Three lathes produce couplings 50% faster Three Takamaz XD-10 lathes, each equipped with integral gantry load / unload, twin opposed spindles, one turret and a central transfer station, are providing a cost effective method of producing high pressure hose couplings and adaptors at the West London factory of Jade Adaptors. Two of the lathes are devoted to manufacturing 3/8 inch and 1/2 inch BSP elbow and 'T' adaptors in one hit from forgings, whilst the third works in tandem with a six-spindle CNC chucker to produce straight 3/4 inch BSP products from hexagonal bar. Supplied by UK agent Yuasa Warwick Machinery between December 2000 and April 2001, the XD-10s join a single-spindle Takamaz X-18 which works alongside a Takang platen-type lathe with short bar magazine, also from Yuasa, for turning one inch BSP adaptors.
These machines together cost less than one typical sub-spindle lathe and produce a component in two operations in a 60 second cycle, 50 per cent faster than on a single turning machine, according to Jade directors and owners, Salvatore Costanza and Dave Reynolds.
An additional benefit is the greater flexibility of having two machines at the company's disposal rather than one.
The XD-10 lathe design is unusual in that one 10-station turret services the two 5.5 kW spindles.
Two gantry-mounted twin gripper arms transfer components between input and output conveyors and the spindles, and also access a central transfer station at the top of the machine.
The latter is key to the lathe's high productivity, as metalcutting on a new blank can take place at spindle 1 while gantry 2 picks a completed component from spindle 2, places it on the output conveyor and handles the part-finished component from the transfer station into spindle 2.
The turret then moves across to the right at 24m/min to start reverse-end machining while unload / load takes place at spindle 1.
The result is virtually uninterrupted production, equivalent to a single-spindle lathe which never stops cutting with the added bonus of front- and reverse-end working capability.
Elbow and T adaptors are machined in just this way from 230Mo7Pb (leaded steel) forgings on two of the XD-10s at Jade.
However the third is employed differently.
Straight adaptors which have undergone a first operation on the six-spindle chucker are fed in on the conveyors at either end for simultaneous second-operation turning at both spindles.
This alternative machining strategy underlines the versatility of the machine.
Conventional sub-spindle lathes with two turrets were again considered, but they were much more expensive especially with the automation equipment added; and the productivity derived from simultaneous cutting at both spindles is compromised by dead time during synchronous pick-off.
Around 25,000 adaptors up to 2in BSP are produced daily at Jade on a mixture of cam-type multi-spindle auto's, rotary transfer machines and CNC lathes of which 14 have been bought in the last three and a half years, representing a GBP1 million investment.
Said Mr Costanza, 'We needed to introduce the rapid set-up and small batch flexibility of CNC turning to reduce economical batch size from hundreds of thousands to within the range 250 to 10,000 off, bearing in mind we have more than 2,000 product lines.
There are something like 40 variants of a straight, one inch BSP adaptor, for example.
'In addition, work in progress has been cut dramatically and we have been able to reduce our stockholding, all of which saves money.
'Our continued investment in CNC plant is very much driven by our customers, 98 per cent of which are overseas.
It has allowed us to turn round orders in three days whereas it used to take between seven and 10 days when we operated exclusively cam-type machines.
Not only has our service improved, but so also has the quality of our products.' Dave Reynolds is in charge of the machine shop.
He explained that tolerances are fairly open, although the thread and the cone have to be within 25 microns.
What he particularly likes about the Takamaz lathes is their repeatability.
'They do not move over an entire day's production,' he enthused, 'whereas with our cam machines we are constantly having to tweak the settings to stop parts drifting out of tolerance.' A further advantage of moving over to CNC turning hinges on the more efficient deployment of personnel, according to Mr Reynolds.
With automation fitted as standard to Takamaz machines, one operator can look after several machines.
Moreover, in his experience it is very difficult to find multi-spindle auto and rotary transfer machine setters these days whereas changing over a CNC lathe is far easier.
Both Mr Costanza and Mr Reynolds are agreed that theirs is a competitive, price sensitive business, particularly with the strong pound and the majority of Jade's production destined for export.
Nevertheless, each new CNC lathe they have bought has been financed out of the profit generated by the previous ones, without any borrowings.
In a business where machining cycles are relatively simple and margins are consequently tight, it is testament to their choice of production machines.