16. Wildcard Week
Vacuum Forming
This week, I tried working with a vacuum forming machine for the first time. It was an interesting and valuable experience, as I had never used this type of equipment before. During the process, I learned how to prepare molds, which materials can be used for forming, and which parameters affect the quality of the final product. Working with the machine requires precision and attention to detail, but the result is worth it — the final product is durable and has well-defined features.
The DIY vacuum forming machine consists of the following main components:
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Material holding frame – secures the plastic sheet around the edges to ensure an airtight seal.
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Forming platform – the object to be formed is placed here.
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Heating source – a heat gun is used to evenly heat the plastic until it becomes flexible and moldable.
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Vacuum system – a standard shop vacuum cleaner is used to create the vacuum. Once the plastic is heated and the frame is placed onto the platform, the vacuum is switched on to extract air and press the softened plastic tightly against the mold.
Before working with the vacuum forming machine, it is important to follow certain safety precautions. It’s worth noting that our machine is homemade and does not have a built-in heating element. To heat the plastic, we use a heat gun, which requires additional care.
During operation, it is necessary to:
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Work in a well-ventilated area, as some types of plastic may release unpleasant or harmful fumes when heated.
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Pay attention to the position of the heat gun — do not aim it at flammable materials and never leave it on unattended.
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Keep a fire extinguisher or another primary fire suppression method nearby in case of emergency.
Following these rules will help ensure safe operation and achieve good results.
Plastic Thick Test
To start, I decided to use a 0.3 mm thick plastic sheet with a leather-like texture. Before forming, the material needs to be secured in a special frame. To ensure an airtight seal during the vacuum process, I left a 20 mm margin on each side of the sheet. This allows the material to be clamped tightly in the frame and helps prevent any loss of pressure during vacuuming.
After securing the material in the frame, the next step is to heat it. A heat gun is used for this process. As the plastic sheet is heated, it initially starts to shrink and wrinkle — this is a normal reaction to the temperature change. As the heating continues and becomes more uniform, the surface gradually smooths out, and the material becomes elastic and ready for forming.
During heating, it is important to keep the heat gun at a safe distance from the surface of the material. If it is held too close, the hot air stream can damage the plastic, it may overheat, heat unevenly, or even tear. One of the signs of overheating and material damage is a noticeable thinning in certain areas. In these spots, the plastic becomes too thin and loses its strength. To prevent this, the material should be heated evenly by continuously moving the heat gun and avoiding prolonged exposure to any single point.
After the material is evenly heated, the key moment comes placing it on the vacuum forming machine. It is important to have the vacuum system turned on in advance. As soon as the frame with the plastic sheet is lowered onto the working surface, the air is immediately sucked out, and the heated plastic is pressed tightly against the model placed on the platform, accurately taking its shape. At this stage, it is crucial to act quickly while the material is still elastic.
If the material cools down before being placed, it can be reheated carefully. However, it's important not to overdo it overheating can lead to damage.
This is how the material looked after vacuum forming.
Leatherette Test
Next, I decided to run an experiment using leatherette — a synthetic leather material with a fabric backing. I was interested to see how this material would behave during the vacuum forming process and whether it would conform well to the mold without damaging its surface texture.
Due to its fabric backing, the material was unable to accurately capture the shape, it did not conform to the model as precisely as plastic and failed to reproduce fine surface details.
PVC Test
Next, I tested a 0.5 mm thick PVC sheet. I wanted to see how well this material performs in vacuum forming and whether it can accurately replicate the shape of the mold.
I created a 3D model of the mold and printed it using a 3D printer. Since the shape was complex and included areas where air pockets could form during vacuum forming, I added small holes in those spots to help release the trapped air. After that, the mold was printed and prepared for the forming process.
I secured the sheet of material in a larger frame to test how vacuum forming performs over a wider area and how this affects the material's ability to conform to the mold. Increasing the surface area allowed for a better assessment of the material’s behavior under more demanding forming conditions. After fixing the sheet, I began heating it, but I noticed that this type of material required more even, thorough, and prolonged heating compared to previous tests. This is likely due to both its thickness and its physical and chemical properties, which influence its softening point and elasticity.
The material didn’t immediately start conforming tightly to the mold, so additional heating with a heat gun was required. During this auxiliary heating, small holes began to appear on the surface of the material, likely caused by localized overheating and prolonged exposure to hot air. Despite this, the mold was generally captured well, and the resulting defects did not significantly affect the final outcome of the forming process. The finished surface retained the main contours of the model, and overall, the test can be considered successful in terms of evaluating the material's performance.
Final Results of Vacuum Forming
Here is the final result obtained using the 3D-printed mold. The material replicated the shape quite accurately, including the main contours and surface details, despite some technical difficulties during the forming process.
After use, the 3D-printed mold became deformed. This was caused by exposure to high temperature and pressure during the forming process, which is typical for plastics not intended for thermal stress.
Here is the result obtained using a metal mold. In this case, the mold withstood the process without deformation and allowed for more precise material conformity and better detail reproduction.
Conclusion
During the experiments with vacuum forming, various types of materials and molds were tested — from thin textured plastic sheets to leatherette and PVC, as well as both 3D-printed and metal molds. These tests provided a deeper understanding of the characteristics of working with a DIY vacuum forming machine, the requirements for heating the material, the importance of even heating, and the impact of mold quality and stability on the final result.
Both the limitations and advantages of different approaches were identified. For example, 3D-printed molds proved to be sensitive to high temperatures, while metal molds demonstrated stability and high precision. It also became clear that overheating the material can cause damage, but with proper temperature control and secure fixation, a high-quality result can be achieved.