What would one need to do to make 3D printed PLA cookware safe to use?
It's possible to 3D print cookie cutters or measuring cups or dumpling makers with PLA, however its not certain that doing so would be safe.
The two problems people mention are,
- Possible impurities or chemicals in the PLA
- The microscopic pores in the object created by the 3D printing process which gives bacteria a place to hide.
Is there a way of solving those problems?
2 answers
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Despite what other answers say, no, don't do this.
Just "PLA" isn't a good enough specifier. In theory, PLA is inert enough to not interact with food. However, there are many details and variants of something as broad as "PLA". For example, your PLA probably comes in different colors. Are you sure the coloring agents are OK? I certainly wouldn't be without specific promises from the manufacturer to that effect.
I have had to get plastic parts made to handle drinking water as part of my day job. You have to specifically look for formulations and processes that are "food safe". Plastic manufacturers are all aware of this. Many ordinary plastic are not food safe, even though in theory the plastic is suitably inert.
Check with the manufacturer of the specific PLA you are using for your 3D printer, and ask them whether it's food safe. Even that needs some qualification. There are various standards of "food safe". For example NSF/ANSI 61 is about contact with drinking water. Even for that standard, plastics are only certified compliant over certain temperature ranges, and for some maximum surface area to volume ratio. It gets complicated. Some plastic may only be food safe for foods within a limited pH range, for example. Something to handle wine, for example, may be unsafe for cookie dough, or vice versa. You can't assume a particular plastic is safe just based on the general properties of the plastic family.
To give you some idea of this issue, here is a snippet from a datasheet for one specific plastic:
I recognize NSF 61 as the certification for contact with drinking water. The 7 different FDA standards listed are probably for various food-handling and medical applications.
It costs the manufacturer real money to get their plastic certified to each of these standards. This should prove that it's important, and that responsible customers insist on the proper certification for their particular use.
The same manufacturer probably makes non-certified variants of the same basic plastic. Those might have an additive that enhances the molding process, modifies the surface texture, changes the melting point, the viscosity when melted, the color, etc. The point is you don't know whether something is safe for contact with food unless it has been explicitly certified for that.
The "PLA" for a consumer 3D printer is probably optimized for melting and hardening characteristics, and price otherwise. You should assume it is not food safe without a specific statement from the manufacturer.
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The following users marked this post as Dangerous:
| User | Comment | Date |
|---|---|---|
| Olin Lathrop |
Thread: Dangerous Not guaranteed to be food safe. See my answer. |
Oct 5, 2021 at 18:17 |
The good news: PLA itself is non-toxic, and is often used in molded applications for food-safe tools.
Everything else is pretty much bad news. Your intuition is correct: The print resolution is going to give you lots of crevices for bacteria to hide in. All of the chemical smoothers are toxic.
You can use carefully applied heat to melt and seal the exterior. You can use abrasives to get a smooth finish. A cookie cutter or a measuring cup would be a reasonable use; I think a dumpling maker would be problematic from both a crevices perspective and from a mechanical stress perspective.
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