Blow Mold Operator at work.

What does a Blow Mold Machine Operator do?

Blow molding (or moulding) is a manufacturing process for forming and joining together hollow plastic parts. It is also used for forming glass bottles or other hollow shapes.

In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and injection stretch blow molding.

The blow molding process begins with melting down the plastic and forming it into a parison or, in the case of injection and injection stretch blow molding (ISB), a preform. The parison is a tube-like piece of plastic with a hole in one end through which compressed air can pass.

The parison is then clamped into a mold and air is blown into it. The air pressure then pushes the plastic out to match the mold. Once the plastic has cooled and hardened the mold opens up and the part is ejected. Water channels are carved into the mold to assist in cooling.

Operator Duties and Responsibilities:

1) Sets up operates blow molding machine to mold plastic products according to specifications.

2) Turns valves to start flow of water release air pressure to machine.

3) Moves machine controls to set timing unit & temperature of heating unit start automatic feed mechanism.

4) Adjusts machine mandrel aligns mandrel with mold chamber, using wrenches.

5) Starts molding machine that automatically feeds material from mixing unit to mandrel to mold chamber.

6) Closes chamber to mold product under heat pressure.

7) Removes workpiece from mold after timing device opens mold, and trims excess material from workpiece, using knife or bandsaw.

8) Regrinds excess material unsatisfactory workpiece for reuse, using grinding machine.

9) May weigh completed workpiece to define accuracy of machine operation.

Education Requirements

  • High school diploma or general education degree (GED) required.
  • AS degree is preferred.
  • Formal education in: Prefer an apprenticeship and/or formal training in area of specialty.
  • 1-3 years of experience in the field or in a related area.