A PETG medical tray is judged on three things that have nothing to do with how it looks: whether it seals, whether it survives sterilisation, and whether the validation paperwork holds up.
A device manufacturer in Bavaria moved a line of instrument trays from PVC to PETG for a European market. The first validation run failed on seal strength, not on the plastic itself: the lid coating was matched to PVC sealing temperatures.
PETG medical tray material and gauge
- 0.8 mm: instrument trays to 60 mm deep, light contents
- 1.0 mm: the general-purpose gauge, trays to 80 mm
- 1.2 to 1.5 mm: deep trays, heavier instruments, sharp edges
- Wall check: corner wall must stay above 0.5 mm after forming
The corner wall is the real specification. A 1.0 mm sheet drawn into a 60 mm tray thins to about 0.65 mm at the base radius. Below 0.5 mm the tray punctures on handling, and the puncture is not visible until the pack reaches a theatre.
Sealing, sterilisation and the lid that decides it
Sealing is a system question. PETG seals best to a coated lid stock with a peelable or weld seal, in a narrow temperature window, typically 130 to 160 C at the seal bar depending on coating. A coating designed for PVC will not bond reliably, which is exactly what the Bavaria line discovered.
Sterilisation changes the material slightly. Gamma at 25 to 50 kGy causes some yellowing and a modest loss of impact strength; EtO is gentler on the plastic but leaves residuals that must be aerated. Either way, the validation has to run on the assembled pack, because the seal and the lid behave differently from the tray alone.
Particulate control is a cleanroom issue, not a material one. Trays formed and packed in an ISO 8 area, with a documented cleaning step before forming, meet most device specifications.
For the material compliance side, the PETG FDA compliance guide covers food-contact grades, and the PETG thermoforming guide gives the heat cycle that keeps the corner wall above the limit.
If the tray also carries a printed label, the surface energy of PETG matters for adhesion, and the note on corona treatment in the PETG packaging guide applies.
Send your tray drawing, sterilisation method and annual volume to oversales@rpplexiglass.com for a material and forming quotation.
Frequently Asked Questions
Which PETG grade is used for medical trays?
A medical-grade PETG with documented biocompatibility and lot traceability. Standard packaging grades may meet the physical requirement but lack the paper trail a device manufacturer needs for validation.
Can PETG trays be gamma sterilised?
Generally yes at 25 to 50 kGy, with some yellowing and a small drop in impact strength. The effect has to be validated on the assembled tray, because the lid coating and the seal are part of the system.
What thickness PETG for a thermoformed medical tray?
0.8 mm to 1.0 mm for instrument trays up to 80 mm deep, 1.2 mm to 1.5 mm for deeper trays or heavier instruments. Wall thinning at the corners is the limiting factor, not the starting gauge.