Here at PlastiCert, we perform maintenance on each mold after it has seen duty on the production floor. It is fortunate for us that we have a mold shop in house, as then time and availability is not an issue. It also alleviates some of the lessor known trappings of mold maintenance.
One of the biggest is the mold’s suitability for use itself. Reflecting back to the mold’s original design and build work, the goal at hand is to craft a mold that, when it functions correctly, will make the molded part(s) correctly. That is usually the case if both the mold shop and the molder are under one roof. If they are separate organizations, sometimes the mold shop can get fixated on crafting a mold that functions the way it was designed, with molding the part the afterthought. Such a scenario commonly results in modifications and refinements to achieve a molded part to specification.
After approval and release, post part production the mold will be maintained, going through various levels of clean up and preservation. Before putting the mold back on the shelf, we treat it so that oxidation does not set in before its next use. Sometimes, the mold maintenance function, being removed from the molding floor, can result in viewing the mold from a functioning perspective rather than a molding perspective. The mold technician will focus on the moving and interfacing parts to ensure adequate clearance and lubrication. Tunnel vision can develop and the goal of having a mold ready for the next molding run can morph into the goal of having a, no interference, well moving, greased and preserved mold sent to the shelf. Too much grease and preservative can result in a longer set-up in its next run due to the parts being contaminated. Contacting surfaces can move well but parting lines can get eroded and plastic flow altered.
So next time you are auditing or evaluating your supplier’s molding process, include the mold maintenance function. Assure yourself that the focus is always on molding good parts rather than making a mold that opens and closes well.
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