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Thread: Decent espresso

  1. #1861
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    Quote Originally Posted by DavecUK View Post
    too true, I remember front wheels falling off when the kingpins failed. The all aluminium engine with steel wet liners was modern, but again prone to failure (cylinder heads - overheating)...the bloody gear linkage (damm thing). I had an Imp and an Imp super, my dad was a mechanic, so yes, I know the cars well. I liked it well enough, but they did have issues.
    Well, pfff. Customers reporting design flaws is the worst thing that can happen for a manufacturer. Havering quality issues is normal as long as the design is good. But design issues is not to be forgive.
    Automotive, aviation and other linked industries are using some tools to mitigate faults, issues, that may occur during use of the product they design. One of those tools is called DFMEA, D stands for design (I'll let you Google for the rest) and it' starts at early stages of the design process, as soon as the high level functions are decided. It helps to define and mitigate the failure modes. While not perfect and not suficient, it helps mitigate most of design issues that might slept trough otherwise. But this is a proces that sould be followed through all the design phases and during development as well when any function of the product is changed so not many industries are happy to adopt it as it requires knowledge and and too much brain storming, brain squeezing and brain stretching so it is expensive in a way.
    Vesuvius stainless steel pipework / VST18 / Mahlkoenig Peak / Fiorenzato F64evo / Torr flat brass

  2. #1862
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    Default Espresso Puck Simulator

    preview-full-EDM cutting.jpg IMG_8846.jpg

    This week, we received a small batch of "blind portafilter baskets" (a basket with no hole in it), but that we'd modified by having a very tiny hole precision cut in it.

    Our goal is to be able to simulate a coffee puck's water resistance but without coffee. We want to do this for stress testing, and so we can calibrate under pressure.

    The "Scace 2" is what we've used to do this in the past, but
    1) it's very expensive
    2) the hole in it is a bit larger than real espresso
    3) it clogs very easily.

    I'm wondering if anyone else would find these "espresso puck simulators" useful. They were quite expensive to make as one-offs but if people had their own uses for this, we could get them made in quantity, likely at a reasonable cost.

    Ideally, these:
    1) would not be expensive
    2) would have realistic hole size(s) that mimic espresso pucks better
    3) would clog less often, and if clogged, would be much easier to clean (a sewing needle should do it).

    Any interest?
    Last edited by decent_espresso; 1 Week Ago at 08:37.

  3. #1863
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    Quote Originally Posted by decent_espresso View Post
    preview-full-EDM cutting.jpg IMG_8846.jpg

    This week, we received a small batch of "blind portafilter baskets" (a basket with no hole in it), but that we'd modified by having a very tiny hole precision cut in it.

    Our goal is to be able to simulate a coffee puck's water resistance but without coffee. We want to do this for stress testing, and so we can calibrate under pressure.

    The "Scace 2" is what we've used to do this in the past, but
    1) it's very expensive
    2) the hole in it is a bit larger than real espresso
    3) it clogs very easily.

    I'm wondering if anyone else would find these "espresso puck simulators" useful. They were quite expensive to make as one-offs but if people had their own uses for this, we could get them made in quantity, likely at a reasonable cost.

    Ideally, these:
    1) would not be expensive
    2) would have realistic hole size(s) that mimic espresso pucks better
    3) would clog less often, and if clogged, would be much easier to clean (a sewing needle should do it).

    Any interest?
    That will be similar to what Breville uses to clean their Espresso machines if I remember correctly (although it is plastic or silicone in their setup). I always thought that backflushing a machine can be really stressful for the pumps (but I have no scientific proof of that) and I am asking myself if that could be used for the same and hopefully be gentler on the machine. I am assuming it should be easy to test.

    Now, I think you have a good opportunity for your machine here. You could theoretically use a calibrated pressure filter to calibrate the machine regularly, and it should be easier than the flow method, and more precise as you can wait for pump pressure stabilization. That will require some code writing and an engineer to think about the most precise way to do it, but I think it should be useful, and you get to sell us another little piece of accesory.

  4. #1864
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    Most machines have an opv which means when the brew path hits 9bar (or whatever it is set to) the excess water and pressure is diverted back to the reservoir.

    Basically, back flushing should be no more stressful for the pump than pulling a shot, less so infact as you don't need to run a back flush for 25+ seconds.

  5. #1865
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    I guess youd want to create a filter basket adapted to take various standard sizes of flow restrictor disc.....ie just pop in a new disc to represent a grind/volume of coffee. Better than having lots of filter baskets with precision holes of different sizes.
    Gaggia Classic Chrome - Mignon Specialita 55

  6. #1866
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    For calibration that would be a nice tool!


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  7. #1867
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    Quote Originally Posted by Andreugv View Post
    Now, I think you have a good opportunity for your machine here. You could theoretically use a calibrated pressure filter to calibrate the machine regularly, and it should be easier than the flow method, and more precise as you can wait for pump pressure stabilization. That will require some code writing and an engineer to think about the most precise way to do it, but I think it should be useful, and you get to sell us another little piece of accesory.
    Spot on, that's exactly what we're planning. Not with these baskets though, because the tolerance is not tight enough.

    Our plan for about-six-months-from-now is using a military grade (not joking, it's the only part we buy from the USA) flow restrictor and we can calibrate both pressure and flow with.

    Quote Originally Posted by jj-x-ray View Post
    I guess youd want to create a filter basket adapted to take various standard sizes of flow restrictor disc.....ie just pop in a new disc to represent a grind/volume of coffee. Better than having lots of filter baskets with precision holes of different sizes.
    Yes, that's possible, but my problem with that is that flow restrictors are typically quite long and thus easy to jam up, and fussy to clean. For this use above, I wanted "easy to clean"

    It's a totally different product, and not so cheap to make, but we have prototypes here of a "Sensor Basket" that takes calibrated flow restrictors, also has a temperature and pressure sensor, and this talks to a small computer that gives you digital flow, pressure, and temperature readings. A "super-Scace" of a sort. Picture below.

    -john

    DJF9stmUEAAUvHj.jpg

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    Quote Originally Posted by decent_espresso View Post
    Spot on, that's exactly what we're planning. Not with these baskets though, because the tolerance is not tight enough.

    Our plan for about-six-months-from-now is using a military grade (not joking, it's the only part we buy from the USA) flow restrictor and we can calibrate both pressure and flow with.



    Yes, that's possible, but my problem with that is that flow restrictors are typically quite long and thus easy to jam up, and fussy to clean. For this use above, I wanted "easy to clean"

    It's a totally different product, and not so cheap to make, but we have prototypes here of a "Sensor Basket" that takes calibrated flow restrictors, also has a temperature and pressure sensor, and this talks to a small computer that gives you digital flow, pressure, and temperature readings. A "super-Scace" of a sort. Picture below.

    -john

    DJF9stmUEAAUvHj.jpg
    Sweet! About the production tolerances, it would not really matter, I believe, as long as you could measure the whole extremely accurately and calculate the restricted flow that this hole will have. Isn't it you guys that use microscopes to ensure hole uniformity on the baskets? You could use the same approach.

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    Quote Originally Posted by decent_espresso View Post
    It's a totally different product, and not so cheap to make, but we have prototypes here of a "Sensor Basket" that takes calibrated flow restrictors, also has a temperature and pressure sensor, and this talks to a small computer that gives you digital flow, pressure, and temperature readings. A "super-Scace" of a sort. Picture below.

    -john

    DJF9stmUEAAUvHj.jpg
    Take my money

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    Quote Originally Posted by Andreugv View Post
    Sweet! About the production tolerances, it would not really matter, I believe, as long as you could measure the whole extremely accurately and calculate the restricted flow that this hole will have. Isn't it you guys that use microscopes to ensure hole uniformity on the baskets? You could use the same approach.
    Each hole in our portafilter baskets can have an error of +/-.05mm. Over the many holes in a basket, the average error mostly cancels out (some ever so slightly larger, some ever so slightly smaller).

    However, if a basket only has 1 hole, and we want to calibrate against it, we're looking for 4x better tolerance. This is quite hard to achieve, which is why calibrated orifices are expensive
    http://www.theleeco.com/products/pre...s/restrictors/ and made by very few companies. The best ones, that we use, are made for the US military, for jet fuel injection systems.

    As to measuring "the actual hole size" with a microscope, I don't know of any practical way to do that. Every basket would have a different labelled hole size, it wouldn't be repeatable, and even this assumes that the hole is perfectly circular, which at these dimensions, isn't usually the case. Here's a photo example I took of a competitor's basket some time ago.

    cheap_holes.jpg

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