The solution was Sumitomo Electric Hardmetal’s Wave Radius Mill RSX Series developed specifically for machining exotic alloys. Says Mark Easter, general manager of the family-owned, Sheffield-based SMP: “Not only have we slashed consumable costs with the new face-mill cutters and inserts, we have also totally improved machining conditions through added predictability, better swarf control and have been able to increase machining parameters. We have also reduced the average number of passes from 60, over the six faces of the raw forged material, to just 45 and even reduced cycle times by up to 15%.”
When the project started, however, the Wave Radius Mill RSX Series was not available and initial thoughts from SMP’s long-serving tooling distributor Matrix Tooling Services were that there was little room for improvement for the set-up on SMP’s Hartford Blockbuster PRO-3150AG vertical machining centre, so called in Sumitomo’s area sales engineer, Trevor Hague. But at that time he agreed with that conclusion, saying: “My first impression was that no matter which tooling supplier was brought in, improvement to the set-up, cutting data and cost reductions would be very marginal at best.”
However, within weeks, Sumitomo released its latest RSX Wave Radius Mill Series of high rake angle face-milling cutters with the newly developed ACM insert grades for machining alloy and stainless steels. Offering a highly rigid cutter body, an insert generating very low cutting resistance that minimises vibration, plus a PVD-coated insert that boosted performance and tool life, Sumitomo performed the first ever cutting trials of the new cutter and inserts at a UK customer site and chalked up an immediate success.
Says Hague: “The material was very stable in the cutting cycle, so we tried to improve performance using the different grades and sharper geometries of the new inserts. We maintained the same proven set-up – speeds of 31.3 m/min and feeds of 80 mm/min – but with the ACM button-style insert were able to directly increase the depth-of-cut by 50% to 1.5 mm.”
Immediate benefits seen by the company were better swarf control and reduced insert costs per edge. But then cutting speed was increased to 35.3 m/min for the 125 mm diameter RSX face-mill, raising feedrate by 35% to 108 m/min, which led to the average number of finished parts per insert being raised from 1.3 to 1.42.
Concludes Easter: “With the success of the Sumitomo RSX face milling cutter and ACM inserts, combined with the rigidity of the Hartford machine, we have established the ideal base for quoting very confidently and competitively for additional work on similar very difficult materials.”
This article was first published in the Tooling & Workholding supplement of the May 2016 issue of Machinery magazine.