While the depressed oil and gas sector is affecting business for UK sub-contractors, Unilathe Ltd (
www.unilathe.co.uk), Stoke-on-Trent, sees the downturn as a small ‘bump in the road’, thanks to its strategy of diversification and investment; the company has spent more than £3 million on machine tools over the last four years.
The investment includes two heavy-duty mill-turn centres from Mazak and WFL, along with vertical turning centres from Honor Seiki and Doosan. It has allowed Unilathe to accommodate the ‘cost down’ demands of the oil and gas sector, while improving the productivity and lead times of large components for the aerospace, hydraulics, rail and
general-engineering sectors.
To help it get the most out of its machine tools, Unilathe has been working closely with the Wetherby-based tooling company TaeguTec UK Ltd (
www.taegutec.com). Unilathe’s manufacturing director, Mark Oakley, says: “Our work is extremely diverse with regard to material type, part size and machining process, so we use a wide variety of cutting tools from TaeguTec. We’ve worked with the company for over 15 years, and TaeguTec engineers frequently call in with new products to continually improve our productivity and processes.”
It was during one of these frequent visits in 2013 that TaeguTec’s technical sales engineer John Handley introduced the Chase2Hepta face-milling cutter; it is now the face mill of choice for Unilathe’s applications requiring heavy stock removal.
When Unilathe won a contract to produce 150 large forged carbon-steel ‘mud valves’ for the oil and gas sector, the inserts in the face mill it historically used for this type of application wore rapidly and sometimes broke. This unacceptable performance gave the Chase2Hepta an opportunity to shine.
Running on a Toyoda horizontal machining centre with a BT50 spindle, the 100mm-diameter Chase2Hepta with seven double-sided inserts allowed the cutting speed to be increased from 190 to 220m/min and the spindle speed from 620 to 700rev/min — plus the inserts cost 15% less.
TaeguTec also increased the feed rate from 800mm/min to 1,500mm/min while retaining the same 3mm depth of cut as the previous tool. The result was a reduction in cutting time from 26 to 14min for each of the four flange faces on the mud valve — and a metal removal rate of 309cm3/min compared to the previous 167cm3/min.
The insert cost saving of £270 and the productivity improvement gave a total saving of £1,800 for this one batch of parts alone. The Chase2Hepta delivered more than just cost savings; the XNMU insert (a right-hand helical cutting-edge insert with a sharp positive chip-former) in grade TT9080 gives improved surface finish and chip flow; it also reduces the vibration and forces on the machine spindle. The spindle monitoring on the Toyoda machine showed that the Chase2Hepta was drawing 38% of the available spindle power, whereas the previous tool was drawing over 85%.
Mr Oakley adds: “In the last couple of years, we have applied the Chase2Hepta to parts across a range of industry sectors, including rail, aerospace, oil and gas and heavy industry. Materials machined include duplex stainless steel, mild steel and various cast materials.
"For each of the material types and machining applications, TaeguTec has supplied the inserts best suited for the job. For example, we now use the ML-geometry insert in TaeguTec’s grade TT8080 to machine duplex stainless parts and the M-geometry insert in grade TT9080 to machine mild-steel parts.
“In every instance, the Chase2Hepta has reduced cycle times, tooling costs, spindle stress and vibration, while at the same time improving component quality, consistency and surface finishes. The Chase2Hepta is undoubtedly the preferred face mill for our 45deg milling needs.”
As well as the Chase2Hepta, Unilathe has been using other TaeguTec tools, including ChaseMold and ChaseBall. Together, these cutters have allowed the sub-contractor to cut its average monthly tooling bill from £35,000
to £25,000.
TaeguTec is now looking to trial its new ChaseHepta milling cutter. Mr Handley says: “The Chase2Hepta, which was developed for robust heavy-duty machine tools, offers high stock removal rates and the economic benefit of double-sided inserts; it has been remarkably successful on BT50 machines.
“The new ChaseHepta has been designed to bring these benefits to lower-powered machines with a BT40 spindle; and because it offers lower cutting forces, it can be used with unstable thin-walled components.”