Silicon mold making is a simple technique that helps provide a frame of reference for accurate measurement, and shapes of various products, and is primarily used to cater to the on demand manufacturing market. It works by designing a hollow shaped object designed as the outer surface of the product being made, with a liquid that’s poured inward to obtain the desired shape.
Silicon molds can be manufactured by a number of techniques, with each method having its own advantages and disadvantages, and the best technique is adapted depending on the case scenario. Some of these techniques include rapid prototyping through Additive Manufacturing (known as 3D Printing), CNC milling, Multi-Part molding, LSR and Open Face (1-part) molding along with other similar techniques.
The general process involves measuring the outer surface of the object that will be replicated with the mold. Then, the silicon rubber coating is applied along with the polyurethane casting that will make up the mold. It should be noted that the coating should be handled with high care as a difference could result in the replicas coming out with a different shape. Once the silicon is poured, it’s left around the object to finish, with the expected time being dependant on the technique involved. Once the silicon mold is ready, the object is removed and the hollowed surface is examined for surface quality to remove any imperfections, such as air bubbles that could diminish the quality of the mold fill.
Advantages of Silicon Molds
Silicon rubber, being able to tolerate a high degree of heat, is the primary choice of manufacturing companies for use in silicon mold making, as several kinds of materials can be poured in liquid form to obtain the desired shape. It provides an accurate scale of measurement and defines geometry and shape during the production of a diverse range of products.
Silicon molds can be used as a diverse range of products such as baking equipment, windscreen glass, plaster for figurines, architectural moldings, ceramic products etc.
The techniques for silicon mold making are adapted, taking into account different design considerations, such as the type of material (in liquid form) that will be poured into the mold. Aluminum seems to work well with Vacuum forming, while it does not perform very well with Open Face or Multi-Part molding. Additive Manufacturing seems to be the technique of choice when dealing with rapid prototyping, and is known to be compatible with Ceramics, PLA, Resin and can produce an average number of silicon batches without the need to attend to them. Other design considerations to be kept in mind are whether the technique will be able to produce the desired mole which is complex in shape, the cost per part, speed, and how many parts can be made. A technique such as 3D printing, while providing the user with high production speed and low cost, can make a small number of silicon molds which might not be as accurate as say with a technique like LSR, which provides a higher production rate but with a significant increase in cost.
Using the proper design technique in silicon molds is widely adopted during on demand manufacturing where complex and accurate shapes are desired. In this regard, silicon molds provide an efficient and low-cost option for manufacturers to achieve the desired product.
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