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Problem of Vacuum Casting

Nov 10,20

Problem of Vacuum Casting
Vacuum Casting is a common handicraft technology, which is mainly used in the production of hand model with material requirements, small batch model production and small batch production. The application industry has intelligent hardware, modified car parts, toys, communication equipment, plastic shell, medical equipment shell, robot shell, etc. The advantages of silicone hand model are: the viscosity of silica gel is thin, easy to operate, no deformation, no shrinkage, easy to remove the mold, the surface of the mold is smooth, and the simulation effect is good.
Common problems encountered:
1 Dimensional deviation product deformation

Causes and solutions: it has a great relationship with the production process of the compound mold, especially the temperature control of the mold. Other reasons, such as the scale of the prototype and the shrinkage of the material, should also be controlled. Products with a length of more than 1.5 meters need to be made with reinforced moulds

2The product produced cannot be assembled

Causes and solutions: the drawings of product engineers are set according to the injection molding process, often without considering the difference between the re molding process and the injection molding process. Due to vacuum adsorption molding, the precision of the product can be controlled within ± 0.1 mm. For assembly products with higher precision requirements or hand feel tightness requirements, small batch production engineers need to adjust the prototype of the duplicate mold, plus the assistance of post-processing, to meet the assembly requirements
3The finished product becomes brittle and cracked
Causes and solutions: mainly due to the use of domestic low-quality materials and defects in the re molding process. The solution is to ensure that the channel of material procurement is guaranteed. If there is no problem with the materials, improve the process, and pay attention to control the oven temperature and heating time, cooling time, cooling method, etc.

4Bubbles and voids

Causes and solutions: the bubbles produced by the compound molding products are related to the reaction of Vacuum Casting material and curing agent. The time of vacuum pumping should be controlled properly. If the time is too long or too short, bubbles will be easily generated. In addition, it is related to the product structure and the position of the feed inlet. Bubbles on the surface of products will greatly affect the appearance and durability of materials
5Product details missing
Causes and solutions: in the production process of some relatively slender products, it is easy to lose details. The main reason is that the silica gel mold is not baked well and easy to deform, resulting in the loss of details. In addition, in the process of making the mold, the damage of the prototype of the product directly leads to the loss of details of the product out of the duplicate mold. In addition to the solution to improve the process, we must carefully check each link of prototype grinding, mold making and finished product mold manufacturing.

6The surface is rough and uneven

Causes and solutions: the quality of the re molded product is closely related to the prototype. The surface quality of the finished product needs to be improved. First of all, the manufacturing process and surface effect of the prototype should be improved. The prototype can be made by CNC. In addition, the use of domestic inferior silica gel will also lead to the surface roughness of the mold. The solution is to adopt the imported silica gel mold production, select the most appropriate process to make the prototype, to ensure the material hardness, surface and material compatibility.

7Discoloration and surface orange peel after coloring

Causes and solutions: the problem of decolorization is related to the flatness of the product surface, the selection of primer and topcoat. It is a problem involving multiple reasons. The main solution is to select a primer compatible with materials, such as two-component primer and automobile special paint. Good paint can not only improve the surface effect of the product, but also increase the aging resistance and corrosion resistance.