Product category:
CNC turning centres, mill/turning, multi-tasking centres, horizontal and VTLs.
News Release from: Colchester-Harrison | Subject: Tornado T8MS mill/turn centre at SEM
Edited by the Manufacturingtalk Editorial
Team on 06 December 2007
Mill/turn centre speeds changeover on
batches
A CNC mill/turn centre equipped with a sub-spindle provides quick job changeover times when producing 500 different motor shaft types in a 'single-hit' cycle.
To meet rising market demands, the UK's largest manufacturer of AC and DC permanent magnet servomotors, SEM based in Orpington, Kent, has purchased a Colchester-Harrison Tornado T8MS mill/turn centre It has brought the machining flexibility to produce 500 different motor shaft types in a 'single-hit' cycle
This article was originally published on Manufacturingtalk on 5 Jul 2001 at 8.00am (UK)
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During the last 12 months, the latest Tornado T8MS mill/turn centre with sub-spindle offers quick changeover to for machining small batches and has provided the necessary flexibility to meet the operational strategy of the business.
Manufacturing engineering manager, Richard Strama, said: "Demand is very high as a result of our competitiveness to accommodate small quantities of motors that involve considerable variations in their specification.
Such has been our success that production has risen some 25 to 30% over the last two years and we are now investing to improve our flexibility further and also increase efficiency." Due to the wide variety of customer requirements he explained how the company is trying hard to cut down on unnecessary levels of complexity.
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To illustrate the enormity of the job in hand, he showed one of recently assembled servo motors.
"You need to realise we could have over 35,000 variants involving different motorshafts, combinations of length, feed-back devices, connectors, terminations, brakes and mountings," he said.
It was this need for flexibility that led him and production engineer Tim Allen, to use the UK's MACH 2006 machine tool exhibition to find a sub-spindle equipped mill/turn centre that would provide a 'single-hit' cycle for improving shaft production.
The machine had to be changed over quickly, not only for shaft work but also for chucking operations, to produce five types of aluminium housing as well as drive and non-drive motor end caps when needed.
The two engineers failed to find a machine to match the capacities of the Tornado T8MS without seriously denting their budget.
The spending limit was set because there were several other live improvement projects vieing for a share of the GBP 500,000 spend to meet the growing demand.
Allen said that the company already had CNC lathes installed for larger quantities.
SEM was also using an older Colchester and a turret lathe for small batches of specials.
But as the frequency of these specials was rising fast and batch quantities were shrinking, the company had a priority to automate this area as a priority.
The Tornado T8MS has an MBF1000, integrated bar feed system that is programmable from the Fanuc 18i-TB CNC, and was seen as ideal particularly with the programmable B-axis subspindle.
This unit has a 7.5kW 6,000 rev/min drive.
The Tornado T8MS was regarded as the only sub-spindle machine they could find within the price, that would accommodate diameters up to 45.5mm and parts up to 500mm long.
The main 22kW, 5,000 rev/min spindle also had a useful, for SEM, 77.5mm through bore.
Following budget approvals and negotiations to purchase, the machine was finally installed and commissioned in June 2006 by the Southern Technical Centre operation of Colchester-Harrison, RK International of Erith, in Kent.
As well as being the UK's largest servomotor manufacturer, the Orpington company, has an enviable track record with 93% of sales are exported worldwide with over half of all production directed towards the global machine tool industry.
The balance is sold to machinery control and systems companies, OEMs and distributors supporting general automation, robotics, packaging, printing and textile sectors.
According to SEM sales and marketing manager, Steve Jackson: "Consistent quality and the ability to cater for a number of varients in specification within a customer's overall requirement have been major factors in the growth of the business.
This is best qualified by the demand during the summer of 2007 that broke all sales records for the business".
He explained that miniaturisation in design, especially through the latest HDM, a compact, high torque motor delivering an excellent power to weight ratio and the ability to meet user requirements for larger bearings and motorshafts, have also influenced demand.
This is why the Tornado T8MS is a key machine.
Strama said: "The Tornado T8MS has been very reliable, but just as important to us is its flexible characteristics to cope with a massive schedule and variety of small batch work.
As parts are finish turned in a single operation ready for final grinding, this also enables us to prepare and control work flow".
* Machining shafts - the machining time for different shaft types varies between 2.5 and 6 min with parts produced from bar between 17mm and 50mm diameter.
Part lengths vary however, between 70mm and 580mm in EN8, EN16, EN 19T and 416 stainless steels.
Changeovers tend to take between 10 and 30 min, including first-off approval and the longer time taken if there is a need to change spindle liners.
When changing over to accommodate aluminium housing production, the Tornado also has to be thoroughly cleaned and that means resetting takes around 1.1/2 to 2h including pass-off.
Colchester-Harrison told manufacturingtalk.com that Strama was very complimentary about the consistency of the parts being produced.
Consistency and machining accuracy was helped the 'Duo-Stable' construction, which gives some 300% greater thermal and dynamic stability when compared with cast iron.
Strama said: "On batch sizes of between 50 and 300 housings we easily hold tolerances of 8 micron and rarely have to change program offsets." He commented too how the Heidenhain linear scales fitted to the turret slides have such an important influence on holding dimensional consistency.
The Fanuc 18i-TB control with its simple macro programming enables the operator to quickly input variables according to drawing differences between batches.
The machine is DNC linked for program storage.
Operations performed include turning, threading, undercutting, tapers, plus drilling and tapping of the shaft ends with 'on-the-fly' transfer at 30m/min between main and sub-spindle.
In retrospect, Allen wished they had specified the +/-40mm Y-axis cross feed to the turret in the T8MSY.
"This would have given us even greater flexibility for producing features with a good milling and an off-centre machining capability.
But at the time, budgets were so important.
Still the machine does everything we ask and has certainly relieved any bottlenecks that would have been caused by the production demands of our rising order book.".
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