Mould maintenance: why you shouldn’t put it off

Mould maintenance encompasses all the tasks required to keep an injection mould in a condition fit for production. This can be preventative, based on a cycle schedule, or corrective, following a breakdown. The difference between the two lies in planning, costs and downtime. Delayed maintenance always leads to higher costs than planned maintenance.

What a mould endures every cycle

An injection mould operates under extreme conditions. High injection pressure, significant temperature fluctuations and the mechanical force of closing and opening: this is repeated tens of thousands of times. After every cycle, the mould is a fraction more worn than before.

With proper maintenance, this wear and tear is manageable. Minor damage is repaired in good time, cooling channels remain clear and ejector pins function correctly. Without maintenance, minor problems accumulate, leading to quality deviations, dimensional changes or, ultimately, mould damage that can no longer be repaired.

Preventive versus corrective: the difference in practice

Preventive mould maintenance follows a schedule based on the number of production cycles. Typical intervals are 50,000, 100,000 or 250,000 shots, depending on the mould’s complexity and the material being processed. At each interval, you carry out a set of fixed inspection points.

Corrective maintenance takes place following a breakdown or quality deviation. That sounds reactive, and it is. The mould is out of action, production stops, and the repair costs are higher than with planned maintenance, because urgency always comes at a price.

What we check during every maintenance service

A full mould maintenance service is a structured inspection. These are the standard points of focus:

• Mould walls and core surfaces: scratches, erosion or caked-on plastic residues that affect dimensional accuracy.
• Cooling channels: flushing and cleaning to remove limescale and plastic deposits.
• Ejector pins and plates: lubrication, alignment and wear on the pin heads.
• Ventilation: cleaning of ventilation slots to prevent burn marks and incomplete filling.
• Seals and O-rings: replace during every major service.
• Mould-closing surfaces: damage here leads directly to flash formation on the product.

Repair following damage: what the options are

Not every instance of mould damage requires replacement of the entire mould. Minor scratches and erosion are welded and filed down. Damage to core sections or sliders may require replacement of a specific insert, not the entire mould.

Mould maintenance and product quality are directly linked

A well-maintained mould produces consistent results. Dimensions remain within tolerance, the surface is free from defects and cycle times remain stable. Quality complaints received by can, in most cases, be traced back to delayed or inadequate mould maintenance.

Would you like to find out more about our mould maintenance and mould services?