Cutting Insert Triples Machining Rate, Doubles Edge Life
Ingersoll CNMX Gold Duty indexable coated carbide inserts helped reduced valve bonnet production time from 1 ¾ or 2 hours to about 45 minutes while increasing tool life and chip control.
Improving cycle time, chip control and tool life can be a challenge during heavy turning of gummy metals. In fact, it is common to sacrifice at least one of these factors, if not two. For instance, cutting deeper improves chip control and speeds up the operation, but it also raises the risk of rupturing the tool at any moment. Cutting shallower may prevent tool rupture, but it also slows down the operation, requires more passes and can create long, stringy chips that are hard to manage.
In the case of AWC Frac Valve, sudden edge failure often prevented the company from manufacturing even a single complete valve piece before its tooling failed. By retooling the application with a new insert from Ingersoll Cutting Tools (Rockford, Ill.), the company tripled the material removal rate and more than doubled tool life while eliminating tool failure.
AWC Frac Valve, a division of Archer Well, manufactures very large valves for the oil and gas industry in its 35-man shop located in Conroe, Texas. The company, running 24/5, uses a Doosan 400LM turning center for heavy-duty turning and facing operations in which a 480-pound billet of gummy 4130 steel is reduced to a 250-pound valve bonnet.
To produce this piece, the company used a conventional CNMG negative-rake tool that rarely lasted through one part. “We had to keep two back-up tools in the turret just to keep things going when one tool popped,” says Jim Beaver, AWC’s assistant production manager. “Often, the tool would rupture midway through the first piece.”
Such short tool life was not an option for Mr. Beaver, who was charged with implementing plant-wide continuous improvement. Instead, he set a new tool-life requirement for the application of at least two pieces per edge. He pointed out the challenge to the company’s Ingersoll rep during their regular weekly plant walk-through. The scale of the operation and the cutting forces involved prompted the rep to bring in Eric Strieby, Ingersoll field turning product manager. Under Mr. Strieby’s guidance, AWC tested the Ingersoll CNMX Gold Duty indexable coated carbide insert on-site.
“It was like a beta test, but on a commercialized tool,” says Kirk Cudd, AWC production manager. “Should the tool break during the test, we wouldn’t have to pick up the tab.” By contrast, he says, many tool providers offer on-site testing and reduction to price, but only after the customer purchases the tool and pays for any replacements.
CNC lead man Ben Molinar ran the test on live parts through heavy OD roughing, OD finishing and facing on 4130 steel. The results appear in the table below. For comparison, Mr. Beaver tested the latest CNMG inserts from two other providers, but neither could meet the two-pieces-per-edge requirement consistently.