5 M’s of Molding Revisited

Plastic injection processing can be a real challenge. Our goal of 100% efficiency, zero scrap and repeatable processes can sometimes be hindered by poor set ups or changes in the molding process.

In the past, I wrote a series on the 5 M’s, which are: Man, Mold, Machine, Material, Method . Over the years, I have developed two separate 5M systems. One applies to auditing mold changes before start up. The second applies to troubleshooting changes within a validated process. This article will explain the applications, and how they can be used to consistently identify and correct molding problems.

SET UP: Man, Mold, Machine, Material, Method

This 5M configuration is used when auditing a mold change before start up. It serves as an outline for the entire audit process, and when repeated every time a mold change is audited, it helps to prevent poor set up from leading to poor start up events. Here is the steps taken for each:

MAN: Man applies to area set up and notification of the supervisor that the press is about to start. This gives the supervisor time to schedule the operator and get them into place when parts start moving down the belt. Cell layout is verified as being correct for the new job. All old packaging, labels, components are verified as removed from area, and all needed components are confirmed to be in place.

MOLD: It is now time to inspect all stages of the mold set up. The mold should be clean, and ready to start. Clamp speeds should be verified. Mold components should be inspected for damage, and proper working condition. Water should be verified as on, and hoses checked for proper placement and flow. Low pressure close should be verified. Hot runner cords should be verified as properly connected, and hot runner and mold temperature set points and actuals should be verified. Verify core hook ups and operation. Verify valve gate hook up and manually operate to assure readiness.

MACHINE: Machine refers to all mechanical, including auxiliaries. Verify correct robot End of Arm, and that robot program is loaded. Check any and all auxiliaries for readiness and correct operation. Verify dryer is on and at correct temperature. Verify the correct tip is installed.

MATERIAL: Verify the correct material has been loaded, and that no other materials are present. Verify color feeders are set properly. Verify the press has been purged thoroughly, and is ready for operation. Verify barrel temperatures are correct, and actuals match set points. Verify material purged looks clean, and doesn’t exhibit signs of moisture.

METHOD: Method refers to process. Process should be verified to the set up sheet that was developed when the process was validated. At a minimum, temperatures, shot size, transfer position, hold pressure and injection speeds should be verified as correct.

TROUBLESHOOTING: Man, Mold, Machine, Material, Maintenance

When troubleshooting, the 5 M’s change slightly. Method is exchanged for Maintenance. There is a reason for this. The first steps of troubleshooting is cleaning/ inspecting the mold and verifying that the process (Method) is correct. This should be automatic. Once completed, the 5M’s again come into play.

The same inspections are performed as noted earlier in the article, only now the processor is looking for what has changed. Is the operator causing a defect? Has something changed with the mold? Could a change have occurred with the material we are using? Is the press functioning properly, or do I need to get maintenance involved?

Using the 5M’s, we are given a direct path for inspection that is thorough and improves our ability to quickly audit or troubleshoot problems and poor set up practices. As we develop our approach, our auditing practices become stronger which reduces down time and scrap events. Tools such as this not only improve our odds of success. They improve the profitability of the companies we represent.

Plastic Injection Expert Network