Material characteristics
Red copper: electrolytic copper forged without impurities is the best.;
Graphite: Fine-grained dense, isotropic high-purity graphite.
Finishing
Copper:
- 1. Low electrode loss;
- 2. The processed surface can reach Ra≤0.1μm, suitable for mirror surface processing;
- 3.If there are lines on the surface, the lines etched out by the copper are more uniform.
Graphite:1. Large loss of finishing electrode.;
Roughing
Red copper: 1. After being used, it can be reused after restructuring, with high utilization rate.
Graphite:
- 1. Fast opening speed and good air permeability;
- 2. Low electrode loss, suitable for processing enlarged cavities.
Material utilization:
Machining performance
Copper:
- 1. The machining performance is poor, and it is difficult to finish grinding in fine turning. The improvement method: welding copper on the steel base;
- 2. Easy to deform, difficult to grind, not suitable for processing fine parts;
- 3. Easy to shape
Graphite:
- 1. Good machining performance, easy to form and correct;
- 2. When making thin and deep bone electrode, it will not be deformed, it is very brittle, and would rather break than deform;
- 3. It can withstand high temperature without deformation;
- 4. Only high-speed machines can be processed, brittle and hard, and the tools are easy to wear, so special graphite knives are required
- 5. It is easy to collapse, large dust, easy to fall off, easy to deposit carbon, and slag. Pay attention to the protection of machine tool guides.
Ways to improve
Immerse the graphite in spark oil for a period of time before processing the electrode, and the chipping angle can be significantly improved.
price
Graphite is cheap, and copper electrodes are durable but expensive.
Graphite:
- 1. Low density, suitable for making large parts or tool electrodes for mold processing, with low overall quality
- 2.It is prone to arc burns.
Selection principle
Red copper: fine processing, mirror processing.
Graphite: rough machining, thin and deep bone machining.
Graphite is easy to process, and the processing efficiency is at least three times higher than that of copper, and the discharge speed is much faster than that of copper.As a mold with high efficiency and short delivery time, graphite is the development trend.
Advantages of graphite
1. Electrode design
- 1. The number of single electrodes can be reduced/combined electrodes can be made
- 2. It can save electrode fixture system to save cost
2. Electrode processing and production
- 1. High-speed milling roughing is 3 times that of copper block
- 2. High-speed milling finishing is 5 times faster than copper
- 3. Good processability
- 4. Able to realize complex geometric modeling
3. Light weight, its density is less than 1/4 of copper
- 1. Good thermal stability (no deformation)
- 2. The number of single electrodes can be reduced/combined electrodes can be made
- 3. No need to deburr
- 4. The electrode is easy to clamp
4.EDM
- 1. Low electrode loss during rough machining
- 2. High work removal rate
- 3. The number of single electrodes can be reduced/combined electrodes can be made
- 4. No pollution to the environment in the electrolyte
- 5. Light weight, its density is less than 1/4 of copper
- 6. Excellent thermal stability, the electrode does not deform
- 7. Selecting fine-grained graphite electrodes can process high-quality workpiece surfaces
First of all, graphite and copper are compared in terms of materials: graphite is light and brittle, and copper is tough and heavy.
The discharge capacity of the two is determined according to the size of the electrode. Under normal circumstances, the spark level of the larger electrode is larger. In general, the precision is 0.03-0.1mm. The material selection should be based on the actual situation, and each has its advantages: In terms of small ribs, graphite is easy to deform during processing. Copper will be deformed and difficult to process. In terms of large electrodes, the difference between the two is weight. The damage to CNC is larger than that of copper, because graphite is produced It is powder, which is extremely harmful to the CNC track. At this time, it is necessary to protect it, and the sheath of the vacuum cleaner and the guide rail must be added. Copper is generally selected as copper as the electrode.
Graphite electrode is a kind of granular structure, and it cannot be processed into a mirror surface. If you want to process a mirror surface, the best is the copper electrode. There are also graphite electrodes that generally do not need to be polished. The processing speed of graphite electrodes is fast but the surface roughness is not as good as that of copper electrodes. Graphite electrode consumes a lot. Generally, the graphite electrode of the mold parts is rough and the red copper electrode is refined, so I personally think it is more ideal. The graphite electrode has better cutting performance for CNC machining than the copper electrode. There is a special CNC machine for graphite CNC machining. Taiwan. The common gap of graphite electrode is 0.11mm 0.08mm 0.03mm
