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I am working with a bunch of Makerbot Replicator+ printers and one Z18 in a classroom. I would like my students to be able to print cups and stuff to drink from if they want. I know I need a food-safe material AND a food safe nozzle if it can be managed.

So, I wanted to check the following:

  1. Is there a material data sheet for the PLA filament that Makerbots use? I am told you need to check for each color, so the general one doesn't seem to be what I need. If anyone knows where to find it, please let me know.

  2. I am told stainless steel nozzles are best. I saw several sold on amazon and the like that will supposedly fit the Smart Extruders. Recs on which I should use (if any) are welcome. Especially as the nozzle width will differ, the stock nozzle I think is 0.4mm? I assume I will need to adjust the settings on the printer as well anyway if I swap out the stock nozzle.

  3. Another procedure my research yielded was that I would probably want to coat the 3D prints in resin. It seems there are several food-safe brands. Would such resins stand up to acidic liquids like orange juice and the like? What about alcohol? I know they won't work with coffee or something because PLA melts as such a low temperature. Recommendations are welcome here, and whether I should paint on or dip the 3D print?

3a. Even if the PLA isn't itself officially food safe would just coating it in resin solve that problem?

Any assistance here is much appreciated.

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  • $\begingroup$ Why use PLA at all? Seems a terrible choice $\endgroup$
    – Kilisi
    Commented Sep 2, 2022 at 11:36
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    $\begingroup$ It's what I have available. And with a Replicator+ it requires less fiddling about, but if there's another filament that I can use without too much of a problem in that particular model of 3D printer by all means tell me! $\endgroup$
    – Jesse
    Commented Sep 2, 2022 at 11:48
  • $\begingroup$ Printing food safe items is not safe or easy, and the results will likely not be durable or cleanable. You'd be better off printing some of the thousands of toys and fidget widgets, and they'd probably print faster than a cup too. $\endgroup$
    – user10489
    Commented Sep 3, 2022 at 15:59

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FDM itself is not particularly food-safe, coating the print may prevent bacteria to settle in crevices. Furthermore, the filament should be able to withstand high temperatures for extended periods of time in case you want to clean the printed cups to kill bacteria.

An overview of food-safe filaments is given by All3DP. Without going into details, this overview recommends the use of certain TPU, nylon, high-temperature resistant co-polyester, PETG and ABS filaments. All these filaments are located at the higher-end temperature region of the filament pool.

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    $\begingroup$ Unfortunately the higher temp plastics (nylon, ABS in particular) emit toxic fumes when heated, so unless your 3d printer has a closed chamber with either filtered airflow or vented outside, it's differently dangerous. PETG and TPU might be good alternatives though, but the heat resistance isn't that much higher. $\endgroup$
    – user10489
    Commented Sep 3, 2022 at 15:57
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A better alternative would be PETG, it's food safe on it's own and has more heat tolerance than PLA. It prints with much the same ease as PLA.

I'm not familiar with your particular printer, but nozzles are standard sizes. Swapping a brass nozzle for a stainless steel one doesn't need anything extra done. They both work the same, just the steel nozzle is harder wearing.

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  • $\begingroup$ Brass contains lead, therefore it is recommended to use a steel nozzle. But, I'm not aware of studies of lead contaminating the print from the nozzle. $\endgroup$
    – 0scar
    Commented Sep 2, 2022 at 12:23
  • $\begingroup$ @ZeissIkon Indeed, but brass nozzles do wear, even with PLA, albeit not much, but they do. I don't expect that there are concentrations found like the Romans had in their wine... $\endgroup$
    – 0scar
    Commented Sep 2, 2022 at 12:56
  • $\begingroup$ Thanks I thought of PETG - I just wasn’t sure how well it would work in a Makerbot Z18 or replicator plus. $\endgroup$
    – Jesse
    Commented Sep 2, 2022 at 14:32
  • $\begingroup$ The amount of lead contamination from a brass nozzle is minuscule, even if your students ate kilograms of extruded filament. Stainless is better, but printed utensils from a brass nozzle are by no means unsafe. $\endgroup$
    – Chris
    Commented Sep 2, 2022 at 16:43

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