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From food containers to medical blister packs, thermoforming has become the go-to manufacturing process for producing packaging trays that are lightweight, durable, and cost-effective.
But not all thermoforming methods are the same. Different thermoforming techniques—such as vacuum forming, pressure forming, and plug-assist forming—offer unique advantages depending on the material type, tray design, and production requirements.
In this article, we’ll explain the different types of thermoforming processes for packaging trays, how they work, and how to choose the right method for your packaging application.
Thermoforming is a plastic forming process where a thermoplastic sheet is heated to a pliable temperature and then shaped over a mold using vacuum, pressure, or mechanical force.
After forming, the plastic is cooled, trimmed, and cut into packaging trays used in industries such as:
Food packaging (meat, snacks, ready meals)
Medical packaging (sterile blister packs, device trays)
Consumer goods (electronics, cosmetics, hardware)
The process is widely used because it allows high-volume production, low tooling costs, and excellent material efficiency.
3.1 Vacuum Forming
How It Works
Vacuum forming is the most common thermoforming method for packaging trays. The plastic sheet is heated until soft and then draped over a mold. A vacuum draws the air out from between the mold and sheet, pulling the material tightly to form the desired shape.
Machine Features
Roll-fed or in-line production system
Heating oven with precise temperature control
Vacuum pump and forming station
In-line cutting and stacking systems
Advantages
Ideal for high-speed tray production
Low tooling cost
Simple and efficient process
Suitable for thin-gauge plastic sheets (typically 0.2–1.5 mm)
Applications
Food trays and clamshell packaging
Disposable containers and lids
Medical and pharmaceutical trays
Vacuum forming is perfect for mass production of lightweight packaging trays where cost efficiency and output speed are essential.
3.2 Pressure Forming
How It Works
Pressure forming enhances vacuum forming by applying compressed air (up to 100 psi) on top of the heated sheet while vacuum pressure pulls from below. This dual-force method allows the plastic to capture fine details, sharper edges, and textured surfaces.
Machine Features
Dual pressure chambers
High-precision temperature zones
Pressure-resistant molds
PLC or servo-controlled forming systems
Advantages
Produces trays with superior surface detail
Achieves tight tolerances and clean edges
Allows logo embossing or detailed textures
Excellent for premium or display packaging
Applications
Cosmetic and electronic product trays
Medical device packaging
Branded retail trays
Pressure forming is ideal when aesthetic appearance and precision are key selling points.
3.3 Plug-Assist Thermoforming
How It Works
Plug-assist forming adds a mechanical plug that pre-stretches the heated sheet before vacuum or pressure is applied. This ensures uniform material distribution, especially in deep-draw trays.
Machine Features
Plug mechanism made from Teflon, aluminum, or composite
Adjustable forming depth control
Vacuum or pressure system integration
Advantages
Consistent wall thickness
Better strength and appearance
Reduces material thinning in deep areas
Ideal for deep or complex-shaped packaging trays
Applications
Food trays with multiple cavities
Pharmaceutical and laboratory trays
Industrial parts packaging
Plug-assist forming provides excellent dimensional control for deep or intricate tray designs.
3.4 Twin-Sheet Thermoforming (for Specialty Packaging)
How It Works
Twin-sheet forming uses two separate heated plastic sheets formed simultaneously and fused together to create hollow or double-walled packaging trays.
Advantages
High stiffness and durability
Can include insulated or structural packaging
Allows multi-material combinations
Applications
Heavy-duty industrial trays
Reusable transport packaging
Specialty protective trays
Though less common in disposable packaging, twin-sheet thermoforming is valuable for reusable or high-strength packaging systems.
| Feature | Vacuum Forming | Pressure Forming | Plug-Assist Forming | Twin-Sheet Forming |
| Forming Force | Vacuum only | Vacuum + Air Pressure | Plug + Vacuum/Pressure | Two Sheets + Pressure |
| Detail Level | Basic | High | Medium–High | Complex, Structural |
| Wall Uniformity | Moderate | High | Very High | Dual-Walled |
| Tooling Cost | Low | Medium | Medium | High |
| Cycle Time | Fast | Moderate | Moderate | Slow |
| Applications | Food trays, blisters | Cosmetic, medical trays | Deep trays | Reusable trays |
The most common thermoforming materials include:
PET / PETG: Clear, recyclable, food-safe (compatible with all standard thermoforming machines)
PS (Polystyrene): Rigid, low-cost, easy to form (ideal for vacuum forming machines)
PP (Polypropylene): Heat-resistant and flexible (works well with pressure and plug-assist machines)
PVC (Polyvinyl Chloride): Excellent formability (less eco-friendly; check machine material compatibility)
HIPS (High-Impact Polystyrene): Durable and printable (suited for high-speed thermoforming machines)Material choice depends on your application, transparency needs, and recyclability goals—while ensuring compatibility with your chosen thermoforming machine’s capabilities.
Lightweight and cost-efficient (driven by thermoforming machine’s material efficiency)
Customizable shapes and sizes (easily adjusted on most thermoforming machines)
Hygienic and food-safe (machines can be equipped with sterile production features)
High-volume productivity (automated thermoforming machines enable scalable output)
Recyclable material options (modern machines support eco-friendly plastics)
Excellent strength-to-weight ratio (enhanced by machine’s precise forming control)Modern thermoforming machines amplify these advantages by reducing downtime, improving quality consistency, and adapting to changing production demands—making thermoforming the most widely used process for modern packaging trays across global markets.
Thermoforming offers several flexible options for producing packaging trays — each with its own strengths.
Vacuum forming is fast and cost-effective.
Pressure forming delivers high precision and visual appeal.
Plug-assist forming ensures uniform wall thickness for deep trays.
Twin-sheet forming creates robust, reusable designs.
By understanding these different types of thermoforming processes, packaging manufacturers can select the right method to balance cost, performance, and design quality — ensuring both efficiency and product appeal in a competitive packaging market.
Ready to choose the ideal thermoforming machine for your products? Speak with our experts today and get tailored recommendations for your production needs.
What is the most common thermoforming process for packaging trays?
Vacuum forming is the most commonly used process due to its speed, cost efficiency, and suitability for thin-gauge materials.
What is the difference between vacuum forming and pressure forming?
Vacuum forming uses air suction, while pressure forming combines suction with compressed air to produce higher detail and better surface finish.
Why use plug-assist thermoforming?
Plug-assist forming ensures even wall thickness and structural strength in deep or multi-cavity trays.
Which materials are best for food packaging trays?
PET, PP, and PS are widely used because they’re food-safe, form easily, and offer recyclability options.
Can thermoforming produce recyclable packaging?
Yes. Many thermoformed trays are made from recyclable PET and PP, aligning with global sustainability standards.
What industries use thermoformed packaging trays?
Food, medical, electronics, cosmetics, and industrial sectors all rely on thermoformed trays for secure, custom-fit packaging solutions.
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