Wire EDM (Electro-Discharge Machining)
A specialist process also known as Wire Erosion.
This extremely accurate process allows the cutting of intricate shapes and fine details in hard and difficult to work materials such as castings, carbides, titanium, hardened steels and super-alloys although it is possible to process virtually any conductive material. The hardness of the material does not present a problem.
There is no force involved in machining or other difficulties associated with conventional machining such as tool wear, work hardening, stress relieving etc. The process is extremely quiet and it produces a surface finish superior to laser or water-jet cutting.
The Wire EDM Cutting Process
The EDM process involves a moving wire (usually hard-drawn brass wire of 0.1 – 0.3mm diameter) which is fed from one spool to another. The wire is electrically charged and acts as an electrode to simply ‘burn’ or melt the material away. As the wire is fed between the spools the bed of the machine moves the component in order to create the desired shape.
This non-conventional machining process is tightly controlled for use in the aerospace industry because by its very nature EDM produces a microscopic re-melt layer that forms on the surface of the parent material. This is often removed by media blasting for the sake of appearance, but sometimes also by necessity.
This ‘crust’ can hide imperfections and evidence of ‘arching’.
The NADCAP program exists to ensure that all parameters during EDM are closely monitored, machines are routinely maintained and inspection of components is thorough and in accordance with customer (subscribers) requirements.
For customers such as Cessna, GE Aviation, Goodrich, Hawker Beechcraft, Honeywell, MTU Aero Engines, Rolls Royce and Pratt & Whitney the prerequisite is that suppliers must have a valid NADCAP accreditation.
VES Precision holds the following:-
NM#183358 – certificate no. 5444183358 NADCAP approval for AC7116 Rev. C – Non-conventional machining and AC7116/3 Rev. C for wire EDM.
We have 15 Fanuc EDM machines making us one of the largest NADCAP approved EDM specialists in the UK.
VES Precision is based in Crewkerne, Somerset and was established in 1991 in order to provide precision machining services with capabilities including CNC milling, turning, EDM Wire Erosion, grinding, lapping and surface blasting as well as a dedicated in-house inspection facility.