CAST plastic - a special material based on polymethylmethacrylate with the addition of special plasticizers. The material is prepared specifically for printing objects used in casting according to burnt models. The results of the test at the Moscow State University Research Center for thermogravimetric analysis in a dynamic air atmosphere showed that the mass fraction of ash is less than 0.1% of the mass of the printed object when it is burned at ~405°C.
FEATURES OF BURNING CAST PLASTIC
The printed model is impregnated with wax before being sent to the foundry – this allows you to get a better casting surface.
In the foundry, a gating system is formed around the model printed on a 3D printer - a system of channels from a riser and feeders for supplying liquid molten material. Then the block of parts begins to be immersed in the molding mixture, with the help of which an integral shell, ceramic or gypsum filling, form is gradually built around all the parts.
The molding mixture is applied in several layers, each of which dries before applying the next layer.
Next, the models are removed from the resulting form by burning at a temperature of 405 °C. In order for the mold to be more durable, before being sent to the furnace, it is placed in a metal container and covered with a refractory material.
Before starting to fill with metal. The container with the mold is removed from the oven, pierced. Next, the finished mold is extracted and the molten metal is poured into it. After cooling and hardening of the cast product, the mold is knocked out, the cast object is cleaned and the gate valves are cut off from it.