Thermoforming is an old, versatile manufacturing method. Do you wonder how those big refrigerator liners or medical devices are created? The answer is often through this process. It takes a thermoplastic sheet, heats it until soft, then stretches it over a mold. Finally, it is trimmed to make a product. For product developers and manufacturers, choosing this process is a major win. It allows for faster product development and significantly lower thermoforming tooling costs. This is true compared to methods like injection molding. If you work in prototyping or high volume packaging, understanding thermoforming is key.
This guide will break down the entire thermoforming process. We will detail the crucial design rules. We will show you exactly where it fits in the future of sustainable production.
Thermoforming Process: A Simple 5-Step Guide
The thermoforming process is simple. It prepares a plastic sheet, heats it, shapes it, and finishes the part. This manufacturing process only uses thermoplastic materials. These plastics can be repeatedly melted and reshaped.
Step 1: Clamping the Sheet
A flat sheet of plastic is clamped into a frame. This frame keeps the sheet flat and taut during heating and forming.
Step 2: Heating and Softening
The clamped sheet moves into an oven. Heaters raise the sheet’s temperature precisely. This makes the plastic soft and rubbery. This is the ideal consistency for the thermoforming stage.
Step 3: Forming the Part
The soft sheet goes onto or into the mold. Shaping happens when a differential pressure is created:
- Vacuum Forming: Air is sucked out under the mold. This pulls the thermoformed plastic onto the mold surface.
- Pressure Forming: High-pressure air is used above the sheet. It pushes the plastic forcefully onto the mold. This results in higher detail.
Step 4: Cooling and Solidification
The formed plastic must cool down. It must go below its softening temperature. Once cool, the plastic becomes solid. It is now in its permanent new shape.
Step 5: Trimming and Finishing
The newly thermoformed part is removed from the excess material. The product is cut out using robotic cutters or CNC routers. The remaining scrap material is gathered and recycled. This dramatically improves cost effectiveness.
Types of Thermoforming Processes: Choosing Your Method
It is a category for several distinct thermoforming processes. Each one is used for a different part quality and shape. If you want to know more about the material options, explore the world of Thermoplastics.
1: Vacuum Forming and Pressure Forming
These are the two main methods. Vacuum forming and pressure forming shape parts using air pressure. Vacuum form molding is low-cost and simple. Pressure forming makes high-fidelity parts. Its quality often rivals plastic injection molding cost without the high tooling investment.
2: Twin Sheet Forming
This advanced technique heats two sheets at once. Both sheets are formed over their molds. They are then fused together while still hot. The final part is hollow and double-walled. Twin sheet forming is perfect for applications like air ducts. It is also great for a rigid large part.
The Real Cost Advantage: Why Tooling is Cheaper
The strongest reason to choose it is the lower initial injection molding tooling cost. The lead times are also faster than other methods.
The financial difference is major. It only needs one mold face. This is unlike injection molding, which needs two high-pressure mold halves. This difference alone drastically reduces the injection molding mold cost. A single thermoforming mold is often much cheaper than an injection mould tool. If you are looking for experts to hire in plastics and polymers, Cornerstone Management Solutions can help.
Critical Design Rules: Avoiding Costly Rework
Successful thermoforming relies on specific design rules. These rules account for how soft plastic moves and cools.
- Draft Angles: You must taper the side walls slightly. This is usually 3∘ to 5∘ minimum. This Draft Angle is vital for easy part removal from the thermoforming mold.
- Corner Radii: Sharp corners cause the thermoplastic materials to stretch too thin. Always use rounded corners (radii). This helps the plastic flow evenly. It maintains consistent wall thickness, ensuring impact resistance and durability.
Materials: Matching Plastic to Performance
Since it uses thermoplastics, the most common commercial plastics can be used. Selecting the right material options is key to performance. This is especially true for automotive interiors or medical devices.
| Material | Key Properties | Typical Uses |
| PET/PETG | Excellent clarity, tough, chemical resistant | Food packaging, clamshells, thin walled parts |
| ABS (Acrylonitrile Butadiene Styrene) | High impact resistance, rigid, holds texture well | Electronic enclosures, automotive interiors, luggage |
| Polycarbonate (PC) | Extreme strength, high temperature resistant | Machine guards, skylights, and large part thermoforming |
For companies looking to start new thermoforming manufacturing lines, talent is crucial. Our Hiring Solutions can connect you with specialists in plastics thermoforming.
The Future: Automation and Sustainable Manufacturing
This industry is changing quickly. It is driven by speed and environmental needs. Modern thermoforming equipment is very automated. It allows for in-line processing. This reduces lead times and lowers the cost per piece. This makes it competitive for high volume production.
It is sustainable by nature. It uses thermoplastics, which are fully recyclable. The scrap web from trimming is always reground and reused. This supports the circular economy. This is a key point of comparison when debating thermoset vs thermoplastic applications. We consistently post new Job Openings in this evolving sector.
FAQs
The main thermoforming processes are vacuum forming and pressure forming. Vacuum forming uses air removal to pull the plastic onto a mold. Pressure forming adds positive pressure to the top of the sheet. This creates finer detail, comparable to plastic injection molding parts.
The thermoplastic materials are loaded as a pre-cut plastic sheet or a continuous roll. The sheet is first clamped into a frame. This frame moves it through the heating station. Then it positions it over the thermoforming mold before forming begins.
A thermoforming machine, or equipment, is a full manufacturing system. It includes the clamping frame and a heating oven. It has a forming station and often a trimming station. These machines come in a wide range of sizes.
Mold material depends on the production volume needed. For low volumes, molds can be made cheaply from wood or 3D printed plastics. For high-volume production, metal molds are used. This includes machined or cast aluminum. If you are a Job seeker interested in tooling design, this is a key area.
