Around 20 years ago, Gareth Davies started Burton-on-Trent company TAS Engineering as a steel, stainless steel and aluminium fabrication shop.In 2014, he established a machine shop to add extra value to the products the company was forming and welding. Today, there is a pair of three-axis vertical machining centres on-site and a trio CNC lathes, the latest of which is a pre-owned Cincom L20 sliding-head turning centre from Citizen Machinery.

What prompted the purchase in October 2023 of this 20-year-old lathe, the company’s first sliding-head model, was a desire for more efficient turningof components in various materials from bar up to 20 mm in diameter. A case in point is the ongoing production of a 16 mm diameter, 316 stainless steel magnet holder, which is welded to a small, laser-cut and bent plate to form part of a safety unit for industrial switchgear. The turned component, of which 200 are required per month, was previously produced complete on one of two fixed-head, twin-spindle lathesin a 2.5-minute cycle.

It was apparent that the steel magnet holder could be produced more quickly on a modern Citizen L20 twin-spindle sliding-head turning centre due to the faster axis motions of the gang tool carriers on the former compared with the turret movements of fixed-head lathes. However, Davies was surprised to find it was possible to machine the part more than three times faster on the Cincom: the cycle now takes just 48 seconds.

He says that although the purchase price of the lathe was only about 24% of the investment needed for a modern 20 mm capacity L-series Cincom, he was treated by all Citizen Machinery UK staff as though he were purchasing a new L20.

For further information www.citizenmachinery.co.uk

It is only within the past five years that Nuneaton-based subcontractor Oaston Engineering, which specialises in work for the aerospace and biotechnology industries, has embraced sliding-head turning. July 2018 saw the arrival of the firm’s first sliding-head lathe, a 20 mm bar capacity Cincom L20-VIIILFV from Citizen Machinery UK. It was followed in October 2022 by a second, larger model, a 32 mm capacity Cincom L32-VIIILFV.

Oaston Engineering’s managing director Sean McCarthy says: “We were always led to believe that sliding-head lathe operation was a dark art and that you need to produce large batch quantities, say 50,000, to justify setting them for a new run. We had been looking at the technology since MACH 2008 and, a decade later, when the Cincom L20 was delivered, we discovered the myths were untrue.”

Oaston Engineering had a particular job in mind for the Cincom L32: the production of a light aircraft pump camshaft from martensitic stainless steel.

The component, which is produced from 1.25-inch bar, formerly needed seven separate operations: outside diameter turning and grooving; milling on a machining centre; two separate turning operations in offset fixtures to machine the cams to a dimensional tolerance of 0.07 mm; drilling a longitudinal bore on a machining centre; cross drilling a tooling hole in another operation; and off-site grinding of two spigots to within 0.015 mm.

The camshaft produced in this way required a total of 18 minutes 30 seconds of cutting time, plus inter-machine handling, as well as 30 to 60 seconds for deburring and more time for inspection at each stage. Now, six of the operations are performed in one hit in less than 15 minutes on the Cincom before the part goes out for grinding.

For further information www.citizenmachinery.co.uk