Machine Design

Secret to good surface finish: Nonfouling coolant

A die caster of zinc handles found that problems with porosity and surface finish disappeared after a change to a special heat-transfer fluid. The previous coolant had been ordinary water from the municipal tap.

But its temperature was unreliable and was causing a build-up of mineral deposits in coolant channels. Part quality was suffering as a result. The Grand Rapids, Mich., firm switched to hot-oil temperature-control systems charged with NF heat-transfer fluid from Paratherm Corp., Conshohocken, Pa. ( Scrap rates dropped and production has doubled to about 1,200 finished parts/8-hr shift. Paratherm NF is nonfouling, nontoxic, and rated for service at 650° F.

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