A precision automotiove components subcontractor has bought more CNC lathes to get flexibility of production, quick change-over and rapid response to customers' demands.
As a precision subcontractor serving the needs of the medical, automotive and general engineering sectors, Wellington Engineering of Hayes in Middlesex is constantly facing new challenges to produce a wide range of components in fairly small batches. And for much of its turned parts work, the company now relies heavily on Colchester lathes purchased and supported by southern distributor, RK International of Erith in Kent. Indeed, Wellington now has four Colchester CNC machines, including a Combi K2 manual/combination lathe which was installed last autumn, and a brand new three-axis Tornado 220 M with driven tooling which has just been commissioned.

'Due to the variety of turned components we machine, flexibility of production, quick change-over and rapid response are key to our whole business strategy,' maintains managing director Daimon Wellington.

'That's why we have installed two additional Colchester CNC lathes in the last seven months.

We have found that to service our customers these machines give us the combination of versatility and power; are easy to set-up, program and operate; represent good value for money and we know we get good service and back-up from RK International.' The reason for buying the Combi was to meet the growing demand for a versatile combination type chucking lathe.

The machine was seen to be ideal to provide both manual and CNC turning requirements for batches of up to 10 precision components and allow the flexibility to optimise machining performance across a whole spread of work.

'After looking at several different machines,' continued Daimon Wellington, 'we decided that the K2 best met our requirements as it had a slant bed, was well-built on rigid castings for making accurate cuts and was just so simple to program and operate.

In order to meet our planned schedule of work for this machine, we also specified it with the eight-station indexing turret and swarf conveyor options,' he said.

Installed at Wellington's 12,000ft2 factory in September 2001, the Combi has proved to be an instant hit with the workforce.

In fact, one manual lathe operator who was about to leave the company in order to gain CNC experience elsewhere, decided to stay and combine the best of both worlds on the Colchester machine.

This is the key feature of the Combi, which can be programmed in several different ways including: simple digital readout, on-screen CAM based programming, electronic handwheel teach and repeat, cut and paste, traditional G-codes and by direct numerical control.

While both the company's operators started programming the K2 using on-screen CAM simulation in order to learn the system, virtually all programming is now carried out on the machine's Fanuc 210-TA digital control using standard G-code routines.

On average, the Combi now spends over 80 per cent of its production time being used as a full production CNC lathe.

However, its manual capability does provide added production cover and this method of operation is regularly used for simple shoulder and facing type operations - as it is quicker than writing a program.

With a swing of 400mm over the bed, the Combi tends to be used by Wellington on parts up to around 203mm diameter and in batch sizes ranging between five and 10 parts.

Much of the work involves machining aluminium alloy components with tolerances down to 0.02mm such as bearing heads for motor sport simulation equipment which are required in batches of eight.

These 180mm diameter by 130mm long aluminium parts have an 80mm diameter through bore and various profiles and recesses on the front face.

While programming and machining the first of these quite complex parts took just over five hours, each subsequent bearing head is then produced in less than 45 min under full CNC.

As Daimon Wellington confirms: 'Manually turning components such as these would have taken over four hours each, so the Combi is more than three times faster for the complete batch, and once one part is inspected and passed-off, we know the following components will all be the same.' Established in 1992, Wellington Engineering has progressively expanded its subcontract operations and today employs 30 people.

It now has some 17 CNC machine tools of which eight are vertical machining centres.

The BS EN ISO 9002 approved company has invested heavily in six new CNC machines during the last five years and recently updated its computer system.

Medical work now accounts for around 40 per cent of the business and involves machining a range of components for cryogenic equipment and optical systems along with the production of thermal links, weld bushes, baffles and special nuts.

Automotive projects, which tend to be mainly for the motor sport sector, represent around a third of turnover involving production of manifolds, bearings, heads, piston rods, links, shafts and load cells.

While the Combi K2 lathe very capably bridged the gap between manual and full CNC, Wellington's latest investment takes the company into the realms of one-hit machining cycles.

With the installation of the Colchester Tornado 220 M three-axis CNC lathe with six driven tool stations and a 65mm capacity bar feed, the company will be able to produce complex mill/turn components in a single-set-up.

While the machine has only just been commissioned, Daimon Wellington is in no doubt as to the difference it will make by eliminating second operation work.

'We have a number of potential jobs lined-up for the Tornado and its ability to turn, mill and drill in a single set-up will enable us to win new work we just could not have economically quoted for in the past.

While on certain existing projects, the one-hit nature of the machine will help us reduce manufacturing and tooling costs, ensure high quality especially on geometric tolerances and further improve delivery performance.' Even on fairly simple components like transit flap assemblies, for example, the 220 M is already making a big difference.

While these 75mm diameter, aluminium discs only require OD turning, facing, and recessing, they have four 9mm diameter holes equally spaced on a common pitch circle diameter.

The ability to drill these holes in the same set-up, without having to transfer the parts to a machining centre, is enabling production time cycles to be cut by almost 40 per cent! While on potential new work for a customer in the valve sector, the Tornado should be able to reduce machining times on quite complex 'T' valves by up to almost 500 per cent compared with conventional, multi-machine methods of working.

'As such, we will now be able to quote very competitively for such projects,' he says.

The new Tornado 220 M machine has a 510mm swing over the bed, a 65 mm bar capacity, full C-axis with disc brake, 22kW spindle drive with 3.7kW available at the tool drive.