1. Blow molding mold design process is different, blow molding mold design is injection + blowing; Injection molding is injection + pressure; Roll molding is extrusion + pressure; Blow molding must have the head left by the suction pipe, injection molding must have a gate section, rolling plastic cutting must have burr
Blow molding die design
2. Generally speaking, injection molding is solid core, blow molding and roll molding is empty core. Injection parts surface is bright, blow and roll plastic surface is uneven. Blow molding and roll molding comparison at least blow molding has a blowing mouth. This is a general comparison. I wonder if you can understand!!
3. Shrinkage of plastics and its influencing factors
Thermoplastics have the property of expanding when heated, contracting when cooled, and of course shrinking when pressurized. In the process of injection molding, the molten plastic is first injected into the mold cavity, after the filling, the melt is cooled and solidified, and the shrinkage occurs when the plastic parts are taken out of the mold, which is called forming shrinkage. Plastic parts from the mold to the stability of this period of time, there will still be a small change in size, a change is to continue to shrink, this shrinkage is called post-shrinkage. Another variation is the expansion of certain hygroscopic plastics due to moisture absorption. For example, when the water content of nylon 610 is 3%, the size increase is 2%; When the water content of glass fiber reinforced nylon 66 is 40%, the size increase is 0.3%. But forming shrinkage plays a major role.
Post time: Jul-26-2022