‘Extra large’ CNC lathe opens new doors for forward thinking subcontractor

Published : June 23, 2009

This latest investment – a 50hp/1500 mm swing over bed lathe equipped with Siemens 840D ShopTurn conversational control – is indicative of the Melksham, Wiltshire, subcontractor’s successful progression to larger, more complex machining. It is also in sharp contrast to the ISO 9001-accredited company’s beginnings, when the original 2000 sq. ft. workshop housed various small manual lathes, turret mills, capstan lathes and pillar drills.

Prior to establishing KPL in 1987, the directors had minimal experience of CNC machining. However, as the business grew year on year, with KPL demonstrating its expertise in the machining of prototypes and small to medium batches to tight tolerances and a high standard, the company began to invest in CNC turning machines, machining centres and CADCAM software. These days, having moved to 6000 sq. ft. premises in 1990, KPL’s experienced and enthusiastic 15-strong team provides a comprehensive ‘one stop’ machining service, supplying precision CNC machined components to customers in a wide range of industries, including power generation, automotive testing, and oil and gas. Any additional requirements such as plating, painting and heat treatment are project managed by KPL, the primary objective being to deliver consistent high quality work at competitive prices. 

 “We are a skills-based company,” says Kelvin Stone, Director, “and this, in combination with a comprehensive range of CNC machine tools, means we are very flexible. We can CNC turn components up to 1500 mm diameter by 1000 mm long and CNC mill up to 2000 mm by 750 mm by 700 mm in most materials. These materials include plastics as well as ferrous and non-ferrous metals, with particular emphasis on difficult-to-machine materials such as stainless steels, titanium, Inconel and Hastelloy.”

KPL already had two large facing lathes, but machining of the 1350 mm OD stainless steel seal rings has been allocated to the new XL 1500 because the machine is more efficient and provides pinpoint accuracy. The machining sequence involves skimming the front face and machining several grooves, then machining the bore some five thou under size to allow for expansion and parting-off through to a depth of up to 30 mm.

The key dimensions of the machined ring are checked in situ using a portable co-ordinate measuring arm before parting-off takes place. This is the final stage of the machining sequence, as parting-off provides a finish machined rear face to the component, eliminating the need for a second machining set-up. However, because of the unpredictability of the expansion of the machined component, off-machine inspection is used to confirm the crucial bore/outside measurements of the first-off and any program adjustment, if required, is then made on the XL 1500 CNC lathe prior to machining successive components. The final 100 per cent inspection of the machined component is then carried out on a large co-ordinate measuring machine.

KPL’s first XYZ purchase was a pre-owned 1010 VMC vertical machining centre, says Peter Hellyer, Director: “We had been hearing good reports of XYZ VMCs and decided to trial one of their machines. It has since proved to be a steady, sturdy and dependable machine.” This assessment led to the installation in early 2008 of a new 20 hp/ 12,000 rev/min XYZ 1060 HS high speed vertical machining centre equipped with 4th axis capability, Siemens 840D ShopMill control and NSK linear roller bearings for vibration-free 43 m/min rapid traverses in X, Y and Z axes.

Described by Kelvin Stone as “the best VMC in the machine shop”, the performance and reliability of this 1020 mm (X axis travel) x 610 mm (Y) x 620 mm (Z) VMC prompted the retrofitting of a new Siemens 810D ShopMill control to the older XYZ vertical machining centre. In fact, the ease of use of the Siemens controls now fitted as standard to all XYZ full-CNC machines was one of the key factors in KPL’s decision to install the XL 1500 CNC lathe. Other influencing factors included the new lathe’s one-piece Meehanite bed and base casting, with its 692 mm bed width giving added rigidity under heavy cutting conditions, substantial 125 mm diameter/Morse Taper 6 tailstock, and constant surface speed (CSS) software.

“Everyone on the shopfloor likes the Siemens conversational control, the price of the XL1500 was right, and we are very happy with the support provided by XYZ,” says Kelvin Stone. As for new opportunities resulting from its installation, a company in Edinburgh already using KPL for large milling work has decided that the Melksham subcontractor should now take on its large turning work as well.

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