The dream and ambition of many subcontract machinist firms has been realised by Andair in developing its own product. As a result, it has the security and control over areas of quality and margins against the challenging factors that face subcontractors such as when a customer dictates through an enthusiastic buyer, meeting the challenge of cost-down demands and last minute variance in orders or new delivery deadlines.
Said Managing Director Owen Philips: “My father Andy built up a very successful precision machining subcontract business supplying customers in autosport, local aerospace and paint spraying equipment. But it was in 1991 that opportunity knocked on his door that set the change in motion for us to become an OEM and to design, develop and put into production our own fuel valve selector for light aircraft.”
Today the company, no longer under the pressures of subcontract manufacture and employing 10 people in a 3,600 ft2 facility in Havant, is producing some 600 different components for its own range of pumps, fuel selectors, gascolators, check valves, filters and accessories. It has invested over £400,000 in the last 18 months in new equipment including the latest Miyano ABX-64SYY2 multi-axis turn-mill centre from Citizen.
The transformation came about from Andy Philips’ passion to build his own Vans RV6 sports aircraft (he is currently on his third project) and when the four large crates arrived from the America, his engineering breeding and keen machinist’s eye was drawn to the design and immediate apparent level of quality being applied to a particular and very critical inflight fuel selector valve.
Over the next two years any spare time from machining was spent designing, then producing prototypes in his machine shop. Ready for launch in 1994, he set off to an airshow in America taking a chance with a suitcase of valves to try and set up a distributor network and successfully explaining to US immigration they were: ‘Just a few samples’.
Having a fairly warm reception as a Brit selling at the US show, on arriving back in the UK some 50 plus order faxes introduced a totally new era to his family life requiring his subcontract operation to support the initial launch. As a result the subsequent growth of Andair, now run by son Owen, has spawned a range of products that has created a host of customers worldwide including highly respected names in the world of sports, classic, amateur and commercial light aircraft.
As demand grew, in 2005 the need for reliability, precision and accuracy led father and son to buy their first Miyano BND-42S5 for its production turning followed by a second identical machine the next year. Both significantly helped set the company’s future strategy of ‘produce in-house’ which applies to everything except specialist items such as magnets and stators and lower cost standard fixings. This internal working concept also led to investment in a series of machining centres.
In the meantime Owen, using his experience of Brunel University, was setting about designing from a blank sheet of paper a new concept in pressure relief valves for light aircraft which have duplex chambers able to aid economy by recirculating any unburnt fuel back to tank. This was followed by his own concept of a brushless motor design in 2007 and both product lines were developed totally around the turning capability of the BND machines.
With several larger capacity versions of a high pressure fuel boost pump able to feed up to 60 gallons per hour at 60 psi now on the drawing board, Owen ordered a further Miyano in 2014, this time a BND-51SY2 to give a greater 50 mm bar capacity for his new project which was followed in December 2015 with a high specification Miyano ABX-64SYY2.
He said: “The ABX machine has taken us into a different production world giving us all the advantages of single operation machining cycles. Having nine axes and the added flexibility of two spindles and twin, 12-station all-driven turrets each with Y-axis cross feed, it is absolutely ideal for our needs.”
Within six months of installation, 30 different key components have been programmed and machined with another 70 or so on the stocks that will benefit from the machine’s capability against existing methods. As an example, a valve body that was previously machined in two operations on the two spindle, 6-axis, single turret BND-51SY2 in eight minutes, this is now machined complete in one cycle in under 4.5 mins on the ABX with all the added advantages of the insurance of maintaining geometrical relationships between different features.
Said Owen Philips: “All our parts are machined out of L168 aluminium which has a high mechanical strength and is free machining. We generally work to 0.01 mm tolerances on important features and surface finish has to be visually excellent. As the machine has proven to maintain the level of precision we demand, we run batches between 60 and 350 parts and we can set during the day and leave the machine to run overnight on bar fed components.”
Amongst the operations performed on a very complex bypass housing produced direct from bar, this 42 mm diameter by 31 mm long housing, is faced and the OD turned along with a 30 mm dia spigot. A flat-bottom bore 27 mm dia by 15 mm deep is then interpolated. Five holes 3.1 mm are drilled and two holes drilled and roll-tapped M3 x 8mm deep on a pitch circle. An internal form is then milled using the Y-axis and a flat with radius blended edges is milled across the outside dia which is then bored 8 mm through and counterbored to 10 mm dia. Two fixing holes are drilled 5.5 mm deep and two grooves 5 mm and 1.8 mm wide are formed between the OD and the spigot.
The part is then picked-up with the secondary spindle. It is faced and a form, slot-drilled in the bore. A special kidney shaped slot is then milled to an included centreline angle of 84 deg in the bottom of the bore and three holes 8 mm dia drilled by 25 mm deep to partially break into the 5 mm pre-machined groove in the outside dia. A further hole 1.5 mm dia is drilled 3 mm deep from the face. The part is then deburred in cycle.
The fixed headstock Miyano ABX-64SYY2 is able to use both turrets to simultaneously machine at the 15 kW, 4,000 revs/min main and secondary 7.5 kW, 5,000 revs/min spindles. The machine has two 12-station, 3-axis upper and lower turrets with Y-axis cross feeds. Each driven tool position has 4.5 kW with 40 Nm of torque available and top speed of 6,000 revs/min. Drill sizes up to 20 mm dia can be accommodated.
