Product category:
CNC automatic lathes
News Release from: Star Micronics GB | Subject: Star sliding-head CNC lathes
Edited by the Manufacturingtalk Editorial
Team on 23 December 2002
CNC Sliding head autos bring in the work
CNC sliding head autos win further high-added-value work owing to the complexity of components that may be produced on these modern machines, says an experienced user.
There can be few people in the UK with more experience of sliding-head turning than Bob Gregory, owner of Haydon Precision Turned Parts, East Sussex Since completing a seven-year apprenticeship during the 1960s in two of the largest cam auto shops in Switzerland, Delta Precision and D?colletage St-Maurice, he has run his own sliding-head turned parts subcontract business in Boreham Street, near Herstmonceux, latterly with his sons, Andrew and Mark
This article was originally published on Manufacturingtalk on 14 Jul 2000 at 8.00am (UK)
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It is a far cry from the banks of cam autos that Mr Gregory ran for three decades, up to as recently as 1995.
Haydon, a BTMA member, specialises in work for the medical, electronics, defence and aerospace sectors.
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Magazine feeds small diameter, full-length bars
Designed for feeding sliding-head and fixed-head automatic lathes with bar in the diameter range 2 to 16 mm, the new Turbo 2-16 has been added to the lower end of FMB's standard bar magazine range.
It has tended to look for contracts that involve awkward machined features and difficult-to-machine materials like stainless steel and titanium, as these generally offer higher margins.
With his CNC lathes he is able to win further high-added-value work owing to the complexity of components that may be produced on these modern machines.
Said Mr Gregory, "It was clear by the mid to late 1980s that CNC sliding-head technology was the way to go and I spent some time researching the market.
I decided to opt for lathes from the Japanese manufacturer, Star, as they appeared to have more experience than other manufacturers as well as a larger installed base in the UK and mainland Europe.
In addition, the machine I bought - an RNC-16 for turning bar up to 16mm diameter - was easy use and the tooling was relatively inexpensive." Soon after it was commissioned, the machine was running 24 hours a day, seven days a week, doing the work of at least three cam automatics.
Mr Gregory said that the CNC lathe was able to carry out a wide variety of work, not only in terms of increased complexity, but also because the range of bar diameters that it could accept was much greater than any cam automatic could handle.
The other big difference is that where it used to take three to four hours to make a set of cams, today's programs can be written in as little as 30 minutes, so there is far less machine downtime.
A further advantage of CNC over cam controlled lathes is that much smaller batches are economical.
From the outset, a PSISTEM PC software package from Independent Computer Enterprises was installed to up- and down-load programs via DNC links, and to give Haydon the flexibility to program either off-line or on the shop floor.
To date, more than 8,000 programs have been written and stored in the system, allowing rapid machine changeover for a repeat job as well as assisting in the creation of new programs by allowing a similar one to be called up instantly and edited.
Early 16mm CNC lathes from Star did not have driven tooling or a sub-spindle, so about 25 per cent of work coming off Haydon's first machine had to go on to a second operation.
After the success of the RNC-16, a VNC-20 was installed which not only had six driven tools but also accepted bar up to 20mm in diameter.
The result was that larger, more complex work could be produced in one hit.
It is rare for any part from this machine to go to a second operation which, as any turned parts subcontract knows, adds considerably to the cost of production.
One of Haydon's customers, a medical equipment manufacturer, liked the subcontractor's expertise and approach to turned parts manufacture and discussed with them taking on the production of a range of otoscope and ophthalmoscope parts.
The contract was subsequently placed and as a result, a Star SV-32 was installed.
This is equipped with a C-axis, sub-spindle and capacity for more than 50 tools, many of them driven and some mounted on a 3-axis turret.
It took sliding-head technology at the Herstmonceux works a stage further by allowing 32mm diameter bar to be turned, milled, cross-drilled and rigid tapped.
Once installed, the SV-32 began producing components, 24 hours a day, to the required delivery schedule.
Gregory commented that doctors are notoriously fastidious about even the slightest blemish in an instrument, so cosmetic finish is also important to avoid expensive product returns from around the world.
Batch sizes are typically between 500- and 4,000-off and the lathe is employed for about 75 per cent of its time on this medical contract.
All parts come off the machine complete, even one that requires 14 operations in a five minute cycle.
Concluded Gregory, "Star sliding-head lathes are versatile machines and the SV can perform turret-type work.
Many of the components we manufacture are complex and short, sometimes measuring less in length than in diameter, which you would normally associate with production on a fixed-head lathe.".
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