BY MIKE JONES
The previous two parts have focused on minimizing product manufacturing and warranty costs through manufacturing process selection, part design, and testing. In Part 1, we covered defining volumes, process, and DFX. In Part 2 we covered improving reliability. With high volume product manufacturing the quantity of materials, duration of the project and number of people involved have implications beyond that of low volume and small prototype builds. Now, we must also consider reliability and stability of the product supply chain, minimizing changes as adapting to change may be difficult, the safety and health of those involved, and the environmental impact. Here are some of the key factors to consider.
A reliable supply of quality parts is a key element to the success of high volume product manufacturing. Here are some questions to consider when selecting production vendors.
- Component Cost – is the vendor competitive with other vendors?
- Tooling Cost – how does the tooling cost compare with alternatives? What is the expected life of the tooling?
- NRE Costs – will the vendor do any engineering on the part or sub-assembly?
- Warranty Costs – will the vendor cover costs related to defective parts?
- What is the development time from start to first articles?
- What is the expected response time to design changes that affect tooling or repair or replacement of tooling?
- Competency – has the vendor demonstrated the processes on similar products?
- Capacity – is the vendor capable of achieving production rates and adapting to rate changes?
- Does production involve toxic materials? If so, are they properly handled and disposed?
- Does production create pollutants? How are they managed?
- Are waste materials recycled?
- Is there a plan to recycle the manufactured goods at end of life?
Health and Safety
- Are materials transported and handled safely?
- If hazardous materials are involved are employees using PPE? Are employees trained for hazardous spill management? Is there a safety team?
- If tests or measurements are involved is the vendor trained and equipped? Do they have systems in place to track manage the data?
- ISO certification – is the vendor certified demonstrating capabilities in resource management, measurement, analysis and continuous improvement?
In-flexibility for change
High volume production can be inflexible to design changes. Changes to parts and assemblies may need re-qualification. Tooling changes can be expensive. Disposition of current production parts and assemblies can be expensive. A tool release checklist can help minimize initial changes. Here is a partial list.
- Design: drawings complete, critical to function features identified with dimensions and tolerances, processes evaluated for capability against the tolerances, measurement systems documented qualified and evaluated on prototype parts
- Cost: BOM complete, design cost and production cost gap is acceptable, tooling cost reviewed
- Tooling: prototype parts have completed functional evaluation, differences between prototype and production parts identified and reviewed (materials, gating, draft, etc.)
- Tool design, timeline, and life reviewed
- Supplier: qualification plan ready, material available and at cost target, capacity reviewed, process capability reviewed
Product material life cycle
High volume production can involve the large quantities of materials. In the context of this discussion were are concerned with the life cycle of those materials and how the management of them affects factors such as environmental impact and sustainability. Here are some factors to consider:
- Raw material: availability, supply stability, environmental impact of extraction
- Manufacturing and distribution: energy use (carbon foot print), proximity to use and transportation costs
- Use and maintenance of the assembly or component
- End of life: disposal or recyclability
Production volume strongly influences many aspects of product design. High volume production methods often have high tooling costs and long lead times. However, the resulting lower part cost yields an economic advantage that pays for additional and necessary design effort. Further economic gains are achievable by designing parts and assemblies for manufacturing, assembly and service. Doing so improves efficiency and reduces manufacturing time and assembly mistakes. Competition and exposure to warranty costs can drive reliability goals. There are many design and test methods that one can apply for reliability improvement. Lastly, high volume production can mean large volumes of materials used. Evaluate the life cycle of the materials for manufacturing stability and environmental impact.
About the Author: Mike is a Systems Engineer at SIGMADESIGN with a background in controls design and system integration. He is a certified “Black Belt” in “Design for Lean Six Sigma”. He enjoys the creative phase of the design process and working cross-functionally with the teams to achieve customer goals.