Using GP and GP HT Resins for RTV Silicone Moulding

RTV Silicone Moulding is used especially for jewelry parts where we require multiple wax copies of the same part. The process begins with a master pattern which can be printed using our GP LC/ GP SD/ GP HT Resin on any 3D Printer which supports our material (please check list of supported machines on Collections Page to know whether your machine can print in GP LC/ GP SD/ GP HT Resin).

After the printing process is complete, the pieces need to be washed using Acetone/ Isopropyl Alcohol. Please note that both these solvents are highly volatile and care must be taken to not ingest the solvent/ inhale solvent vapors. Using a ultrasonic cleaner to supercharge the cleaning process is a good idea as it ensures that resin is removed from every portion of the part. 

After solvent cleaning, support removal needs to be done manually, by a skilled worker. A sharp surgical blade/ nipper-cutter is used to cut the supports. Deburring is done at portions with support marks. Deburring and polishing is done using emery paper (1000 Diamond Grit). After deburring, you would notice a white powdery texture on the surface of the part (exactly where the emery/ sand paper was used). This can be cleaned off by dipping the piece into a beaker of benzene and placing the beaker (filled with benzene) in an ultrasonic cleaner. Please use a respirator, face cover and hand gloves while handling benzene. Long-term exposure to benzene can be harmful. 

Now our pieces are ready to be moulded. Initially, a wax rod is soldered at bottom portion of the part. This wax rod will serve as a gate for the mould during wax injection process. Next the mold is created. RTV Silicone rubber is first deaerated (to remove any air bubbles present in the mixture). Liquid mould is then poured into an adjustable fixture. This fixture is created such that we can adjust the volume of the final mould based on the size of the parts. The liquid mould is then allowed to settle for minimum of 8-12 hours. If one needs to expedite the process, heat can be used. Heat can be applied by placing a halogen lamp in close proximity to the mould fixture you use. 

After the silicone is fully cured (approximately one day), the master pattern is removed by cutting the mould along the centre line as shown below:

The mold is then reassembled, after which wax can be injected into it to get final wax pieces. 

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