Shrinkage dents: dents on the surface of the wax mould, mainly due to insufficient injection working pressure and time, or high temperature of the wax material, insufficient cooling time sometimes too much release stripper, also likely to reduce the characteristics of the wax material. The surface shrinkage involves a relatively large total area and is more difficult to repair. The surface is not smooth: because the injection working pressure is too small, or the injection rate is not sufficient, the relative density of the wax material touching the inner surface of the press is not sufficient to realistically reflect the surface of the press, more serious also accompanied by wrinkles.
Deformation: after the wax mould is taken out from the press, in addition to the specification to produce a small change, because of the Shanghai precision casting when taking down improper skills and human factors lead to deformation. Because the wax mould is still cooling and the temperature gradient changes, tensile strain deformation is common. Therefore just from the press in the wax mold still should be carefully placed, generally to compare the large plane figure as the standard put right, when necessary, the application and deformation of the position of the same look, made of metal material block placed in the wax mold to avoid deformation, also even if its sufficient cooling. It is also very likely that the wax material is too soft and the constituent parts of the press type are not suitable, etc.
After pickling passivation and passivation treatment, if the cleanup is not clean, the residual liquid will remain and the stainless steel plate will be immediately leached. For example, in the pickling passivation process, the acidic and alkaline liquid state enters the shrinkage of the casting part and subsequently reflects with oxygen, causing yellow spots on the surface of the casting part. Laser cutting: rust-prone raw materials, such as large casting casting laser cutting slag, spatter and adhesion of corrosive substances can lead to primary cell reactions and cause electrochemical reactions. Hairy fins (phi seam): this is also a common shortcoming, that is, in the press type of the joint, Zhongshan precision casting press type consists of blocks of the joint, the core and the core seat of the two sides of the area such as a very thin wax flakes escape. The factors that cause this are mainly the lack of precision of the press type, the analysis surface of the press type or the welding surface of the parts within the type suffer damage or adhesion of unclean things, or insufficient closing force, the injection working pressure is too high. Or the temperature of the wax is too high, the hairy fins must be completely eliminated before the wax mould can be applied.