Because different molding die tools have been applied in many fields, plus the manufacturing technology of professional die tools has also changed and developed over the years, so in this part, the general design rules of vacuum blister molding die tools are summarized.
The design of vacuum suction molding mold includes the batch size, molding equipment, precision conditions, geometric shape design, dimensional stability and surface quality, etc.
1, the size of the batch for experimental use, mold production hours, can be manufactured using wood or resin. However, if the experimental mold is used to obtain data about shrinkage, dimensional stability and cycle time of the product, etc., a single-cavity mold should be used for experiments, and it can be guaranteed that it can be used under production conditions. die tools are generally made of plaster, copper, aluminum or aluminum-steel alloy, rarely used aluminum - resin.
2, geometry design, design, often to consider the size stability and surface quality. For example, the product design and dimensional stability requires the use of a negative mold (concave mold), but the surface requirements of high gloss products require the use of a positive mold (convex mold), so that the plastic parts orderer will take into account both points, so that the products can be produced under the best conditions. Experience has proven that designs that do not meet the actual processing conditions are often failures.
3, dimensional stability, during the molding process, the surface of the plastic part in contact with the mold is better than the dimensional stability of the part leaving the mold. If the material thickness is required to be changed later due to the need of material stiffness, it may lead to the conversion of the positive mold to the negative mold. The dimensional tolerance of the plastic part should not be less than 10% of the shrinkage rate.
4, the surface of the plastic part, as far as the molding material can be wrapped, the plastic part can meet the surface structure should be molded at the contact with the mold. If possible, the glossy surface of the plastic part should not be in contact with the surface of the mold. Just like the case of using a negative mold to manufacture bath tubs and laundry tubs.
5. Trimming, if the clamping edge of the plastic part is sawed off using a mechanical horizontal saw, there should be a margin of at least 6 to 8 mm in the height direction. Other trimming work, such as grinding, laser cutting or jet, must also leave a margin. The gap between the cutting lines of the knife edge die is minimal, and the distribution width of the punching die trimming is also small, these are to be noted.
6, shrinkage and deformation, plastic easy to shrink (such as pe), some plastic parts easy to deformation, no matter how to prevent, plastic parts in the cooling stage will be deformed. In this condition, we have to change the shape of the molding mold to accommodate the geometric deviation of the plastic part. For example, although the wall of the plastic part is kept flat, its reference center has deviated by 10mm; the base of the mold can be raised to adjust the shrinkage of this deformation.
7, the amount of shrinkage, in the manufacture of blister molding die tools must take into account the following shrinkage factors. ① shrinkage of the molded product. If the shrinkage of the plastic cannot be clearly known, it must be obtained by taking samples or using similarly shaped die tools through tests. Note: By this method, only the shrinkage rate can be obtained, not the deformation size. ② Shrinkage caused by the unfavorable influence of intermediate media, such as ceramics, silicone rubber, etc. ③ Shrinkage of the material used in the mold, such as shrinkage when casting aluminum.
热门资讯
