AGIE EDM technology enters the space race

Citation

(1999), "AGIE EDM technology enters the space race", Aircraft Engineering and Aerospace Technology, Vol. 71 No. 3. https://doi.org/10.1108/aeat.1999.12771cab.017

AGIE EDM technology enters the space race

AGIE EDM technology enters the space race

Keywords Aerospace industry, AGIE EDM, Satellites, Waveguide

Luton-based precision engineering company, Multispark Erosion, has recently completed production of an order for waveguide filters for communication satellites using AGIE EDM machines.

The company, which uses EDM to manufacture individual and small series components, and prototypes for the aerospace industry, specifies AGIE machines for their ability to erode difficult-to-maintain materials.

Plate 7 Two of the refurbished autoclaves at Brookhouse Composites Ltd

The order for the waveguide filters, produced in a small series of 16 from an iron and nickel alloy, posed four very distinct potential problems that could only be overcome using EDM: the Invar iron-nickel alloy is extremely difficult to machine; the waveguide filter had to be produced from one piece; the finished workpiece had to be absolutely free from stress; and, despite its small series production, a high repeatability of quality and geometric precision was essential (Plate 8). Following trials to determine material behaviour and machining sequences, Multispark commenced production using the company's AGIE Mondo Star 50 diesink EDM.

The tolerances laid down were extremely strict. Each of the 16 parts needed to be produced with a tolerance of ±0.05 mm, a surface roughness of Ra = 1.2 µm and wall thicknesses of just 0.9 mm. In addition, machining reliability became ever more important as the value of the workpieces increased as each neared completion.

We understand that despite the intricacy of components, Multispark was able to conduct many of the operations unsupervised. The AGIE Mondo Star's Adaptive Current Optimisation and Adaptive Current Control functions, and integral five position electrode changer, enabled Multispark to utilise a large number of forming electrodes for roughing, semi-finishing and finishing processes unsupervised. In addition, data input for further machining steps or electrode changing could reportedly be conducted whilst the AGIE was operational using its multi-tasking and real-time process optimisation capabilities.

Plate 8 This communication satellite waveguide is manufactured from one piece using an AGIE Mondo Star 50 diesink EDM

Preparation and set-up times amounted to approximately 40 hours, with a further 40 hours required to produce the electrodes and total electro-discharge machining approaching 100 hours. The total project time of 180 hours equated to a delivery time of less than one month.

The AGIE Mondo Star 50 diesink EDM has been designed for manufacturers requiring flexibility for complex machining operations within a limited budget. It accommodates workpieces of up to 860 x 650 x 315 mm, weighing up to 500 kg, and features the FUTURA V generator allowing a maximum working current of 64A and a removal rate of 500 mm3/min.

The complexities of implementing multicavity, planetary, helical shape and deep rib erosion are simplified. The integrated C-axis can be used to erode, position or rotate, and erosion on all four axes can be programmed on a step-by-step basis. Productivity is further enhanced by a choice of magazine for up to 5 right electrodes.

Dowty Aerospace is another company that has re-invested in AGIE EDM equipment to help it meet demand for key aerospace components which would be extremely difficult to proceed using other processes.

Dowty Aerospace Isle of Man, part of the Dowty hydraulic and actuation group of companies, has chosen an AGIE Compact 2 diesink EDM to boost production of valves and hydraulic locking devices for undercarriage systems (Plate 9). The company supplies components for both civil and military aerospace programmes. The new machine joins Dowty's existing AGIE 2U EDM in a direct response to an increase in orders for components for the Airbus A319, A320 and A321.

The 2U and Compact 2 are used to erode cavities ranging in size from 0.007 inches in diameter up to 0.7 x 0.4 inches wide, achieving tolerances of 0.001 on the diameter and 0.0005 on position. In addition to a high level of accuracy, profiles for critical porting features need to be machined internally which would be difficult or impossible to reach using conventional machining methods.

Plate 9 Dowty Aerospace, Isle of Man, has invested in an AGIE Compact 2 to boost production of key aerospace components

Dowty has now doubled its production of Airbus components from 9 to 18 sets a month, and relies on the machines' unmanned production capabilities to help achieve this. After an initial setting, the AGIE machines are left to run for unsupervised day and lights-out machining. Technological advances in EDM mean that the Compact 2 also offers the company a 25 per cent reduction on previous cycle times.

The Compact 2 is completely compatible with the 2U and has fitted straight into Dowty's manufacturing unit, creating a flexible system able to run programmes on either AGIE machine.

"High precision, the ability to run long periods unmanned, and reliability all led to the choice of our second AGIE EDM", commented Malcolm Macdonald, director and general manager of Dowry Aerospace Isle of Man. "We wouldn't have got the go ahead if the existing machine did not provide all this, but our experience justified re-investment in AGIE. We deliver finished parts direct to customers in Toulouse and Hamburg so they have to be right and we bought the Compact without any hesitation. With a new machine there is generally a learning curve ­ you have to go backwards before you can go forwards, but the AGIE machine fitted in right away and we started production almost immediately after installation. The new machine is even more advanced and apart from the improvement in cycle time, programming has been further simplified to make it more user-friendly."

Further details from AGIE Ltd, Tel: 01675 463112.