DIY Mocha Cooker

Food-grade 3D printing filament is on the rise and it is nice to have a custom coffee mug in the office to instill a little envy in the locals. [Stefan] took it upon himself to create a Mocha Machine that he would 3D print and test the boundaries of his filament.

[Stefan] used Fusion 360 to replicate the famous Bialetti Moka Express pot in it true octagonal shape. Since the pot brews coffee under pressure, he tested tolerances in Fusion 360 to make sure all the thicknesses were right. While the design was being printed, a steel washer was added to facilitate induction heating since you can’t really put a plastic pot over a flame. The print uses Formfutura Volcano PLA which is annealed for an hour at 110 degrees Celsius.

Below is a video of the whole process and though the material may not be food grade, the project is definitely a step in the right direction. Since the printed parts can withstand temperatures of up to 160 degrees Celsius, projects that involve boiling water or experiments with crystallization can benefit from a custom design.

We really hope to see more projects that use this technique, however, for those looking at their coffee machine right now, take a look at more coffee machine hacks as well as alarm clock hacks to get the coffee brewing in the morning.

Thanks for the tip [Nils Hitze]

27 thoughts on “DIY Mocha Cooker

    1. there are plastics that are truly food safe though, even at elevated temperatures.

      “plastics” is like “metals” there are many different kinds, you wouldn’t get me to eat lead or cadmium but i have eaten gold on several occasions.

  1. I’m sorry, but this is not food grade 3D printing filament. It is hardly as simple saying that “PLA is food safe.” Very few polymers are actually useful in their native form. There are plasticizers and additives added nearly all of the time to get both desired melt / processing performance and room temperature performance.

    I can imagine that a version of PLA with this high temperature resistance is likely heavily modified, and very likely to not be food safe.

    You really need to find a polymer that’s specifically rated by a reputable manufacturer to be FDA compliant. This generally means the base polymer, *along with* all plasticizers and additives are within a list of acceptable chemicals for food contact. I say reputable manufacturer, because you still have to be knowledgeable enough to keep track of what materials are being used in production. I can imagine many novice filament manufacturers starting off with an FDA compliant PLA resin – and then coextruding it with a colorant that isn’t food safe, or using a release / processing aid that isn’t food safe.

    The problem after that of course is that your printer, print head, feeders, etc. are not food grade. There is a good chance some amount of of grease from your rails, bearings, motors, etc. get into the print. It’s a risk you might accept, but on any manufacturing scale, this is not acceptable at all. At the very least, clean your part throughly with a sufficiently strong degreaser after a print.

    If you’ve ever tried to design something (genuinely) food grade, you’ll find that you very quickly become limited in what types of things you can safely do in terms of production methods and materials. It’s really rather annoying, really, but if you want to be safe, that’s sort of what you have to do.

    1. Paragraph 3: “and though the material may not be food grade, the project is definitely a step in the right direction”
      Please read the whole article before jumping to comments.(Or at lease ctrl+F for your buzz word of choice”

  2. Aaaand there we go:

    “You wouldn’t download a car”

    is of course ridiculous.

    But: Shapeways is offering (or mediating) services to 3D print a signature shaped coffee maker (there’s infinitely many ways to make a functionally identical coffee maker, but this one is Bialetti-shaped). In this particular case, frankly, there’s no risk for “brand confusion” – bialettis are made of aluminium, full period. This is obviously something different, innovative, even to the untrained eye.

    I really applaud Stefan for all the engineering that went into this (and from my perspective, this is far from a “knock-off”)! But, let’s be honest here, what 3D printing services offer are indeed commercially produced replicas of products where someone established a brand through very specific shaping. And I personally think that this kind of product piracy is not OK.

    That’s like someone offering cheap no-name soda cans with “custom print”, only that they already offer Pepsi Cola printing. Totally not going to lead to someone leeching off Pepsi’s advertising budget to sell more cheap sodas at a higher price. And I’m truly not a fan of large multinational food companies.

    So, while this project definitely hits all the right things – demonstrating the feasibility of 3D printed pressurized, heat-resistant devices – the fact that it’s only a matter of time until there’s someone making a dime from every time someone gets a print of a shape that Bialetti not only came up with, but also promoted, feels wrong.

    Pretty much like it feels wrong to you know, import digital multimeters that look *exactly* like Fluke’s, having the same shape and color, and then wondering why import control stops that shipment. Looking at you there, I remember the puny HAD uproar when a farking commercially imported container of Fluke-imitations got sacked through Fluke’s intervention. There’s enough engineers on here that earn their money only because the companies that sell products based on their work know that they don’t have to compete with someone not having the same R&D and marketing cost as them, but selling essential a copy of their product.

    I doubt shapeways’ business model is based on the audacity to see other people’s designs, and think “hey, these are good, if I imitate them, I get the customers without the R&D”, but personally, as soon as people offer devices that are meant to look like the real thing, rather than what Stefan did here, namely innovating based on a design, things might be going southwards rather quickly!

  3. >Since the pot brews coffee under pressure
    How much pressure? Because pressure, hot/boiling water and 3D-printed plastic… I would stay away from this thing while in use (and not drink the coffee because not food-safe as mentionned).

        1. More like *everyone* been doing it wrong. i’ve almost never tasted a good cup of coffee from one. Recirculating the same water in a loop is just a poor design, that’s all. Espresso makers are far better in every way indeed.

          1. You must tend it and remove it from the heat source instantly after the slurp sound has ended. You only have seconds until it burns or something and turns into that undrinkable bitter tar. When you get it right you have the best coffee that man can make.

          2. … water doesn’t get recirculated in a moka pot, perhaps you’re thinking of a percolator?
            In a moka pot, a metal tube draws up water from a reservoir in the bottom a the pot is heated. This water then mixes with coffee grounds stored in a secondary chamber, where the pressure builds. Finally, the pressure forces the extracted coffee up through a nozzle, and into the final chamber that you pour from.
            No loops, or recirculation.

  4. Guys – go watch the video before commenting on food safety, pressure rating etc!
    Stefan evidently did not intend this as food-safe everyday coffeemaker, but as a showcase for a high-temp low-shrinkage annealable material. And for that it works beautifully, I for one particularly liked the shrink-fitting used to fit two pieces of different types of PLA with different annealing shrinkage properties. Great video, hats off to Stefan!

  5. “However a typical moka coffee is extracted at relatively low pressures of 1 to 2 bar (100 to 200 kPa), while standards for espresso coffee specify a pressure of 9 bar (900 kPa). Therefore, moka coffee is not considered to be a true espresso and has different flavour characteristics.” (Wikipedia)

    It’s a great piece of construction (particularly in terms of getting an accurate sieve print) but…I have a “real” Moka sitting on the stove and while I applaud the design and construction of this, I don’t see the pressure relief valve in the copy that the original has. Heating liquids in a closed container? 7th grade science class fail. Also it copies the design that was executed in a substantially different material – a “good” Moka workalike would probably have a spherical-section chamber on the bottom, but that’s speculative.

    As far certifying the material as a Food Contact Substance (as would likely be required for commercial production), I’ll just leave the current process documents from the FDA. It’s unlikely that a filament producer would go through this, but would instead rely on the resin supplier for certification.

    https://www.fda.gov/RegulatoryInformation/Guidances/ucm081818.htm

  6. Hands up if anyone actually read the article and watched the video!!

    Hmm thought so.

    Take a couple of minutes to watch the video.
    You’ll learn who created the original design of the “pot” when it became popular
    The effects of anealing pla and how to go about it.
    Some of features of fusion 360
    Testing while wearing safety gear.
    Not to drink the coffee
    And how to make a plastic pot that works on an an induction cooktop.

    All in all pretty freakin awesome

    1. You have just written a brilliant introduction to this article. I skimmed the article and didn’t watch the video because to me it says “Cool dude printed a moka pot replica with a new filament s/he is promoting.”
      Now you made me interested and will read and watch.

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