One-shot wonder: Turning Performance

END USER: General Products Corp., (260) 668-1475, www.general-products.com. SOLUTION PROVIDERS: Haggard & Stocking Associates Inc., (800) 622-4824, www.haggard-stocking.com; Rigibore Inc., (262) 363-3922, www.rigiboreinc.com. CHALLENGE: Overcome the concerns of applying fixed-pocket, brazed-PCD boring tools. SOLUTION: Special “one-shot” adjustable boring tools that accept replaceable PCD inserts.

Fixed-pocket, brazed-PCD boring tools can run for long stretches of time while producing mass quantities of high-quality parts, but only when everything in the setup is correct. That includes the setting of the PCD cutting edges, TIR, clearance, back taper and hone.

However, if some aspect of the costly cutters isn’t right, problems result, with the potential to halt production, according to Dennis Amstutz, manufacturing engineer at General Products Corp. The Livonia, Mich., job shop provides machined assemblies found in almost all modes of transportation, including automotive vehicles and medium- and heavy-duty trucks.

Rigibore designs and develops CAT 50 special boring tools and special turning tools, including ones for General Products. Images courtesy Rigibore.

Amstutz said a new brazed-PCD boring tool costs from $2,000 to $7,000 and, on average, it costs about $2,000 to have one reconditioned when it dulls and begins to generate inconsistent bore sizes and finishes. In addition to the expense, the lead time for a retipped tool is typically 8 weeks or more.

Regardless of the lead time, reconditioning a PCD-brazed boring tool that’s been run 2 years or more and machined in excess of 65,000 parts doesn’t mean it will perform as well the second time around. Size, taper and TIR can change during the retipping process, and General Products couldn’t “plug and play” a reconditioned tool with confidence. “It’s a 50/50 shot whether it’s going to be correct or not,” Amstutz said, adding that the company sometimes needs to modify part programs to produce acceptable parts.

There’s no guarantee that a new fixed-pocket boring tool is going to cut correctly either, Amstutz noted. He added that having everything right on a boring tool is especially critical for General Products because a lot of the bores on its parts have tolerances of ±12µm (0.0005″). “It’s just kind of a crapshoot.”