Wax injection

Wax injection can be carried out after the plastic mold is opened. In wax injection operation, attention should be paid to factors such as wax temperature, pressure, and pressing of rubber mold. The wax used for making wax molds is generally blue model wax, with a melting temperature of about 60 ℃ and a wax injection temperature of about 65 ℃. There are some other colors of paraffin, with slightly different properties. Wax temperature and injection pressure are determined by the wax injection machine. There are usually two types of wax injection machines: air pressure type and vacuum type. The wax injection principle of these two wax injection machines is similar, that is, the molten wax is injected into the glue mold by using air pressure. The difference between the two is that the vacuum wax injection machine can vacuum the plastic mold first and inject wax into the plastic mold; The air pressure wax injection machine can only inject wax directly into the plastic mold. Therefore, it is usually easy to operate the vacuum wax injection machine, while the wind pressure wax injection machine requires some experience.

The heater and temperature sensor in the wax injection machine can make the wax liquid reach and maintain a certain temperature. Generally, the temperature of the wax in the wax injection machine should be kept between 70~75 ℃, which can ensure the fluidity of the wax liquid. If the temperature is too low, the wax liquid is not easy to fill the wax mold, causing the wax mold to be incomplete; On the contrary, if the temperature of the wax is too high, it will cause the wax to overflow from the gap of the plastic mold or from the wax injection port, which is easy to form flash or scald fingers.

The pressure in the wax cylinder of the wax injection machine is provided by the external air pump. Generally, it should be kept between 0.5~0.7at (or kg/cm2), that is, 0.051~0.071bar. It can also be adjusted appropriately according to the volume and complexity of the wax mold.

Before wax injection, the rubber mold should be opened first to check its integrity and cleanliness. If it is a used plastic mold, it should be sprayed with a dewaxing agent (or a small amount of talc powder) to the plastic mold, especially at the position with a small and complex shape, 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, you should use both hands to clamp the plastic mold in the plywood (which can be plexiglass board, wood board, aluminum plate, etc.), and pay attention to the distribution of fingers to make the plastic mold press evenly; Align the nozzle of the glue mold with the wax injection nozzle and push it in parallel. Hold the wax injection nozzle firmly and keep your hands still. Gently step on the wax injection switch with your feet and then release it. After your hands stay for 1~2 seconds, place the glue mold for a moment, and then open the glue mold (if the glue mold has a bottom, you should first pull out the mold bottom) and take out the wax mold. After taking out the wax mold, check it carefully. If there are serious problems such as missing edges and broken feet, such wax mold belongs to scrap. If there are some minor defects, the wax mold should be repaired.

Trimming wax mold

Generally speaking, the wax molds taken out after wax injection will have some problems more or less, such as flash, multiple edges, broken claws, sand holes visible to the naked eye, partial or overall structural deformation, small hole blockage, unclear flower headlines, flower head overlapping edges, etc. For defects such as flash, multiple edges, unclear flower heads, and flower heads with overlapping edges, the surgical blade can be used to polish them; For sand holes and broken claws, the wax welder can be used for welding repair; If the hole is blocked, it can be penetrated by welding needle; The deformation of wax mold can be corrected in hot water at 40~50 ℃.

In addition, for rings with different hand sizes, if you wait until holding the mold and then change the finger ring, it will undoubtedly cost both labor and materials. Therefore, general production enterprises directly change the finger ring when repairing wax molds. It is very convenient to change the finger ring to use a wax welder. After welding, trim the weld with a blade.

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