At the set room temperature (or constant temperature), the wax mold sprayed with a layer of fine sand naturally dries, but the shape change of the internal wax mold is not affected. The natural drying time depends on the complexity of the product itself. The air drying time for castings is generally around 5-8 hours.
Once the sand is sprayed and naturally dried, the surface of the wax mold is further sprayed with industrial adhesive (silicon slurry) and a second layer of sand. The particle size of the second layer of sand is larger and coarser than that of the previous layer. The second layer of sand after spraying is also set at a constant temperature to allow the wax mold to air dry naturally.
After the second sandblasting is completed and naturally dried, proceed with the third sandblasting, fourth sandblasting, and fifth sandblasting in sequence. Requirement: - Adjust the sandblasting frequency according to the surface requirements, volume, self weight, etc. of the product. The general sandblasting frequency is 3-7 times- The size of sand particles used for each sandblasting varies. Generally, the sand in the subsequent process is coarser than that in the previous process, and the drying time is also different. Generally speaking, the production cycle for a complete wax mold sanding is around 7-15 days.
Before the baking process, the wax molds that have undergone sandblasting treatment are evenly coated with a layer of white industrial latex (silicon slurry) to bond and solidify the sand mold, as well as seal the wax molds, in preparation for the subsequent baking process. At the same time, after the baking process, it can also improve the brittleness of the sand mold, making it easier to break the sand layer and remove a blank.
During the baking process, the wax molds fixed on the mold head and subjected to sandblasting and air drying processes are heated in a specialized metal enclosed oven (usually a kerosene steam oven). Due to the low melting point of industrial wax, with a temperature of about 150 ° C, the wax mold is heated and melted to form wax water flowing out along the gate. This process is called dewaxing. The dewaxed wax mold is just an empty sand shell. The key to precision casting is the use of this empty sand shell. This wax can generally be used multiple times, but it must be re filtered, otherwise it will affect the surface quality of the blank, such as surface sand holes, pitting, casting shrinkage, etc.
Roast eggshells. In order to make the shell more sturdy and stable, the shell must be baked, usually by pouring stainless steel before high temperatures (about 1000 degrees Fahrenheit).
The stainless steel water that has dissolved into a liquid at high temperature is poured into the sand shell after wax removal. The liquid stainless steel water fills the space before wax forming until it is completely filled, including the middle mold head part.
Due to the mixing of different components of materials in boilers that dissolve stainless steel, factories and enterprises must pass the material percentage testing. Then we adjust and interpret according to the required proportional relationship, such as increasing the learning elements to achieve the desired effect.
After the liquid stainless steel is cooled and solidified by water, the outermost sand shell is crushed by mechanical tools or manual labor to expose the original wax shaped solid stainless steel product, which is the final required blank. Then cut them one by one, separate and roughen them to form a single billet.
Inspection of blank: rough holes and pores on the surface must be repaired by argon arc welding, and in severe cases, the waste should be cleaned and returned to the furnace. Clean the blank: The blank that has passed the inspection must go through the cleaning process. Conduct learning on other production processes until the finished product.