Because different mold has been applied in many fields, and professional mold manufacturing technology has changed and developed in recent years, the general design rules of vacuum suction molding mold are summarized in this part.
The design of vacuum suction molding die includes batch size, molding equipment, precision conditions, geometric design, dimensional stability and surface quality.
1. The size of batch test, modulus per hour, can be made into wood or resin. However, if the experimental mold is used to obtain data such as product shrinkage, dimensional stability and cycle time, the single cavity mold should be used for experiments to ensure that it can be used in production conditions. Mold is generally made of gypsum, copper, aluminum or aluminum alloy, rarely aluminum resin.
2. Geometric design, dimensional stability and surface quality shall be considered in the design. For example, the design and dimensional stability of a product requires a female die, but a high gloss surface product requires a positive die. Experience shows that the design which does not meet the actual processing conditions often fails.
3. In the process of forming, the contact surface between the plastic part and the mold has better dimensional stability than the part leaving the mold. If the thickness of material needs to be changed in the future due to the need of material rigidity, it may lead to the conversion of positive mode to negative mode. The dimensional tolerance of plastic parts shall not be less than 10% of shrinkage.
4. On the surface of plastic parts, the visible surface structure of plastic parts shall be formed in case of contact with the mold, so that the molding materials can be covered. If possible, the smooth surface of the plastic should not touch the surface of the mold. It's like using a negative die to make a bathtub and a washing basin.
5、修改时，如果用机械横锯锯掉塑料零件的夹紧边，在高度方向上，至少有6 ~ 8mm的余量。其他的修整工作，如研磨、激光切割或喷射切割，也必须留有余地。需要注意的是，刀模的切割线间隙更小，冲模的分布宽度也很小。
5. During modification, if the clamping edge of plastic parts is sawed off with a mechanical cross saw, there shall be at least 6 ~ 8mm allowance in the height direction. Other finishing work, such as grinding, laser cutting or jet cutting, must also leave room. It should be noted that the cutting line gap of the die is the smallest and the distribution width of the die is also very small.
6. Shrinkage deformation, plastic easy to shrink (such as PE), some plastic deformation, in any case to prevent, in the cooling phase will occur plastic deformation. In this case, it is necessary to change the shape of the mold to adapt to the geometric deviation of the plastic parts. For example, the base center of the plastic part is offset by 10 mm, but the plastic part wall is kept in a straight line; the mold base can be raised to adjust the shrinkage of this deformation.
7. Shrinkage, the following shrinkage factors must be taken into account when manufacturing the Blister molding die. (1) Product forming shrinkage. If the shrinkage of the plastic is not known, it must be obtained by sampling or testing with a similar shape of mold. Note: this method can only obtain shrinkage, not deformation size. Shrinkage caused by adverse effects of media, such as ceramics, silicone rubber, etc. (3) Shrinkage of materials used in molds, such as cast aluminum.
The above is a detailed introduction to the mold design principle of Jinan. For more information, please click http://www.jnhjgs.cn