Is Other Tooling Required in the Thermoforming Process?

Thermoforming transforms plastic sheets into precise shapes using heat and molds, but additional tooling like heating systems¹, vacuum or pressure devices, and trimming tools² is essential for a complete production cycle.

Thermoforming relies on more than just molds; heating equipment, forming systems, and trimming tools work together to create parts for packaging, automotive, and medical applications, ensuring efficiency and quality.

Understanding the full scope of tooling in thermoforming is key to optimizing production and achieving high-quality results. This guide explores the process, tooling requirements, and practical considerations to help you make informed manufacturing decisions.

What is Thermoforming and Why is Tooling Important?

Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable state, shaped over a mold, and trimmed to create a usable product. While the mold defines the part’s geometry, other tools are critical for heating, forming, and finishing.

Thermoforming combines molds, heating systems, vacuum or pressure devices³, and trimming tools to produce lightweight, durable parts across industries like packaging, automotive, and consumer goods.

Tooling Type	Function	Importance
Mold	Shapes the plastic sheet	Defines part geometry
Heating System	Softens the plastic	Ensures uniform pliability
Vacuum/Pressure System	Forms the sheet to the mold	Achieves detailed shaping
Trimming Tools	Cuts excess material	Finishes the part

The Role of Each Tool

The mold is the cornerstone, but heating systems ensure the plastic is pliable, vacuum or pressure systems conform it to the mold, and trimming tools refine the final shape. Each component is indispensable, and overlooking any can compromise quality or efficiency.

What are the Different Types of Thermoforming Processes?

Thermoforming includes several methods, each with unique tooling needs and suited to specific applications, offering flexibility for various part complexities and production scales.

Thermoforming⁴ processes—vacuum forming, pressure forming, mechanical forming, and drape forming—cater to diverse needs, from simple packaging to detailed automotive components.

Vacuum Forming

Vacuum forming uses a vacuum to pull the heated sheet onto the mold, ideal for simple shapes like packaging trays.

Pressure Forming

Pressure forming applies air pressure to push the sheet into the mold, enabling finer details for applications like medical housings.

Mechanical Forming

Mechanical forming employs matching male and female molds for high precision, used in aerospace or complex parts.

Drape Forming

Drape forming drapes the sheet over a male mold, suitable for large, simple shapes like signs.

Process Type	Tooling Involved	Typical Applications
Vacuum Forming5	Mold, vacuum system	Packaging trays, cups
Pressure Forming6	Mold, pressure system	Automotive panels, medical
Mechanical Forming	Male and female molds	Aerospace components
Drape Forming	Male mold	Signs, light covers

How Does Thermoforming Compare to Other Manufacturing Processes?

Thermoforming offers unique benefits and trade-offs compared to alternatives like injection molding and blow molding, making it ideal for specific scenarios.

Thermoforming excels at producing large parts with lower tooling costs, while injection molding suits high-volume, complex parts, and blow molding targets hollow items.

Thermoforming vs. Injection Molding

Thermoforming has lower tooling costs and faster setup, perfect for low to medium volumes, whereas injection molding offers precision for high-volume production.

Thermoforming vs. Blow Molding

Blow molding creates hollow parts like bottles, while thermoforming produces open shapes like trays or panels.

Aspect	Thermoforming	Injection Molding7	Blow Molding8
Tooling Cost	Low to moderate	High	Moderate
Setup Time	Short	Long	Moderate
Part Size	Large parts	Small to medium	Medium to large
Precision	Moderate	High	Low to moderate
Production Volume	Low to medium	High	Medium to high

What are the Key Steps in the Thermoforming Process?

Thermoforming involves a series of steps, each requiring specific tooling and careful control to produce consistent, high-quality parts.

The thermoforming process⁹ includes material selection¹⁰, heating, forming, cooling, trimming, and finishing, with each step critical to the final outcome.

Material Selection

Choosing the right thermoplastic—e.g., polystyrene or ABS—depends on the application’s needs.

Heating

The sheet is heated to its forming temperature (e.g., 120-200°C) using ovens or infrared heaters.

Forming

The heated sheet is shaped using vacuum, pressure, or mechanical molds.

Cooling

The part is cooled with fans or water-cooled molds to set its shape.

Trimming

Excess material is removed with tools like CNC routers or knives.

Finishing

Optional steps like hole punching or surface treatments refine the part.

How Do Different Materials Affect the Thermoforming Process?

Material selection influences forming temperatures, shrinkage, and tooling, directly impacting the process and part quality.

Materials like polystyrene, polypropylene, and ABS vary in forming temperature¹¹ and shrinkage, requiring tailored tooling and parameters.

Polystyrene (PS)

Easy to form and cost-effective, but brittle; used for packaging.

Polypropylene (PP)

High impact resistance, ideal for food containers; has higher shrinkage.

ABS

Strong and detailed, suited for automotive parts; moderate shrinkage.

Material	Forming Temperature	Shrinkage Rate	Common Applications
Polystyrene	120-180°C	0.3-0.5%	Packaging, disposables
Polypropylene	150-170°C	1.5-2.2%	Food trays, automotive
ABS	130-160°C	0.5-0.8%	Consumer goods, panels

What are the Design Considerations for Thermoforming?

Effective design ensures parts are formable and functional, accounting for process and tooling limitations.

Key considerations include draft angles¹², undercuts, shrinkage, wall thickness, and trimming to optimize thermoforming outcomes.

Draft Angles

Use 3-5° for male molds and 1-2° for female molds for easy demolding.

Undercuts

Avoid or use removable mold sections to prevent sticking.

Shrinkage

Adjust for 0.5-2% shrinkage¹³ based on material.

Wall Thickness

Maintain uniformity to avoid thinning.

Trimming

Design for accessible, precise trimming.

When Should You Choose Thermoforming Over Other Processes?

Thermoforming shines in specific scenarios, balancing cost, speed, and part requirements.

Opt for thermoforming for large parts, low to medium volumes, and when tooling costs and setup time are priorities.

Decision-Making Guide

• Part Size: Large parts impractical for injection molding.

• Volume: 100-10,000 parts annually.

• Budget: Lower tooling costs.

• Lead Time: Faster setup.

What are the Related Technologies in Thermoforming?

Thermoforming integrates with broader manufacturing processes, enhancing its utility.

Related technologies include sheet extrusion, trimming, finishing, and assembly, linking thermoforming to upstream and downstream operations.

Upstream Technologies

• Plastic Sheet Extrusion: Produces the raw sheets.

Downstream Technologies

• Trimming and Finishing: Refines parts with cutting or treatments.

• Assembly: Combines parts with other components.

Conclusion

Thermoforming is a versatile process that goes beyond the mold, requiring heating systems, vacuum or pressure devices, and trimming tools to produce high-quality parts. Understanding these tooling needs ensures efficient production and optimal results across industries.