Product category:
CNC automatic lathes
News Release from: Citizen Machinery UK | Subject: Citizen M32 CNC sliding head autos
Edited by the Manufacturingtalk Editorial
Team on 25 December 2001
Sliding head autos win work for
subcontractor
C and M Precision, a turned parts specialist, quoted a diving equipment maker and won the contract to produce complex air manifolds using parts machined in Citizen CNC lathes.
Recently featured on Tomorrow's World Awards, Chelmsford based Minibreather's scuba diving aqualung broke a tradition of breathing apparatus design spanning some half a century Such is the significance of Minibreather's design, that it is reckoned to cost a third of the price of existing equipment
This article was originally published on Manufacturingtalk on 27 Apr 2004 at 8.00am (UK)
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When Target Sports bought its first Citizen B12 Type V, CNC sliding headstock lathe, it wanted to machine high quality brass dart bodies - it was quickly followed by a second machine.
It has even found a place within the British Science Museum, and on a commercial footing, has been endorsed by the professional Association of Diving Instructors for use in its training schools, which involve some 80,000 centres around the world.
Just down the road from Minibreather is C and M Precision, a turned parts specialist which quoted the diving equipment maker and won the contract to produce the complex air manifold which connects all the flexible piping from the air tank, regulator and gauge of the aqualung.
And, such is the importance of the contract, that it could lead to C and M producing upwards of 300,000 of these components a year on one of its two Citizen M32 CNC sliding head autos supplied by NC Engineering of Watford.
Further reading
Sliding heads raise productivity by two-thirds
To help meet growing demands for torque control tooling, MHH invested in two Citizen sliding head lathes from NC Engineering, and is now achieving an average 65 per cent higher productivity.
Sliding head lathe slashes cycle times
Dawson Precision Components of Oldham has acquired its first Citizen CNC sliding headstock lathe and has been able to allocate multiple-operation work into single set-ups.
NC Engineering awards retiring engineer at Deans
In recognition of spending the last 20 years maintaining the 100 CNC machine tools at Deans Engineering, NC Engineering presented Alan Imrie with the latest Citizen watch.
Maintains C and M's managing director John Cable: "Reliability and rigidity are two key features for us of the Citizen lathes, while their inherent flexibility is a big bonus.
The flexibility allows us to produce a layout for our M12 or two M32 lathes having two tools cutting at the same time and once the part is in the sub spindle.
We generally try to get three tools in cut so we can simultaneously turn, drill and finish a feature in one go.
By overlapping operations we save a vast amount of time and, because we have driven tooling on the lower turret this allows us to simultaneously mill, for instance, two flats at the same time, which halves the normal milling cycle." Established in 1992, C and M Precision has become a specialist turned parts manufacturer.
It started life in a 1,000ft2 industrial unit in Maldon which it quickly outgrew and moved near to Chelmsford to double its working area before taking over its current 4,000ft2 facility.
However, having reached a turnover of 1 million pounds, plans are already underway to expand the building with another 1,500ft2 at the back.
Approximately 50 per cent of turned part sales are exported predominantly for the telecommunications and micro electronic industries.
Says John Cable: "One of our American customers is a big player, the 11th largest company in the world with a turnover of 40 billion dollars." C and M has also just completed a wave guide component contract, via another leading household name in the American telecoms business.
This was machined on one of the Citizen M32s featuring milled pockets and tapped holes in the side.
It also had scalloped shapes at one end and drilled holes as well as drilled and tapped holes on a pitch circle diameter.
He says: "They had to be perfect, without a scratch or imperfection because that could cause reflection and result in crossed lines." Having started with a single CNC fixed headstock lathe, of which the company now has four, it quickly gained a reputation for timely delivery of very high quality components.
But C and M's co-founder, John Cable realised demand was increasing for long, slender components for which he decided Swiss-type CNC sliding headstock lathes was the way forward and led C and M to purchase three machines.
However, he says: "This did not work out for us.
The machines were unreliable and we were losing too much time setting.
So, we decided to cut our losses and replace one with a Citizen M12 and then such was the increase in productivity we ordered two more larger capacity Citizen M32 lathes.
These machines have proven to be entirely different 'kettles of fish' and already some 1,300 programs have been written." Just eight people work for C and M, all of whom are highly skilled and focus on setting the machines during the day.
They operate a split/overlapping shift system, from 6 o'clock in the morning until 5 pm at night, with two people coming in at lunchtime and working through to midnight.
But from midnight until the start of the next shift, the Citizen lathes are run totally unmanned.
An important benefit of employing skilled staff comes from maintaining the level of quality required as John Cable explains: "We have a first-off inspection but don't operate a final inspection department, that's too late.
There is no point in finding out that the parts are wrong when you have made boxes of them.
So, we have a continual process of inspection, all our skilled people continuously oversee the quality throughout the production process." The very first order machined on the M12 involved 150,000 parts in brass with a hexagon section in the middle.
Each flat was individually milled, with each complete hexagon taking about five seconds.
It worked out that one milling cutter produced 900,000 flats at a feed rate of about 1.5m/min.
"The tool life and feed rate we could maintain underlined to us the rigidity of the M-Series machine," which John Cable reckons, "will mill as well as a machining centre but with the benefit of 'one-hit' cycling on the lathe." One job the M12 produces extremely well is the turning of tiny contacts only 2mm diameter but 41mm long.
"We are holding between one and two micron all day long, regardless of temperature fluctuations in the workshop," he says.
"The drawing tolerance allows 30 microns, so it's no problem whatsoever and we machine the part with total confidence." Although both of the M32 machines are identical, the work that they produce is very different.
One has been set up for an extended component run, while the other has frequent change-overs.
John Cable explains: "Since installation it has been permanently set for four months producing a fuel system part from hexagonal bar using around 250 bars a week." Like the M12, the other M32 tends to run batches of 1,000 upwards.
"If it's a complex part we will tend to run smaller batches of 500," says John Cable.
He goes on to say: "We program off-line and then order any special tooling.
When the job is ready, we DNC link to the machine.
We like to get jobs set up early in the week and run larger jobs through the week and weekend and reset again the following week.
We produce parts from materials as diverse as brass, mild and stainless steel, phosphor bronze and aircraft alloys." Although the M32 has a generous tool capacity which can be up to 80 tools, generally the machine is reset each time.
As John Cable says: "It doesn't take that long, I know some companies put their jobs into families.
But, in our game, you can never plan that far ahead what you are going to have to do next." On one particular steel component the company is using a 2mm diameter Titex drill to produce a 27mm deep hole in the back face.
The driven tool is counter rotated to the sub-spindle which gives a combined speed of 10,000 revs/min and allows the hole to be completed in about six seconds.
But as John Cable is keen to point out, it has a mirror-like internal surface finish.
>From its base of about 20 companies, around a third are very frequent customers.
Some are long standing, as John Cable says: "We have been machining the outside case for a Geiger counter probe for one company, in batches of between 50 and 500, for 10 years.
They are really high quality anodised aluminium." Another customer in South America wanted edge filter components 4.8mm diameter by 32mm long for a fuel pump system.
Most of the length of the part has a 10 micron tolerance, and it has six slots up the sides of which three face one direction and three the other, worse still, each 'fin' has a subtle difference in diameter so that when installed in the fuel line, it allows fuel to flow over the gap and down the line.
"We could never have dreamed of leaving the previous machines to run unattended because we found we were chasing offsets all day long.
With the three Citizen's we are now getting better parts that are far more accurate, in less time.
Our very low level of rejects demonstrates how important it is to buy critical machines very carefully," he concludes. Request a free brochure from Citizen Machinery UK ...
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