Materials & compliance
What is thermoforming, and how is it different from injection moulding?
Short answer
Thermoforming heats a plastic sheet until it softens, pulls or presses it over a mould with vacuum or air pressure, then cools and trims it. It makes thin-walled packs such as punnets, clamshells, trays and blisters. Injection moulding instead forces molten plastic into a closed mould, which suits thick, solid parts but costs more in tooling. AVI extrudes its own PET sheet and thermoforms it in-house.
Part of the guide: Pack types explained: punnets, clamshells, trays and more
- InputPlastic sheet (PET, rPET, PVC, PP)
- Typical productsPunnets, clamshells, trays, blisters
Examples of thermoformed packs
| Pack | Type | Size (L × W × H) | Empty weight | Holds | Per carton | Enquiry |
|---|---|---|---|---|---|---|
| PNG 250 / 75 | Hinged lid | 128 × 94 × 75 mm | 9 g | 250 g | 1,225 | |
| A-30 / 45 | Flat lid heat-sealed to base | 145 × 120 × 45 mm | 7 g | 250 g, 250 g heat-seal | 2,100 | |
| TE 750 / 24oz | Hinged clamshell with tamper-evident closure | 189 × 145 × 60 mm | 34 g | — | 310 | |
| 30 EGG TRAY | Open tray | 290 × 242 × 65 mm | 100 g | — | 200 |
All packs are rPET. Figures from AVI's catalogue; tolerances and fill depend on the produce, so samples are the final check.
AVI products for this
- Thermoforming: Fresh Produce, Food & Deli, Specialist PacksAVI Global Plast thermoforms rigid packaging for fresh produce, food service and specialist applications, from PET,...
- Custom ThermoformingBespoke thermoforming and tooling from AVI Global Plast for non-standard packaging briefs — in-house from sheet to...
How it works
- Heat: the sheet passes under heaters until it is soft.
- Form: vacuum, air pressure or a plug pushes it into or over the mould.
- Cool: the shape sets against the cooled mould.
- Trim: a cutting tool separates each pack from the sheet; the trimmed skeleton is recycled.
Thermoforming or injection moulding
| Thermoforming | Injection moulding | |
|---|---|---|
| Starts from | Sheet | Pellets |
| Walls | Thin, even | Thick, can vary |
| Tooling cost | Lower | Higher |
| Best for | Packaging, trays, blisters | Caps, solid parts, containers with thick walls |
Why it suits packaging
Thermoforming makes light, clear packs at high speed, and new tooling costs far less than injection moulds, so custom packs pay back at lower volumes. AVI controls the whole chain: it extrudes the sheet, builds tools in its own tool room and forms the packs.
Related questions
Is vacuum forming the same as thermoforming?
Vacuum forming is one kind of thermoforming, where only vacuum pulls the sheet onto the mould. Pressure forming adds air pressure from above for sharper detail.
Thermoforming or thermosetting?
Different things. Thermoforming is a process; thermosetting plastics cure permanently and cannot be reheated and reshaped. Thermoforming uses thermoplastics such as PET, which can be reheated and recycled.