Staffordshire-based Alcon Components Ltd — a specialist in brake and clutch systems — is reaping the rewards of investing in a turn-key machining cell developed by Mills CNC (www.millscnc.co.uk), the exclusive distributor of Doosan machine tools in the UK and Ireland.

Installed at Alcon’s Tamworth facility last year, the cell has helped to deliver a 40% reduction in brake disc machining cycle times.

It contains three Doosan 15in chuck V8300 vertical turning lathes with Fanuc controls and is part of a process improvement solution designed by Mills CNC in partnership with Alcon production engineers.

Alcon’s advanced braking systems are used in the motor-sport, automotive and defence sectors, and the company supplies its systems and solutions direct to motor-sport teams, automotive OEMs and defence contractors.

It also make braking systems for a large international after-market, with around 70% of its braking systems destined for export.

Prior to the acquisition of the new Doosan lathes and the implementation of the new machining cell, Alcon machined its brake discs on three horizontal fixed-head lathes.

While still performing satisfactorily, these legacy machines were relatively old; they were purchased in 1983 when Alcon was first established.

As a consequence, the machines were considered to be too slow and were increasingly prone to breakdown.

Brian Cutler, Alcon’s production engineering manager, said: “Our business is growing, and demand for our braking systems is at an all-time high.

“While this is clearly good news for the company, such an increase in demand was beginning to put pressure on our existing machining methods and manufacturing processes”.

An internal review undertaken by Alcon identified that its brake disc manufacturing operation was a ‘pinch point’ that was affecting the company’s overall productivity and operational efficiency.

Mr Cutler said: “It was clear that we needed to invest in — and significantly upgrade — our brake disc manufacturing cell.

“We also made the decision with the new cell to move away from horizontal lathes in favour of vertical turning lathes (VTLs); we drew up a list of machine tool manufacturers who could not only supply the new machines but also develop a robust, flexible and repeatable machining process.”

VTLs are considered best suited for machining wheel-, plate- and disc-shaped components that are characterised by their relatively large diameters and short workpiece lengths, making the machining process inherently stable.

With VTLs, the workpieces stand upright and need less clamping force (due to the effects of gravity) than when horizontal lathes are used.

VTLs also enable higher cutting forces to be applied, which improves removal rates and reduces cycle times.

Alcon already had a relationship with Mills CNC and had invested in a number of Doosan CNC machine tools in the last seven years.

These included horizontal and vertical machining centres, plus multi-tasking lathes.

Mr Cutler said: “We have a good relationship with Mills CNC. Doosan machines deliver excellent performance, and they are competitively priced.

“The machines are also backed up by Mills’ technical and after-sales services, which are also first-class.”

As well as Fanuc controls, the vertical turning lathes feature an integral box guideway design that helps to reduce vibration and facilitates heavy-duty and high-precision machining.

All three machines are equipped with powerful (45kW/2000rev/min) high-torque (2592Nm) spindles and fast servo-driven 12-station turrets for rapid indexing and accurate positioning.

The machines have axis travel of 495mm in X and 780mm in Z, plus a maximum turning diameter of 830mm and a maximum turning height of 750mm.

They offer 20m/min rapid rates on the X and Z axes.

The V8300 lathes at Alcon are positioned in close proximity to each other, enabling rapid part transfer between them; they are being used to machine a range of different-size brake discs, which are made from cast iron and are machined to tight tolerances and high surface finishes in low volumes.

Alcon currently machines about 500-600 discs per week in the new cell; the diameters vary in size (from 200mm to 405mm), depending on the end application.

Mr Cutler said: “All our brake discs are produced in three operations — one per machine.

“Initial roughing-out operations are performed on one machine, before the disc is transferred to the second and third machines for machining the top face and bottom faces of the brake discs.

“Having three machines at our disposal means that production is not affected or interrupted if one machine goes down.

“The machining process, developed in collaboration with Mills and using the three V8300 vertical lathes, has enabled us to ramp up production and to reduce part cycle times by up to 40%.

“We are now tweaking the process continuously to make it even more efficient and effective.”