A manufacturer is replacing a stainless steel component with one made from a glass filled nylon. Discuss the advantages and disadvantages of this change of ...

Replacing stainless steel with glass-filled nylon involves a trade-off between lower mass and easier high-volume manufacture, against lower long-term structural performance.

• Glass-filled nylon has a much lower density than stainless steel, so the component will be lighter, and it will not corrode. [1]
• Glass fibres increase nylon's stiffness and strength, although it still does not generally match steel. [1]
• It can be injection moulded with fixing features formed in the same cycle, removing separate machining operations. At high production volumes, this can greatly reduce unit cost. [1]
• However, the injection-mould tool is a large fixed cost, so this saving is only likely to repay over a long production run. [1]
• Nylon can creep, meaning it gradually deforms under a sustained load, and its properties reduce at raised temperatures. [1]
• Unlike steel, it cannot normally be welded or repaired in the same way. [1]

Judgement: glass-filled nylon is a good replacement where low mass, corrosion resistance and large-volume moulding matter more than maximum stiffness, high-temperature performance and repairability. It would be unsuitable for a component that must retain its exact shape under a high continuous load or heat.