The items designed and manufactured by Luzzo Bespoke Ltd range from the minute hands of dashboard clocks, through complete jewel-encrusted clocks (one example contained gemstones worth £40,000), to bespoke picnic hampers and photographic/art installations 5m tall x 4m wide for photographer Alistair Morrison’s Adoration Trilogy: Searching for Apollo.

The company does work for luxury-car brands such as Rolls-Royce, Bentley, Bugatti, McLaren, Morgan and Jaguar Land Rover; it also works with high-end furniture manufacturer Linley.

With this type of work, much of what Luzzo produces begins life as a concept; the company then works with its clients to develop the idea and turn it into reality.

Alan Sawyer, Luzzo’s sales and creative director, said: “Much of what we create is the fine finishing touches that mark one luxury product out from another for an individual customer.

“By its very nature, this means that we are not involved in big-run production, with batch sizes ranging from five-off upwards.

“As the business has grown, machining has become a big part of what we do; over the past 10 years, the machine shop has developed from having no CNC machines to being virtually fully CNC, including five-axis machines with a multiple-pallet-loading capability.

“This gives us versatility, as we can never be sure what is coming through the door next; and when work does come in, it is normally needed at short notice, which is why flexibility of production is key.

“Machining is a costly thing to do, so now we must work smarter, be more efficient and maximise the available machine capacity.

“Our palletised machines have the ability to run ‘lights out’, so by investing time — and some money — we have greatly improved both efficiency and productivity.”

Maximising run time

One of the first areas that Luzzo looked at was work-holding, assisted by Warren Howard, a technical sales engineer from Sheffield-based Ceratizit WNT Ltd (www.wnt.com).

The key area was maximising spindle run-time to allow ‘lights out’ machining; Luzzo also wanted to reduce set-up times.

The solution from WNT was the use of its ZSG4 centric vice system, which has high clamping forces and a large clamping range.

The maximum gripping force of 35kN allows significant rates of metal removal, even when components are gripped on just 3mm of material.

Furthermore, high levels of accuracy are ensured by the design of the vices. These feature precision matched slides that give a repeatability of ±0.01mm, as well as a totally enclosed clamping system that prevents the ingress of swarf to the ballscrew spindle, making them easy to maintain.

Across its two palletised machines, Luzzo is using 160mm and 300mm vices, which can grip billets up to 163 and 303mm wide respectively. The company is also making use of WNT’s MNG Zeropoint baseplates, which allow a combination of vices to be used to suit specific applications.

Luzzo five-axis programmer Matt Garret says: “A big advantage of the ZSG4 system is the fact that it is modular. One of our pallet machines — a Mikron XSM 600 — has a 42,000rev/min spindle but low torque and is ideal for high-speed finishing; the other — a Mikron HEM 500U — has a 20,000rev/min high-torque spindle, which we use for roughing.

With the ZSG4 vices, we can easily transfer parts from one machine to another, knowing that positional accuracy will be maintained.

“The ZSG system opens up many more possibilities to improve efficiency through different set-up solutions. Being confident to grip on just 3mm of material also means we can reduce material wastage without compromising on cutting data.”

Metal-cutting performance

With issues relating to work-holding settled, attention next turned to improving metal-cutting performance.

Again, working closely with WNT’s Warren Howard, the engineering team at Luzzo looked to maximise the benefits of its five-axis capability and the Gibbs CAM software, which featured the Volumill ultra-high-performance tool-path option.

Mr Garrett said: “We recognised that there were some gains to be made, so we had additional training on the software from Tech CADCAM — a GibbsCAM UK distributor based in Bury St Edmunds — then called Warren back in to discuss tooling. His suggestion was to switch to WNT’s CircularLine CCR-AL solid-carbide cutters.”

These four-flute tools are designed to take large depths of cut and benefit from being used with the trochoidal milling strategy, which makes use of a continuous high-speed tool-path to maximise metal removal and reduce cycle times.

The results of this switch have provided significant savings. One example, based on machining a part from ‘7-series’ aluminium, sees 80% of the material removed from a 200 x 160 x 50mm billet.

The original cycle time was 90min, using conventional milling strategies; this was reduced to just 38min when using CCR-AL cutters and trochoidal milling.

In conclusion, Mr Garrett said: “The benefits we are seeing thanks to the combination of the WNT ZSG4 vices and CCR-AL cutters are significant, and they have been helped by the relationship we have developed over the years with WNT and Warren, who we know is always ready to offer advice and technical support if we need it.

“We will now expand our use of CCR cutters and trochoidal milling, using it not only on aluminium work, but also titanium and other materials.

“These cutters — in a variety of flute lengths and corner radii — are now being added to our WNT vending machine, so that they are instantly available when we need them.”