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Process introduction

3/4 of the blow molded products are manufactured by extrusion blow molding. The extrusion process is to force the material through a hole or die to make a product.

The extrusion blow molding process consists of 5 steps: 1. Plastic preform (extrusion of hollow plastic tube). 2. Close the flap mold on the parison, clamp the mold and cut off the parison. 3. Blow the mold to the cold wall of the cavity, adjust the opening and maintain a certain pressure during cooling. 4. Open the mold and remove the blown parts. 5. Trim the flash to get the finished product.

Extrusion hollow blow molding process
Extrusion hollow blow molding is to melt and plasticize the plastic in an extruder, and then extrude a tubular parison through a tubular die. When the parison reaches a certain length, the parison is heated into the blow mold. Compressed air is then blown in to make the parison close to the wall of the mold cavity to obtain the shape of the cavity, and under the condition of maintaining a certain pressure, after cooling and shaping, the blown product is obtained by demolding. The process of extrusion blow molding is as follows.
Plastic → plasticizing and extrusion → tubular parison → mold closing → inflation molding → cooling → mold opening → take out the product
Extrusion blow molding can generally be divided into the following five steps, as shown in Figure 1-1.
① The polymer is melted through the extruder, and the melt is formed into a tubular parison through the die.
②When the parison reaches a predetermined length, the blow mold is closed, the parison is clamped between the two mold halves, and the parison is cut and moved to another station.
③Inject compressed air into the parison to inflate the parison to make it close to the mold cavity to form.
④ Cool down.
⑤Open the mold and take out the molded product.


Post time: Aug-04-2021