FEATURE ON CNC LATHES AND TURNING CENTRES

Lathe takes over production of prismatic parts

Looking at the cuboid aluminium components produced for medical diagnostic equipment by subcontractor AES Precision Engineering, one would think they were milled, drilled and tapped on a machining centre rather than a lathe; indeed they used to be, from sawn billet in two separate operations on a pair of three-axis vertical-spindle machines in a total cycle time of 12 minutes.

However, since April this year, they have been machined complete from round bar in one operation on an Italian-built Biglia B565-YS 6-axis turn-mill centre supplied by UK agent Whitehouse Machine Tools. Program run time has more than halved to 5.5 minutes, accuracy is improved and there is no handling between machines or work-in-progress on the shop floor, significantly reducing the cost of production. Only two turning tools can be found in the machine’s 12-station turret, one for facing the bar end and another for parting-off, the remainder are axially and radially driven tools.

Mark Wilson, director of the family-run subcontracting firm, says: “We asked four potential suppliers to offer a turnkey package based on production of the aluminium medical part. Whitehouse demonstrated the best process in terms of quality, capability and cost on a Biglia lathe at its Kenilworth technical centre.”
Production engineer Trevor Orman adds: “The quality of the Italian lathe is high for this class of machine, costing under £200,000 with tooling. Although tolerances on the medical part are fairly open at 0.1 mm, the Biglia repeats to within microns, which means we no longer have to chase tolerance all day as the temperature varies on the shop floor.
“The machine’s accuracy will also be invaluable for the production of more tightly toleranced components, while its rigidity means that tool wear is noticeably lower than on our other lathes,” he concludes.
For further information www.wmtcnc.com

ProTurn lathe boosts gunsmithing service

With over 30 years of gunsmithing between them, along with 20 years’ international shooting experience, good friends and business acquaintances Stuart Anselm (Osprey Rifles), Pete Walker (Walker Custom Rifles) and Gary Costello (March Scopes) decided to pool their resources to capitalise on the niche market of bespoke gunsmithing by creating PGS Precision Engineering.

Much of the work that the three partners are involved with is one-off commissions, which would not justify investment in CNC machining capability. However, a recent contract for higher volume work made the possibility of upgrading from manual machining a feasible proposition.
“This was our first contract for large 50-calibre military rifles and, in addition to the chamber, we had to carry out turning and threading to fit the rifle action, as well as the suppressor [silencer],” says Anselm. “These increased volumes led us to look into CNC.”
PGS Precision Engineering opted to purchase an SLX 355 ProTurn lathe from XYZ Machine Tools, which scored highly due to its easy-to-use ProtoTrak control system; in particular the ‘TRAKing’ facility that allows the operator to manually run through the program using the hand-wheels before pressing cycle start.
“We are machining barrels much faster than we ever could using our manual lathes and with the reassurance of consistent accuracy and quality,” says Anselm. “Adding the automatic toolpost was a great decision as we can now complete the turning and threading cycles in under three minutes.
For further information www.xyzmachinetools.com

VTL sold into oil industry application

Mills CNC, the exclusive distributor of Doosan CNC machine tools in the UK and Ireland, has supplied a new, large-capacity Puma VTS 1620M vertical turning lathe to Fife-based National Oilwell Varco (NOV) Flexibles UK – a group within NOV Subsea Production Systems and a manufacturer of flexible pipe systems for the offshore oil and gas industry.

The machine was installed at the company’s recently upgraded and extended manufacturing facility in Glenrothes, and represents part of an ongoing multi-million pound investment made in plant, machinery and equipment. Doosan’s VTS 1620M is being used to machine a diverse range of NOV’s proprietary and patented, complex components, as well as repair (re-machine) worn parts that require refurbishment. These components, made from difficult-to-machine materials, many of which have undergone Inconel weld overlay, inlay cladding and heat treatment processes, include large-diameter end fittings and flange connectors – components that provide the required secure interfaces between flexible pipe systems and topside/subsea facilities such as FPSOs/FPUs, platforms, well-heads and subsea installations.
A box-guideway vertical turning lathe equipped with a 63” chuck, the VTS 1620M has 2000 mm maximum turning diameter capacity. In addition, the machine has a number of on-board technology features that make it suitable for the productive and precise machining of large-diameter components.
Alex Mitchell, Flexibles UK’s maintenance manager, says: “The VTS 1620M, like our other Doosan machines, is reliable, versatile and delivers impressive cutting performance. We continue to invest in Doosan machine tools because they are technically sound and are competitively priced. They are also backed by Mills CNC’s aftersales service and support which, from our experience, is difficult to beat.”
For further information www.millscnc.co.uk

Latest Colchester MultiTurn unveiled at EMO

600 UK launched its Colchester MultiTurn two-axis manual/CNC lathe at EMO 2017 in Hanover last month. The new MultiTurn is a simple, flat-bed CNC lathe that now incorporates a Siemens 828D control with ShopTurn as a standard feature, although Fanuc 0iTF with Manual Guide i can be fitted if preferred.

The Siemens 828D control with ShopTurn has a reputation for being user-friendly and intuitive, ensuring that operators can machine parts quickly and easily with very little training. However, the ShopTurn system is also powerful enough for more advanced CNC users to output maximum productivity quickly, says the company.
600 UK offers six Colchester MultiTurn models, starting with the compact MultiTurn 1000, which has a 330 mm swing over bed and a 7.5 kW motor outputting spindle speeds of 3500 rpm, through to the heavyweight MultiTurn 6000, which has a 760 mm swing over bed and an 18.5 kW motor giving spindle speeds of up to 1400 rpm. The MultiTurn 6000 has bed length options ranging from 1.5 to 6 m.
Paul Rushworth, 600 UK sales director, says: “The new Colchester MultiTurn, with the addition of Siemens 828D with ShopTurn, gives customers even more flexibility when choosing a new turning machine. We are constantly expanding our range of Colchester and Harrison products, and the MultiTurn is a natural progression in adding more options that customers want.”
For further information www.600uk.com

Machining lead-times cut for hydraulic bodies

Following the recent acquisition of a Miyano BNE-51MSY multi-axis turn-mill centre from Citizen Machinery, Wednesbury-based precision subcontractor Machine Tech Engineering (MTE) has been able to slash production lead-times on batches of hydraulic bodies from three weeks for the first operation, plus a week for the second operation, to machining the entire batch complete in just five days. Batch sizes on the Miyano, although early days, are between 100 and 300.

The eight-axis Miyano BNE-51MSY with Iemca Kid 80 barfeed has created an advantage in lead-time reduction for MTE due to the ability to overlap in a cycle and cut with up to three tools simultaneously. Featured on the machine are two 12-station driven turrets, one with three axes, and the other with two axes that can service either or both spindles at the same time.
In producing a hydraulic body from 38 mm bar, a 22 mm spade drill is used to a depth of 57 mm, then, using a special flat-bottom tool a face and corner relief is created at the bottom of the bore prior to final boring to within 0.03 mm. A further bore is then drilled and reamed to 11.9 mm diameter (0.03 mm tolerance) by 76 mm deep, and the initial bore threaded 1” x 20 TPI Whitworth by 8 mm deep. After, the OD is turned and threaded 11/2” x 16 TPI Whitworth over a length of 100 mm.
The part is then taken by the three-axis secondary spindle, faced, and a 30 mm A/F hexagon is milled by 20 mm long before a 6 mm straight-knurled shoulder is created. Following this operation, a through-bore is drilled to break into the 11.9 mm bore, which is finally tapped 7/16” x 20 TPI UNF by 26 mm deep.
For further information www.citizenmachinery.co.uk