Choosing PETG for vending machine fronts is a decision about cleaning chemicals and impact, not about clarity. A vending operator replaced 60 machine fronts in one season. The specification was 3 mm clear acrylic, chosen for clarity. Within four months, panels cleaned daily with a sanitising spray had developed a fine haze and two had cracked at the coin slot cutout.
The material was not defective. It was the wrong material for a surface that gets cleaned twenty times a day and knocked by trolleys. PETG sheet for vending machine display work handles both better.
Why PETG for vending machine fronts beats acrylic
PETG is a copolyester. It is tougher than acrylic under impact, resistant to a wider range of cleaning chemicals, and it thermoforms and die-cuts cleanly. It is slightly less clear than cast acrylic and slightly softer, which is the trade a vending front should make.
The cleaning point is decisive. Acrylic crazes when alcohol or ammonia based sanitisers are used repeatedly; PETG tolerates them far better, which removes a maintenance instruction that no operator follows.
Thickness and the shape of the front
Flat windows run 2 to 3 mm. Curved or thermoformed fronts run 2.5 to 4 mm, because the draw ratio and the radius both need material to work with. Above 4 mm the forming temperature window narrows and the part becomes expensive without improving performance.
- 2 mm: flat product windows and display apertures behind glass.
- 2.5 to 3 mm: the standard for flat machine fronts and graphic panels.
- 3.5 to 4 mm: thermoformed fronts with a radius under 150 mm.
- Avoid: thickness above 5 mm for formed parts, where draw and cooling become difficult.
Thermoforming PETG without clouding
PETG forms at 120 to 160 degrees Celsius. Too cold and the part springs back; too hot and the sheet crystallises into a milky haze that no polishing recovers. The practical control is a uniform sheet temperature across the whole blank, checked with an infrared gauge rather than by touching the sheet.
Pre-dry the sheet before forming if it has been stored in a humid warehouse. Moisture in PETG produces surface bubbles that look like sand under a light. Four hours at 65 degrees Celsius is the usual figure for 3 mm.
Our guide to thermoforming PETG covers the heat cycle in more detail, including the cooling stage that decides whether a formed front stays flat.
Printing, masking and the coin slot
Screen printing and UV digital printing both adhere well to PETG after corona or flame treatment. Without treatment, ink adhesion fails at the edges within weeks of handling.
The coin slot, card reader and dispense aperture are the stress risers. Cut them with a routed or die-cut edge, radius every internal corner to at least 3 mm, and keep the aperture at least 15 mm from the panel edge. Sharp internal corners are where cracks begin on any plastic front.
Specification for a converter or a machine builder
State grade, thickness with tolerance, colour (clear or tinted), print treatment, aperture drawing with corner radii, and the cleaning chemicals the operator will actually use. That last line is the one that decides between PETG and acrylic.
River People supplies PETG sheet in 2 to 4 mm, clear and tinted, with masking and cut-to-size service for machine front programmes.
Send the front drawing, cleaning regime and annual quantity to oversales@rpplexiglass.com and we will confirm the petg sheet for vending machine display thickness and finish that survives your operator routine.
Frequently Asked Questions
Is PETG better than acrylic for vending machine fronts?
For fronts cleaned daily with sanitisers and exposed to trolley knocks, yes. PETG resists chemicals and impact better. Acrylic is clearer and harder, so it remains better for a protected display case.
What thickness PETG for a curved machine front?
Use 2.5 to 3 mm for flat panels and 3.5 to 4 mm for formed fronts with radii under 150 mm. Thicker sheet narrows the forming window without adding useful strength.
Why did my formed PETG panel turn milky?
Overheating during forming crystallises the sheet, or moisture was left in the material before heating. Dry the sheet and hold a uniform 120 to 160 degrees Celsius across the blank.