Under a My Tech Fun test of JLC3DP’s resin and nylon, a viewer asked about a series on food safe prints. They pointed out that AMT claims food safety for vapor-smoothed SLS PA12, and that Xometry will even sell parts with compliance paperwork. Then they asked, “but is it really food safe?” That’s the right question to ask about food safe SLS, and the answer depends on which test you read.
Is vapor-smoothed food safe SLS real?
For the conditions AMT tested, its sheet says yes. Nothing broader than that. AMT’s July 2020 health and safety summary reports a food contact pass for SLS-printed PA12 vapor smoothed on its PostPro3D. The test followed EU Regulation 10/2011, using overall migration methods from DS/EN 1186 at 2 hours and 70 °C. Across four food simulants (10% ethanol, 3% acetic acid, 95% ethanol and isooctane), average migration ran from 1.7 to 4.6 mg/dm².
That’s one process, one material and one set of conditions. A part that sits in hot oil for hours, or goes through a dishwasher every day, isn’t what was tested.
Does that cover MJF parts too?
Not the food test. The same sheet tested MJF-printed PA12 for cytotoxicity and for bacterial growth reduction against MRSA and E. coli, and it passed those. But the food contact line names SLS parts only. Xometry’s vapor smoothing page repeats the same table.
HP’s side is cautious. BASF’s public data sheet for Ultrasint TPU01, an HP MJF material, says flatly that “the HP fusing agent does not have food contact approval.” It adds that applications close to food without direct contact, such as robot grippers, have to be judged case by case with a risk analysis. That note is on a TPU sheet, but the fusing agent is part of every MJF part.
What’s the honest answer for a customer?
Unsmoothed nylon from either process isn’t something to promise for food. Vapor-smoothed SLS PA12 has one published migration test behind it. Every claim you make should point back to the exact material, process and conditions on that sheet, and AMT itself says parts for food use must conform to local regulations before final use. Food-contact compliance for a finished part is the manufacturer’s responsibility, and no test sheet or smoothing step certifies it for you.
BASF’s data sheet does suggest one fallback for parts near food: a functional barrier, such as aluminum foil or PET film at least 25 µm thick for room-temperature use.
How should you quote it?
Quote the part, not the food claim. Attach AMT’s test sheet, write the printer type and powder on the quote, and ask the customer in writing what the food, temperature and contact time will be. If those fall outside 2 hours at 70 °C, they need their own migration test.
Related on the Solvi blog: Should You Dye MJF Parts Black or Vapor Smooth Them?; MJF Watertight Parts: Can PA12 Hold Water Under Pressure?; SLS Nylon Yellowing: Why White Parts Turn Yellow.
Sources: YouTube: SLA vs SLS (JLC Black Resin vs Nylon), My Tech Fun, viewer question; AMT PostPro3D health and safety test summary (PDF); Xometry vapor smoothing page; BASF Ultrasint TPU01 technical data sheet (PDF).