General purpose CNC EDM wire cut machine is a kind of mechanical processing equipment. It uses electrode wire (molybdenum wire, tungsten molybdenum wire, etc.) as tool electrode. Under the action of pulse power supply, spark discharge is formed between the tool electrode and the workpiece, and the spark channel generates a lot of heat instantly, which melts or even vaporizes the surface of the workpiece. The wire cutting machine moves the electrode wire along the predetermined trajectory through the movement of the XY pallet and the UV pallet, so as to achieve the purpose of processing the workpiece.
CNC EDM wire cut, which is like EDM, also directly uses electric energy and heat to process the workpiece, and can process various conductive materials that are difficult to process by ordinary cutting methods, such as high hardness, high brittleness, high toughness, high heat-sensitive metal or semiconductor materials. As one of the important supplements of machining, wire EDM has opened up a new way for the trial production of new products, the manufacture of precision fine parts and molds.
During wire EDM cutting, the electrode wire is connected to the negative pole of the pulse power supply and the workpiece is connected to the positive pole of the pulse power supply. Add a pulse power supply between the positive and negative poles. When an electric pulse comes, a spark discharge is generated between the electrode wire and the workpiece, and the temperature in the center of the discharge channel can reach over 10000 °C instantaneously. The high temperature causes the workpiece metal to melt, and even a small amount of gasification occurs. Part of the working fluid between the workpieces is vaporized. These vaporized working fluids and metal vapors rapidly thermally expand instantaneously and have the characteristics of explosion. This thermal expansion and local micro-explosion throw the melted and vaporized metal material to realize the electro-erosion cutting of the workpiece material. It is generally considered that the discharge gap between the electrode wire and the workpiece is about 0.01mm. If the voltage of the electric pulse is high, the discharge gap will be larger.
(1) Programming and drawing are one of the main functions of EDM wire cut machine
In addition, the functions of mirroring, symmetry, and translation and rotation of the workpiece can also be realized in the computer. It also has an excellent feature. When the machine has a short circuit, the CNC EDM wire cut machine can be automatically processed. The circuit can be corrected and the operation can continue normally. Unless all lines are shorted, the machine can automatically shut down and prompt the operator for repairs. Because the general processing of some workpieces is more complicated, the EDM wire cut machine can also perform reverse processing according to the processing requirements to meet the special requirements of some workpieces. According to the requirements of the workpiece, any section of the workpiece can be selected for processing, and other parts of the workpiece that do not need to be processed will not be damaged. If the proportion of the workpiece to be processed is large, the workpiece can also be scaled proportionally in the computer, so that it is very convenient to process.
(2) EDM wire cut machine can also realize power-off protection
In the event of a power failure, the general purpose CNC EDM wire cut machine will automatically stop and save the set data. When the power is turned on, it can continue to work without resetting. During processing, the EDM wire cut machine can automatically correct the center position of the workpiece without manually comparing the workpiece to find the center. The EDM wire cut machine also has a man-machine dialogue function. This function is very powerful. Some instructions can be directly issued to the machine without inputting through the computer, which is convenient for operation. The current technology of EDM wire cut machine is quite advanced. It uses the most advanced mold processing technology in the world. From computer control, it can grasp the processing track and time at any time, and make timely corrections.
(1) Reasonable matching of pulse electrical parameters
When wire cutting is processing aluminum parts, a wider pulse width is likely to produce relatively large alumina or particles with alumina on the surface. If the pulse interval is too small, larger particles will also be generated.
However, these larger processed particles are easily adhered to the molybdenum wire, which has a great negative impact on the processing. Increasing the no-load voltage amplitude of the pulse power supply and reducing the pulse width and the machining pulse gap can reduce the possibility of machining chips adhering to the electrode wire.
(2) Requirements for working fluid
At present, the aqueous solution of emulsion is often used as the working fluid for CNC high-speed wire cutting processing. The conventional configuration ratio is 1:10 (1 part of emulsion and 10 parts of water). When processing aluminum materials, the ratio of 3:8 can be used. In order to keep the working fluid clean, make it work normally and effectively, and prolong the service life of the working fluid, a thick sponge can be used to prevent debris from flowing into the water tank, keep the working fluid unblocked and reduce the adhesion of machining debris on the electrode wire. Clean or replace sponge pads regularly. The amount of water sprayed up and down the working fluid should be uniform, so as to remove the corrosion in time.