What are the steps in the wax injection process of dewaxing casting? Die-casting and dewaxing casting is one of the glass manufacturing processes. The main process is to heat the glass to a high temperature and fluidly enter it into the precast mold for forming. Since the mold shell is obtained by removing the wax mold after heating, it is called dewaxing casting.
Dewaxing casting process.

After the die is opened, wax injection can be performed. The wax filling operation should pay attention to factors such as wax temperature, pressure and compression of the rubber mold.

The wax used to make wax molds with blue model paraffin is generally about 60°C, and the wax injection temperature is about 65°C. There are also other colors of paraffin with slightly different properties. The wax temperature and injection pressure are determined by the wax injection machine. Wax injection machines are generally divided into two types: pneumatic and vacuum.

The wax injection principle of the two wax injection machines is basically the same, that is, the molten wax is injected into the rubber mold by air pressure. The difference is that the vacuum wax injection machine can first vacuum the rubber mold and then inject wax in the rubber mold, while the air pressure wax injection machine can only inject wax directly on the rubber mold. Therefore, under normal circumstances, the operation of the vacuum wax injection machine is relatively easy to master, while the air pressure wax injection machine requires certain experience.

The heater and temperature sensing device used in the waxing machine can reach and maintain a certain temperature. Under normal circumstances, the wax temperature of the wax injection machine should be maintained at 70~75℃, this temperature can ensure the fluidity of the wax liquid. If the temperature is too low, the wax liquid is not easy to inject into the wax mold, causing the wax mold to be incomplete; on the contrary, if the temperature of the wax liquid is too high, it will cause the wax liquid to overflow from the gap of the rubber mold or overflow from the wax injection port, which is easy to form flashing Or burn your fingers.

The pressure in the wax cylinder of the wax injection machine is usually provided by an external air pump, and should generally be maintained at 0.5~0.7at (or kgf/cm2), that is, between 0.051 and 0.071 Bar. It can also be adjusted appropriately according to the volume and complexity of the wax mold.

Before waxing, first open the rubber mold and check whether the rubber mold is complete and clean. If you have used the plastic mold, spray a dewaxing agent (or sprinkle a small amount of talcum powder) on the plastic mold, especially the thin and complex parts, to facilitate the removal of the wax mold; secondly, preheat the wax injection machine, Turn on the air pump and adjust the pressure and temperature.

When injecting wax, clamp the splint (which can be a plexiglass plate, a wooden board, an aluminum plate, etc.) by hand, and pay attention to the distribution of fingers to make the rubber mold evenly pressed; the nozzle of the rubber mold is aligned with the wax nozzle and pushed in parallel to firmly inject the wax Do not move your hands behind your mouth, gently step on the wax injection switch with your foot and release it immediately. After holding your hands for 1 to 2 seconds, put the plastic mold in, and then open the plastic mold (if the plastic mold has a bottom, pull out the bottom of the mold first) ), take out the wax mold.

After the wax mold is taken out, check it carefully. If there are serious problems such as missing edges or broken feet, the wax mold is a waste product. If there are some minor defects, wax mold repairs should be carried out.