Mold Maintenance Guidelines For Injection Molding Operations

The service life of injection (plastic) molds is closely related to proper maintenance. In reality, there are numerous cases where molds become scrapped due to improper maintenance. Some companies encounter such incidents countless times:

• Molds costing ¥100,000 to ¥200,000 to develop

• Developing abnormalities after producing only a few products

• High repair costs required

• Delays in customer delivery cycles

• Loss of customer confidence

Therefore, it is essential for machine adjustment technicians to develop basic mold maintenance habits to extend mold service life.

1. Mold Maintenance Before Injection Production

1.1 Surface & Water Channel Preparation

• Clean oil stains and rust from the mold surface

• Inspect cooling water channels for foreign objects and blockages

1.2 Component Inspection

• Check for damage to the arc in the sprue bushing

• Remove any residual foreign objects

• Verify proper operation of moving parts (no abnormalities, smooth movement)

2. Mold Maintenance During Injection Production

2.1 Daily Guide Component Care

• Inspect all guide pillars, guide bushes, slide cores for damage

• Apply lubricating oil regularly (twice daily: at start and end of shift)

2.2 Surface & Ejector Maintenance

• Clean parting surfaces and exhaust grooves of:

• Foreign objects

• Plastic threads

• Oil residues

• Inspect ejector pins for abnormalities and apply oil regularly

• Clean parting surfaces and runner surfaces twice daily

• Lubricate guide pins, bushings, and positioning pins once daily

2.3 System Checks

• Regularly verify water channel flow (unobstructed)

• Tighten all fastening screws

2.4 Mechanism Inspection

• Check limit switches for abnormalities

• Inspect angle pins and lifters for proper operation

3. Mold Maintenance After Injection Production

1. Turn off cooling water channels

2. Blow out residual water from mold water channels

3. Clean surface of residual plastic threads and foreign objects

4. Apply anti-rust agent evenly

5. Accurately complete process records

6. Attach the last produced plastic part as reference