A. Limit size: 15~20mm at the thickest part, and 30mm in diameter if it is a sphere. Generally, the recommended size of the thickness is not more than 3MM. When it is more than 3MM, it will take more curing time and increase the cost. The thinnest treatment can reach 0.2MM in theory, but the thinnest 0.3MM is generally used in the design, and 0.4MM is recommended.

B. Relative size: In terms of thickness difference, it is recommended that the thinnest part and the thickest part should not exceed 3 times. Such problems mainly depend on the temperature and pressure requirements of the material during vulcanization.

C, shrinkage rate. The shrinkage rate of silicone material is related to the hardness of the material. The secondary materials provided by the manufacturer are mostly between 1.022 and 1.042. For the material of 40 to 50 degrees, the shrinkage rate is generally 1.03. Compared with plastic, silicone products will not produce similar obvious surface defects due to shrinkage.

D, dimensional accuracy: Because silicone products are mostly one mold with multiple cavities, there are many cavities compared to plastic products. Therefore, the size control is not as convenient as plastic products. The general accuracy is plus or minus 0.1, and the high-precision product is plus or minus 0.05. When the fit is used for the fit between the hole of the plastic part and the button, the minimum gap is 0.1 on one side, and the recommended value is 0.2 on one side.

E. Shape design: For rubber sleeve parts, it is generally sufficient to provide the mold factory with the original drawing according to the product's outline drawing, and the explanation of the matching problems is left to the mold factory's own decision. Under normal circumstances, depending on the size of the product, the fit between the rubber sleeve and the product is generally a negative deviation of 0.2 to 0.5 on one side.