Drill problems made so easy
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• Seemingly trivial production problems are often the ones that cause most aggravation. If access is difficult, the removal of a drill burr from inside an awkwardly shaped component, for example, can border on the insuperable.
Mining and Chemical Products, which specialises in lowmelting-point alloys, believes it knows a way to prevent these internal burrs arising in the first place. Most burrs occur when the drill breaks through the wall and the pressure be hind it fracturs the uncut metal at the periphery of the hole.
MCP says that a clean burrfree hole can be obtained by supporting the wall internally with low-melt alloy. By resisting the pressure on the drill, this eliminates the sudden break through as the wall metal thins.
The bismuth-based alloy is melted — typically at 70°C but as low as 47°C if required — and poured into the component, where it fills the cavity and solidifies without contrac tion. The component becomes, temporarily, a solid piece. After drilling, the alloy is simply melted out — with hot water — and used again.
MCP says the approach is practicable on components in any metal. It may also be applied to plastics parts as long as they are not sensitive to the very low temperatures involved.
Mining and Chemical Products