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Identifying relevant data collection points in the injection molding process is a key step in calculating true production efficiency.

Garrett MacKenzie

March 9, 2024

4 Min Read
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gorodenkoff/iStock via Getty Images

At a Glance

  • Properly quoting material part weight and minimizing waste is vital to plant profitability
  • A plant’s primary goal is to keep all machines running as much as possible
  • Scrap is one of the strongest inhibitors of full efficiency

Plastic injection molding is a complex business. There are many different data measurements that are key to determining success or failure on the production floor. Many companies fail to understand which data provide the best analysis key points, and that can lead to long-term failures. This article will identify the data collection points that best identify system failures. It will also recommend approaches to recognizing system failures and explain how to adjust and improve production scores.

Overall efficiency

True efficiency is determined by multiple data measurements that either benefit or detract from a production run. It is the primary measurement of a plant that establishes whether a company is succeeding or failing to perform well. The categories below are the key determining factors to calculate efficiency.

Quoted cycle

When quoting work to a customer, it’s critical to properly explain how much machine time will be required to produce parts to satisfy the customer’s timing requirements. Failure to meet deadlines not only places the customer requirements in jeopardy, it adversely affects a company’s ability to accurately schedule work. If a quoted cycle can be improved upon, plants reap efficiency rewards, and this also improves a company’s ability to improve scheduling procedures.

Material utilization

Properly quoting material part weight and keeping material waste to a minimum is vital to plant profitability. Poor material changeover practices and purging also are detrimental to a company’s success. Poor cleaning procedures of material-handling equipment negatively affect overall material utilization. Track all material usage accurately and effectively. Material shortages caused by poorly tracked material inventories lead to unnecessary mold changes and unplanned down time.

Machine utilization

Idle presses are profit stoppers! A plant’s primary goal is to keep all machines running as much as possible. Scrap and down time seriously inhibit press profitability! Unplanned maintenance is another example of machine time loss. Focus on reducing mold changes, drastic color changes, poor scheduling strategies, and large scrap events to improve machine utilization.

Labor utilization

Operators misused to perform production duties seriously hamper overall efficiencies. Be sure to plan operation strategies to effectively utilize the operators in your plant. When situations occur that limit your work force from performing production work, use them for housekeeping, part inspection/rework, and plant improvement to effectively streamline plant performance strategies. Plan labor utilization in advance whenever possible to ensure that your entire workforce is being used effectively.

Scrap

Scrap events are by far one of the strongest inhibitors of full efficiency. There are many different scrap factors that will lead to production instability. Startup scrap can sometimes occur due to poor changeover procedures. Improper mold changes lead to poor startup. Large scrap events that occur during startup can lead to poor overall profitability. Scrap also has a monumental effect on machine time. Presses producing large amounts of scrap adversely affect a company’s ability to meet customer demands and complicates scheduling. Scrap also triggers rework events. Operators must be used to reinspect parts on hold, which damages labor utilization numbers.

Yield

Production yield calculations determine machine efficiencies after scrap. If production efficiencies are at 103%, but scrap rates are at 10%, final yield is only at 93%, a clear indication that the production system has failed. Machinery that is not running at 100% capacity is not performing to the best of its capability and strongly affects a cell’s performance rating.

Production data is a clear and proven indicator of overall plastic plant performance. Failure to clearly analyze and respond quickly to this data can lead to poor, if not failing, plant systems. Quickly reacting to system data will lead to successful growth within your overall manufacturing system. Take the time to evaluate, respond to, and monitor the manufacturing process. It will give you all the tools you need to achieve success.

Got a problem with this, that, or the other thing? You might find answers in some previous "Troubleshooter" columns:

How to Identify and Correct Shear-Related Splay Defects

The Role of Moisture in Injection Molding Splay Defects

Preventing Flash in Injection Molded Parts

How to Prevent Common Failure Modes in Injection Molding

Building a Validated Plastic Injection Molding Process

Fixing Color Defects in Injection Molded Parts

Key Steps for a Stable Injection Molding Process

Fundamentals of an Injection Molding Plant or Cell Startup

What to Consider When Buying an Injection Molding Machine

The Troubleshooter: How to Prevent Mold-Change Failures

Fundamentals of Injection Molding Press Startups

Preventing Speed- and Time-Related Defects in Injection Molded Parts

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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