The manufacturing of moulding dies is diverse, so we are also diverse in the choice of processes.The following mainly analyzes the design content of vacuum blister moulding dies, mainly including: large batches, moulding equipment, precision conditions, geometric design, size Stability and surface quality.
1. For batch size experiments, the mould output is small, and it can be made of wood or resin. However, if the experimental mould is used to obtain data on shrinkage, dimensional stability, and cycle time of the product, a single cavity mould should be used for experiments, and it can be guaranteed to be used under production conditions. moulds are generally made of gypsum, copper, aluminum, or aluminum-steel alloys, and aluminum-resin is rarely used.
2. Geometric shape design. When designing, often consider comprehensive dimensional stability and surface quality. For example, product design and dimensional stability require the use of moulds, but products with higher surface requirements require the use of male moulds.In this way, the plastic orderer will take these two points into consideration to make the product under the * conditions in production. Experience has shown that designs that do not meet actual processing conditions often fail.
3. The size is stable, in the moulding process, the surface of the plastic part in contact with the mould is better than the size of the part of the mould is stable. If the thickness of the material is required to be changed in the future due to the rigidity of the material, the male mould may be converted into a mould. The dimensional tolerance of the plastic part must not be less than 10% of the shrinkage.
4. The surface of the plastic part, as far as the moulding material can cover, the surface structure of the visible surface of the plastic part should be formed in contact with the mould. If possible, the cleansing surface of the plastic parts should not contact the mould surface. Just like the case of making bathtubs and washing tubs with moulds.
5. Modification. If the clamping edge of the plastic part is sawed off with a mechanical horizontal saw, there must be at least 6 ~ 8 margin in the height direction. Other dressing work, such as grinding, cutting, or jetting, must also allow margin. The gap between the cutting edges of the blade die is small, and the distribution width of the punching die when trimming is also small. These should be paid attention to.
6. Shrinkage and deformation, plastic is easy to shrink (such as PE), some plastic parts are easy to deform, no matter how to prevent, plastic parts will deform during the cooling stage. Under this condition, it is necessary to change the shape of the forming mould to adapt to the geometric deviation of the plastic part. For example: although the plastic wall remains straight, its reference center has deviated by 10; the mould base can be raised to adjust the shrinkage of this deformation.
7. The amount of shrinkage, the following shrinkage factors must be taken into account when manufacturing plastic moulding moulds. ① The moulded product shrinks. If the shrinkage of the plastic cannot be clearly known, it must be sampled or obtained by testing with a similarly shaped mould. Note: Only shrinkage can be obtained by this method, and deformation size cannot be obtained. ② Shrinkage caused by the adverse effects of intermediate media, such as ceramics and silicone rubber. ③ Shrinkage of materials used in the mould, such as shrinkage when casting aluminum.