Blow molding plastic is a procedure where hollow 3D articles are produced using various kinds of thermoplastic materials. These materials are usually available in powder or granular form. The simplest blow molded tool has two parts, which are closed and consist of a cavity inside.
Hold Molds Work in Extrusion Blow Molding Technology
A plasticizing cylinder is used by blow molding manufacturers for softening the granular or powder materials, which are then thrust into a parison (vertical tube). An open mold surrounds this parison that is later closed. Thus, the bottom end is sealed effectively and then, the other end is used for sealing it in a pneumatic manner.
The mold’s geometry and the parison’s size determine what the distribution, wall thickness and other dimensions of the manufactured article would be. This makes them important factors, along with the die design, which is affected, by backpressure, land length, melt compression and melt flow pattern. For producing bottles that have uniformity in wall thickness, the wall thickness of the parison is controlled using various pre-stated steps by manufacturers.
Advantages of Extrusion Blow Molding Plastics
Advantages: Because of lower pressure, the mold costs in extrusion blow molding are lower as compared to injection molding and the machinery costs are low as well. Also, it’s easy to mold external threads. Making open-ended parts that are large can be done by splitting open a closed molding.
Disadvantages of Using Extrusion Blow Molding
Disadvantages: As the diameter of the mold increases, the corners and areas with the thinnest walls have close tolerance. Plus, extrusion molding has longer cooling times than injection molding. Also, it is not possible to mold in holes except after the molding.