Which are the food-safe materials and how do I recognize them?
What materials which are commonly used in 3D printing, are food-safe?
Are there any certifications/grading process for such materials, which can help me with my cross-checking and selection?
I have been using an FDM printer.
Consider narrowing down your question by mentioning what type of printer you are working with.
@TomvanderZanden I am using an FDM printer, so is it possible to print such materials with this printer? If yes, then I would edit my question :)
Hello @Dawny33, I noticed your question has been up for a while now. Have any of the answers below been able to solve your question? If so, would you mind accepting the appropriate answer. If not, what is missing so that we may help you further? Also, if you have figured it out on your own, you can always answer and accept your own solution. Thank you.
Related, but for a specific machine and based on certification as food-safe: https://3dprinting.stackexchange.com/questions/6937/ender-3-is-capable-of-food-safe-printing/6941#6941
Food safety is a property of both the process and the material. You can't stick food-safe material in a printer that has previously been used to print something food-dangerous and expect the result to be food safe.
The only way to know if a given material is food-safe is to ask your supplier, but a lot depends on how you then process it. For instance, FDM printers often have brass nozzles, which contain lead. To print food-safe materials, you need to use a stainless steel nozzle.
Food safe materials can be identified by mean of an universal symbol.
Moreover, to ensure food-safety of a 3D printed model you may need to further process it (for instance, by vapor smoothing or coating with a food-safe lacquer). Some claims circulate on the internet that 3D printed models may have surface porosity in which bacteria can grow, but I've not been able to find a reliable source for this claim. Still, you need to be cautious.
Thank you for answering. Are there any official grading norms by which I can make sure? (instead of relying on the supplier's words)
From what I have seen, you really can't assume a 3d printed part will be food safe when it comes off the printer, even if you are using a food safe filament. The best part of this answer is the final paragraph. **Use a food safe lacquer, or some other food safe coating.** If the object is fully covered in a food safe lacquer, then it is food safe, regardless of what lies underneath the lacquer.
@ScottLemmon - "regardless of what lies underneath" has a hidden dependency on "provided the think lacquer layer is intact". I would not trust the lacquer exclusively, I would rather use it as an extra precaution on top of supposedly food-safe material...
@mac, the point is that FDM is not a food safe process (at least with any consumer printers) regardless of the nozzle and filament you use. You *MUST* use a sealant of some sort to completely isolate the food from the surface of the print to ensure food safety. It's not an extra precaution, but a requirement. This is because FDM is porous, which leaves areas bacteria to thrive, even with the most rigorous of cleaning methods.
@ScottLemmon - People have eaten and drank from wood objects for millennia (which is way more porous, and offer organic material for bacteria, fungi and algae to grow)... and yet most wood species are food safe materials (re: cutting boards). I got what _you_ mean of course, what _I_ meant was that I wouldn't eat from a lead plate even if coated with the most advanced of lacquers! :)