When Bolton based subcontract engineering firm Velden Engineering (UK) Ltd was faced with spiralling tooling costs on one particular milling operation, it turned to WNT’s technical applications team to provide a viable solution.
When machining high value components with extended cycle times process security is paramount as cutter failure leads not only to lost time, but also the risk of scrapping valuable components. This was a problem faced by Velden, which was using a 63mm diameter facemill, using small, single side, high feed inserts to machine components for the oil and gas industry out of 17/4PH stainless steel. They could achieve the cycle time required with the original tool it was using, but Velden was finding that this tool life was extremely inconsistent, ranging from 14 minutes upwards, with no indication when tool failure would occur. These insert failures were catastrophic, wiping out the cutter body on each occasion. “It got to the stage that we were spending £8000 – £9000 per month on this particular cutter and inserts, which simply wasn’t sustainable, the tooling supplier blamed our material, but we had no issues with other operations, so we had to find an alternative,” says Lee Valentine, Velden Engineering’s Plant Manager.
It was at this time that an e-cast promoting WNT’s new HCN 5235 and HCF 5240 carbide grades landed in Lee Valentine’s inbox These grades have been developed specifically to improve performance when machining difficult to cut alloys, such as those found at Velden, which go into products for the offshore/subsea sector. A cutter and inserts were ordered and they matched the the toolife of the competitor inserts, but consistently. Also, the RNHU 1205M5 inserts from WNT also featured indendations that allowed accurate indexing of the insert as an edge became worn. The combination of the improved reliability of the tool life and the accurate indexing eliminated all of the insert failures that Velden had been experienceing. “I have seven or eight smashed cutters on my desk from the previous supplier, since changing over to the WNT inserts we have not damaged a single cutter and, we can confidently rely on the tool life to determine when to change the inserts, leading to significant cost savings,” says Lee Valentine.
From this initial success Velden then took up the offer of additional applications support from WNT. Making use of WNT’s Technology Centre in Sheffield, Velden shipped over samples of material and WNT’s technical applications team got to work to investigate the optimum tooling strategy for the part. WNT took the opportunity to test a number of inserts, grades and geometries on the material, but came back to the original RNHU inserts in grade HCN5235. The result was slightly modified cutting data that reduced cycle time on the components by an additional 10 per cent. The 12 mm button inserts are now running in production at 180 m/min surface speed, 1500 mm/min feed rate and at a depth of cut of 2.5 mm. Tool life remains constant and to date not a single cutter body has been damaged.
“Key to this service for Velden was the fact that WNT took the evaluation of the machining process off-site to its Technology Centre in Sheffield. Up to now if we had wanted to test, or develop, machining strategies we would have had to do it on our machines, eating into valuable production time to carry out tests that may, or may not have been beneficial. The fact that WNT took over responsibility for all of that and we didn’t lose a single minute of machine time was a major benefit for Velden.” says Lee Valentine.
The HCN 5235 insert grade from WNT (UK) is making significant in-roads into reducing cycle times and cutting tool costs, as they are focussed on the machining of heat resistant alloys and titanium. The success of the grade is down to the combination of new carbide substrates, high technology coating, and the latest generation chipbreaker geometries. These combine to give excellent swarf control and protection to the cutting edge, resulting in improved cutting
performance and productivity.
“The value of our applications support team is perfectly illustrated in this example at Velden. We can utilise WNT’s in-depth knowledge of cutting tools and materials, and develop optimum machining strategies for customers by looking at the methods, tooling and workholding as a total package, before presenting our findings back to the customer. All of which can be done without any interruptions to the customer’s production schedules,” says Tony Pennington,
Managing Director, WNT (UK).