The material is heated until it becomes pliable. Then the mold is pressed into the material and the air between the mold and the sheet is removed. This creates a vacuum, and atmospheric pressure pulls the softened plastic tightly over the mold. Once cooled, the plastic retains its shape, and the mold's negative form is captured in the material. Nearly all thermoplastics (plastics that become soft when heated) can be used in this process.

The vacuum former can also be used to shape synthetic fabrics. Since most fabrics are not airtight, the fabric is placed between the mold and a plastic sheet to create patterns. Creating relief in synthetic fabrics is experimental — the result is unpredictable. Mesh-like fabrics tend to produce the best outcomes.

Preparation
To shape a plastic sheet or synthetic fabric, you’ll need a mold. You can either create your own mold or use found objects that are suitable. There are a few requirements for a usable mold:

• The mold must be made of a material that holds its shape when heated (up to 200°C). For example, polystyrene foam is unsuitable.
• The mold must be rigid enough. A cardboard box will collapse under pressure, while a LEGO brick will hold its form.
• To prevent the mold from getting stuck in the plastic, it must have a release angle. Think of the shape of a muffin tin or chocolate bar. The mold’s sides can be vertical up to 5 mm high, but above that, the sides must slope outward at an angle of 80° or less.

Suitable materials for making your own mold include plaster, MDF, or clay. You can also use the laser cutter to make shapes for molds.

Want to try vacuum forming? Come to the Makers Lab. One of the staff members will show you how to operate the vacuum forming machine. This takes about twenty minutes.

Material and Costs
You can bring your own materials or use the limited stock available in the lab.
For plastic suppliers, see the Materials page.

Specifications

Small vacuum former:

• Max mold size small frame 20 x 22 x 10 cm
• Max mold size large frame 22 x 42 x 10 cm

Large vacuum former:

• Max mold size small frame
• Max mold size large frame