Posted by Paula Hynes | 03 / 24 / 15 1 Comment

A Low Maintenance Approach to Mold Care

 "The time and care you invest in upfront maintenance will keep costly repairs at bay."

 Let’s face it, our parents were right.  Take care of your things, and they will last a very long time.  It was a matter of necessity.  Back in the day, products were made well and made to last as long as you didn’t abuse them. The same is true in a manufacturing environment.  Take care of your equipment, and it will take care of your production needs for a long time. 

 In the plastic manufacturing environment, the key to consistent quality parts is to start with a quality, well-made mold. We call this our “low-maintenance” approach to injection molding. We begin the process with a solid mold design and a high-quality tool build.  We run prime resins on some of the best machines available.  All of these factors impact quality.  According to Lowell Allen, Sr. Vice President of Manufacturing at The Rodon Group, “When running a 24/7 operation, you can’t afford to have shoddy workmanship.” In order to maintain part quality, it is imperative to maintain the plastic injection mold. When you consider what a mold experiences throughout a processing cycle, there can be some wear and tear.  It is important to perform regular mold maintenance to offset the daily strains that can take place.  Molds may make thousands of cycles throughout the day.  Regular maintenance will keep your mold running at optimum performance levels.  Some companies may ignore regular checks and only respond when a problem occurs.  This downtime can be costly and impact production commitments, as well as customer relationships.

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How Much Maintenance Makes Sense

Like any piece of machinery, there are certain mold components, including leader pins and bushings that should receive special care and attention on a regular basis.  By having a maintenance plan for each mold, you can avoid costly delays and product defects.  The plan for each mold may vary based on the number of cycles, cavities, mold material and the material being processed.  At Rodon, we have molds that run continuously.  These molds are pulled every four to six months for maintenance checks.

The base metal used to make a mold impacts mold maintenance. Molds made from softer metals, like aluminum, do not demonstrate the wear resistance of steel and are more inclined to need maintenance if they are used to run at high-volumes.  Molds made from heat-treated (hardened) stainless steel can withstand a high-production environment. In addition, certain materials, particularly those that are abrasive or require higher temperatures or pressures to achieve proper flow, can put additional strain on a mold.

Mold size and complexity may also warrant a more rigorous injection mold maintenance program.  Molds that have higher cavitations or more complex processing mechanisms such as cams or core-pulls may require more frequent maintenance checks. Monitoring part quality will let you know if maintenance is needed. Hot runner molds have a history of requiring more upkeep.  The heating systems must be monitored to ensure proper temperatures are maintained throughout the mold. Hot-runners have many more moving (and heated) parts that include valves, manifolds and heating elements.   If a gate becomes blocked, maintenance is required.

Maintenance Basics

There are certain checks and procedures that should be performed as part of the regular maintenance of any mold.  The plates should be examined for any dings or burrs and should be re-surfaced as needed.   Of course, part quality is a great indicator of required maintenance.  Part dimensions will tell you if there is some level of wear or damage to the mold.  Mold cavities and gating should be visually inspected for wear or damage.  The ejection system should also be inspected and lubricated along with any cam slides, leader pins and bushings.  All surfaces should be cleaned with a solvent to remove any dirt, and all water lines should be flushed and drained to remove any excess moisture.  At The Rodon Group, we use only non-toxic lubricants and cleaners.  No hazardous chemicals are used in the plant. LowellAllenquote

Maintaining a Mold in Storage

Molds should get a thorough maintenance review prior to storage.  Once the mold is removed from the machine, all plates should be separated and cleaned.  The ejector system, cam slides, leader pins, ejection pins, sleeves and bushings should be cleaned and lubricated.  Replace and/or repair any parts, such as ejector pins, worn bushings or leader pins. While this is a time- consuming process, this investment will pay dividends in the future.  The goal is to preserve the mold in the best possible condition.  The mechanisms should be able to be put back into service with minimal effort if the storage maintenance is done properly.

Special attention should be made to the cooling system.  It should be checked for leaks and thoroughly cleaned and flushed.  The system should be checked for calcium build-up and drilled out if any exists.  Calcium can insulate the water lines and cause poor heat exchange.  At The Rodon Group, we treat our water to keep minerals in suspension, so they don’t precipitate out and clog the lines.

Mold surfaces should be checked as well to insure the production requirements are maintained.  Some surface features can become worn or damaged and should be checked and repaired if needed.

Once the mold and its component parts have been reviewed, repaired, and resurfaced a lubricant can be applied.  Molds that are not made from hardened stainless steel should also receive an application of a mold saver.

Avoiding Costly Maintenance Issues

A strong offense makes the best defense; this is also true in mold making.  While maintenance must be done on a regular basis, the goal is to minimize the amount of required upkeep.  To accomplish this goal, molds must be built to exacting standards using only the highest grade steel available. 

We know that things can and do go wrong; however our goal is to minimize any production interruptions by building in a “low-maintenance” approach to our molding processes.  We use only the highest grade materials in our molds.  They are built by master craftsmen with an average of 20 years of tool making experience.  Our facilities are kept clean of dirt and debris.  We use only non-toxic colorants and resins.  We run FDA-regulated products and use resin sources that are certified by FDA, RoHS, REACH and NSF. 

 “As a custom molder, we must be ready to run a mold at all times. We could pull a mold on Monday and get a call on Thursday for more parts.” says Allen.  “Keeping our molds and facilities in top shape allows us to meet the needs of our clients quickly. We build quality into all of our molds, and the materials we use demonstrate our commitment to maintaining the highest standards in the industry.  In fact, we have a 72-cavity mold that has been in continuous operation for nearly 15 years.  If you build with the best stainless steel and perform regular maintenance, a quality mold can perform for decades.”

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Topics: Plastic Injection Molding, Injection Molding Basics


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