What factors affect the machining accuracy of a Sodick EDM?

The following are some of the factors that will affect the machining accuracy of Sardick spark machine:

First, the electrode factors

Electrode materials: different electrode materials have different physical properties, such as copper electrode conductivity is good but relatively large loss, graphite electrode loss is small but the processing surface quality may be slightly worse, the choice of electrode materials will affect the processing accuracy. For example, in the processing of some high-precision molds, according to the requirements of the mold and the material characteristics of the choice of the appropriate electrode material.

Electrode precision: the manufacturing precision of the electrode is directly related to the machining accuracy, if the electrode itself is not up to the standard size tolerance, shape accuracy, then the precision of the processed workpiece will also be affected. Generally speaking, the manufacturing tolerance of the electrode should be controlled at about 1/2 of the tolerance of the workpiece.

Electrode loss: In the process of spark machine machining, the electrode will produce loss due to discharge, uneven electrode loss will lead to a decline in machining accuracy. For example, in the processing of corners, edges and other raised position, the electric field strength is higher, the electrode loss is faster than the flat position, thus affecting the shape of the workpiece precision.

Processing parameters

Pulse width and peak current: increasing the pulse width and peak current will increase the individual pulse energy, which will lead to an increase in the roughness value of the machined surface, affecting the machining accuracy. However, if you want to improve the processing speed, often need to correspondingly increase the current, which requires a balance between the processing speed and accuracy.

Discharge gap: the size of the discharge gap and its consistency has an important impact on the machining accuracy. Discharge gap is too small, easy to produce arc, short circuit and other abnormal discharge phenomena, damage to the electrode and the workpiece, affecting the machining accuracy; discharge gap is too large, it will make the processing of dimensional deviation increases. In addition, the secondary discharge caused by galvanic corrosion products will also affect the stability of the discharge gap, which in turn affects the machining accuracy.

Servo base: servo base set unreasonable will lead to electrode and workpiece discharge between the state is not stable, affecting the machining accuracy.

Third, the working fluid factors

The type and performance of the working fluid: different working fluids have different insulation properties, cooling performance and chip removal performance, choose the right working fluid can improve machining accuracy. For example, in finishing, the need to use a lower viscosity, good insulation properties of the working fluid, in order to obtain a better machining surface quality.

The degree of contamination of the working fluid: the dirtier the working fluid, the more opportunities for secondary discharge, which will lead to an increase in the number of electrode liftback, so that the machining slope increases, affecting the machining accuracy.

Fourth, the workpiece factors

Workpiece materials: different workpiece materials have different electrical conductivity, coefficient of thermal expansion and other physical properties, these properties will affect the machining accuracy of the spark machine. For example, some of the high hardness, high strength materials are more difficult to process, easy to produce cracks and deformation, affecting the machining accuracy.

Workpiece clamping and positioning: workpiece clamping and positioning accuracy directly affects the machining accuracy, if the workpiece is not firmly clamped or positioning inaccurate, displacement and vibration will occur during the machining process, resulting in reduced machining accuracy.

Fifth, equipment factors

The precision and rigidity of the machine tool: the precision and rigidity of the Shadick spark machine itself is the basic factor affecting the machining accuracy. If the machine's coordinate axis movement accuracy is not high, the table flatness is not good, the spindle verticality deviation, etc., will lead to reduced machining accuracy.

Control system: Advanced control system can realize more precise machining control, such as precise electrode feed control, discharge energy control, etc., so as to improve machining accuracy. If the performance of the control system is not good, there will be control errors, affecting the machining accuracy.

Temperature and humidity: Changes in ambient temperature and humidity will affect the precision and stability of the machine tool, which in turn affects machining accuracy. For example, the deformation of cast iron at a temperature difference of 1°C is about 1.1μm/m. Excessive humidity will affect the life of the circuit boards in the machine.

Vibration: Vibration during machining will make the discharge state between the electrode and the workpiece unstable, resulting in obvious line marks, affecting the machining accuracy.