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How to successfully train your injection molding processor

Garrett MacKenzie

March 11, 2016

7 Min Read
How to successfully train your injection molding processor

For some time now, many plastics companies have struggled trying to find well-trained processors. The ideal candidate has a wealth of knowledge in a variety of molding skillsets. It may seem as though the “jack-of-all-trades” technician has faded from our industry, but the truth is that this type of individual is developed over a long period of time. This article outlines a series of steps to develop and train your current and future processors.

The plastics industry has grown exponentially in the last few decades. Many training programs are available to us, but in reality these forums can be narrowly focused toward various tasks or abilities that a processor will need to perform certain functions required in his job. The purest training core for any technician comes from the training he receives in the position he holds. Outside training merely complements the core training he receives in his work environment. For a processor to have strong technical knowledge, he must be exposed to nearly all departments within his working environment. The following sections outline specific departments and training that your processor should be exposed to, and the benefits of a long-term training approach.


One of the best ways to troubleshoot problems within the scope of production is to understand the requirements of the operation itself. A technician should be able to perform every task that the operators are responsible for carrying out. Place your processor in every position within the framework of your production line. This gives him the ability to understand what the physical/ mental requirements are for each position on the floor. With this knowledge, he is better able to evaluate and control production needs as he addresses various technical problems. In addition, it also allows the technician to experience the true nature of the operations he is overseeing. This type of hands-on training can potentially produce continuous improvement opportunities. The technician better understands what the positive and negative actions are for the operator responsible for the task. With this knowledge and experience, solutions are more apt to be based on wisdom rather than supposition.


The quality system of your plant is an important key variable to the overall success or failure of your molding facility. As such, it is critical that your processor have a full understanding of how your quality system operates. In addition, quality requirements for every job need to be fully communicated to the processor. Training should include several days to a week of shadowing auditors, reviewing reject histories and learning what defects are most common to each job. In addition, it is important for the processor to be fully versed in each part’s aesthetic, dimensional and fit-to-function characteristics. A good processor quickly identifies problems and uses the best approach to alleviate them because he has a solid understanding of the quality system. Make sure that your technician has the ability to read blueprints, use inspection measuring instruments and is familiarized with all of the testing equipment used in your plant.


It is vital that your processor understands the entire material side of molding. Quite often, poor material handling or malfunctioning dryers are the root cause of troubleshooting events. Material suppliers often offer classes to equip those attending with solid training in all aspects of the material operation. It is important that your tech understand material drying, contamination, dryer operation, dryer throughput, filtering and so forth in order to be properly able to diagnose material-related errors. A processor with no material handling background will often struggle because of a lack of understanding material properties and procedures. It is highly recommended that your processor be trained thoroughly in the material-handling procedures of your plant, so he can best utilize material personnel effectively. In addition, use your maintenance employees for training purposes regarding the proper preventative maintenance and troubleshooting of all material-handling equipment and dryers. Use your senior processors to teach proper machine start-up and shut-down procedures to prevent poor starts related to improper material usage.

Set up

It is hard for any processor lacking set-up experience to diagnose/troubleshoot problems that stem from poor set-up procedure. It is imperative that your tech have a strong skillset in performing mold and equipment changeovers. An effective technician can easily identify changeover-related issues because he has hands-on experience of how the mold should be set, watered and so forth. In addition, this gives your technician a firm foundation by ensuring that he is aware of the faults and quirks of each individual machine and mold. For instance, a mold could require a specific knockout pattern to perform properly, or reversing a supply-and-return water line could limit water flow due to a baffle system. By performing the set-up tasks required for each tool, and implementing all of the associated auxiliary equipment, the technician has a solid foundation of knowledge that will improve his ability to troubleshoot problems. Even if you have hired an experienced processor with years of experience in another facility, it is important that he be introduced to your organization and has spent time setting up the molds and machinery for which he is responsible.


Processors can receive invaluable training by working as part of a maintenance team for a couple of weeks. This gives them the opportunity to develop strengths that can help them to troubleshoot various equipment-related issues they might come across as they perform the duties of their position. A strong processor has the ability to pinpoint various machine malfunctions by understanding the symptoms of the machinery. This also helps him to more efficiently communicate press/equipment problems to the maintenance department, thus streamlining maintenance’s approach toward finding a solution. In addition, maintenance has the best understanding of what preventative maintenance procedures are required for the molding department. By including your technician in the preventative maintenance schedule, this reduces the workload for maintenance personnel and puts a person in place to quickly identify low oil, worn hoses, oil leaks and other issues.


One of the strongest requirements within the processing skillset is a solid understanding of the molds in house. Use your moldmakers to develop your processor’s tooling strengths. One of the best ways to do this is to put your processor in the tooling department for a number of weeks and receive training in disassembly, cleaning and assembly of the molds. This type of training helps to develop the processor’s understanding of the molds he is troubleshooting and can help him to develop an understanding of the most common tooling problems associated with individual molds. In addition, give him some exposure to small repairs, such as replacing broken pins and masking off/sandblasting texture, so he can build himself mentally and be able to recognize opportunities on the floor for in-press mold repair. In addition, it imparts a better understanding of what each mold component is for, as well as the unique identifiers for each component (such as heel blocks, support pillars and such). This will improve his ability to communicate tooling issues to the moldmakers for better and more complete tooling repair or modifications.

Tool design

Not all facilities will have a tool design department, but if the opportunity is available, let your processor spend some time with your design team. Having a better understanding of how tools are made and the design features that affect molding properties is a great asset to any processor’s portfolio. For instance, support pillars are something a designer may have to improve if a situation arises where high pressure is causing a plate in the tool to flex. Molders may also benefit from a basic understanding of Moldflow, another tool used by designers to calculate material flow and watering applications. By giving your processor exposure to the different facets of designing, he will be better able to make suggestions regarding potential tooling modifications that may help in particular molding situations.

All in all, there is a vast assortment of training tools available within the confines of your facility that can exponentially benefit the progressive training of the processor you are developing. Take advantage of the tools and expertise that exist within your overall manufacturing unit. There are many different venues outside the plant that can offer specific training approaches. But, overall, the real education comes from within the walls of your plant. By consistently exposing your processors to the various skillsets within your plant, over time you will build weaknesses into strengths. Develop a complex skill matrix that outlines the skillsets your technical support team needs to possess, and then use that matrix to plan a training approach specifically tailored to each of your processors. As the technical background of your team matures and grows, so will your profits and efficiency.

Garrett MacKenzie is the former owner and editor of www.plastic411.com. Mackenzie started in plastics at the age of 19 as an operator, eventually moving up through the ranks to engineering over a 29-year timeframe. He currently works as a plastic injection consultant in engineering and training capacities. He can be contacted at [email protected].

About the Author(s)

Garrett MacKenzie

Garrett MacKenzie is the owner/editor of plastic411.com and a consultant/trainer in plastic injection molding. He has provided process-engineering expertise to many top companies, including Glock, Honda, Johnson Controls, and Rubbermaid. MacKenzie also owns Plastic411 Services, which provides maintenance and training support to Yanfeng Automotive Interior Systems, IAC, Flex-N-Gate, and other top automotive suppliers. He was inducted into the Plastics Pioneers Association (PPA) in 2019, where he serves on the Education Committee evaluating applications from college students seeking PPA scholarships. You can reach him via e-mail at [email protected].

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