1 The inside of the mold cannot be hollow.

This is a congenital limitation of the blister vacuum forming process and cannot be improved. Unless new forming techniques are used, such as thick plate vacuum forming, plastic injection, and even 3D printing. However, the cost of vacuum forming blister molds is quite cost-effective, so there is still a place in the design and packaging materials.


2 The mold can not be barbed in the direction of drawing.

This limits the cut-out of the vacuum formed bulb to a flat surface. Even if a three-dimensional section is cut using a stamping die, the cross section may be rough and unattractive. Unless the cnc five-axis engraving machine with thick plate vacuum forming is used for cutting, the problem of unsatisfactory cut surface can be overcome, but the processing cost is about 10 times that of ordinary vacuum forming, which is quite expensive. However, in the tray design of the tray, the work tray and the lining, the vacuum forming of the bulb can be made into a simple barb groove, which can fix the contents. For example: lining boxes, food packaging boxes. Remind that the mold design of this barb card groove can not be used too much, so as not to be able to release the film, or even the deformation of the finished shell.


3 The rougher the surface of the mold, the more difficult it is to demold.

Although the mold material for vacuum forming of the bulb is mostly made of aluminum. Usually, the blister case is transparent and beautiful, and the mold is polished and polished. However, in order to improve the corrugation unevenness of the surface of the bulb (commonly known as the wind), the mold will be sandblasted. At this time, the surface of the bulb is rough, and attention should be paid to the problem that it is not easy to demould. The solution is a smooth coating on the spray surface, for example: Teflon. But when the mold is used for many years, the paint will fall off. It is worth mentioning that when vacuum forming is used in the design, the surface of the mold is likely to be rough and not smooth. This in turn leads to difficulty in demolding.