this post was submitted on 09 Jan 2024
15 points (82.6% liked)

3DPrinting

15575 readers
423 users here now

3DPrinting is a place where makers of all skill levels and walks of life can learn about and discuss 3D printing and development of 3D printed parts and devices.

The r/functionalprint community is now located at: !functionalprint@kbin.social or !functionalprint@fedia.io

There are CAD communities available at: !cad@lemmy.world or !freecad@lemmy.ml

Rules

If you need an easy way to host pictures, https://catbox.moe/ may be an option. Be ethical about what you post and donate if you are able or use this a lot. It is just an individual hosting content, not a company. The image embedding syntax for Lemmy is ![](URL)

Moderation policy: Light, mostly invisible

founded 1 year ago
MODERATORS
andypiper@lemmy.world
j4k3@lemmy.world
henry_rowengartner@lemmy.world
GrayBackgroundMusic@lemm.ee
15
I'm confused on food-safe printing (lemmy.kde.social)
submitted 10 months ago by tubbadu@lemmy.kde.social to c/3dprinting@lemmy.world
14 comments fedilink hide all child comments
 

Hello! I'd like to print food safe objects to use in the kitchen, like spoons and glasses and so on. Looking on the web it seems that the problem with 3d printed objects is that the space between layers is like bacteria's heaven, so after one use you have to throw them away. The only way I found on the web is "coat with resin", but I don't like this very much, as scratches can remove the coating. also "print a negative and use it like a stamp" seems like too much work for a simple spoon.
so the question is, what if I use a filament that can go into the dishwasher, so I can clean it with boiling water? the web didn't help me much on this, as I found different opinions on the matter: some people said that PETG could go in the dishwasher, some said no.

what is the real answer? can I 3d print PETG objects, use them, put them in the dishwasher, and then safely reuse them?

you are viewing a single comment's thread
view the rest of the comments
[–] Bishma@discuss.tchncs.de 2 points 10 months ago

To even approach food safety you'd need to do the following

  1. Use a material with a higher glass transition temp than PETG that is also a food safe plastic. You really need to be able to wash in HOT water. I'm not sure if PC blends are food safe, but if they are that might be the way to go.
  2. Ensure that EVERYTHING in your filament path is food safe. E.g:
    1. No toxic lubrication in the feeding mechanism
    2. No possible contamination from other filaments: never use that hot end for anything else.
    3. The nozzle and meltzone are made of food safe materials with food safe production (many brass things end up contaminated with lead)
  3. Seal or smooth: Its not just layer lines. As the plastic cools it will form microcrazing (tiny cracks) that serve as an ideal place for bacteria to hide during washing/sanitizing. Even if you use a material that can go in the dishwasher if those cracks are still there you'll still end up loaded with bacteria/fungi/mold.