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Decent Espresso Machines (DE1) - Any thoughts?

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  • Each heater is 2200W, but we control how much current we draw in firmware.

    The DE1 chops up each AC cycle, and hands them out to each heater in a % based priority basis. Thus, we could (in firmware) use up a 20A circuit. We will likely have to have a firmware switch for Australia, which runs on 10A, as opposed to the 13A the UK has. The firmware will then hand out that much power to the heaters.

    I believe the current steam results are at a 2300W current draw. We can go further in time. The other DE1 models limit their draw to 1500W.

    Either way, the limiting factor at the moment is not power consumption but heat transfer. We do use the full 4 meters of tubing, and by increasing the boiling point to 152C at 5 bar, we greatly increase our heat transfer ability during steaming.

    If we ever get to a point where current is the limiting factor, we do know about the different plugs and have planned to be able to swap out the rear plug on the DE1CAFE for a higher amp version. The extra 6cm of depth of the DE1XL/DE1CAFE chassis give us a bit of room to play in.

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    • 338
      338 commented
      Editing a comment
      Very smart solution!

    • Ted2013
      Ted2013 commented
      Editing a comment
      How durable do you think the electronics behind that firmware is? If it fails the machine will not be able to operate. I would be nervous about having delicate electronics parts near a hot and possibly wet environment as in an espresso machine unless some very special precautions were undertaken.

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    50 at once....

    6 months ago, we were shipping 50 machines a month, now we need to be making 200 machines a month, if we're going to keep up with demand and shorten the queue https://decentespresso.com/queue

    Last week, we made 20 v1.4 machines in 3 days, and then another 20 machines in 4 days. There were 4 small teams responsible for groups of 5 machines each, and I noticed a bit of competition among the groups, that I wasn't sure was entirely healthy. Fabrice and I have been wanting to move to a large-batch, specialist approach, for a while, and so...

    This past monday, we did that.
    • we're now building 50 machines at once.
    • each sub-assembly has a "Master" assigned.
    • The Master is responsible for building the assembly, testing, installation, and feedback to engineering.
    • This also means that if something goes wrong, we know who to talk to.
    • It does mean for a less interesting job for each person (less variety) but it should yield higher quality and speed.
    • For now, we're going to aim for 8 days to build 50 machines, which would give us 150 machines per month.
    • That would still be a massive speedup over our previous best of 111 machines in a month.
    • And with time, we'll try to shorten the 50 machine cycle to a 6 day week, and eventually to a 5 day week, so that my staff can get their saturdays back.

    As it happens, with this first batch of 20 v1.4 machines, Desmond, the "Master" of testing, though that some of the machines were not regulating temperature at pressures, as well as he thought it should (off by 1.5ºC). He's been doing all the testing/calibrating for a month (when he was hired), so he's become adept at this now. He brought the issue to me, for commentary and validation of his hunch.

    Last night, a master repairman (SK) and new hire Keith worked late, moving single parts from one "good" machine to one "bad" machine until the problem went away. We're pretty sure that we've isolated the problem of two different value flow constrictors being installed backwards, which only creates a problem at low pressures, when the precise flow constrictor resistance values matter the most. We're testing that right now, and if so, just need to swap two flow constrictors to fix the 20. And then develop a process to make sure this doesn't happen again, as the flow constrictors are so small that you can't tell which is which, so this is an easy problem to cause.

    Meanwhile, we're at step #6 out of 20 steps today, in our assembly of 50 machines. They'll hopefully be finished next week, but it might take a few days longer, as this is our first time changing the process so much.

    -john

    Comment


    • Originally posted by decentespresso View Post
      How durable do you think the electronics behind that firmware is? If it fails the machine will not be able to operate. I would be nervous about having delicate electronics parts near a hot and possibly wet environment as in an espresso machine unless some very special precautions were undertaken..
      All espresso machines have to worry about their PCB. The GS/3 famously has the PCB compartment open at the top, where water can drip down into it and fries the PCB.

      We keep the PCBs in a metal box, sealed, with fan blowing in. And we have a thermometer watching the PCB compartment temperature. I had a GS/3 for many years, and their design "choice" greatly influenced my design to greater protect the PCB.

      Thus far, we haven't had DC PCB fail in the field, but we have had AC PCB fail, usually due to bad electricity (or plugging a 120V machine into 230V!).

      The PCB is a part, like any other part. You can buy them like any other part https://decentespresso.com/c?s=13041+1+73104+1 though thus far, we've paid for any failures as warranty service.

      But no, we are now on our 4th year, and PCB failures haven't registered as something that breaks. We've had pressure sensors (USD$4 to replace), O-rings (USD$0.50 to replace) and a certain number of cracked moulded resin parts, as the most common things that break, now after 4 years. We've paid for all repairs for all our customers, except for 2 machines that were used out in the desert, and couldn't be repaired. Oh, and one guy who thought he'd make extra strong coffee by putting drip coffee into the water tank. <sigh>

      -john

      Comment


      • Well that is reassuring. I assume you have high quality surge protection built in. I own an expensive German washing machine that failed twice under warranty (the control board) and suspect mains voltage spikes. Since adding an external surge protector had no issues with it

        Comment


        • Originally posted by Ted2013 View Post
          Well that is reassuring. I assume you have high quality surge protection built in. I own an expensive German washing machine that failed twice under warranty (the control board) and suspect mains voltage spikes. Since adding an external surge protector had no issues with it
          Yes, in fact we have an expensive German made MOV in our A/C PCB.
          https://electronics.howstuffworks.co...protector1.htm

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            Which is the real 3M?

            Decent Engineer Ben Champion noticed today that the tablet on his prototype DE1CAFE wasn't sticking all that well to his tablet stand.

            He investigated, and found that the color, material, and stickiness of this
            "premium product" (3M makes good stuff) does not seem right.

            We suspect that we've just been handed a batch of counterfeit 3M adhesive tissue. We're contacting our supplier, who is the same we've used for years.

            We're also having 3M officials urgently come to our factory, as they've visited us before, and they've been exceedingly helpful. We're paying for the real stuff, so we want to receive it, thank you very much. And I'm sure 3M doesn't want their reputation tarnished.

            If you received a DE1XL from us recently, it's possible that you have this inferior 3M adhesive on the back of your tablet. Naturally, if you have any problems, we will send you a free replacement, just as soon as we sort out with 3M, what's going on.

            This might also temporarily delay the shipping of our new v1.4 machines, for a few days, as all v1.4 machines from us now use the same tablet stand as te DE1XL model does.

            -john

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