How to Clean Injection Molds

Injection molding is an industrial plastic-making process.

Injection molding is a production process in which plastics are heated until liquid and sprayed into a mold where they cool and are given the final shape of the manufactured product. As the project cools, it shrinks away from the mold walls, allowing it to be ejected. To keep this process working efficiently, molds need to be systematically and regularly cleaned. Although most molds are cleaned haphazardly and by hand, there are also a number of technological solutions available.

 

Instructions

1.                            Cleaning Molds by Hand

1

Disassemble the mold using a screwdriver to disconnect the parts. Separate the parts that are most susceptible to corrosion and contaminate build-up. These include the front and rear clamp plates, bubbler plates, bushings, water lines and wear plate grease grooves.

2

Spray the pieces of the mold with a cleaning spray, or place them in a solvent bath. More abrasive cleaning chemicals may work more quickly, but they will also cause wear and tear on the mold that can shorten its life.

3

Scrub the mold with a stiff brush to remove the contaminants, then wipe dry.

2.                            Cleaning With Dry Ice Pellets

4

Connect a dry-ice pellet blasting system to an air line near your mold. A double-line system introduces the pellets at the spray nozzle, while single-line systems introduce them at the hopper and offer a more powerful spray.

5

Disassemble the mold and strongly secure the parts to be cleaned. The force of the dry-ice pellet impacts can easily knock over unsecured parts, possibly damaging them.

6

Ensure the area is clear. These guns spray dry ice at 900 feet per second, which can cause severe injury.

7

Put on safety gear. This includes a face mask, gloves and an apron as well as ear protection that can block the 102-decibel noise produced by the sprayer.

8

Turn on the air line and squeeze the trigger to spray the parts. The dry ice will dissolve on impact, taking residue with it. This method, however, may not be very effective at rust removal.

3.                            Cleaning Molds Ultrasonically

9

Disassemble the mold and immerse the parts in a detergent solution. The exact type of detergent depends on what kind of contamination is to be removed. Heavily alkaline solutions like sodium hydroxide are very effective with most contaminants, but are dangerously caustic. Mildly acidic solutions are better for rust, but will turn steel gray.

10

Connect an ultrasonic generator to a shop power line. This generator transforms regular current into the very high frequencies necessary for ultrasonic cleaning.

11

Attach transducers to the bottom and sides of the tank. These transducers will vibrate at the high frequencies coming in from the generator, which produces tiny bubbles in the water that impact the mold pieces with force enough to strip away contaminants, while leaving the metal mold undamaged.

12

Set the timer on the generator, and walk away. The cleaning process will proceed on its own.

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