What Types of Plastics Are Used in the Thermoforming Process?

Thermoforming is a common manufacturing process where a plastic sheet is heated to the point of being pliable, molded into a specific shape using a mold, and trimmed to produce a functional product. It’s a generalized technique applied in industries like packaging, automotive, medical devices, consumer goods, and so on. However, not all plastics respond the same way under heat and pressure, so selecting the right type is important to achieving the desired performance, durability, and at an affordable price.

In this article, we will look at the different types of plastics used in thermoforming, which includes their features, benefits, popular uses, and why they are chosen for particular goods.

Understanding Thermoforming Process

Thermoforming is a widely used manufacturing process where a plastic sheet is heated until soft, then shaped over a mold to create specific products. This technique is popular for producing packaging, automotive parts, and consumer goods due to its cost-effectiveness and fast production speed. The process starts by heating the plastic sheet to a pliable temperature.

Once soft, the sheet is stretched and formed onto or into a mold by vacuum, pressure, or mechanical means. After cooling, the plastic retains the mold’s shape. Thermoforming allows for detailed designs with excellent surface finish and can accommodate various plastic materials like ABS, PET, and PVC. It’s ideal for medium to large production runs with low tooling costs compared to injection molding.

Understanding thermoforming process helps businesses choose the right method for custom plastic parts, improving efficiency and reducing manufacturing costs. Optimizing this process can boost product quality and meet market demands effectively.

Thick-Gauge and Thin-Gauge Thermoforming

For plastic part manufacturing, material thickness is an important factor in terms of use. This is generally divided into 2 types – thick & thin-gauge – based on the required durability or flexibility of the finished product.

Thick-gauge thermoforming is the preferred choice for rigid & heavier-duty components. The process employs plastic sheeting that is from around 0.06 to 0.5 inches in thickness, which is perfect for structural parts such as automotive panels, medical device enclosures, outdoor equipment & appliance interiors. Whether pressure forming or vacuum forming, this process provides the strength and stability where they are needed.

However, thin-gauge thermoforming uses significantly lighter material – typically ranging from 0.01 – 0.06 inches. These are ideal for large-scale packaging and products where flexibility, cost-efficiency & disposability are priorities, such as clamshell packaging, food packaging, or cosmetic tops.

For companies, it’s all about functionality, appearance, and application usage. If your application requires a longer life cycle, a thick one is probably your best option. If speed, volume, and packaging-friendly elements are most important to you, thin-gauge is the more practical choice.

Types of Thermoforming Plastics List

Thermoforming uses various types of plastics, each suited for different applications and product requirements. Common plastics include ABS, PET, PVC, polystyrene (PS), and polypropylene (PP). Choosing the right plastic affects the final product’s durability, appearance, and functionality. Understanding these material options is essential for selecting the best plastic for your thermoforming project.

1. ABS (acrylonitrile butadiene styrene)

ABS is a strong and durable thermoplastic known for its excellent resistance and ability to maintain shape. It’s easy to form and works well in applications that demand structural toughness. Additionally, ABS can be easily painted and textured, making it suitable for both functional and decorative uses.

Key Properties:

• High resistance to impacts
• Good resistance to heat
• Tough and strong
• Simple to paint and machine

Applications:

• Interior parts of automobiles
• Baggage
• Cases for appliances
• Electronics for consumers

2. High Impact Polystyrene (HIPS)

HIPS is a cost-effective and widely used plastic in thermoforming, particularly for packaging applications. It is preferred in cases where transparency is not necessary but affordability and good flexibility are important.

Key Properties:

• Lightweight
• Easy to thermoform
• Printable surface
• Low cost

Applications:

• Clamshell packaging
• Point-of-purchase displays
• Disposable cups and trays

3. Polyethylene Terephthalate (PET or PETG)

PET and its glycol-modified version, PETG, are transparent and durable plastics commonly used when both visibility and toughness are required. PETG is preferred for thermoforming because it retains its clarity and strength after forming. Additionally, it is food-safe and can be easily sealed.

Key Properties:

• Great clarity
• High impact resistance
• FDA-compliant (PETG)
• Recyclable

Applications:

• Food containers
• Medical packaging
• Retail blister packs

4. Polyvinyl Chloride (PVC)

PVC comes in both solid and flexible forms, but rigid PVC is commonly used in thermoforming. It offers toughness and chemical resistance, making it ideal for strong, tamper-resistant packaging and applications where product protection is crucial.

Key Properties:

• Strong and long-lasting
• Flame retardant
• Chemical resistant
• Printable

Applications:

• Clamshells and blister packs
• Construction products
• Medical trays

5. Polycarbonate (PC)

Polycarbonate is a high-performance thermoplastic known for its exceptional clarity and impact resistance. It is chosen for applications where both strength and visibility are critical. Although more expensive, it offers superior durability and optical performance.

Key Properties:

• Optical clarity
• Extremely strong
• UV and heat-resistant
• High dimensional stability

Applications:

• Safety equipment
• Machine guards
• Automotive parts

6. Polypropylene (PP)

Polypropylene is a lightweight, flexible plastic with strong chemical resistance and FDA approval for food contact. It’s commonly used in applications requiring durability, heat resistance, or chemical protection. Microwave-safe, it’s often found in food service products.

 Key Properties:

• Heat resistant
• Good chemical resistance
• Lightweight and flexible
• Recyclable

Applications:

• Food packaging
• Medical trays
• Lab containers

7. Polyethylene (PE)

Polyethylene, available in both High-Density (HDPE) and Low-Density (LDPE) forms, is widely used in thermoforming due to its strength and moisture resistance. PE is ideal for producing durable, low-cost items with excellent chemical and water resistance.

Key Properties:

• Impact resistant
• Flexible
• Moisture barrier
• FDA-compliant (HDPE)

Applications:

• Industrial containers
• Liners
• Bottle caps
• Food packaging

Summary Table

Conclusion

Thermoforming is a advanced technique that changes flat plastic sheets into functional, long-lasting, and attractive objects. Nevertheless, the success of the process relies significantly on the chosen material. The various plastics used in thermoforming each have some distinct advantage, and the plastic to be used must fit the final application, environmental conditions, and price. If you’re considering thermoforming for your next product or packaging requirement, learning these material possibilities is the first step towards making the best decision.

ZHANSHI is a leading thermoforming machine manufacturer, focused on developing advanced plastic machinery for a wide range of thermoplastics. Have a product idea? Talk to our experts today and start turning your concept into reality.