Thermoforming machines

A thermoforming machine heats plastic sheet, forms it into a mould with vacuum, air pressure and often a plug, then trims the parts out. For food packaging, choose a roll-fed machine. Pick form-cut-stack for flexible, high-output tray and lid work, and in-mould cutting when cups, lids or containers need very tight trim registration.

How thermoforming works

Sheet comes off a roll, or straight from an extruder on some lines, and chains carry it through the machine. Infrared heaters, or on contact-heat machines a heated platen pressed against the sheet, bring it to forming temperature. In the forming station the mould closes, a plug pushes material into the deep areas, and vacuum and compressed air press the sheet against the cooled mould. Once the part has set it is cut out of the web, stacked and counted, and the leftover skeleton is wound up or ground for reuse.

Thin-gauge and heavy-gauge forming are separate trades. GABLER, a German builder, puts roll-fed work at roughly 0.1 to 2 mm thick and sheet-fed work at about 1.5 to 10 mm and above, with roll-fed machines running far higher cycle rates. Everything in this category is roll-fed and aimed at packaging.

Main machine types

Form-cut-stack with a separate cutting station

The part is formed in one station and trimmed downstream in another. Forming moulds stay simpler, and trim position can be adjusted to the formed part. The GN800 follows this layout: a multi-zone infrared oven, top and bottom servo plugs, 75 tonnes of force in both the form and cut stations, and up to 60 cycles per minute. The Kiefel KMD 78.2 Speed runs up to 50 cycles per minute with its separate cutting station, or 45 when it forms and punches in one station, on PET, PP and PS trays, clamshells and cold cup lids.

In-mould cutting (cut in place)

Here the parts are trimmed while still in the mould, so every cut sits in exact register with the formed shape. The WM Thermoforming FT 700 uses punch and die tooling in the mould, then tilts the lower platen to pass the parts to its stacker, a layout used for cups, lids and dairy pots. The Canadian-built GN3021DX combines contact heating with in-mould cutting for APET clamshells, cups, lids and deli containers. The trade-off is that mould and cutting tool form one unit, so every product change swaps both.

Cutting tools compared

The summary follows a Plastics Technology article on trimming PET, which also explains why PET is hard on tools: the knife has to go almost all the way through the sheet before it breaks cleanly, where many other plastics part at about half depth. The article cites about 400 lb of force per linear inch of die (roughly 70 N/mm) as a standard figure. You can see the effect in GN's own figures: the GN3021DX is rated for 8,500 mm of knife on APET but 9,525 mm on other materials.

How to choose: key specs explained

• Forming area and sheet width. These set how many cavities fit per cycle. The GN800 forms up to 830 x 570 mm on 910 mm sheet; the KMD 78.2 Speed forms 760 x 580 mm on film up to 810 mm.
• Depth of draw. Deep cups and tubs need more. Published maximums are 150 mm above and below the sheet line on the GN800, 150 mm on the FT 700 and 125 mm on the GN3021DX.
• Sheet thickness. The GN800 runs 0.25 to 2.00 mm, the Kiefel 0.2 to 1.8 mm and the GN3021DX 0.15 to 1.00 mm (0.006 to 0.040 in).
• Cycle rate. Published maximums range from 22 cycles per minute on the GN3021DX to 60 on the GN800. Real rates depend on material, gauge, draw depth and cooling, so ask for a rate on your part.
• Clamping and cutting force. Force limits how much knife length you can cut per cycle, which matters most on PET.
• Materials. GN lists CPET, PET, PP, HIPS, OPS, PVC, CPLA and PLA for the GN800; Kiefel lists PET, R-PET, C-PET, PS and PP.
• Stacking and tool change. Up-stacking, A/B stacking, pick and place and roto stackers suit different parts. Kiefel quotes 30 to 60 minutes for a tool change on the KMD.

What your plant needs

• Power. Loads vary widely. GN lists a 380 to 480 V, 250 A supply and about 42 kVA running for the GN800, and about 7.5 kW for the contact-heat GN3021DX. Ask for connected and running load, and plan for 600 V; see our 600 V power guide.
• Compressed air. Forming air must be clean and dry. The GN800 needs 6.2 to 9.6 bar (90 to 140 psi); the GN3021DX needs at least 6.8 bar and about 1,315 L/min (48 CFM).
• Cooling water. The mould removes heat from every part. GN lists 65 to 200 L/min (17 to 53 US gal/min) for the GN800 and offers a mould temperature control unit and chiller as options, so plan a closed-loop system.
• Floor space. A form-cut-stack line is long: the GN800 measures about 14.8 m x 3.5 m x 3.3 m high (48 ft 9 in x 11 ft 6 in x 10 ft 10 in) depending on configuration. The GN3021DX is 2.9 x 1.85 m and 3,420 kg. Our floor preparation guide covers anchoring and access.
• Sheet and scrap handling. Roll storage, a roll lift, and a skeleton winder or granulator, plus clean handling for food-contact parts.
• Tooling. Each product needs its own mould, plugs and cutting tool, usually built by a tool maker to the machine's platen size.

Running costs

Sheet is the largest cost, and two decisions shape it: the gauge you can run while the part still passes its tests, and how much skeleton is left after the parts are cut out, which depends on cavity layout. The other drivers:

• Heating energy, mostly the ovens on infrared machines.
• Tooling: new moulds for new products, plus resharpening, re-ruling or replacement of cutting tools, which wear faster on PET.
• Downtime for tool changes and start-up scrap, which grows with the number of products per week.
• Compressed air and chilled water.
• Labour at the stacker and packing table, reduced by automatic stacking and counting.

Typical applications

Roll-fed thermoformers make drink cups and lids, portion and dairy pots, meat, poultry and produce trays, bakery clamshells, deli containers and confectionery inserts. Many of these customers sit in food packaging and disposables. For the Canadian market, note that foodservice ware containing expanded or extruded polystyrene foam, PVC, carbon-black plastic or oxo-degradable plastic falls under the federal Single-use Plastics Prohibition Regulations, which remain in force as of 2026. Containers for that market are therefore made in other materials such as PET, PP or PLA; the single-use plastics guide explains the scope.