts-brass-chain-round-3-3/1016256_32455287982.html

    https://www.aliexpress.com/store/product/Free-shipping-bracelet-necklace-material-DIY-steel-chain-accessories-Jewelry-parts-brass-chain-5-5-7/1016256_32458185495.html

    https://www.aliexpress.com/store/product/Free-shipping-bracelet-necklace-material-DIY-accessories-Jewelry-parts-steel-chain-4-4-5mm-silver-smb1087/1016256_32447546503.html

    https://www.aliexpress.com/store/product/Free-shipping-bracelet-necklace-material-DIY-steel-chain-accessories-Jewelry-parts-brass-chain-4-10mm-anti/1016256_32403846359.html

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    Decent team,

    Would simultaneous steam/brew feature be as simple as a future BIOS, software upgrade for DE1PRO+ (220v / v1.0) or would it be a parts/component limitation to it?

    I've been fascinated with your machine and have been watching /reading pretty much e-v-e-r-y-t-h-i-n-g about it for the past several weeks. I only struggle with the fact that it doesn't steam and brew simultaneously (and I understand the reasons why). But I remember reading somewhere that the DE1PRO+ 220v could have enough power to feature steaming and brewing simultaneously, hence the question...

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    Chain Free

    The fourth of the five chain samples is not too bad. Chain is by its nature, abrasive. I would suggest instead coated wire rope ("aircraft cable".) It is available in very small diameters (like a tiny .35mm) with clear, black or colored plastic coating so as not to be abrasive. Here are a couple of examples:

    https://www.aliexpress.com/item/50me...58403965.html?

    https://www.aliexpress.com/item/Whol...46371185.html?

    Pick the diameter for your preferred aesthetic since strength is mostly irrelevant for this application.
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  5. #955
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    Quote Originally Posted by fredrodrigues View Post
    Would simultaneous steam/brew feature be as simple as a future BIOS, software upgrade for DE1PRO+ (220v / v1.0) or would it be a parts/component limitation to it?
    The water path can't support it, because we have two pumps (hot and cold) to make espresso, and those are therefore busy whilst making coffee, and not available for steam. A 3rd pump would need to be added.

    Quote Originally Posted by fredrodrigues View Post
    I've been fascinated with your machine and have been watching /reading pretty much e-v-e-r-y-t-h-i-n-g about it for the past several weeks. I only struggle with the fact that it doesn't steam and brew simultaneously (and I understand the reasons why). But I remember reading somewhere that the DE1PRO+ 220v could have enough power to feature steaming and brewing simultaneously, hence the question...
    At 220V we can either give you great steam w/o espresso at the same time, or OK steam during.

    The reason I've been avoiding steam-during brew is that steam that had inconsistent power (depending on whether you're making coffee or not) would very annoying.

    We'd assume (incorrectly) that we'd be allowed to have two 220V plugs in to overcome this, but for safety reasons we've learned this is not allowed. Thus, steam during brew will only be possible with a separate, dedicated (small) steaming unit.

    -john

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    Quote Originally Posted by HBDecentRefugee View Post
    Chain Free
    The fourth of the five chain samples is not too bad. Chain is by its nature, abrasive. I would suggest instead coated wire rope ("aircraft cable".) It is available in very small diameters (like a tiny .35mm) with clear, black or colored plastic coating so as not to be abrasive. Here are a couple of examples:
    https://www.aliexpress.com/item/50me...58403965.html?
    https://www.aliexpress.com/item/Whol...46371185.html?
    Pick the diameter for your preferred aesthetic since strength is mostly irrelevant for this application.
    Thanks for the recommendations. I'm hoping that the paint on the chain (I ordered matte black) will make it non abrasive.

    I previously avoided the black-wire route because the cable doesn't "flop" pleasantly onto the case, instead keeping its odd bend. Also, how to fix the rope to the tablet and back wasn't obvious. A grounding tab would work, but didn't look great.

    We're using m3 torx screws, so I specifically looked for chains that had an internal diameter where the torx screw could simply hold the chain down. That way, one screw that currently holds the plastic back panel on, would get a chain link segment and we'd be good to go. And easily removed.

    -john

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    Just about to power up our first two machines, with everything built right. Both machines are "splayed open" so that we can poke around with oscilloscopes and multimeters to ensure everything is working as expected.

    Next week, Ray can hopefully start work on final firmware calibrations now that all components are final-final.

    IMG_7922.jpg IMG_7921 2.jpg

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    Quote Originally Posted by decentespresso View Post
    Thus, steam during brew will only be possible with a separate, dedicated (small) steaming unit.
    Plans for Decent dedicated steaming unit?

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    Quote Originally Posted by fredrodrigues View Post
    Plans for Decent dedicated steaming unit?
    Very much so, and currently being worked on by Ben and Ray as a high priority. Ideally, we'll have it in beta around the same time that we have the DE1CAFE start shipping (April). It's essentially an espresso machine with a water heater and group head removed.

    It will still talk bluetooth, as we want to have "steam profiling" as a feature, so that you can choose your mix of pressure/flow/temperature for steam. This has a surprising effect on the taste of the milk.

    -john

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    Cabling Love

    IMG_7925.jpg

    Enough custom-made electrical cables for 350 espresso machines arrived today (yes, they're VERY late in their delivery). We've been making these cables by hand for machines so far, which is time-consuming and error-prone, so we're really happy to receive these.

    Each power cable in our espresso machine has a different connector on it so that it's literally impossible to wire it up incorrectly. However, that means each cable is different and custom-made, too.

    Clockwise from top-right:
    - two pumps: hot and cold water
    - one group head heater
    - two heaters: espresso and steam
    - centralized (8 pin) cable to turn all the valves on/off (water routing)
    - small cable to engage the relay to give full AC power the machine, as controlled by the logic board

  11. #961
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    That Christmas tree's looking a bit scrawny..

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    Heater Stand-off

    preview-full-image.jpg

    Intertek has asked for detailed information on exactly how our hot water heaters are built as part of their UL compliance review. Unfortunately, our manufacturer considers this information confidential and will only share some of the details. A bit of a stand-off now exists between the safety compliance reviewer and a desire to keep information secret by the hot water heater manufacturer so that they're not cloned. Both sides have a reasonable position, and we're negotiating in the middle to reach a compromise.

    To move things forward, we sliced through one of our heaters in order to see what's really inside, as much as we can. We know that the water tubing is 304 stainless, and the insulating material around the heater coil is magnesium powder. We don't yet know what the heating element is (but it's probably nickel-chrome) and we're pressing to be confirmed that's the case, and at what diameter (though we can dig it out and measure it).
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  13. #963
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    It sounds like Intertek don't want you to build the machine.
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    IMG_7944.jpg

    Mechanical Engineering Student Interns Tommy and Charlotte are today using our new tube-cutting machine to precisely cut lengths of silicone water tubing. This tubing is used to bring water into the flow meter and pumps, and at that point, there is only low pressure, which is why silicone tubing is used.

    We just recently decided--down to the millimeter--how long these tubes should be, which is why they're cutting them now, in quantity, for 300 espresso machines.

    The tube lengths aren't something you can simulate in software, you have to actually build a machine, try different lengths, and decide what's best. That's why it's being done now, just before building machines in quantity.

    The students measured the tubes and found a 2mm error margin on a 200mm long tube: about a 1% tolerance. That's pretty accurate.
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  15. #965
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    Hi John,

    A couple of questions about your grinder...

    When will it be available to buy? and

    In one of your videos you mentioned it has conical burrs...I'm just wondering...Does this machine have conical burrs or flat burrs?

    Cheers.

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    Quote Originally Posted by bigdaddy View Post
    A couple of questions about your grinder... When will it be available to buy? and In one of your videos you mentioned it has conical burrs...I'm just wondering...Does this machine have conical burrs or flat burrs?
    I assume you're referring to https://decentespresso.com/pro_grinder which is in this photo below.

    These have been available for pre-order for a while, and I have a pallet of 50 grinders in stock. However, these grinders are then hand modified by us to have a X/Y/Z adjustable portafilter stand, as my focus with this grinder is getting the mound centered and also weighed. The scale stands were the last design for us to really nail down. In the photo, if you look carefully, you'll see that the left hand side grinder is missing the thumb-screws that the right hand model has. We previously had height adjustment holes at set intervals, but I decided to move to thumb screws and continuous adjustment.

    The sheet metal company suddenly wants an additional USD$680 to deliver these, which wasn't agreed to. I suspect this is a "get it before chinese new year" negotiating tactic (sigh) so we might have to wait until they come back from their 2 week holiday to start assembling our grinders.


    BURRS

    I also wanted to sort out an upgrade (and replacement) path for the burrs. They are 64mm flat burrs, as the web page mentions. I need to totally redo the video as soon as we start shipping the grinders, which will be immediately after Chinese new year (about 2 weeks). You are correct that in the video I incorrectly state that they're conical.

    We've been working Hansung@SSP burrs https://www.instagram.com/SSP_grinding/ to use his burrs as an upgrade/replacement burr. The burr upgrade effectively increases the quality of the grinder from a Mazzer Super-Jolly level to a Mahlkonig K30 level, and this is guaranteed to be the case by SSP. The SSP burrs are much admired also by Socratic https://www.instagram.com/Socraticcoffee/ and their testing has yielded some nice results.

    We're also going to be selling the SSP burrs to people who want to upgrade their existing grinders, as I'm not sure there are any sources besides SSP in Korea at the moment, for them.

    On Home Barista they've been talking about the SSP burr upgrade recently:
    https://www.home-barista.com/grinder...od-t48458.html
    with what appears to be good results.

    IMG_7952.jpg
    Last edited by decentespresso; 7th February 2018 at 02:28 PM.
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    Calibrating to Reality

    calibrating.jpg

    Our "first production machine" is now up and running, and we're working through the final problems before making a lot more identical machines.

    Here's what we've found so far:

    FLOW METER DIDN'T WORK
    It turns out that which-wire-does-what changed between model numbers and so our flow meter cables need to have their pins re-arranged. This takes about 30s per cable, and Jennifer can be seen doing this on the top left.


    CALIBRATING PRESSURE
    Photos: left middle, top right.
    Next, we got to test the calibration steps that I've written for the Android tablet. Why do we need to do this? Because: the specifications a manufacturer gives us for a part aren't necessarily what you actually get. The pressure sensor comes with a "magic number" to convert resistance to pressure, but physical variation means the "magic number" will be slightly off. To test the pressure, we use a Scace II portafilter, which is a $600 piece of test equipment that independent reports pressure and temperature. We then change the "magic number" in our pressure sensor so that our readings now agree with the Scace. 91PSI=6.27 bar, so we were 4.5% off until calibrating.

    Incidentally, on the middle-left photo, you can see the cooling effect of the unheated stainless steel mass of the Scace 2. Our temperature probe is reading the effect of this cooling, and our water mixing technology tries to compensate for it by putting in hotter water. In this case, a -2.5C cooling effect was over-compensated for between seconds 10s->25s. Running a hot water shot or two, to preheat the Scace, would remove this temperature fluctuation at the puck.


    CALIBRATING FLOW
    Photos: bottom right and left.
    Using the Bluetooth scale to measure flow rate into the cup, we can obtain an accurate flow measurement, based on weight rather than moving water. At lower speeds to water, the flow meter readings get quite noisy (see on the oscilloscope) and a bit of tweaking on the noise filter was needed to make this wor better. Here, the calibration was needed to correct a 4% to 8% error.
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    I've just cut and pasted post 966 and put it into the decent espresso grinder thread and added a post so not to clog this thread up with grinder questions.

    Cheers.

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    Down to the wire

    down_to_the_wire.jpg IMG_7981.jpg

    We are color coding all our wires and sensors in 11 different colors, using a colored fiber sleeve.

    To make the colored sleeve, we've been using our automatic-tube-cutting machine, and then cleaning up the splayed mess (bring right tubes next to Josephine's left elbow) with a hot air gun (bottom left photo).

    The resulting tube no longer splays (blue tube in the bottom right photo) but it looks sloppy and takes up precious space next to other connectors on the PC boards. I've not been happy with this, and have looked to improve it.

    This week, a temperature controllable "hot wire knife" arrived, and the results (grey tube, bottom right photo) are so much better.

    You can see Josephine in the photo redoing the already-cut tubes so that they have a clean, melted cut. I'm not super-happy with the safety aspects of this process, so we'll be soon making a plastic guard with a "cut slot" in it, to prevent an accident.

    And speaking of accidents, many thanks to Jeff W on Coffee Forums UK for bringing to my attention the risks of loose hair in the shop, which he noticed in one of my recent photos. A humorous "hair on fire" poster now graces the shop wall, and we'll order a shop helmet after Chinese New Year.

    safety.jpg
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    Getting organized

    getting_organized.jpg

    Our espresso machine factory is slowly starting to look a bit civilized, as we prepare to ramp up production (and hire more people) in about 5 weeks from now.
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  21. #971
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    Thanks for the update. How's it going with Intertek?
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    I'm just thinking a bit into the future and if I was to buy. With all the new electronic sensors and technology on this machine (which I think is fantastic)... Will it need any type of regular calibration and continual/extra maintenance to keep it accurate in the future?

    I can see one thing which would be no big deal...I can see the need for regular updates to be installed on the tablet, but I was thinking more on the hardware side of things...I don't know, but maybe there will be a requirement for yearly serving where all these things may or may not be adjusted or maybe there is no need or maybe there will be a need to do it at home?

    Cheers.

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    Quote Originally Posted by JMcCee View Post
    Thanks for the update. How's it going with Intertek?
    WhatsApp message from the big boss (a few days ago): "we haven't forgotten you. We're having an internal conversation and need a few more days".

    Separately, as I mentioned a few days ago, the examiner wanted specs on our heaters. By cutting them apart, and measuring various parts (resistance can be measured) as well as a few yes/no questions the manufacturer was willing to answer (until they decided we'd asked too much, got nervous, and stopped answering), we were able to make quite nice drawings with most specifications of both the group head cartridge heater, and the water heater. That's now back with Intertek for review. No new "fails" yet.

    Quote Originally Posted by bigdaddy View Post
    I'm just thinking a bit into the future and if I was to buy. With all the new electronic sensors and technology on this machine (which I think is fantastic)... Will it need any type of regular calibration and continual/extra maintenance to keep it accurate in the future?
    For the flow meter and pressure sensor, our understanding is that mechanical variation at manufacturing is the issue, though at high altitude the pressure sensor will be incorrect at zero bar. For the temperature sensors, they might drift with time (as many thermometers do).

    It's really a question you have to ask yourself:
    --> if the device consistently gives the same result, but is off by 5% to the official measurement, does that matter to me?

    In other words if your coffee tastes best at what you believe to be 8.2 bar, but actually you're at 8.6 bar, do you care?

    If you do care, then you'll want to have pressure, temperature and flow recalibrated.

    For flow rate, you would buy our $99 bluetooth scale, and make sure you have a DE1+ or better model.

    For temperature and pressure, you would either buy a Scace 2 portafilter, or (when we ship it) our alternative to the Scace.

    In both cases, the protocol is very simple:
    1) run a 6 bar shot (no puck), write down what pressure the Scace sees it at
    2) run a 2.5 ml/s flow profile shot (no puck), and write down what the bluetooth "flow rate into the cup" as measured by weight.

    There will be a page on the tablet software where you can enter the test you performed, the goal and the measured value.

    Quote Originally Posted by bigdaddy View Post
    I can see one thing which would be no big deal...I can see the need for regular updates to be installed on the tablet, but I was thinking more on the hardware side of things...I don't know, but maybe there will be a requirement for yearly serving where all these things may or may not be adjusted or maybe there is no need or maybe there will be a need to do it at home
    If you have your DE1 serviced for whatever reason, part of the process will be a no-cost recalibrating of your machine.

    As far as regular updates to the tablet software, that is the plan, but I don't see the *need* for it. Most kitchen devices don't get better (more features, more accuracy) with time.
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  24. #974
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    Quote Originally Posted by decentespresso View Post
    WhatsApp message from the big boss (a few days ago): "we haven't forgotten you. We're having an internal conversation and need a few more days".

    Separately, as I mentioned a few days ago, the examiner wanted specs on our heaters. By cutting them apart, and measuring various parts (resistance can be measured) as well as a few yes/no questions the manufacturer was willing to answer (until they decided we'd asked too much, got nervous, and stopped answering), we were able to make quite nice drawings with most specifications of both the group head cartridge heater, and the water heater. That's now back with Intertek for review. No new "fails" yet.


    For the flow meter and pressure sensor, our understanding is that mechanical variation at manufacturing is the issue, though at high altitude the pressure sensor will be incorrect at zero bar. For the temperature sensors, they might drift with time (as many thermometers do).

    It's really a question you have to ask yourself:
    --> if the device consistently gives the same result, but is off by 5% to the official measurement, does that matter to me?

    In other words if your coffee tastes best at what you believe to be 8.2 bar, but actually you're at 8.6 bar, do you care?

    If you do care, then you'll want to have pressure, temperature and flow recalibrated.

    For flow rate, you would buy our $99 bluetooth scale, and make sure you have a DE1+ or better model.

    For temperature and pressure, you would either buy a Scace 2 portafilter, or (when we ship it) our alternative to the Scace.

    In both cases, the protocol is very simple:
    1) run a 6 bar shot (no puck), write down what pressure the Scace sees it at
    2) run a 2.5 ml/s flow profile shot (no puck), and write down what the bluetooth "flow rate into the cup" as measured by weight.

    There will be a page on the tablet software where you can enter the test you performed, the goal and the measured value.


    If you have your DE1 serviced for whatever reason, part of the process will be a no-cost recalibrating of your machine.

    As far as regular updates to the tablet software, that is the plan, but I don't see the *need* for it. Most kitchen devices don't get better (more features, more accuracy) with time.
    John, one consequence of DEx machines' variation from spec will be the impact on one of the main future features - sharing recipes in the cloud. As you say, in the home environment, why should we care about absolute values if whatever settings we choose work for us. But that changes in the sharing environment. This will mean that sharing a recipe is only an approximation that has to be tweaked in unknown ways to replicate someone elses success. I know this is only a practical consequence of component variability and quality control issues which you've discussed before, but it brings home to me that these machines aren't 'reference machines' that are standardised despite the appearance in those graphs slithering across the screen of the tablet.

    Although I will get the bluetooth scales I'm very unlikely to stretch to the expense of a Scace for occasional calibration.

    Appreciate your updates very much, and at this stage, especially the updates on Intertek, which is obviously defining the timing of the production process and delivery dates going forward.

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    Perhaps I'm also, or more to the point, asking if there are any expected corrosion or build up etc issues on the sensors or not. It's all fine in the kitchen if everything is equal then it doesn't matter where your datum point is or what it reads so long as it is consistent with the other readings but I'm asking if there is any forseen corrosion or build up issues that could vary the individual readings over time thus causing the need for calibration and maintenance from time to time.

    If I could indulge and draw an analogy to cars and I know they are a completely different beast, but the sensors etc are checked regularly and dealt with if any issues occur..Just wondering if regular checking would be needed on the DEx models or not.

    Cheers.
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    Quote Originally Posted by gc View Post
    John, one consequence of DEx machines' variation from spec will be the impact on one of the main future features - sharing recipes in the cloud. As you say, in the home environment, why should we care about absolute values if whatever settings we choose work for us. But that changes in the sharing environment. This will mean that sharing a recipe is only an approximation that has to be tweaked in unknown ways to replicate someone elses success. I know this is only a practical consequence of component variability and quality control issues which you've discussed before, but it brings home to me that these machines aren't 'reference machines' that are standardised despite the appearance in those graphs slithering across the screen of the tablet. Although I will get the bluetooth scales I'm very unlikely to stretch to the expense of a Scace for occasional calibration.

    You’re absolutely right, but I’d like to add a few comments to what you’ve said:
    1) all machines will be factory calibrated to be identical, as they leave the factory

    2) thus far (3 years) we haven’t seen any corrosion or calcification around sensors. Valves and the group head have been where corrosion builds up, as well as lime scale deposit back into the water tank, as a positive, intended consequence of our water cycling design. Waste water after each shot is sent back to the water tank, far away from the intake, so that calcium deposits settle rather the recirculate.

    3) we don’t know how much sensor drift there will be, and what its consequences are. If the drift is < 5% I don’t expect it to have much impact.

    4) if you mainly use flow profiling to make espresso (which is what we do, and Rao recommends now too, and I suspect Perger will too) then
    (a) this method is more tolerant of variation and
    (b) this is inexpensively recalibrated using our bluetooth scale.

    If there are any espresso machine repairman reading this, maybe they can comment on inter-machine variation they’ve seen in the field. So-called "9 bar" machines, used everywhere, have been Scace measured by me between 7 and 9.5 bar. I often take a Scace with me when I visit a cafe for a chat with the owner, and take measurements. The owner and I are both interested.

    And finally, we’re planning on our Sensor Basket eventually being a Scace competitor at a lower price, with a digital interface to the DE1+, making recalibration very easy.

    Quote Originally Posted by bigdaddy View Post
    Perhaps I'm also, or more to the point, asking if there are any expected corrosion or build up etc issues on the sensors or not. It's all fine in the kitchen if everything is equal then it doesn't matter where your datum point is or what it reads so long as it is consistent with the other readings but I'm asking if there is any forseen corrosion or build up issues that could vary the individual readings over time thus causing the need for calibration and maintenance from time to time. If I could indulge and draw an analogy to cars and I know they are a completely different beast, but the sensors etc are checked regularly and dealt with if any issues occur..Just wondering if regular checking would be needed on the DEx models or not.
    I’d say that like a car, if you want peak performance, then regular maintenance is a good idea. Commercial espresso machines typically receive maintenance in a cafe every 60 days.

    Back when I used to drink Nespresso, I never cleaned or decalcified the machines, and they regularly died within 2 years.

    I should also mention that my v1 machine, the first one we built from 3 years ago, finally "gave up the ghost" with a valve being so calcified that it won’t routinely open. I purposely never cleaned it, never decalcified it, to see what the MTBF is. It’s made about 3000 espressos.

    I could have avoided the total failure by decalcifying it when the valve started to not be reliable (after about 20 espressos made) - the problem started 18 months ago, at a demo at Prufrock in London. I also mention that when we started to see this problem, we decided to change valve suppliers, and move to ODE, who makes the valves for La Marzocco.

    At this point, we haven’t been able to cause a machine failure programmatically (by repeated use). It seems that water deposits, from turning the machine off and letting the deposit dry and collect, is the most likely failure mode for our machine, as is the case for other machines (so we've been told by repairman)

    Oh, also, if you never clean your steam wand, eventually the milk will gum of the tip and you won’t have steam any more. This is easy for you to repair, by unscrewing the tip, and soaking/cleaning it with a sewing needle through the hole. I've caused this twice.

    For what it's worth, 3.5 years ago, I paid to have my three engineers spend two weeks working at two Seattle based espresso repair shops, and our design has, from the very beginning, been about minimizing calcification buildup. I've posted about those design decisions here in the long-ago past.

    But, to be brief, I'll simply say that the removable water tank absolutely collects calcification and should be washed out regularly, with a scratchy sponge. Calcification will slightly adhere to the enamel finish on the ceramics, but much less so than on other materials, which was another plus to the ceramic choice.

    -john
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  27. #977
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    It's all a Bit Draining

    hole.jpg

    I hadn't looked at how our final sales numbers broke down until last week, and I was surprised to find that 42% of our first 300 customers had opted for the PRO option, which allows you to "plumb" your Decent Espresso machine. Connecting "Water In" is something we solved two years ago, but we'd never finalized how dirty water would drain out.

    Our intention was to either drill a hole in our existing drip trays, or to make new ones. My preference was to drill holes, but given that these are made out of porcelain "stoneware" that was never a sure thing.

    Our hopes, a few weeks ago, were, shall we say, "shattered" <ahem> when we actually tried to drill holes in porcelain.

    A few days ago the right tool for the job, which is to say "diamond tipped drill bits", arrived. I fitted an 8mm bit onto our drill press, drilled whilst fully immersed (to keep the bit cool) and 1 minute later, a fairly clean hole emerged.

    Unfortunately, the exit hole is not as clean as the entry hole, even though I'm using a wood block as a support under the tray (top right photo).

    If you have experience drilling ceramic and have some "shop tips", please speak up!

    As far as a fitting goes, we wanted:
    - food safe, preferably brass for longevity
    - nearly flush with the bottom of the drip tray
    - nice looking
    - sharp right angle bend, so that the drainage tube could be led to the back of the espresso machine

    We tried boat draining parts, oil can drainage, and traditional plumbing. Nothing was quite right.

    Then, amazingly, Ben found that there is a whole category of "tea tray draining" hardware, for when you spill tea and want it elegantly swept away. A silicone tube fits over the exit barb, and voila. We tried a rubber gasket, but in the end preferred plumber's Teflon tape, to get a good seal around the fitting.

    As you say in the UK, I'm 'well chuffed" at how this turned out.
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  28. #978
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    Quote Originally Posted by decentespresso View Post
    You’re absolutely right, but I’d like to add a few comments to what you’ve said:
    1) all machines will be factory calibrated to be identical, as they leave the factory

    2) thus far (3 years) we haven’t seen any corrosion or calcification around sensors. Valves and the group head have been where corrosion builds up, as well as lime scale deposit back into the water tank, as a positive, intended consequence of our water cycling design. Waste water after each shot is sent back to the water tank, far away from the intake, so that calcium deposits settle rather the recirculate.

    3) we don’t know how much sensor drift there will be, and what its consequences are. If the drift is < 5% I don’t expect it to have much impact.

    4) if you mainly use flow profiling to make espresso (which is what we do, and Rao recommends now too, and I suspect Perger will too) then
    (a) this method is more tolerant of variation and
    (b) this is inexpensively recalibrated using our bluetooth scale.

    If there are any espresso machine repairman reading this, maybe they can comment on inter-machine variation they’ve seen in the field. So-called "9 bar" machines, used everywhere, have been Scace measured by me between 7 and 9.5 bar. I often take a Scace with me when I visit a cafe for a chat with the owner, and take measurements. The owner and I are both interested.

    And finally, we’re planning on our Sensor Basket eventually being a Scace competitor at a lower price, with a digital interface to the DE1+, making recalibration very easy.
    many thanks for the explanation. I guess we will discover point three above over time and, as you say, hope that it has an insignificant impact.

    I always use an undersink dual filter cartridge setup for my HX machine and despite checking internally annually, don't seem to have any scale issues [I really don't understand why after more than a decade].

    I was having trouble getting my head around pressure profiling given the inconsistencies in my grinder, so am glad those who know also support flow profiling. And the fact that your BT scale will calibrate that is a real plus for me.

    BTW, what is the latency between BT measure on scale and hardware response in the DE through tablet software to adjust flow? Is it greater than say, 500ms - 1.00sec?
    Last edited by gc; 13th February 2018 at 12:37 PM.
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    Quote Originally Posted by decentespresso View Post
    hole.jpg

    I hadn't looked at how our final sales numbers broke down until last week, and I was surprised to find that 42% of our first 300 customers had opted for the PRO option, which allows you to "plumb" your Decent Espresso machine. Connecting "Water In" is something we solved two years ago, but we'd never finalized how dirty water would drain out.

    Our intention was to either drill a hole in our existing drip trays, or to make new ones. My preference was to drill holes, but given that these are made out of porcelain "stoneware" that was never a sure thing.

    Our hopes, a few weeks ago, were, shall we say, "shattered" <ahem> when we actually tried to drill holes in porcelain.

    A few days ago the right tool for the job, which is to say "diamond tipped drill bits", arrived. I fitted an 8mm bit onto our drill press, drilled whilst fully immersed (to keep the bit cool) and 1 minute later, a fairly clean hole emerged.

    Unfortunately, the exit hole is not as clean as the entry hole, even though I'm using a wood block as a support under the tray (top right photo).

    If you have experience drilling ceramic and have some "shop tips", please speak up!

    As far as a fitting goes, we wanted:
    - food safe, preferably brass for longevity
    - nearly flush with the bottom of the drip tray
    - nice looking
    - sharp right angle bend, so that the drainage tube could be led to the back of the espresso machine

    We tried boat draining parts, oil can drainage, and traditional plumbing. Nothing was quite right.

    Then, amazingly, Ben found that there is a whole category of "tea tray draining" hardware, for when you spill tea and want it elegantly swept away. A silicone tube fits over the exit barb, and voila. We tried a rubber gasket, but in the end preferred plumber's Teflon tape, to get a good seal around the fitting.

    As you say in the UK, I'm 'well chuffed" at how this turned out.
    I like your software ideas, some of your hardware ideas are ok, but this is just plain crazy. I think you really need to get a coffee professional on board who has experience with machines. For something that has been ongoing for 3 years this drain hole solution is very poor. All you will get is a pool of sticky water about 1cm deep, or however high it needs to get over that brass fitting and it will be a pain to keep clean. Since you are using ceramics (why not stainless?) you had the perfect chance to incorporate a lower section into the design that pools water, fed by drain channels from all 4 corners, leaving the main tray essentially dry and clean. You could have had a nice clean hole in the design as well, rather than drilling and causing chips and cracks. No hole customer? have a different tray or just use a nice simple plug.

    I think this is not a solution at all. Sorry.

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    I suppose eventually the drip trays will be premade with the drain barbs already set into the ceramics by the ceramic company which makes the trays but for now, I would suggest to look at the shape of the drill bit, (having a look at shaping HSS drill bits for sheet metal as a template may work) it's different to the normal shape and ground that way to stop wobbles and to stop the finished holes not being round) plus, I would also pay particular attention to the recommended cutting speed at which you are cutting the hole into the drip tray. Another thing you may want to do is to partially cut the drain hole, but do not go completely through anywhere, on one side then flip the tray upside down and drill back from the other side. This will involve accurate marking of the centre point of the last hole but if done correctly you should not get your chipping....Now for the addition of the hose barb...Hmmm...I agree that having the nuts or whatever protruding onto the inside of the tray is not ideal but I don't have any other fitting suggestions at this stage, sorry.

    Cheers.

  31. #981
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    Quote Originally Posted by HBexile2 View Post
    I like your software ideas, some of your hardware ideas are ok, but this is just plain crazy. I think you really need to get a coffee professional on board who has experience with machines. For something that has been ongoing for 3 years this drain hole solution is very poor. All you will get is a pool of sticky water about 1cm deep, or however high it needs to get over that brass fitting and it will be a pain to keep clean. Since you are using ceramics (why not stainless?) you had the perfect chance to incorporate a lower section into the design that pools water, fed by drain channels from all 4 corners, leaving the main tray essentially dry and clean. You could have had a nice clean hole in the design as well, rather than drilling and causing chips and cracks. No hole customer? have a different tray or just use a nice simple plug.

    I think this is not a solution at all. Sorry.
    This has bothered me a little for some time. I could never understand the thing about ceramic trays when an existing stainless tray for the DE 1 could be easily modified in the manufacturing process to suit the pro. Or even after.
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  32. #982
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    Quote Originally Posted by HBexile2 View Post
    I like your software ideas, some of your hardware ideas are ok, but this is just plain crazy. I think you really need to get a coffee professional on board who has experience with machines. For something that has been ongoing for 3 years this drain hole solution is very poor. All you will get is a pool of sticky water about 1cm deep, or however high it needs to get over that brass fitting and it will be a pain to keep clean. Since you are using ceramics (why not stainless?) you had the perfect chance to incorporate a lower section into the design that pools water, fed by drain channels from all 4 corners, leaving the main tray essentially dry and clean. You could have had a nice clean hole in the design as well, rather than drilling and causing chips and cracks. No hole customer? have a different tray or just use a nice simple plug. I think this is not a solution at all. Sorry.
    You might not see it, but I'm surrounded by coffee professionals. I have a half dozen cafe owners as direct advisors on private forums. We've also studied other drip tray plumbing solutions, and what we're using is used in the almost identical scenario of "tea tray draining".

    If you Google search forums about the La Marzocco GS3 drip tray, its plumbing and refilling, and you'll find that this is what people disliked most about that espresso machine. They're an impressive company with decades of R&D behind them, and even they didn't nail it. For example, they used a "nice simple plug" on their drip tray outlet, and it leaked.

    How to design the humble drip tray is not a "solved problem".

    Quote Originally Posted by bigdaddy View Post
    I suppose eventually the drip trays will be premade with the drain barbs already set into the ceramics by the ceramic company which makes the trays but for now, I would suggest to look at the shape of the drill bit, (having a look at shaping HSS drill bits for sheet metal as a template may work) it's different to the normal shape and ground that way to stop wobbles and to stop the finished holes not being round) plus, I would also pay particular attention to the recommended cutting speed at which you are cutting the hole into the drip tray. Another thing you may want to do is to partially cut the drain hole, but do not go completely through anywhere, on one side then flip the tray upside down and drill back from the other side. This will involve accurate marking of the centre point of the last hole but if done correctly you should not get your chipping....Now for the addition of the hose barb...Hmmm...I agree that having the nuts or whatever protruding onto the inside of the tray is not ideal but I don't have any other fitting suggestions at this stage, sorry.
    We'll look for more flush fittings that we can buy, and we might end up designing and brass casting our own. We probably can get the protrusion down to 0.5mm.

    As to a premade barb, that's what we designed prototyped two years ago. However, ceramic will not mould into such shapes and no supplier would do it. The standard way this is done, even with stainless steel drip trays, is with a hole and a gasket.

    Sinks have this same problem to solve and the standard fitting for a drain looks like this:

    LK9-2.jpg

    What I do think we'll do in the future is make another batch of ceramics with the hole pre-made, so that the enamel covers the hole nicely. What I don't know is what the size tolerances will be for that hole, due to ceramic shrinkage.

    We also looked at how boats handle this, and also oil pans. All the similar problems we found used the same approach.

    Quote Originally Posted by JMcCee View Post
    This has bothered me a little for some time. I could never understand the thing about ceramic trays when an existing stainless tray for the DE 1 could be easily modified in the manufacturing process to suit the pro. Or even after.
    Every decision is a trade off, and two years ago, the design and material choices were extensively discussed for each part.

    Here is a very short summary for the reason for a ceramic drip tray:
    Food safety was an issue, as people told us they drain the drip tray water onto their garden. The aesthetics are much nicer than plastic. Enamel also is very anti-stick so it will not degrade with time, unlike plastic. My gs3 drip tray is thin metal and warps scarily when I lift it out full of water.

    I've been demoing the machine live for a year and a half, and people have repeatedly called out the ceramic as a point they like.

    The big decisions have all been made in public, largely on homebarista.com, as a discussion between myself and that community.

    I can't please everyone, and every decision will have its detractors, as well as well understood tradeoffs.
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    Quote Originally Posted by decentespresso View Post


    We'll look for more flush fittings that we can buy, and we might end up designing and brass casting our own. We probably can get the protrusion down to 0.5mm.

    As to a premade barb, that's what we designed prototyped two years ago. However, ceramic will not mould into such shapes and no supplier would do it. The standard way this is done, even with stainless steel drip trays, is with a hole and a gasket.

    Sinks have this same problem to solve and the standard fitting for a drain looks like this:

    LK9-2.jpg

    What I do think we'll do in the future is make another batch of ceramics with the hole pre-made, so that the enamel covers the hole nicely. What I don't know is what the size tolerances will be for that hole, due to ceramic shrinkage.

    We also looked at how boats handle this, and also oil pans. All the similar problems we found used the same approach.
    And I would think you have also thought about recessing around the drip tray hole, just like kitchen sinks do to house the fitting shown above? If you think it is possible and your ceramic manufacturer will do it at a reasonable price for you then you may not need to manufacture your own fitting? As you may be able to get the standard fitting to sit flush. I would still think you will get some crevices around the fitting but it may be possible to get it reasonably flush this way. Then if concerned about the crevices maybe silicon around the joints to make it all flush. Personally I don't like silicon but it may or may not be useful here. I'm probably reinventing the wheel here and you probably have already thought about it but...

    Cheers.

  34. #984
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    I'm sure I will prefer the ceramic when I finally see it. It certainly sounds nicer.

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    With respect to the hole blowout problem, could you drill a small pilot hole and then drill the larger hole to the middle, from both directions?

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    Quote Originally Posted by bigdaddy View Post
    And I would think you have also thought about recessing around the drip tray hole, just like kitchen sinks do to house the fitting shown above? If you think it is possible and your ceramic manufacturer will do it at a reasonable price for you then you may not need to manufacture your own fitting? As you may be able to get the standard fitting to sit flush. I would still think you will get some crevices around the fitting but it may be possible to get it reasonably flush this way. Then if concerned about the crevices maybe silicon around the joints to make it all flush. Personally I don't like silicon but it may or may not be useful here. I'm probably reinventing the wheel here and you probably have already thought about it but...Cheers.
    We started with the recessed design, two years ago, and commissioned two designs. Photo below, both drilled and undrilled (we're practicing drilling on the other one).

    The problem we encountered is that the ceramic has to be much thicker on the bottom in order to have a thinner section that is still strong. This increased the weight, but more importantly, the ceramics companies were not happy about this thick a base. Even drying at this thickness was more difficult, and there was more chance of warping as well as a lower yield.

    As an aside, I note that the bar in this version of the drip tray was to slow down the flushing espresso water, not to splash you. We eventually built a "flush diffuser" inside the machine to do this, as the drip tray way of doing it failed when the drip tray started to fill up.

    FYI the way ceramic sinks achieve recessing is by having much larger holes and pipes, so that larger tolerances can be accomodated. That wouldn't look great with our small machine.

    However, we might be able to revisit this "depression" idea in the future, by making it very minor, perhaps just 1mm, and using our own bespoke drain fitting, that sits no more than 1mm proud.

    But to put things into perspective: if the biggest complaint people have about our machine, in one year's time, is this drip tray drain scheme, I will dance a happy dance indeed. There's a lot of innovation going on here, and this the drip tray drain is one of the easiest to repair post-sale if we managed to cock this up.

    IMG_8042.jpg
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  37. #987
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    Quote Originally Posted by MrJack View Post
    With respect to the hole blowout problem, could you drill a small pilot hole and then drill the larger hole to the middle, from both directions?
    Yes, absolutely.

    That's one of two very good suggestions i've received on the UK Coffee Forum, that we're piloting at the moment..

    Another suggestion involves a rubber compression pad on the outlet hole, and apparently this is a well known technique in certain circles for solving this problem.

    That's one reason I'm on these forums: often somebody pops up who an expert on my current particular problem.

    -john
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  38. #988
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    What about laser drilling?

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    Quote Originally Posted by decentespresso View Post
    Yes, absolutely.

    That's one of two very good suggestions i've received on the UK Coffee Forum, that we're piloting at the moment..

    Another suggestion involves a rubber compression pad on the outlet hole, and apparently this is a well known technique in certain circles for solving this problem.

    That's one reason I'm on these forums: often somebody pops up who an expert on my current particular problem.

    -john
    G'Day again John

    The drilling issue:
    I would contact Bosch and Sutton (and maybe Irwin) as the drill manufacturers that have undoubtedly run into this problem many years ago and solved it. My current Bosch 10mm masonry drill bit goes through 1/2" thick ceramics like tissue paper (drilling after a 2mm pilot hole) and leaves no "exit wound" that I noticed. I am 90% sure my old Sutton ones did the same. The other issue you may run into - all drill machines are far from equal when drilling ceramics.

    The drainplug issue:
    The best solution I know off is to have a thicker "plug shaped" portion on the base of the tray (say 30mm diameter), with a pre moulded (say) 20mm hole centred. There is plenty of space to use a locking drain fitting from underneath. As the drain diameter is larger than the hole there is "near zero" water retention (actually it probably is zero). Has worked well in some arctic fishing ships for centuries. Whether modern ceramics can do that portion as well as the old ones I have no idea - the older one usually developed "all over" hairline cracks with age so I doubt they would get approval these days.

    Good luck.

    TampIt
    PS: FWIW, when you have the concurrent steaming / shot pulling sorted my order will also be for plumbed in...

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    Here's a link to an "Advanced drilling tips" article that I found excellent, with some choice bits quoted below:
    Diamond Drill Bit Drilling Techniques

    diamond drill bits are specifically designed for use on very hard materials as shown in the materials section. The extremely hard nature of the materials requires that the diamond drill bits be used with proper drilling techniques. Improper use can overheat and damage the drill bit and may also cause heat fractures and material breakage.

    When drilling in hard, abrasive materials such as limestone, sandstone, hard ceramic and porcelain tiles, marble or granite, it is critical to have lots of lubrication. With these hard materials, it is common to drill under water or to have a small amount of water constantly running over the drill bit and bore hole. In either case, the "pumping" technique described below is needed to assure water reaches the very tip of the bit.

    Pumping Technique: No matter what lubrication method is used, a periodic "pumping" action will significantly improve lubrication at the drill tip. Because of the pressure on the drill tip, water has trouble reaching the very tip of the drill bit. A "pumping" technique allows lubrication to reach the very tip. While drilling, merely raise the drill up and down a fraction of an inch once in a while as you drill (maybe every 15 to 20 seconds or so). This assures that water enters the drill tip area completely and fully lubricates the very tip. Pumping the drill improves lubrication at the tip and will improve drill bit life considerably.

    Drill Pressure
    When using diamond drills, it is very important to have only light to medium pressure on the drill and to let the bit "drill at its own speed". Increasing pressure will not speed up the cutting noticeably, but it will increase the friction considerably and quickly cause the bit to overheat. This not only burns up the bit, but it also heats up the surrounding surface and can cause heat fractures or breakage to occur.

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    Quote Originally Posted by TampIt View Post
    I would contact Bosch and Sutton (and maybe Irwin) as the drill manufacturers that have undoubtedly run into this problem many years ago and solved it. My current Bosch 10mm masonry drill bit goes through 1/2" thick ceramics like tissue paper (drilling after a 2mm pilot hole) and leaves no "exit wound" that I noticed. I am 90% sure my old Sutton ones did the same. The other issue you may run into - all drill machines are far from equal when drilling ceramics.
    The "Diamond Sure" drill bit manufacturer has an extensive section on porcelain, which I found really interesting
    Diamond Drill Bit Drilling Techniques

    The key point they make is:
    When drilling in the newer super-hard tile, using a diamond drill bit is the only reasonable option.

    Our drip trays are made from this sort of super-fine, high density porcelain, and not traditional ceramic.

    And so far, our drilling is going well (I'm following their suggestion for "lubrication pumping"), with a clean exit being our remaining challenge. We haven't yet shattered a single drip tray, which I'm surprised about.


    Ceramic and Porcelain Tile
    Ceramic and Porcelain tile, used on walls, counters and floors, has changed considerably over the years. Ceramic tile was first developed with a heat-hardened vitrified glass finish on the top surface. The inside of the Ceramic tile was still relatively soft. Since the tile was easily scratched, manufacturers developed better manufacturing techniques to make the surface finish much harder. The newer Ceramic tile now has an extremely hard surface that wears very well and the inside of the tile is also relatively hard. While this is a distinct advantage from the stand point of wear, the newer Ceramic tile is often difficult to drill without a diamond drill bit.

    Porcelain tile was originally developed as an alternative to Ceramic tile, for use in floor applications where usage and wear was more extreme. Porcelain tile is made with various mixtures of materials, normally including feldspar and quartz, which are two of the major components of natural Granite. The use of Porcelain floor tile was generally limited to commercial applications, but by the late 1980's, Porcelain tile use expanded more into residential construction.

    In the 1990's, tile manufacturers began to expand their Porcelain tile product lines to include many different styles and many that closely resembled natural stones. Because of the natural stone look, Porcelain tile use on walls and counters became more popular. Finally, in the late 1990's tile manufacturer's developed new manufacturing techniques that made the Porcelain tile significantly harder. As with Ceramic tile, this was a major advancement resulting in reduced wear and very long life. However, many Porcelain tiles are now as hard as Granite and some are as hard as a low grade tool steel. The newer type of high-quality, "super-hard", "Class IV" and "Class V" Porcelain tiles are now almost impossible to drill with the older "spear point" carbide drill bits and generally can only be drilled with a diamond drill bit.

    Old fashioned Spear Point carbide bits no longer work
    on the new type of super-hard floor, counter and wall tiles.

    Diamond Drill Bits are the Solution.
    When drilling in the newer super-hard tile, using a diamond drill bit is the only reasonable option. However, even with a diamond drill bit, the extremely hard material is not very forgiving if inappropriate drilling techniques are used. It is important that good drilling techniques be used. Appropriate drill speeds, low drill pressure and good lubrication are critical. Please review the Lubrication Tip & Techniques and the DiamondSure Drill Speed sections.
    I agree with you that the best solution is to have the hole created as part of the mold, and we'll move to that in time. However, there is a minimum order quantity of 2000 parts when making clay parts, and at a $8 per-piece price, that is both a significant investment (plus mold costs), a lot of inventory to store (a container's worth for each design, in expensive-to-rent Hong Kong), and risky as we have thus far only sold 300 machines. I did not want to order 4000 drip trays at launch, and so decided to modify the 2000 drip trays we do have instead.

  43. #993
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    Quote Originally Posted by decentespresso View Post
    The "Diamond Sure" drill bit manufacturer has an extensive section on porcelain, which I found really interesting
    Diamond Drill Bit Drilling Techniques

    The key point they make is:
    When drilling in the newer super-hard tile, using a diamond drill bit is the only reasonable option.

    Our drip trays are made from this sort of super-fine, high density porcelain, and not traditional ceramic.

    And so far, our drilling is going well (I'm following their suggestion for "lubrication pumping"), with a clean exit being our remaining challenge. We haven't yet shattered a single drip tray, which I'm surprised about.




    I agree with you that the best solution is to have the hole created as part of the mold, and we'll move to that in time. However, there is a minimum order quantity of 2000 parts when making clay parts, and at a $8 per-piece price, that is both a significant investment (plus mold costs), a lot of inventory to store (a container's worth for each design, in expensive-to-rent Hong Kong), and risky as we have thus far only sold 300 machines. I did not want to order 4000 drip trays at launch, and so decided to modify the 2000 drip trays we do have instead.
    G'day John

    My Bosch (and the old Suttons if memory serves) are diamond masonry / multi purpose drills. I have not seen the long obsolete "old spear type" carbides in Oz for 40+ years and have never used them (working since the 70's).

    When drilling medical grade stainless steel (more my field), lubrication is also critical. I use a special stainless steel cutting oil* which changes the drilling process from many minutes down to a few seconds. The diamond drill bit remains a lot cooler and also lasts a lot longer. As a partly educated guess, it would probably do the same with the new "hard style" ceramics. Worth a try if your method starts to eat (not so cheap) diamond drill bits!


    TampIt
    * I cannot remember the brand, however there are quite a few competing ones - PM me if you want the exact details and I will look it up in my shed in daylight.
    PS: Drip trays & volume. I would have made the same call. I fully appreciate the problems with starting up a new manufacturing process. I have been involved in quite a few directly and via engineering clients over the years.

  44. #994
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    Insulating the group head

    insultating3.jpg

    Final touches were applied today to our "golden master" espresso machine, and it's now done. We've already built two of them, and we have 6 more almost finished.

    Our "Decent Advisors" will soon get these machines, looking for any major "whoops!" that we missed. After that, machines will start shipping to our "early adopter" espresso machine buyers. So, my current estimate is early March for machines going to customers. We're not waiting for the beta testers feedback to keep building machine, and my hunch is that most problems they identify can be fixed with a software or firmware upload, over wifi.

    Today we added two sets of insulation inside the group head of our "golden master" and made final decisions about the kind of insulation, its shape, and placement. The insulation inside the group head reduces the heat that leaks into the main chassis and also lowers overall power consumption. We've previously found a lot of hot air cascading from the group head into the main body, heating up the mirror-back panel, and thus wasting a lot of electricity. This insulation prevents that.

    We're also insulating directly under the group head cover so that you'll never burn yourself by accidentally touching it. On traditional espresso machines, both the steam and group head are burning-temperature hot.

    Two nights ago this "golden master" lived on our "shaking machine" overnight and we verified that no connections were loosened.

    After the shaking test, we put temperature probes in multiple points inside and ran the machine for 4 hours making "espresso" at 98.5C (to create a worst-case scenario). The group head is sitting at 105F/41C: warm but not painful. With the PC Board fan disabled on purpose (again, worst case scenario) the PC Board area is hovering at 49C. As the previous machine sat at 51C with the fan on, and our goal was to stay under 60C, this is good news. The insulated group head is 41C to the touch, also good. Directly inside the group head, we're at 91, which is good, as we want the heat to stay inside there.

  45. #995
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    Out the door!

    firstout.jpg

    Our first espresso machine to leave Decent (or under my supervision when I've been on tour) went out the door today.

    I believe this might be the first time I've photographed the final machine, and you've never seen the machine with the back panel attached, which cleans up the look a lot. Of course, as I'm writing this post, I noticed the silver screws on the back, which really need to be black. There's always one more thing!

    Our CEO Bugs Harpley spent the past 3 weeks learning crochet to hand-make our lucky "year of the dog" mascot, using a pattern from the amazing web site Ravelry https://www.ravelry.com/patterns/lib...e-new-year-dog

    Our Christmas tree stays up all year long, with each year's hand-made mascot, as well as Chinese symbols of good fortune. We figure we can use all the luck we can get.
    samuellaw178 likes this.

  46. #996
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    A Short Break and a tearful goodbye

    The Chinese New Year holiday starts today in Hong Kong, and so we're enjoying a 4-day mandatory pause from work. Our landlord is painting the common-area floors, so even Bugs and I have to not work.

    We had a self-imposed deadline to get a final machine shipped before Chinese New Year, and the UPS man just took our little baby away.



    Fabrice made "crpes bretonne au Grand Marnier" for everyone before we close our doors for a few days' rest.

    crepes2.jpg
    gc and saintk like this.

  47. #997
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    A substantial Milestone! "Now come to heel, Intertek!"

  48. #998
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    Quote Originally Posted by decentespresso View Post
    You might not see it, but I'm surrounded by coffee professionals. I have a half dozen cafe owners as direct advisors on private forums. We've also studied other drip tray plumbing solutions, and what we're using is used in the almost identical scenario of "tea tray draining".

    If you Google search forums about the La Marzocco GS3 drip tray, its plumbing and refilling, and you'll find that this is what people disliked most about that espresso machine. They're an impressive company with decades of R&D behind them, and even they didn't nail it. For example, they used a "nice simple plug" on their drip tray outlet, and it leaked.

    How to design the humble drip tray is not a "solved problem".
    We can all see you are surrounded by advisors as you mention it all the time, but perhaps you need a different type. IMO you need a specialised machine person on the payroll and that way these small, yet vital details, would not be overlooked. The GS3 drain is certainly cheap and plasticky but mine never leaked when I had it and it was fine and it is the first time I have seen anyone mention the drain plug issue. Also I think you will find that those tea tray fittings require an o-ring or a teflon washer to seal properly on the underside. You can probably get away with wrapping the teflon tape and hope that it seals but it is not the proper way to do it.

    The one thing the GS3 drain is not ideal for is in a commercial setting. The way the drain pipe is fixed to the tray is a mistake, as it is important that you can get the tray out for cleaning and be able to clean under the machine. It is much better to have a small fixed drain cup and the drip tray drains into that.

  49. #999
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    Safely in Seattle

    safely.jpg

    Our first-espresso-machine-out-the-door arrived safely in Seattle. We got a "post-mortem" on our boxing and packaging today.

    While the espresso machine arrived unharmed, the same cannot be said of the cardboard.

    The biggest problem is that we hadn't planned for the outer cardboard box to get rained on, thereby greatly weakening the cardboard's strength. Two hand-holds tore because of there, whereas here in Hong Kong, we hadn't had any worries about that.

    We can also tell that the espresso machine was pushed on a floor, on at least 3 sides, on its journey to us, because those sides are really dirty.

    There is a small amount of scratching damage to the inside cardboard box, which we didn't think was possible, but which appears to have occurred through the torn hand-hold.

    To prevent this problem in future shipments, we've ordered plastic cling-film to wrap the entire outer box with. This should help minimize rain damage to the cardboard. It will also likely make it stick to the floor, making sliding difficult or impossible so that the box will need to be lifted rather than shoved.

    As far as the espresso machine being shipped sideways or upside-down, that's of no consequence, as the machine design doesn't mind that.

  50. #1000
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    Quote Originally Posted by HBexile2 View Post
    We can all see you are surrounded by advisors as you mention it all the time, but perhaps you need a different type. IMO you need a specialised machine person on the payroll and that way these small, yet vital details, would not be overlooked.
    FYI my hardware specialist advisor is Mat North, a cafe owner in Bristol, UK who also does custom installations, for instance with Modbar. And of course I get tons of advice from Facebook and the 3 other forums I'm on. But that's not to say that each decision I make is going to please everyone, no matter how many advisors I have. And of course sometimes we overlook things, but hopefully by doing this process so visibly, we stumble less often than we would otherwise.

    Also, I think there might be a slight misunderstanding on your part about how I work. When I post things here (and elsewhere) I do so while there is still plenty of time to change any potential screwup (or just improve them).

    I post what I'm doing here not as a "fait accompli" but as a "current state of things" and I absolutely intend to fairly-frequently get things wrong.

    That's one of the major benefits to me of participating in forums: my screwups are repaired early, before impacting customers.

    So: I feel that you are totally correct to write that the drip tray drain method I posted above wasn't very good. It wasn't. It's better now, for the battering it's received. It could still be improved, and will be, with yet more community involvement.

    Quote Originally Posted by HBexile2 View Post
    The GS3 drain is certainly cheap and plasticky but mine never leaked when I had it and it was fine and it is the first time I have seen anyone mention the drain plug issue.
    With your GS/3 did you ever plumb it, then unplumb it? That was the problem discussed in forums, namely that once the factory-provided plug was removed, putting it back always led to leaking.

    Quote Originally Posted by HBexile2 View Post
    Also I think you will find that those tea tray fittings require an o-ring or a teflon washer to seal properly on the underside. You can probably get away with wrapping the teflon tape and hope that it seals but it is not the proper way to do it.
    You are absolutely correct, and having received tons of advice now via the forums, we're now using a silicone o-ring on the underside, exactly as you suggest (backed up by a brass washer). We've drip-tested 2 trays so-outfitted, without leaks.

    We're currently looking for a rubber plug we can include so that people who plumb their drip tray, can nonetheless "plug up" the drain for when they want to take their espresso machine traveling, and thus unplumb it for a while.
    Quote Originally Posted by HBexile2 View Post

    The one thing the GS3 drain is not ideal for is in a commercial setting. The way the drain pipe is fixed to the tray is a mistake, as it is important that you can get the tray out for cleaning and be able to clean under the machine. It is much better to have a small fixed drain cup and the drip tray drains into that.
    I agree with you, and my inability to clean out the inside of the GS/3's water tank had a big impact on me, and was one of the reasons I went with a fully removable, porcelain water tank: so that it can be completely cleaned and even sterilized.

    -john
    gc likes this.

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