Tooling Product News

The Eight Stages of Efficient, Accurate Mold Repair

By Steve Johnson

Understanding the value of order in your mold maintenance plan.

While the mold was still being disassembled, two cleaners began pulling tooling out of plates and putting them into buckets in preparation for a good scrubbing—and I mean a scrubbing. Immersing the buckets into a solvent tank, they used their hands like wire whisks as they swished the close tolerance ejector sleeves around, effectively removing any trace of vent residue or track marks on the tooling—and in the process—maybe adding some of their own.

Gone were helpful clues for the repair technicians who had yet to begin troubleshooting and analyzing mold performance and wear. So now, how will they determine if the 63-day production run was too long? If the leader pins, bushings and interlocks were greased properly during the run? And how will they know if all the swishing during cleaning did not create any dings in the sleeves that could be blamed on something else instead of poor cleaning practices? And other questions like does the mold still have excess vent residue in the top right quadrant? Were all the ejector sleeves numbered and in the proper mold position before they were removed?

A seemingly little thing like working out of sequence can foil our best efforts before they begin. Mold maintenance must follow a plan.

Structured Sequence Serves a Purpose

Structure is another word I don’t care for, but it seems to be required in most everything we do. Mold design, mold building, molding parts and yes, mold repair.

For the individual technician, working in a structured approach has several intuitive benefits that are good habits to form and critical to daily shop efficiency and mold performance:

Reduces mental mistakes by working the same format day in and day out.
Improves troubleshooting skills and accuracy.
Reduces repair time through better optimization of equipment—no bottlenecks.
Faster, easier and more thorough training of new technicians.

In mold repair—or anything mechanical that gets used or run, thus worn or broken—structure is critical when working with many pieces of close fitting tooling that are nested into plates.

The type, fit, relational position and shear volume of tooling in some molds can be overwhelming enough without becoming confused on where you are in the process of the repair.

Stages of Repair

Below is an overview of the eight stages of repair, the critical elements of each and a flow chart that demonstrates the order.

PM Preparation
A critical part of any mold maintenance plan provides the technician a historical summation of past issues and corrective actions so they may be aware of long standing or unsolved issues during repairs.

Some technicians skip this first stage entirely until they get a mold disassembled, or stopping in the middle to research a problem whenever they see or feel something they don’t like.

For instance, if you remove 16 ejector pins from a mold and notice that one or two of them feel tight, will you remember which ones were tight later on when you are perusing past records and discover that galling pins have been a problem for the past five production runs? Knowing this information before you split or disassemble a mold removes some of the guesswork involved in root cause analysis.
Mold Disassembly
Molds should never be arbitrarily disassembled without a specific level in mind. To do so is to invite excessive tooling component handling or over-maintaining a mold, which increases the opportunity for damage along with excessive non-productive man hours. Time based (cycles, hours, days or parts produced) mold disassembly levels should be established and practiced.

Three disassembly levels are typical in the industry, with a fourth sometimes being a complete mold rebuild. Those usually practiced are Wipe-down, General and Major.
Troubleshooting
Accurate and efficient troubleshooting past and current defects is based on a repair technician’s ability to understand and relate existing processing/production conditions (tooling wear marks and residue characteristics) to historical data. Issues should be segregated (long gates, specific flash etc.), investigated then corrected one at a time.
Corrective Action
Effective, reliable and professionally implemented corrective actions are factors of a repair technician’s background, experience, and current shop culture and skill level. As problems are addressed and resolved, the troubleshooting and corrective actions stages work hand-in-hand until all issues have been resolved or a next action determined.
Cleaning
Now is the time to clean tooling. Put away all measuring instruments, and hand tools and focus on how best to clean. The type, frequency and method of cleaning molds should be based upon mold-specific factors that will dictate the cleaning process.
Assembly
Accurate mold and tooling component assembly is a critical step in mold repair and is from where many preventable, unscheduled mold stops (breakdowns) are generated. Poor workmanship and mistakes are usually a result of too much speed, lack of focus or physical skills and disorganized work habits. Also, if there are several repair techs involved of the assembly of the mold, communication can break down requiring the mold to be disassembled yet again to correct an over-site, or install something that was forgotten.
Final Check
Before any mold is released for production, it is imperative to put the mold through a series of final check procedures to verify an all systems go approach to minimize any opportunities for the mold to be stopped and returned to the shop for something that should have been caught before it was released, or blue-tagged.
Staging
After a mold has been either cleaned, repaired, changed over and final checked, it needs to be given a new status then moved to one of three areas, usually racked (holding/storing area), reset in the press or staged as a back-up mold in a molding cell operation.

Summary

Mold repair stages are absolutely sequential and should not, as a practice, be mixed up. Actions required and taken in each of the eight stages depends on the preceding stage for accurate data needed for clear objectives in subsequent stages so that information learned in one area can be applied in the next.

Working in a systemized, staged manner promotes a professional approach that rewards technicians with more efficient, effective and consistent results and ultimately higher profits for the company. Try it—you’ll like it.

For more information from MoldTrax call (419) 289-0281, e-mail Sales@MoldTrax.com, visit www.moldtrax.com or visit www.moldmakingtechnology.com.

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