Mold cleaning is a key process in mold maintenance and also a bottleneck that restricts mold maintenance because the mold manufacturing and development speed is much faster than the mold cleaning speed and the mold is ready for the next production immediately after the quick cleaning The time left for mold cleaning was quite limited, and a survey of the factory found that the molds arranged in the corridors and in the shop almost filled up the limited room for the shop, just waiting to be cleaned.
Some companies reset the mold directly after the end of a production without any cleaning treatment and continue to use it for reproduction.If the plastic parts produced are clean, then there is no problem with the operation of the mold.Over the course of time, Will form a kind of 'temporary fire-fighting' cultural concept. Only when the accumulated residue in the mold affects the quality of the part or the mold is worn, it is necessary to clean the mold. The cleaning process is just an incident.
When cleaning and repairing molds, some factories hire some junior mechanics or apprentices in the mold shop to do some miscellaneous cleaning of molds and molds, and then the molds and templates are separated by service technicians, but in fact, Molds and templates also flush out track marks, which creates difficulties for service technicians to find and correctly repair defects in molds and parts.
Indeed, cleaning the mold does not require the skills of a high-level mold-making mechanic, but it is totally unworkable to get a mold-cleaning job in the hands of a novice unfamiliar with the mold's special features and flaws, or without knowing the critical sealing area of the mold. Because the unreasonable distribution of mold cleaning work will lead to the continuous production of mold with performance defects, but also due to the increase in the seam, burrs, corners, premature plating or steel displacement and mold mix, but also will be substantially Increase the mold budget.This kind of problem often originated in the 'temporary fire maintenance' culture of maintenance, never monitor defects or accounting and find out the root cause of the problem.
Standardized cleaning procedures
Systematic mold maintenance is based on consistency of maintenance requirements and maintenance operations To achieve the 'cost-effective' goal of cleaning the mold, care must be taken to: Develop a detailed mold cleaning program When cleaning different parts of the mold, Such as the press internal cleaning, along the edge of the wipe, conventional cleaning, the main part of the cleaning, cleaning methods used are also different.
After the mold runs for a certain period of time and after appearance tests such as electroplating abrasion, track marks and mold residue in the vent and non-vent areas, etc., the technician can determine the procedure and the frequency of the mold cleaning by visual inspection Therefore, It is important to understand the cycle of safe operation of the mold and to archive the observation reports of accumulated build-up of debris and wear inside the mold.
All molds should be documented with relevant maintenance procedures and maintenance intervals, based on the mold's specific operating cycle.Generally, internal grease levels and gear broaching are controlled, the slider, internal pins and bushings and other movements are controlled Other factors affecting production include contamination or blockage of the water line and sprinkler, manifold leaks, rust and corrosion due to water leaks or condensation, and others.
What kind of cleaning is enough?
Often, grime or residue (with some chemical composition and physical properties) is often left on the mold when the forming operation is completed. The final cleaning requirements are not the same for different types of residues. Like polyvinyl chloride This type of resin produces hydrogen chloride gas that can attack many types of tool steel.
Other residues are separated from flame retardants and antioxidants that can cause corrosion of the steel, and some pigment colorants rust the steel and make it difficult to remove the rust. Even ordinary sea water, if placed In the untreated mold surface too long, the same will cause damage to the mold.
Therefore, the mold should be cleaned according to the established production cycle.Every time the mold is removed from the press, you first need to open the mold pores to remove all the mold and template non-critical areas of the oxide dirt and rust to prevent its Slowly corrode steel surfaces and edges. In many cases, uncoated or rust-prone mold surfaces quickly reappear even after cleaning, so even if it takes a long time to scrub the unprotected mold , But the surface rust can not be completely avoided.
Nowadays, many molds come with 'self-cleaning' vent lines that have a high degree of gloss and are cleaned or polished to achieve polishing of SPI # A3 or through milling Grind or grind and discharge the residue to the trash area of the vent line to prevent residue from adhering to the surface of the roughing stand. However, if the operator employs a coarse-grained brush, emery cloth, sandpaper, whetstone or belt Nylon bristles, brass, or steel brushes that artificially grind the mold can cause excessive mold cleaning.
In general, when the mold surface is subjected to high-pressure pulverization and cleaning using hard plastic, glass beads, walnut shells and aluminum pellets as abrasives, if the abrasives are used excessively or improperly, the grinding method also causes the mold Surface porosity and easy to attach residues on it, resulting in more residue, wear, or lead to mold premature rupture or flash phenomenon, but more not conducive to mold cleaning.
Therefore, by looking for cleaning equipment suitable for molds and processing processes, and by referring to the documented cleaning methods and cleaning cycles in the archive, it is possible to save over 50% of the maintenance time and at the same time reduce the wear of the molds.