Basically, changeover refers to the time spent not running a processing line because the product has changed in some way. Regardless of the reason, changeover takes time, and, therefore, costs time and money. If a company can improve changeover activities, its production costs will be reduced. The difficulty is how a meat-processing enterprise systematically implements changeover improvements.
Improving changeover is more complex than some other Lean methods. However, changeover is becoming more frequent as customers demand smaller portions, deli sliced meat from processors, re-sealable packages and varying recipes and formulations. These market influences will not diminish, however, the future of long production runs is diminishing for many processors. For them, improving changeover efficiency is the way to maintain or increase profit margins.
Not all changeovers are the same. The goal for changeover efficiency and effectiveness, however, is always the same. The goal is to resume production quickly after the line is shut down or slowed down for changeover. Given this important and basic goal, the following fundamental principles may lead to improved changeover.
The first principle is to start changeover before ending the current run. This sounds difficult or perhaps even unusual. But numerous engineering studies have confirmed the first step to improved and shorter changeover is the staging of materials and equipment prior to needing them. Moreover, some clean-up and preparation can occur while the equipment is running. If your line or plant is like many others, preparation and transport of new film, labels, equipment and boxes waits until the current run is done. This practice is inefficient. A more efficient method is to have “milk runs” of needed materials brought to the immediate area. Stage equipment for disassembly and assembly in efficient ways to reduce changeover time and increase productivity.
An overall Lean tool that can help with staging and changeover preparation is 5S, which is shorthand for every tool or part having a place and being efficiently arranged for use. This tool enables meat processors to have a place for springs, screws, washers and gaskets for both disassembly and assembly. The arrangement of tools, equipment and materials will certainly reduce the time it takes to changeover a production line. The key is to have what you need, where you need it. Hunting for parts or tools can use up significant minutes and that is not efficient.
The second fundamental principle is reduction of variance. Sure, there will always be variance in any process; less variance, however, is always better. Care must be applied to assure adjustments can be made accurately and repetitively. Effective deployment of this principle on production lines starts with the actual changeover.
For example, changing from a 4-oz. ground-beef patty run to an 8-oz. patty requires changing the die or plate. Additionally, the larger patties require a larger box and a new label. To reduce variance in the product, ensure the 8-oz. plate is registered precisely. Scribe marks, torque wrenches and other methods can be used for precise registration. Precision, of course, is gained from a standard. The precise registration points are found by trial-and-error or plug-andplay. Once found, however, let’s assure that each and every operator can adjust and register equipment based on the standard. Registration marks can also be used for the adjustment of the box-making or handling equipment. The labeler will require adjustment settings that are clearly marked.
In all the plants I’ve worked in, I have found more variance in label settings than any other piece of equipment. I watch operators move the label down a bit then run some boxes or product through. Then they move it up a bit a check the effect. This trial-and-error method is inefficient. Settings on the equipment for specific type and size of labels must be clearly marked. Moreover, some cleaning at the time of changeover can also help reduce defects.
Lastly, train and coach people to work together to beat a time or quality goal during changeover. In short, preparation and variance reduction will not stick if operators and technicians are not encouraged to continuously improve the changeover process. This principle of training and coaching requires leadership from the line leaders and plant managers. Make goals visible to all. Encourage operators to find even better ways to changeover. If changeover is reinforced as an important skill set, then operators will pay attention and help the entire enterprise reduce costs and gain capacity.
Long runs certainly produce product at a more efficient cost per unit, however, long runs don’t seem to be the future of many meat-processing companies. In plants where changeover is a fact of life, these tips can improve efficiency and reduce costs. •
Dr. Glen Miller is Senior Lean Consultant for Performance Essentials, Inc. More information can be obtained regarding Lean Manufacturing at www.performanceessentials.com.