Electrolytic processing is a special processing method that uses a principle that the metal is dissolved in an electrolyte to form a workpiece.
During processing, the workpiece is connected to the positive pole of the DC power supply, the tool is connected to the negative pole, and a small gap is maintained between the two poles.
The electrolyte flows through the interelectrode gap, forming a conductive path between the two poles, and generating an electric current at a power supply voltage, thereby forming an electrochemical anode to dissolve.
As the tool continues to feed relative to the workpiece, the workpiece metal is continuously electrolyzed.
The electrolysis product is continuously washed away by the electrolyte, and finally the gaps between the two poles tend to be uniform, and the surface of the workpiece forms a shape substantially similar to the tool working surface.
Electrolytic machining has significant advantages for the processing of difficult-to-machine materials, complex shapes or thin-walled parts.
Electrolytic machining has been widely used, such as barrel rifling, blades, integral impellers, molds, profiled and profiled parts, chamfering and deburring.
And in the processing of many parts, electrolytic processing has occupied an important or even irreplaceable position.
Characteristics of electrolytic processing
(1) Wide processing range.
Electrolytic machining can process almost all conductive materials, and is not limited by mechanical and physical properties such as strength, hardness and toughness of the materials.
The metallographic structure of the processed material does not substantially change.
It is commonly used to process difficult-to-machine materials such as hard alloys, high-temperature alloys, hardened steels, and stainless steel.
(2) High productivity.
And processing productivity is not directly limited by processing accuracy and surface roughness.
Electrolytic machining can process complex cavities, profiles and holes in a single linear feed motion, and the processing speed can be increased in proportion to the current density.
According to statistics, the productivity of electrolytic machining is about 5 to 10 times that of EDM.
In some cases, it can even exceed mechanical machining.
(3) Good processing quality.
A certain processing precision and a low surface roughness can be obtained.
Machining accuracy (mm): profile and cavity are ± 0.05 ~ 0.20;
Shaped holes and nesting are ± 0.03 ~ 0.05.
Surface roughness (μm): For general medium and high carbon steels and alloy steels, Ra1.6 ~ 0.4 can be stably achieved, and some alloy steels can reach Ra0.1.
(4) It can be used to machine thin-walled and easily deformable parts.
During the electrolytic machining process, the tool and the workpiece are not in contact, there is no mechanical cutting force, no residual stress and deformation, no flash burrs.
(5) The tool cathode has no loss.
In the electrolysis process, only hydrogen gas is precipitated on the tool cathode, and no dissolution reaction occurs, so there is no loss.
Cathode damage can only occur if an abnormal phenomenon such as a spark or a short circuit occurs.
Limitations of electrolytic machining
However, things are always divided into two aspects.
Electrolytic processing also has certain limitations, mainly as follows:
(1) Processing accuracy and processing stability are not high.
The machining accuracy and stability of electrolytic machining depend on the accuracy of the cathode and the control of the machining gap.
The design, manufacture and correction of the cathode are difficult, and the accuracy of the cathode is difficult to guarantee.
In addition, there are many factors affecting the electrolytic machining gap, and the law is difficult to grasp, and the control of the machining gap is difficult.
(2) Due to the difficulty in designing, manufacturing and correcting the cathode and the fixture, the cycle is long, so the cost of single-piece small-batch production is high.
At the same time, there are many auxiliary equipments required for electrolytic processing, and the floor space is large, and the machine tool needs sufficient rigidity and anti-corrosion performance, and the cost is high.
Therefore, the smaller the batch size, the higher the cost per piece of additional equipment.