What are the technical characteristics of silicone moulds in rapid prototyping?Prototech
Silicone moulds are part of the tooling required for the production of vacuum-moulded plastic parts. Their re-use results in significant economies of scale. It is therefore essential to ensure that they are produced in an appropriate manner to permit optimal use. They are characterised by several parameters, the most important of which are listed below:
– The size and weight of the moulds depend on the geometry of the parts.
– The ventilation method and number of openings are linked to the choice of the production technique. The latter differs from one prototypist to another.
– The possible presence of tapers or undercuts may influence the decisions made during the design of the mould, to ensure the removal of the parts without damaging the tooling.
– Each mould has a cavity to allow the liquid material to be inserted during production. This is created by the negative of a master model of the part to be manufactured. This master part is designed either with CNC machining or 3D printing technology.
– The silicone moulds are also characterised by the type of silicone used.
– The quality of the mould depends on the silicone and also the care taken during manufacturing.
– The method of incorporating finishes into plastic parts may differ from one mould to another. In fact, it is possible to apply finishes to the mould directly instead of performing manual manipulations after the removal of the parts.
– It is also possible to overmould inserts on the parts by positioning them directly in the mould.
– In general, a rapid prototyping workshop is capable of performing 20 runs with one mould. In addition, a mould can be used for a period of about 45 days. However, this data differs depending on the geometry of the parts and the type of silicone used to design the mould. The lifetime and the number of possible uses of the moulds can therefore vary and some moulds allow only 5 runs, for example.