In the product manufacturing process, any defective part leads to waste of materials, machine time, and labor. Any rework incurs additional costs.
— The total cost of one defective part is 1.5 times the cost of a good part!
Eliminating or reducing injection molding defects is the responsibility and duty of every factory member. This is because defects not only affect the company's brand but also concern our own interests and those of society!
This is also why any Fortune 500 company places great importance on quality!
Focusing on quality issues is not about assigning blame. It is about finding the root cause and the solution!
Hidden Wastes and the "First Time Right" Principle
Regarding the waste from defects, I believe everyone can recognize it. Therefore, we won't elaborate further here. Let's just review together what specific wastes defects actually cause. This will help everyone realize how crucial it is to do it right the first time! Facing the waste from defects, what measures should we take?
The specific wastes include the following:
- Waste of injection molding materials / Rework labels.
- Waste of time identifying, sorting, and assigning rework.
- Waste of time disassembling (takes twice the time of assembly).
- Waste of time redoing the work.
- Waste of time re-inspecting.
- During rework, production machines that could be running normally are occupied.
- Energy consumption (water, electricity, gas, etc.) by machines during rework.
- Reworked goods pile up, occupying space.
- Rework inevitably involves disassembly/wiring/handling, which can introduce secondary quality risks.
- Rework affects everyone's mood and morale.
- Rework may delay delivery schedules.
- Parts that cannot be reworked need to be scrapped.
- Reworked goods often need to be sold at a discount, etc.
A single rework job can lead to so many problems. What about 10 reworks, or 100? According to our defect rate calculations, there are about 2,000-3,000 reworks per day. Isn't that alarming? It brings to mind the popular phrase: "Where has all the efficiency gone? Before we even start proper production, the efficiency is gone?"
Therefore, everyone must firmly establish the principle of doing it right the first time. Eliminate the waste from defects and reduce product variation. Then, our efficiency will naturally improve.
— A penny saved is a penny earned (Benjamin Franklin).
Solutions: Combining Lean and Six Sigma Tools
Personnel closely involved with quality improvement understand where savings should come from: reducing rework and scrap, eliminating waste, and establishing a smooth production flow.
Many managers seek various methods for quality management. What methods can reduce the number of defective parts in production, eliminate unnecessary waste, and achieve high quality and efficiency?
Lean Manufacturing is highly effective for improving productivity, transforming corporate culture, and streamlining factory operations. But when it comes to solving invisible and intangible quality problems, what effective tools can it provide?
The powerful combination of Lean Manufacturing and Six Sigma forms a strong problem-solving toolkit. These are the very problems preventing companies from meeting their bottom-line revenue targets.
Using these two methodologies together achieves better results than using either one alone. This is a classic case of "1 + 1 > 2".
Lean Manufacturing enhances our drive for action and awareness. Based on the principles of the Toyota Production System and breakthrough continuous improvement methods, Lean focuses on creating a smooth production flow with Just-In-Time (JIT) inventory management and zero stock.
Through a five-day continuous improvement event, a cross-functional team addresses the easier problems in quality and production flow (we call these the "low-hanging fruit"). This yields results such as: shortened lead times and reduced work-in-process inventory.
After picking the "low-hanging fruit", the remaining branches become clearer. You can then identify which problems require Six Sigma's statistical tools to uncover their hidden root causes.
Viewing improvement projects through the dual lenses of Lean and Six Sigma allows you to tackle obvious problems without neglecting hidden ones. You use precise, actionable tools to uncover concealed issues.
If a mold company has a high rework rate and many defective parts, shouldn't you consider starting with process optimization? Use scientific and systematic management methods to improve process quality, enhance product efficiency, shorten product cycles, and achieve customer satisfaction. Only such an enterprise can adapt to market changes and endure permanently!