What is in this article?:
- For Valve Producer, a Breakthrough in Heavy-Duty Turning
- Longer Tool-Life Requirement
By retooling a job involving 4130 steel, a Texas machine shop tripled material removal rates and more than doubled tool life.
- Indexable coated carbide insert
- Fine tuning pays off
- Unique seating scheme
- Spreading a good idea
Big job, big chips. With the breakthrough Ingersoll insert, AWC turns big valve bonnets using depths of cut of nearly 0.33 inch. Free-cutting tool geometry reduces cutting forces to make it possible.
Heavy turning of “gummy” metals usually forces you to into a triage dilemma: You must choose among cycle time or chip control or tool life, but you won’t get all three at once. You won’t even get two out of the three. Cutting deeper improves chip control and speeds up the operation but raises the risk of rupturing the tool at any moment. Cutting shallower may prevent tool rupture, but it slows down the operation, requires more passes and can create long, stringy chips -- with all their associated baggage.
No triage needed at AWC Frac Valve in Conroe, TX, which manufactures very large valves for the oil-and-gas industry — and in the process generating chips the size of cornflakes. With a 35-man shop running 24/5, the company is a division of Archer Well.
By retooling a heavy-duty OD turning and facing job in gummy 4130 steel, the shop tripled its material removal rate and more than doubled tool life. Moreover, they completely eliminated sudden edge failures that had interrupted production before and forced a lot of re-working. “Previously we had to keep two back-up tools in the turret just to keep things going when one tool popped,” said Jim Beaver, assistant production manager. “Often the tool would rupture midway through the first piece.”
The new tool is Ingersoll Cutting Tools’ CNMX Gold Duty, a very advanced indexable coated carbide insert. With radically aggressive top-face geometry, in an advanced seat pocket scheme, it is a generation ahead of the field in large-scale turning, according to Ed Woksa, Ingersoll national turning product manager. AWS is one of the first users of the new insert, he added.
Now the big chips peel off in easily controlled “sixes and nines,” reducing a 480-lb billet of 4130 steel to a 250-lb valve bonnet in about 45 minutes on a Doosan 400LM turning center. The job used to take 105 to 120 minutes – and usually shattered one tool per part.
The retooling began when Jim Beaver set a new tool-life requirement for the operation: two pieces per edge minimum. Their standard insert at the time, an older conventional CNMG negative-rake tool, rarely lasted through one part.
The new requirement was part of a plant-wide “Continuous Improvement” initiative that Beaver was charged to implement. He pointed out the challenge to Ingersoll’s Mike Salewsky during their regular weekly plant walk-through. Because of the scale of the operation and the cutting forces involved, Salewsky brought in Ingersoll field turning product manager Eric Strieby. The new-generation CNMX tool he recommended was just being commercialized at the time, so Streiby offered a free, no-risk on-site test.