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Case study - Industrial
Solving complex mold problems and saving money
Healy Systems manufactures vapor recovery gasoline dispensing systems, and is the only supplier certified by the California Air Resources Board for Enhanced Vapor Recovery.
The part
A two-piece plastic component for a hose breakaway system - the safety device that separates cleanly when a vehicle drives off with the nozzle still in the tank. The plastic piece makes up the major portion of two valves within the breakaway, so its dimensional behavior determines whether the assembly seals.
The problem
Healy consulted six molders before selecting Mold Threads. In a certified emissions product, the part cannot simply be close - a witness mark or a mismatch at the parting line is a leak path in a vapor recovery system, and the certification is built on the assembly not leaking.
What we did
Two changes, both upstream of the tooling.
First, we re-engineered the part design itself, converting features that had been machine-finished into molded features. Every operation removed after the press is a source of variation removed, along with its cost.
Second, we changed the resin. The material originally specified was workable but left a narrow process window, so the part was only right when everything else was right. We selected a resin that is not typically considered suitable for precision molding and made it work - which is exactly the kind of trade we are comfortable with, because our experience is in hard-to-handle materials rather than in avoiding them.
The result
- 30%
- Reduction in part cost
- 0
- Witness marks or parting line mismatch
- 100k+
- Shots holding specification
Initial samples were dimensionally accurate and production ran on schedule. The parts featured imperceptible parting lines with no witness marks or mismatch, and quality control confirmed they continued to meet specification after hundreds of thousands of shots. Total part cost came down 30%.
Why it worked
The six previous conversations were all about how to mold the part as drawn. The useful question was whether the part should be drawn that way at all. Changing the design and the material was more work up front and considerably less work forever after.
If your assembly depends on a clean join, see enclosures and connectors.
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