Mill-Turning Of Tough Auto Parts Is No Problem For Star Sliding-Head Lathe

Established in the 2000, the firm has traditionally operated multi- and single-spindle cam auto's as well as CNC fixed-head lathes. Its first slider, a Star SR-20J, was installed in July 2009 to reduce production costs across a range of four diesel engine components.

Three of them were previously produced in three operations each – blank turning on a cam multi followed by manual milling and then drilling/reaming. The fourth part needed two separate operations. All are now produced from bar in one visit to the Star multi-axis CNC sliding-head lathe.

Steve Clifford, a director of SEC, commented, We produce 6,000 of each diesel engine component on the Star and ship them every month, whereas before we had to spread delivery over two months.

Cash flow is better now, as we can invoice quicker and secure payment earlier.

There is no longer part-finished work-in-progress cluttering the shop floor, which is useful as space is limited at present.

A further advantage is a big saving in labour costs, which helps us to keep prices competitive, despite having to pay for the new machine.

By automating production jobs that previously required a lot of manual intervention, SEC has been able to take advantage of ghost shift working on the Star lathe. The machine is supervised until 10.00 pm and then left to run unattended through the night, enabling the company to benefit from the extra production for free, according to Mr Clifford.

Availability of the Star lathe on the shop floor at Basildon has allowed SEC to bring in-house work that was previously subcontracted. Further turnover and profit is therefore generated.

Additional business has also resulted as a direct consequence of having the slider on the shop floor. For example, a contract was won for the production of a 212A42 steel banjo bolt for the automotive industry. The part is produced in one hit by turning, drilling three cross holes, threadcutting and then parting off for reverse endworking in the counter spindle. There, the component is centre drilled before a 1.5 mm diameter cutter mills a torx fitting in the back end.

The latter feature was formerly broached by another subcontractor, leaving unwanted flags at the bottom that could trap dirt, which had the potential to find its way into the coolant and engine. Star GB helped to develop the milling cycle, creating a smooth base and avoiding the contamination problem. It also pleased SEC's customer, which had been uneasy about the previous broaching process.

Mr Clifford has been impressed with the way that Star's application engineers in Melbourne have continued to provide support, which has been vital as SEC is a first-time user of sliding-head technology. He said that if they get into difficulty, most problems are solved over the telephone in a matter of minutes.

For people who may think that sliding-head lathes are too lightweight for robust machining of tough materials, Mr Clifford points to a shaft-type component of hexagonal cross section that SEC mills from round, high tensile steel bar (606M36T) in one operation on the SR-20J. Previously, the part had to be produced in two operations from hexagonal stock.

As to his choice of sliding-head lathe supplier, Mr. Clifford concluded, We were looking for a supplier that would go that bit further by making sure that the machine installation and after-sales service were right for us.

Star GB was proactive throughout, surprising us early on by setting up one of our three-operation valve jobs on a machine at Melbourne so we could see the component coming off a slider in one hit.

They even made sure that the FMB full-length bar magazine they supplied was a compact version that would fit into a relatively confined space on our shop floor.

Together with the on-going applications support and overall back-up, the service has been exemplary.

At the time of interview, SEC was carrying out sliding-headstock time trials prior to quoting for another automotive contract involving mill-turning of 316 stainless steel. Such opportunities regularly come along now that the Star lathe is available on the shop floor.