The technology of vacuum plastic casting into silicone molds


For casting plastic products in small batches (up to 1000 pcs.), the technology of casting into silicone molds is most often used. This method of casting, in terms of cost and preparation time for production, has an impressive advantage over other methods of manufacturing products. The advantage is that the liquid polyurethane is used for molding plastic products, which is poured into a mold at room temperature, so there is no need to apply high pressure to it. The mold is filled by placing it in a vacuum chamber and this makes it possible not to use a complicated metal mold in work.

Vacuum casting of plastic into silicone molds will be effective in the following cases:

  • small-scale casting of products in small batches from 1 to 1000 pcs;
  • creation of master models for testing, elaboration of product design and, if necessary, further refinement for serial production;
  • production of samples for demonstration to customers until the batch is launched into mass production;
  • manufacture of products for passing the certification process, which requires a sample similar to the future serial product;
  • the need to restore a worn out or broken part, or a product that has already out of stock;
  • covering the primary market demand for a new product until the metal mold is ready (the process of starting silicone mold casting takes a few days, as opposed to injection molding, which takes several months).

Materials used for silicone casting

For molding plastic parts using vacuum casting technology in silicone, usially used two-component liquid polyurethanes. With a help of adding various components to liquid polyurethane, it is possible to obtain different physical and mechanical properties of the finished product. These can be both the properties of the main engineering plastics, such as ABS, polyamide, polyethylene, etc., and the useful properties of polyurethanes, which can imitate the appearance and quality of rubber with Shore hardness from 45 to 97 A, or transparent polyurethanes used in the manufacture of optical parts, as well as heat-resistant materials that can withstand temperatures up to 120 °C.°

Marabu Company

Stages of casting plastic products in small quantities

  1. Manufacturing of a prototype. Most often, a prototype is made from a 3D-model by printing it on a 3D-printer or cutting out on a milling machine.
  2. Creation of a master model. The ready prototype, if necessary, is putty and polished, and to give some texture, a decorative surface is additionally applied to it.
  3. Making a silicone mold. With the help of a master model, is created a silicone mold into which a future details will be poured.
  4. Test casting. Before starting casting in batches, it is necessary to cast the first or test piece to agree it with the customer. At this stage, can be casted a several pieces that differ in their physical characteristics or material color.
  5. Serial casting. After agreeing on all points, you can start casting in small batches. The speed of such casting depends on the selected material, the complexity of the product and the requirements for the surface of the finished product. The production speed can be increased by making several silicone molds.

Why clients choose Marabu Company

For many years, the Marabu Company has been specializing in the casting of plastic products in small batches of up to 1000 pcs. We offer our clients a favorable combination of good prices and high quality products received in a very short time.