Good quality is making the right product (i.e., one that meets the established product specifications) the first time. Defects and waste are the results of failing to produce top quality products. Even a well-run manufacturing operation will have occasional issues with defects and waste. However, defects and waste above 0.01% to 5% are excessive and should be avoided. Defects and waste in manufacturing are two primary challenges to eliminate.
Let’s be clear about what each of these terms mean. “Defects” are products that do not meet the customers' quality expectations. Rusted metal parts, a scratch or dent, etc. “Waste” means excess material waste up to whole products needing to be removed if they cannot be repaired. There are “7 wastes” in manufacturing, which we will cover in a different blog.
3 Steps to Reduce Waste in Manufacturing
The steps presented here will significantly reduce defects and waste in manufacturing if implemented correctly.
1. Monitor Your Raw Materials
The end product is only as good as the material used to make it. Warped bamboo cannot be made into high-quality utensils no matter how well the other processes are running. Factories must have a robust incoming material process to inspect and verify incoming materials, keep them in appropriate conditions, and use those raw materials during their “shelf life”.
There are two elements to this process: the factory and the supplier. On the factory side, purchasing must be clear on the standards, dimensions, and grade of all materials it purchases. The supplier cannot be held responsible for the material for which it did not have the correct specifications. That said, the supplier should be held accountable for delivering the material to the specification. Remember, never accept bad quality and never pass it on.
The second part of monitoring your materials is ensuring they are used during their shelf life. Wood rots, metal rusts, and plastic can warp, especially if they are stored under the wrong humidity and/or temperature levels. If materials are not used within their shelf life, they are far more likely to create defective products or become a complete waste. Both options are expensive and unnecessary.
2. Maintenance of Equipment
Take care of your equipment, and it will take care of you. Maintenance is vital to any manufacturing operation that depends on equipment and is the priority of everyone involved in production. There are two types of maintenance: preventative and breakdown maintenance. Breakdown waits for something to happen (usually a breakdown) to fix the problem, while preventative is routine and keeps the equipment operating even when it may not seem like it needs it. Most factories have been in reaction maintenance, but few have a vigorous preventative maintenance program.
The purpose of preventative maintenance is not just to ensure that there are no breakdowns (which impact production capacity) or to increase the equipment's lifetime. It is to ensure that the equipment is performing its function as intended. Here are two examples:
An auto parts maker had a problem with gas tanks that did not seal properly. The welding equipment system worked (no breakdown), but there was a bit of slag that was not cleaned off after repeated use. The slag prevented the welding equipment from making a proper seal. The problem was addressed by adding cleaning to the maintenance activities.
The eyeglasses maker had many defects, and we traced them back to CNC machines. It turns out that the workers never sharpened the blades, so they became dull, leading to more defects. When asked why they did not perform this maintenance, the supervisor said, “Steel is harder than plastic, so there is no need to sharpen.”
Maintaining equipment properly prevents defects from occurring during production and prevents the waste that occurs when a machine breaks down. It is also a cause of low efficiency.
3. Create Work Instructions
Experienced workers are vital to any company's operation; however, no manufacturing operator should do their job purely through experience. Standard work instructions remove the guesswork from production and show operators exactly how to do their job and what the expected outcome should be. Perhaps more critically, it shows local leaders what the work standards are, and they can ensure people work to the standard.
Defects are often caused by non-standard work. Operators that do not know precisely what and how the product they are working on should look will give their best guess on if the product is correct. They may be correct often, but the odds of defects and waste are much higher.
Remember how we said earlier that you should not accept or pass on bad quality? That applies to the production process as well as raw material intake. Work instructions show not only how the product should look after the operator completes their work; it will how the product should look when he or she receives it.
Operators often continue to pass on defective products to keep the line moving. Non-conforming products should be removed immediately, and the process analyzed to find why the defect occurred.
The Bottom Line
Regardless of size and complexity, every manufacturing facility should follow these steps to reduce defects and waste. There are other tools (see our blogs for more information), but these 3 steps are the foundation for any operation.
Are you interested in process improvement methodologies for your factory? Find out more and get started by clicking the link below.