How to use EDM to process cooling holes for aircraft engine blades?

The Electrical discharge machining(EDM) is a special processing equipment, also known as the EDM machine tool . Its basic principle is based on the electro-erosion phenomenon of pulse discharge. During the processing, the tool electrode and the workpiece are connected to the two poles of the pulse power supply respectively, and the working fluid (such as special oil for EDM or other liquids with good insulation properties) is filled between the two. When the gap between the two poles is small to a certain extent, the pulse voltage causes the working fluid medium to ionize and break down, resulting in spark discharge. The instantaneous high temperature (up to 10000-12000℃) causes the local metal on the surface of the workpiece to melt and vaporize, and is washed away by the working fluid, leaving discharge pits on the workpiece. As the discharge process continues, these pits continue to accumulate, and finally the purpose of processing is achieved. According to the processing method, it can be divided into EDM perforator, EDM forming machine and EDM wire cutting machine.

EDM machines can be used to process cooling holes for aircraft engine blades. These cooling holes are small in diameter, complex in shape, and require extremely high position accuracy and surface quality. EDM can accurately process these small holes on the blades without generating mechanical cutting forces, avoiding deformation of parts caused by cutting forces during the machining process, thereby ensuring the accuracy and performance of the parts.

Recently, Shanghai ANTS Machine Equipment Co., Ltd. successfully received a customer from the United Arab Emirates who needed to use an EDM punching machine to process cooling holes for aircraft engine blades. The size of the engine blade is 350*250mm, and the diameter of the hole to be punched is 0.2mm.

According to the customer’s needs, ANTS engineers successfully matched the customer with a CNC punching machine-MS-DC430A, with a drilling diameter of 0.1-3mm. The travel of the X/Y axis is 400*300mm. The maximum spindle speed is 1500mm/min.

The following are the basic parameters of MS-DC430A:

Next, the engineers of Antis will introduce you to the process of machining cooling holes of aircraft engine blades in detail:

 1.Preparation:

(1) Design and manufacture electrodes: Design and manufacture suitable electrodes according to the shape and size of the cooling holes. Electrodes are usually made of conductive materials, such as copper, graphite, etc.

(2) Prepare blades: Clean and fix the aircraft engine blades that need to be machined with cooling holes to ensure that the blades do not move during the machining process.

(3) Install electrodes and blades: Install the electrodes on the workbench of the EDM machine and fix the blades above the electrodes to ensure that the distance between the electrodes and the blades is appropriate.

2.Adjust machining parameters:

(1) Adjust the machining parameters of the EDM machine, such as discharge current, discharge time, pulse interval, etc., according to the requirements of the blade material and cooling holes.

(2) Select the appropriate working fluid: The working fluid of EDM involves cooling, sheet removal and insulation. Select the appropriate working fluid according to the blade material and machining requirements.

3.Perform machining:

(1) Start the EDM machine to generate discharge sparks between the electrode and the blade, gradually corrode the blade material and form cooling holes.

(2) During the processing, the required distance between the electrode and the blade is continuously adjusted to ensure the processing accuracy and surface quality.

(3) After the processing is completed, turn off the EDM machine and take out the processed blade.

4.Post-processing:

(2) Clean the processed blade to remove the working fluid and residual metal chips.

(2) Check the size, shape and cooling surface quality of the hole, and perform trimming and polishing if necessary.

Heat treat the blade to improve its strength and corrosion resistance.

If you have any questions, please contact Shanghai Antis Machinery Equipment Co., Ltd. through our website information. Engineers will match you with efficient machine tools and professional services.

Keywords: CNC machine tools, EDM machines, EDM machining of cooling holes for aircraft engine blades