New bond improves bi-metal blades

摘要

If you call your product unique, it had better be one of a kind. The L. S. Starrett Co. is so certain that its patent-pending process for manufacturing bi-metal saw blades is sui generis that the Athol, Mass., firm has trade-named the product Bi-Metal Unique. Originally developed for manual and portable power saws, the company is now at work on band saw blades for stationary production machines. For 35 years, the high-speed steel tooth surface of a bi-metal blade has been bonded to the high-strength steel backer or carrier strip by fusion processes, first by electron-beam welding and later by laser welding. What both processes have in common, and what Starrett claims is its Achilles heel, is melting the HSS strip to fuse it to the carrier. "Melting produces a heat-affected zone," says John Caron, global director of research and development for saws at Starrett. "That zone is unavoidable with electron beam or laser welding."