In wax spraying, the rubber or silicone mould is injected with liquid wax, i.e. parts can be produced out of wax in the ordered quantities from the mould, which is ultimately just an impression of the original. These wax parts are just like the original model, if you disregard the low amount of shrinkage.
The wax is kept warm and therefore liquid in so-called wax pots. Pressure is generated in the pot, which results in the wax finally shooting into the mould to be filled. The pressure with which the two halves of the mould are pressed together manually or automatically is just as crucial as the temperature, pressure and spraying time for the wax.
All in all, a large number of errors can occur here, which then become visible in the finished casting. If you try to avoid this and work in a quality conscious way, the wax sprayer has a very demanding job.
Possible errors that should be avoided are for example:
- Parts have not completely flowed out
- The parts’ surface is not "sharp" – blurred rough surface
- Formation of air bubbles, which collapse during investing and lead to cavities in the casting
- Parts are "warped" when removed from the mould and lose their exact shape
- Sink marks when the wax cools down lead to "indented parts" – the part has a sagging surface that is no longer flat.
Our wax parts are therefore carefully checked a second time after production in another work step by a wax quality department. As part of this, seams that are created by separating the mould are also trimmed in the wax. Care is taken to ensure that the edges are not broken or contours are not blurred.
Diamonds or synthetic stones are worked into the wax in two different ways (wax setting or injecting stones) in a special casting process, so-called stone casting. The resulting precious metal casting therefore also contains these stones, and the cost-intensive working into the metal (setting of the stones) is not necessary. However, for this technique the corresponding models have to be prepared for stone casting, which may cause additional costs for the model and is therefore only worthwhile for series production.