SUBCONTRACTOR STAYS LOYAL TO OKUMA
Before starting his own contract machining business, Mick Catherine worked for another subcontractor that was in the vanguard of using a Japanese-built Okuma horizontal machining centre to turn large, often eccentric components to within 10 microns dimensional accuracy.
Rather than employing a rotary table, the machine was programmed to ‘turn-cut’ the features with a single-point turning tool clamped in the spindle whose rotation was synchronised with the speed of circular interpolation in the X and Y axes, while the tool was fed forward in Z.
The advanced function in the machine’s proprietary OSP control, together with the high quality of machine build and the proficient back-up provided by Okuma’s UK agent, NCMT (www.ncmt.co.uk), left a lasting impression on Mr Catherine.
So in 2017 when he opened CNC Subcon Services (www.cncsubcon.co.uk) on the Meltham Mills Industrial Estate in Holmfirth, West Yorkshire, two early lathe purchases were a Genos L400 and an LB25-II, followed more recently by an MU-6300V-L 5-axis mill-turn centre, all manufactured by Okuma.
Mr Catherine commented, “In 1989, I joined as an apprentice the subcontract machinists that later started using Okuma turn-cut technology.
“Since then I have gained a lot of experience, there and elsewhere, in producing parts in small quantities, particularly chassis, transoms, gearboxes and power transmissions for the rail industry.
“When I started CNC Subcon, I decided to specialise in providing technical expertise and advanced manufacturing solutions to the pump and valve sector, including product design. However, we work for clients in many other industries as well including defence, rail, marine, oil & gas and heavy plant & construction.
“Contracts typically involve machining ones and twos at competitive prices in quick lead-times, normally one week. I calculated recently that average batch size here is 1.2.”
The firm operates seven days a week, often responding to urgent requests for replacement pump and impeller parts to repair customers’ equipment that has broken down. More than £100,000 of material is held in stock, mainly steels including stainless but also plastics as well as exotic alloys such as Inconel and Super Duplex. Any part, even damaged cast components, can be regenerated quickly from solid.
Paul Neville, sales and operations manager at CNC Subcon said, “We continue to develop our own components and have a number of patents in place for systems that increase pump efficiency.
“For this and most of our subcontract work we need to machine to very close tolerances, for which top quality equipment like the Okuma MU-6300 mill-turn centre is essential.
“The rigidity of its bridge-type construction suits the machining of difficult materials. CNC Subcon is looking to be the best, so will only buy the best machines.
“With an Okuma you know there won’t be any trouble. It places NCMT, with its reliable back-up and support, high on our list when it comes to new machine purchases.”
The MU-6300V-L fitted with Okuma’s OSP-P300SA control at CNC Subcon has a +90 / -120 degree trunnion carrying a 630 mm diameter table that can turn rotational parts up to 830 mm diameter by 550 mm tall at up to 800 rpm. The machine is also able to mill and drill components within a 925 x 1,050 x 600 mm working envelope using fully interpolative 5-axis cycles. The HSK-A100 spindle is served by a 64-station tool magazine and is rated at 11/7.5 kW, with a maximum speed of 8,000 rpm.
Okuma’s Thermo-Friendly Concept built into the machine, which applies to both the structure and the spindle, feeds data back from temperature sensors to the control. Continual compensation in the part program for thermal drift delivers high accuracy metalcutting in a shop floor environment, even if the ambient temperature varies by as much as eight degrees Celsius.