Product category:
CNC turning centres, mill/turning, multi-tasking centres, horizontal and VTLs.
News Release from: Mills Manufacturing Technology | Subject: Puma 2000SY twin-opposed-spindle mill-turn centre
Edited by the Manufacturingtalk Editorial
Team on 22 August 2003
One mill-turn centre replaces 16 machine
tools
One mill-turn centre has replaced eight chucking automatics and eight multi-spindle drillers in the manufacture of cylinder heads and valve end caps used in radial piston motors.
At the Plymouth factory of Kawasaki Precision Machinery (UK), eight permanently-set chucking automatics and the same number of dedicated multi-spindle drilling machines have been replaced by one Daewoo CNC mill-turn centre for the manufacture of cylinder heads and valve end caps used in the company's Staffa range of high-torque, low-speed, radial piston motors Commented Mike Jonas, Assistant Manager-Production Engineering, "We are currently in the middle of a three-year plan to modernise production machinery and create space in the factory to manufacture additional products and increase turnover at the Plymouth site
This article was originally published on Manufacturingtalk on 23 May 2001 at 8.00am (UK)
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This latest exercise has allowed us to compress what used to consume 290 square metres of factory area into just 45 square metres, which includes space for raw material stillages, a dip tank and temporary finished parts storage." The Puma 2000SY twin-opposed-spindle mill-turn centre, supplied by Mills Manufacturing Technology in April this year (2003), is able to match the same output over two shifts as the 16 now-obsolete turning and drilling machines, producing between five and 14 cylinder heads plus one valve end cap for each of 7,500 motors per annum in 10 varieties.
Changeover from the pre-existing plant to the new machine was completed within three months.
As well as saving valuable factory space, the benefits include lower manufacturing cost per part, which will quickly amortise the lathe purchase.
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A separate rumbling operation has been eliminated, as deburring can easily be included in the mill-turn cycle by putting radii on sharp corners, so work-in-a progress has been reduced.
Despite the machine presently being dedicated to head and cap manufacture, it is nevertheless capable of being reconfigured quickly to produce redesigned or different components, especially as it has a Y-axis which is not used for the current applications.
Advantages in terms of a manning are also apparent, as skilled auto setters are no longer needed; and the operator needs to load and unload 130 parts each weighing up to 5 kg only once per shift, instead of twice, minimising the risk of repetitive strain injury.
This is because the components are machined in one hit on the new lathe without manual intervention, as the synchronous sub-spindle is able to pick up the SG iron casting in a known orientation from the main spindle for reverse-end working after it has been machined on the front end.
Average cycle time across the range of components is two and a half minutes, giving a floor-to-floor time of three minutes, which is equal to or better than at the planned production rates.
Parts are machined well within tolerance, as exemplified by a process capability study carried out by Mills before delivery of the machine.
The component selected was a cylinder head which has a turned spigot diameter with a drawing top limit of 101.52mm and a bottom limit of 101.45mm.
A batch of 30 machined components resulted a standard deviation of 0.005, a mean diameter of 101.501mm, and a process capability index of Cpk = 1.427, considerably better than the required 1.33.
Turning accounts for just 40 per cent of cycle times, the remainder being prismatic machining using live tooling in the 12-station turret, including drilling and counterboring.
Changeover time is faster than expected at between 15 and 20 minutes, thanks in part to the use of quick-change chuck jaws from SMW.
Continued Jonas, "This is a relatively high volume production environment and in addition, we are the sole source of supply within the group for these cylinder heads and end caps, producing them just-in-time to meet customer deliveries.
Reliability of production equipment is therefore paramount, particularly as in this case only one machine is used.
"Since its installation, the Puma lathe has proved to be as reliable as any other machine on site, if not more so.
In addition, when we have needed telephone help or a Mills service engineer to attend, the response has been first class.
"We had no experience of Daewoo machines or the UK agent before this latest project, selecting the Puma lathe as it was 30 per cent less expensive than two machines of equivalent specification on our shortlist.
Based on the positive experience, we have gone back to Mills for a further CNC Daewoo lathe, this time a V550 vertical turning centre.
Installed at the end of July, the machine replaces five automatic chucking lathes for the production of large spool valve housings, which are also a component part of the Staffa hydraulic motor range.
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