Automated turning cells have enabled a UK contract machinist to turn the tables on its competitors in low wage economies by reducing labour cost differentials.
Much has been said of the threat to our subcontractors from China, India and some of the old Eastern bloc countries, but UK firms are fighting back. One contract machinist that has started to turn the tables on its competitors in low wage economies is Treworrick Engineering, Burgess Hill. During one of the worst recessions in UK manufacturing in recent years, the management had the courage to invest GBP 250,000 in two Daewoo automated turning cells from Mills Manufacturing - a bar-fed lathe and a gantry-loaded model - and is now reaping the rewards.
Said Treworrick director and co-owner, Clive Lambert, 'The advantage that low wage economies have over us is that we have to pay our machine operators far more, maybe 30 times as much.
But the labour cost differential becomes small if you minimise operator involvement by automating production.
'Then overseas subcontractors are at a disadvantage.
They cannot offer prices that are much lower, if at all, and need to ship container loads of parts every few months to keep transportation costs down.
This generates work-in-progress that is costly and inconvenient for the customer to stock.' His co-director, Richard Avery, contrasts this with the ability of subcontractors here to supply components and sub-assemblies just-in-time to UK manufacturers, directly to the production line if required.
Moreover the subcontractor is local and can be called in to discuss contracts face to face and troubleshoot any problems.
He commented, 'We have a longstanding customer in the hi-fi business that went straight to an Asian subcontractor for large volumes of a new component.
The company wanted to outsource 150,000 parts per year and did not think we could get close to the price they were quoted overseas, so they did not even approach us.
'However, due to a quality problem with the imported parts, they asked us to tide them over by running off 4,000 and to their surprise, our quote on this quantity based on using the Puma bar lathe was within one per cent of the price they were paying in Asia for the larger volumes.
So we have won all this business; and the customer does not have the hassle of stocking large quantities of parts or dealing at arms length with people over the other side of the world.
To be as competitive as this, however, subcontractors must invest in the latest automated equipment capable of minimally manned, one-hit production.
As soon as a component is handled and set up for subsequent operations, unit price soars, competitiveness suffers and margins vanish.
The two Daewoo lathes, each with live turret tooling and sub-spindle, are typical of the type of machine that is required.
The first, a Puma 230MS installed last Autumn (2002), has a Hydrafeed bar magazine and is capable of producing parts up to 65 mm diameter.
A second 230MS was installed this summer equipped with gantry load / unload to automate production of larger diameter work up to 200mm.
In addition, it can chuck manually-loaded components up to 230 mm, adding to its versatility.
To make room on the shop floor, Treworrick sold two conventional centre lathes of smaller capacity.
What used to be made from billet on these machines, sometimes requiring manual reversal for back end machining followed by further operations on a mill, is now made from bar on the first Puma lathe in one set up.
Likewise the second Puma has automated production of larger mill-turned parts and condensed multiple set-ups into one.
Significant labour savings have resulted and productivity has increased by between 30 and 40 per cent, due in part to being able to run the machines unmanned for two hours between the day and night shifts.
For example, a 25mm diameter by 80mm long EN8M steel part is now machined in 3.3 minutes on the Puma bar lathe, whereas it used to take 7 minutes floor-to-floor on a conventional bar lathe, manual chucker and milling machine.
Prismatic operations are fairly short at about 40 seconds for milling a hexagon and cross hole drilling.
As the combined efficiency of the previous machines was 80 per cent whereas the Puma is 95 per cent efficient, the overall saving on producing this part is nearly two thirds.
In another application, a 152mm diameter by 63mm long EN3A steel billet was formerly produced on two manually operated lathes and a mill in a floor-to-floor time of 11 minutes.
On the Puma gantry lathe, the same part is machined in one hit in 6 minutes and the cycle is expected to fall to below 5 minutes with fine tuning.
So the time saving on this part will be more than half.
Again, the non-turning proportion of the cycle is short at less than 20 per cent.
Clive Lambert took pleasure in pointing out that the component now undergoes its prismatic operations on the Puma lathe faster than it used to take the operator to blow the swarf off in the old lathe and refixture the part on the milling machine.
He therefore feels that he is getting this element of the cycle for free, especially as no operator intervention is necessary.
When it came to the investment in automated turning, both of the Treworrick directors decided that they did not want to plunge straight into the complexities of multi-turret or B-axis lathes.
They consider the single turrets on the Pumas are a better transition for a company such as theirs.
Two other shortlisted machines from other vendors suffered from either poor reputation for service or long turnover time for component reversal on the gantry machine, so Messrs Lambert and Avery opted to source both lathes from Mills.
Concluded Avery, 'We are working routinely to 10 microns total tolerance on the Pumas.
When customers visit and see the machines in action, they have no qualms about the quality of their components.
In this respect, the machines are a very good sales aid.
'Another benefit to us is that steel suppliers can see that we are turning over material quickly and so are happy to for us to hold inventory of bar and billet on consignment, for payment when we have used the material to make parts.
Cash flow is improved as a result.
Our suppliers never offered to do this when we were using the old centre lathes.'
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