Improve Yield for Rubbed Bronze Products

Industry : Plumbing Hardware

Company Type : Shower heads and faucets

Project Title : Improve Yield for Rubbed Bronze Products

Tools Used : Six Sigma DMAIC Process and Project Coaching; Statistical tools and Process Control

Total Savings : Approximately $200K in annual savings due to 25% yield increase.

• Capacity increase of over 3000 units per month due to 25% yield increase
• Improved customer satisfaction.

Problem Statement

Rubbed Bronze finish first pass yield rates are too low preventing effective expansion of the finish to other products desired by customers.

Goal Statement

Identify the top contributing Rubbed Bronze parts with the lowest first pass yield and improve the first pass yield rate for those parts by at least 25% by January 2008. (Note: Without inadvertently lowering the first pass yields for other parts!)

Business Case

The low first pass yield of our Rubbed Bronze Finish shower heads and faucets has increased our rework costs and caused deteriorating customer satisfaction. This finish could be applied to other products and improve our market share if quality would improve.

Improving the yield by 25% on the selected parts will represent $18,000 per month quality cost savings. Improving the yield by 25% on the selected parts will also represent an additional 3,000 pieces per month in terms of capacity which would allow us to increase market share without having to add additional overtime or capacity.

In addition, if we improve our processing and evaluation techniques, our yield on other parts with a similar finish will likely increase.

Project

Root Causes are Proven

1. It was discovered that the amount of Copper applied in the plating process was a key contributor to poor quality. Against conventional wisdom, a thinner copper coat yield better results with a more desirable lighter color.
2. Rack design to move parts through plating was also a key contributor to poor yields. It was uncovered that certain racks allowed parts to touch.
3. Rack cleanliness was also a contributor to poor yield. The more plating on the racks, the poorer the yield.

Remedies Identified with Controls in Place

1. Racks could only be put through the plating process 30 times before cleaning was necessary to ensure higher yields.
2. Plating process had additional controls established to impart the correct minimum Copper coating on parts.
3. The best rack was benchmarked and duplicated. Older racks were discarded.
4. Plating controls were put in place to ensure that Copper thickness and rack cleaning was maintained.

Summary of Results

After 3 months of the remedies being in place, yield on Rubbed Bronze parts increased by 40%. This enabled a capacity increase of 4000 parts produced per month.

The quality cost savings for 3 months was $250,000 for an annualized rate of $300K per year. The other key benefits were safety related and customer service.

The Six Sigma methodologies and tools were applied to analyze this difficult problem and generate solutions that went agai

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