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Thread: Decent espresso

  1. #861
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    I've sort of lost track of this very long thread....does anyone on the forum actually have a decent espresso machine yet?
    Vesuvius DBPP, Izzo Duetto DB BTC Machines: Melitta Caffeo varianza and Caffeo Barista TS Roasters: Amazon Dalian 1kg Drum Roaster: Grinders: Ceado E92: 145kg assorted greens::

  2. #862
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    Quote Originally Posted by Dylan View Post
    For about half a second i thought i had blinded myself, which was what scared the shit out of me, i probably wasn't far off doing so.
    Not so funny really. Glad you're ok. Still a candidate for the muppetry thread though. There's some very good company in there.
    Espresso: Ceado E92 (modified for single dose); Vesuvius; VST baskets and refractometer.
    Other: Aeropress, Sowden and Alessi Moka Pot; Mazzer Robur doser with Auber timer; Mazzer Mini E; Expobar Leva Dual Boiler

  3. #863
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    Quote Originally Posted by DavecUK View Post
    I've sort of lost track of this very long thread....does anyone on the forum actually have a decent espresso machine yet?
    Our first manufacturing run of 300 espresso machines has now sold out.

    We are not taking new orders for espresso machines until we start shipping.

    Once shipping, we will take orders for our winter 2017 manufacturing run, delivering those machines in early spring.
    I guess that is a no just now

  4. #864
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    Quote Originally Posted by Obnic View Post
    Not so funny really. Glad you're ok. Still a candidate for the muppetry thread though. There's some very good company in there.
    Indeed, if there is a competition with prize perhaps I'll enter ^_^

  5. #865
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    Default Tension can lead to failure

    Last week, Ray had a worry that tension from bending a tube might cause the water seal to fail sooner. While none of our connections is leaking now (even under tension), everyone agreed that it would be better to not have uneven tension on the water seal.

    To research if any other manufacturer also worried about this, Jeff went diving through our morgue of dead & disassembled espresso machines. He found one Nespresso machine that apparently had this same worry because that machine had little plastic moulded de-tensioners to hold 90º and 180º bends in place.

    Alex drew up a SolidWorks model inspired by what Jeff had found, and over the weekend he 3D printed our de-tensioners. There's a photo below, showing where they'll go in. They work nicely, and we'll be using them in all the machines we're building.

    This may or may not be an issue, but with these detentioners costing about $0.10 each, it'd be crazy to not use them to make the worry go away.

    IMG_6930j.jpg


  6. #866
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    Default Insulating the heaters not so easy

    A few weeks ago, I mentioned that one of our last engineering problems was to decide how to insulate our two heaters.

    Our interns built a test rig, with a tiny Arduino computer, at both 100ºC and 170º, to test all the different ideas we had.

    Originally, we liked silicone, but our first batch had a nasty chemical smell when heated. Two other manufacturer's samples also had a smell. Also, it's very hard to get air bubbles into the silicone, so the pure silicone insulating solution adds a lot of weight, and is not as insulating as it could be.

    We thought we'd solved that problem when we found a no-smell silicone mix that bubbles when mixed, to a selectable amount between 10% and 30%. The problem is that it's extremely hard to get into a mould and in a regular shape. Immediately upon mixing it swells about 60% but then overnight, as it dries, it continues to swell unpredictably. You end up with a messy "pillow" in the morning.

    We tried making a metal mould to contain the expanding foam, and that helped, but it left some areas under-covered as the foam expands in ways that differ each time (presumably because of uneven distribution of the foaming agent).

    Ray realized that PC boards are made of fiberglass, an excellent insulator, and they're very cheap to have cut into custom 2D shapes. So, he designed a fiberglass box for our heater made from PCB, which is then soldered together.

    It's a bit of an oddball solution, but it worked quite well.

    We then tried foaming silicone inside the box, and the thermal insulation results were amazing--the best yet--but it was really hard to do and the results are very irregular and not pretty.

    In the spreadsheet below, you'll see the results from all our materials, and you'll see that the air temperature (that's the important metric) is OK for all of them. We want to keep it under 40ºC inside the DE1, and all our solutions have done that. You'll notice that PCB+Foam is the best performing, though, by a small amount.

    Today, we're doing our final test, which is placing a pre-cut insulating blanket inside the PCB box, wrapped around the heater. We're expecting that it'll give us a lot of the same insulating benefit of the silicone foam, but be much, much easier and faster to assemble (no pouring into a mould and waiting overnight).

    Below are photos of the various attempts and tests we've done, for those interested in following along with our progress.

    We're awaiting the parts for our "release candidate #3" which are due in about 7 days. That machine will likely use this PCB Box + Blanker heater insulating technique, which is what we'll use for the 300 machines we're building.

    heaters2.jpg heaters1.jpg

    heat-table.jpg

  7. #867
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    Pcb laminate will degrade with time if it gets too hot. You can buy it in a high temperature rated version though. What about ceramic fibre blanket?

  8. #868
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    Quote Originally Posted by GaryM View Post
    Pcb laminate will degrade with time if it gets too hot. You can buy it in a high temperature rated version though. What about ceramic fibre blanket?
    Understood. We're using single layer boards, without laminate, and uncoated as well. We're pretty sure that makes the "PCB" nothing but a single layer sheet of fiberglass.

    If you disagree, please do please let me know, as there are lots of options with PCB.

    Regarding a blanket, the problem is that if there are air gaps, heat will flow out of them. Our heaters are small with lots of connectors that get in the way of a simple blanket pattern. With big espresso machine boilers, the connectors are (by percentage) a small part of the total surface area, and less of an issue. We liked the idea of a silicone dip, because it ensured no air gaps, and we might still figure that one out, but since the PCB solution works well enough, we're going with that for now. We're not going to hold production to find an optimal solution, as all the insulators tested as staying under 40ºC.

  9. #869
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    Quote Originally Posted by decent_espresso View Post
    Understood. We're using single layer boards, without laminate, and uncoated as well. We're pretty sure that makes the "PCB" nothing but a single layer sheet of fiberglass.

    If you disagree, please do please let me know, as there are lots of options with PCB.

    Regarding a blanket, the problem is that if there are air gaps, heat will flow out of them. Our heaters are small with lots of connectors that get in the way of a simple blanket pattern. With big espresso machine boilers, the connectors are (by percentage) a small part of the total surface area, and less of an issue. We liked the idea of a silicone dip, because it ensured no air gaps, and we might still figure that one out, but since the PCB solution works well enough, we're going with that for now. We're not going to hold production to find an optimal solution, as all the insulators tested as staying under 40ºC.
    Probably ok if the laminate isn't touching a hot surface. Get the fr4 175 degree rated material. I don't think there is much cost difference.

  10. #870
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    Quote Originally Posted by GaryM View Post
    Probably ok if the laminate isn't touching a hot surface. Get the fr4 175 degree rated material. I don't think there is much cost difference.
    Thanks, that's helpful.

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