Understanding the Different Types of Thermoforming: A Comprehensive Guide

Various reusable plastic food containers of different shapes and sizes, including trays, bowls, and lidded containers

Thermoforming is a versatile manufacturing process that transforms flat plastic sheets into three-dimensional shapes using heat and pressure. This technique is widely adopted across industries due to its cost-effectiveness, flexibility, and ability to produce both simple and complex parts. Whether you're in packaging, automotive, or consumer goods, understanding the different types of thermoforming can help you select the optimal method for your project.

Thermoforming heats plastic sheets and shapes them using molds, offering a cost-effective solution1 for creating lightweight, durable parts2 in industries like packaging, automotive, and medical.

In this article, we’ll explore the various types of thermoforming3, their applications, technical details, practical design tips, and related technologies. By the end, you'll have a thorough understanding of how thermoforming works and how to leverage its benefits for your needs.

Thermoforming is a cost-effective manufacturing process for plastic parts.True

Thermoforming typically has lower tooling costs and faster production times compared to methods like injection molding, making it ideal for small to medium production runs.

Thermoforming can only produce simple shapes.False

While best suited for simpler geometries, advanced techniques like pressure forming and twin-sheet forming enable the creation of complex parts with detailed features.

What Are the Different Types of Thermoforming?

Thermoforming involves heating a plastic sheet until it’s pliable and then forming it into a specific shape using a mold. The process varies depending on sheet thickness and forming method, resulting in several distinct types suited to different applications.

A collection of various food containers in different shapes and colors, including round, square, and rectangular designs made of plastic and other materials
thermoformed products

Thermoforming types include thin-gauge, medium-gauge, and heavy-gauge based on sheet thickness, and vacuum forming, pressure forming, twin-sheet forming, and mechanical forming based on the forming method.

Types by Sheet Thickness

Type Sheet Thickness Applications
Thin-gauge Less than 1.5 mm Disposable cups, containers, lids, trays, blisters, clamshells (food, medical, retail)
Medium-gauge 1.5 mm to 3 mm Semi-structural parts, emerging applications
Heavy-gauge Greater than 3 mm Vehicle panels, refrigerator liners, pallets, aircraft windscreens, kiosks, medical equipment

Types by Forming Method

Type Description Applications
Vacuum Forming4 Uses vacuum (~15 psi) to pull sheet onto mold Kiosks, ATMs, medical imaging enclosures, diagnostic equipment
Pressure Forming Uses vacuum and air pressure (~45-60 psi) for fine details Parts requiring surface textures, detailed aesthetics
Twin-Sheet Forming Forms two sheets simultaneously for hollow parts Containers with distinct upper and lower shapes
Mechanical Forming Uses mechanical assists, often with vacuum/pressure Specific shaping needs, less detailed applications

Thin-Gauge Thermoforming

Thin-gauge thermoforming5 uses sheets under 1.5 mm thick, ideal for high-volume production of disposable items like packaging trays and cups. Often roll-fed or inline extruded, it’s widely used in food, medical, and retail industries for its efficiency.

Medium-Gauge Thermoforming

Medium-gauge thermoforming, with sheets between 1.5 mm and 3 mm, serves semi-structural parts. Though less common, its use is growing due to its balance of strength and flexibility, filling the gap between thin and heavy-gauge applications.

Person holding a large red plastic mold with smooth edges and indents
thermoformed products

Heavy-Gauge Thermoforming

Heavy-gauge thermoforming6 employs sheets thicker than 3 mm for durable, structural components like vehicle panels and refrigerator liners. It’s suited for low to medium production runs (250-3000 parts annually) and offers cost-effective tooling.

Vacuum Forming

Vacuum forming, the simplest method, uses a vacuum (~15 psi) to shape the sheet over a mold. It’s ideal for shallow, basic parts like kiosks and medical enclosures, offering affordability for prototypes and small runs.

Pressure Forming

Pressure forming adds air pressure (up to 60 psi) to vacuum forming, enabling finer details and sharper features. It’s perfect for parts needing aesthetic appeal or functional textures.

Different types of food containers including black and transparent trays, bowls, and lids
thermoformed products

Twin-Sheet Forming

Twin-sheet forming heats and molds two sheets simultaneously, fusing them to create hollow parts. It’s excellent for lightweight, strong structures like containers and enclosures.

Mechanical Forming

Mechanical forming uses tools like plugs or rams, often with vacuum or pressure, for precise shaping. It’s suited for complex or deep-drawn parts requiring controlled forming.

Vacuum forming is the most common type of thermoforming.True

Its simplicity and cost-effectiveness make it widely used for shallow parts with basic geometries.

Twin-sheet forming can only produce simple shapes.False

It’s designed for hollow parts with complex, distinct upper and lower shapes, suitable for intricate designs.

What Are the Applications of Thermoforming?

Thermoforming’s versatility makes it a go-to process across industries, producing everything from lightweight packaging to robust structural components.

Thermoforming serves packaging, automotive, medical, and consumer goods industries with cost-effective, flexible, and lightweight solutions.

Various types of plastic food trays and containers in different shapes and colors
thermoformed products

Packaging

Thin-gauge thermoforming dominates packaging, creating disposable items like cups, trays, and clamshells for food, medical, and retail use due to its efficiency in high-volume production.

Automotive

Heavy-gauge thermoforming produces structural automotive parts like panels and dashboards. Its lower tooling costs make it ideal for small to medium runs.

Medical

Thermoforming supports the medical field with thin-gauge trays and heavy-gauge equipment housings, meeting needs for sterility and durability.

Two clear plastic blister trays on a gray background
thermoformed products

Consumer Goods

From refrigerator liners to kiosks, thermoforming offers custom shapes for functional and aesthetic consumer products.

Thermoforming is only suitable for low-volume production.False

Thin-gauge thermoforming excels in high-volume packaging, while heavy-gauge suits smaller runs.

Thermoforming can replace injection molding in all applications.False

Thermoforming suits simpler shapes and lower volumes, while injection molding excels in complex, high-volume parts.

How Does Thermoforming Compare to Other Processes?

Thermoforming offers unique advantages and trade-offs compared to processes like injection molding and blow molding.

Thermoforming excels in cost-effectiveness7 for small to medium runs and large, simple parts but lags in precision and material efficiency compared to injection molding.

A variety of different types of food packaging containers including trays and cups
thermoformed products

Thermoforming vs. Injection Molding

  • Tooling Costs: Thermoforming’s tooling is cheaper (half to one-fifth of injection molding).

  • Volume: Injection molding suits high volumes; thermoforming fits lower runs.

  • Complexity: Injection molding handles complex parts better; thermoforming is simpler.

  • Lead Time: Thermoforming offers faster prototyping.

Thermoforming vs. Blow Molding

  • Shape: Blow molding creates hollow items; thermoforming produces open shapes.

  • Speed: Blow molding is faster for hollow part volumes.

Thermoforming is always cheaper than injection molding.False

It’s cheaper for tooling, but injection molding wins in high-volume per-part costs.

What Are the Key Steps in Thermoforming?

Thermoforming involves a series of steps that determine the quality and performance of the final part.

The process includes designing, material selection8, tooling9, heating and forming, trimming, and finishing.

Rolls of BOPP film being manufactured in a factory setting
thermoformed

  1. Design: Optimize draw ratios (<3:1) and draft angles (1.5°-6°).

  2. Materials: Use ABS, polycarbonate, polyethylene, or polypropylene.

  3. Tooling: Create molds from aluminum or composites.

  4. Forming: Heat sheets (e.g., 140-190°C for ABS) and shape them.

  5. Trimming: Remove excess material manually or with CNC.

Material selection has no impact on thermoforming.False

Materials affect forming temperature, shrinkage, and part properties.

What Are the Best Practices for Thermoformed Parts?

Effective design enhances thermoforming outcomes.

Assortment of food packaging containers including trays, bowls, and molds
thermoformed products

Optimize draw ratios10, include draft angles11, minimize undercuts, and choose suitable materials.

  • Draw Ratios: Keep below 3:1 for vacuum forming.

  • Draft Angles: Use 1.5°-6° for easy removal.

  • Undercuts: Avoid or use movable mold sections.

Draft angles are unnecessary in thermoforming.False

They’re essential for part release, especially in deep draws.

How Do You Choose the Right Type of Thermoforming?

Selecting a type depends on your project’s needs.

Various disposable food containers including trays, bowls, and divided plates
thermoformed products

Base your choice on sheet thickness, part complexity, volume, and finish.

Decision Tree

  1. Thickness: Thin (<1.5 mm), Medium (1.5-3 mm), Heavy (>3 mm).

  2. Complexity: Vacuum (simple), Pressure (detailed), Twin-sheet (hollow).

  3. Volume: Thin-gauge for high, heavy-gauge for low-medium.

Vacuum forming suits all parts.False

It’s limited to simple, shallow designs.

What Are Related Technologies to Thermoforming?

Thermoforming connects to a broader manufacturing ecosystem.

Related technologies include sheet extrusion12 (upstream), trimming (downstream), and alternatives like injection molding.

Various types of food containers including trays, cup holders, and boxes
thermoformed products

  • Sheet Extrusion: Produces thermoforming sheets.

  • Trimming: Finishes formed parts.

  • Alternatives: Injection molding, blow molding.

Sheet extrusion is a type of thermoforming.False

It’s a separate process creating input sheets.

Conclusion

Thermoforming offers a flexible, cost-effective way to produce plastic parts, from packaging to structural components. By understanding its types—thin-gauge to heavy-gauge, vacuum to twin-sheet—you can choose the best fit for your needs. With smart design and process knowledge, thermoforming delivers quality and efficiency.


  1. Discover insights on cost-effective solutions in manufacturing to enhance your project's efficiency and budget management. 

  2. Learn about the manufacturing of lightweight, durable parts and their significance in modern industries for better product design. 

  3. Explore this link to gain a deeper understanding of thermoforming, its processes, and applications across various industries. 

  4. Discover the benefits of vacuum forming, a cost-effective method for creating prototypes and small production runs. 

  5. Explore this link to understand the efficiency and applications of thin-gauge thermoforming in various industries. 

  6. Learn about heavy-gauge thermoforming and its role in producing durable structural components for various applications. 

  7. Understanding cost-effectiveness in thermoforming can help you make informed decisions for your manufacturing needs. 

  8. Discover the ideal materials for Thermoforming to enhance product quality and performance in your projects. 

  9. Learn about the significance of tooling in Thermoforming and how it impacts the final product's quality and efficiency. 

  10. Understanding draw ratios is crucial for successful thermoforming, ensuring quality and efficiency in production. 

  11. Draft angles play a vital role in part removal and overall design; exploring this can enhance your thermoforming outcomes. 

  12. Sheet extrusion is fundamental in producing thermoforming sheets; learning more can improve your manufacturing knowledge. 

Hi there! I'm John, dad and hero to awesome kid. By day, I'm a plastic extrusion industry vet who went from factory floors to technical management. Here to share what I've learned—let's grow together!
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