CITIZEN FLEXIBILITY ENSURES REPEAT CONTRACT SUCCESS FOR ADAERO PRECISION

Having a demanding customer base in the medical, hydraulic, scientific and MOD sectors for the supply of complex components often involving difficult to machine materials, has meant that Adaero Precision Components has to be very selective in the machine tools it uses.

“For up to 32 mm diameter small turned parts production, we will only use Citizen CNC sliding head turn-mill centres.” says Mark Pearson engineering sales manager, “from our experience, these machines provide the highest level of flexibility for producing these types of parts, and because of their user friendliness in terms of job changeover, we gain most from the speed and efficiency of resetting.”

Adaero Precision has two Citizen machines installed in the its newly extended facility at Crediton, Devon; a top-of-the-range M32-III and a mid-range L20 with the high pressure CoolBlaster 2,000 PSI coolant system. The machines produce batches of 500 or so parts in Acetal, aluminium, brass and a variety of stainless steels. Such is the complexity of some of the single operational cycles - for instance, an optical focus component that uses 24 tools on the Citizen M32 - that while cycle times can be relatively long at 5.5 mins, the overall benefits are really significant through combining operations and shortening lead times.

Indeed, it was the purchase of the Citizen L20 in June 2007 that led Adaero to win an important medical contract for three variants of an air flow adjuster in 316 stainless steel for anaesthesia equipment. According to Mr Pearson: “We were up against competitors using fixed-head lathes, but due to the capability of the Citizen we were not only able to easily beat their cycle times but we were also able to absolutely trounce them with the quality of the samples we were able to produce.”

Consistency of production from the two Citizens has never been an issue, resulting in the company’s high level of confidence for long periods in limited manning and unattended running. Also, such is the level of setting expertise that requirements to maintain grinding tolerances can be met when turning on features such as seal diameters and grooves, that are then monitored using the latest optical inspection equipment to ensure full compliance to drawing requirements.

Changeover normally takes between two and three hours depending on the complexity of the batch but, according to Mr Pearson, this time is minimised due to machine’s flexibility in being able to accommodate different tooling layouts. Also, as most programming is performed off-line and most jobs have been previously run, efficiency is very high –thus keeping lead times very short.

It was 1988 when managing director Andy Dickinson and his father Anthony set up Adaero Precision for the subcontract machining of aerospace components. Over the last 20 years, the company has built its expertise and customer base in the medical and optical sectors to take the business to a £2.4 million operation employing 42 people. The machine shop also reflects the ‘quality’ of the customer base having impressive layout and cleanliness, and was doubled in size in April onto two floors giving some 1,800 m2 area with windows overlooking the Devon countryside.

With a previous machine tool background, Mr Dickinson is very particular on the choice of equipment to achieve high levels of productivity and the levels of quality demanded, so the turn-mill centres and machining centres reflect this. Mr Pearson maintains that a major influence to the business is the adoption of single operation strategies wherever possible, to reduce labour content, chances of error and handling damage in turn reducing lead times while work is held awaiting further operations.

Here the 13-axis Citizen M32-III is a prime example. Able to hold up to 80 tools, common tooling can be left set on the vertical tool platen and drilling station for back machining as well as on the Y-axis fed, 10-station turret that is able to accommodate up to 50 tools by using its half index capability and special tool holders. Also with the M32-III, three tools can be employed to cut a part simultaneously with the main 5.5 kW, 8,000 revs/min spindle and 2.2 kW, 7,000 revs/min subspindle.

On a 15 mm diameter by 44 mm long eye surgery component contract, that was won because of the Citizen M32 installation, the 316 stainless steel component uses 24 tools to turn the outside diameter, drill, bore and recess and produce an M8 internal thread.

An M14 thread is then chased on the outside diameter up to a shoulder and a waist diameter balance turned to 7.3 mm diameter by 20 mm long using the combination of twin tools in the turret and on the slide. Two flats are then milled and a cross hole drilled and reamed to 2.5 mm diameter, the part indexed and a hole drilled and endmilled into the wall of the component to 2.2 mm diameter to create a flat bottom feature and the component parted-off.

The part is then transferred to the subspindle, faced to length, finish turned, another M14 thread chased up to the shoulder previously turned on the main spindle. The bore is then drilled, bored and coned followed by the threading of the bore to M6.

Once completed on the Citizen, the component is assembled and brazed to a mating component previously turned on the Citizen L20 and a connecting feed tube brazed between both parts.

Explains Mr Pearson: “This is a typical component that you could never match for cycle time using a fixed-head turn-mill centre.” He then follows on to describe that many of Adaero Precision’s 21 main customers now work closely with Adaero to take advantage of the ‘productionising’ of components using the company’s machining expertise and the high levels of flexibility built into the machines. “As a result we can machine parts even more effectively and competitively,” he says, “and with our MRP system and being totally Kanban orientated, we have a distinct advantage that enables us to secure extensive repeat orders from customers.”