Thermoforming, also known as vacuum forming, is a shaping technique that uses heat to bend a substrate into the desired form. This technique is applied to plastic materials, known as thermoplastics, which become soft and moldable at high temperatures. Once cooled, the plastic retains the shape of the mold, which is specially designed for this purpose. Such a mold is also called a die.

Suitable types of plastic

The types of plastics suitable for thermoforming are called thermoplastics. Thermoplastics can be used in film or sheet form for thermoforming. Below are some examples of thermoplastics:

• Polyvinyl chloride (PVC)

• Polyethylene (PE)

• Acrylonitrile butadiene styrene (ABS)

• Polystyrene (PS)

• Polyethylene terephthalate (PET)

• Polypropylene (PP)

• Polylactic acid (PLA)

How does thermoforming work?

The thermoforming process consists of several steps: heating, shaping, and trimming the plastic. Here is a detailed overview of each step:

Creating the Mold

Before starting the thermoforming process, a mold (or die) is created. The mold is used to shape the plastic during thermoforming. Essentially, the mold represents the negative form of the final product. Creating the mold requires expertise, as precision is crucial. The mold's design is the most important aspect, often carved using CNC milling. Additionally, the material for the mold must withstand high temperatures and pressure and remain undamaged when the plastic is removed.

1. Heating the Plastic

Once the mold is ready and approved, the actual thermoforming process begins. The first step involves heating the plastic. Plastic film or sheet material is typically heated using an infrared heater. The material is heated to a high enough temperature to become pliable. The temperature of both the plastic and the mold is continuously monitored to ensure optimal settings for a fast and efficient process.

2. Shaping

When the plastic material is heated and flexible, the next step is to apply the mold. The air is vacuumed out, causing the plastic film to take the shape of the mold. The temperature is then rapidly lowered to cool the material, ensuring the plastic retains the mold's shape.

3. Trimming

The final step in thermoforming is trimming the plastic film. The product is cut out, separating it from the excess material. Any leftover material can be recycled, ensuring no waste is generated.

The thermoforming process is now complete, and the shaped plastic can be used for a variety of applications.

Advantages of thermoforming

Thermoforming offers several benefits, including:

• Lower costs compared to injection molding due to low mold production costs

• The ability to modify molds during production

• Suitable for both small and large production runs

• Short production time

• Ideal for integrating printed electronics into plastic components

  
  

Thermoforming printed electronics

As highlighted above, thermoforming is an ideal technique for shaping printed electronics and integrating them into plastic components. The flexibility of printed electronics is a key feature that makes this innovative technology so versatile.

Flexible printed electronics are used in various innovations. A notable example in the automotive industry is a car steering wheel with capacitive touch. In this case, a fine trace pattern was printed on plastic film using screen printing. This film was shaped to fit the steering wheel perfectly through thermoforming. Capacitive touch via printed electronics enables seamless communication with the onboard computer, offering swipe functionality similar to a smartphone.

Want to learn more about thermoforming?

Would you like to learn more about thermoforming or other techniques Metafas uses to shape printed electronics? Contact our experts, who will be happy to explain the process and answer all your questions.

If you’re curious about the possibilities of flexible printed electronics for your project or innovation, we’d love to brainstorm with you.