Common Problems and Solutions in Slow Wire Cutting

1、 Broken wire

1. Poor discharge state – reduce the P value. If the P value decreases greatly and the wire is still broken, consider reducing the I value until the wire is continuous. This operation will reduce the processing efficiency. If the wire breaks frequently, please refer to the following contents to find out the root cause of the wire break.

2. The liquid flushing state is not good, and the upper and lower nozzles cannot be veneered, or the broken wire is usually located in the processing area during open machining—— Lower the P value and check whether the upper and lower nozzles are damaged. If damaged, replace them in time.

3. The conductive block is seriously worn or too dirty, and the broken wire is usually located near the conductive block—— Rotate or replace the conductive block and clean it.

4. The guide wire is too dirty, resulting in wire scraping. The broken wire is usually located near the guide wire—— Clean the guide wire parts.

5. Too large tension – lower the wire tension FW in the parameter, especially in taper cutting.

6. The quality of electrode wire and workpiece material is defective—— Replace the electrode wire and reduce the P and I values until the wire is continuous.

7. The waste silk in the waste silk barrel overflows and contacts with the machine tool or the bottom surface, causing a short circuit. Usually, the wire will break just after starting the processing—— Put the spilled waste silk back into the waste silk bucket, and clean the waste silk bucket in time.

8. Broken wire at the take-up wheel – check the wire pressing ratio of the take-up wheel. The standard value is 1:1.5~1.6.

9. The cooling water of the conductive block is insufficient, and the broken wire is usually located near the conductive block – check the cooling water circuit.

10. The conductivity of deionized water is too high, and the broken wire is usually located in the processing area – check the conductivity of water. If it is out of tolerance, replace the resin in time.

11. The quality of deionized water is poor, and the broken wire is usually located in the processing area—— If the water in the water tank is turbid or smelly, or there is a problem with the purified water added to the machine tool, clean the water tank in time and replace the filter paper core.

12. The wire is broken, there is waste wire embedded at the ceramic guide wheel of the lower head, or the guide wheel bearing is not flexible—— Clean, readjust and install the ceramic guide wheel, and replace the guide wheel bearing if necessary.

13. The balance wheel shakes too much and the wire conveying is not stable—— The wire speed shall be corrected, and the wire tension shall be corrected with a tensiometer.

2、 Low processing speed

1. The upper and lower nozzles are not processed according to the standard process, and the distance from the upper and lower nozzles to the workpiece is higher than 0.1mm – veneer processing as much as possible.

2. The process file created is incorrect—— Correctly input relevant processing requirements and generate reasonable process documents.

3. The processing parameters have been modified, especially if the P and I values are reduced too much, the processing speed will be greatly reduced—— Discharge process parameters shall be reasonably modified.

4. The flushing state is not good, and the standard flushing pressure cannot be reached—— If it is true that the veneer processing cannot be carried out, the processing speed shall be correctly recognized.

5. The workpiece deformation leads to unstable discharge state during machining, especially during trimming—— Reasonably arrange the process and control the material deformation.

6. If ACO (Automatic Process Optimization) is selected in the parameter, the processing efficiency will be reduced in case of unstable processing—— ACO function can be canceled when cutting is stable.

7. For workpieces with many corners, using high-precision parameters can achieve higher accuracy, but will reduce efficiency—— The machining speed can be improved by appropriately reducing the STR value of corner strategy.

8. In mode 30 processing, the discharge stability is poor, and the speed is slow. Modify the parameter UHP, and 2 values can be increased.

9. Slow trimming speed—— The relative processing amount of each cutter can be reduced a little. To increase the speed of trimming, the offset of the main cutter can be reduced by 0.005mm~0.01mm.

10. The main cutting efficiency is lower than before—— Timely maintain the machine tool.

3、 Filament mark on the surface

1. The quality of electrode wire is defective—— Original consumables are recommended.

2. The workpiece material is defective, or the material contains impurities—— Change the workpiece material.

3. The release of local internal stress in the internal organization of the workpiece will lead to the occurrence of line marks at individual positions of the workpiece—— Optimize the processing technology to reduce the internal stress and deformation of materials.

4. The working fluid temperature is too high or the temperature changes too much—— The refrigerator must be used to control the liquid temperature and ensure the proper ambient temperature.

5. The external environment of the machine tool is harsh and the vibration is large—— Improve the external environment of the machine tool.

6. The conductive block is seriously worn—— Rotate or replace the conductive block.

7. The cooling water of upper and lower conductive blocks is insufficient—— Clean related parts.

8. The guide wire is too dirty—— Maintain the guide wire part.

9. The working fluid is too dirty—— Clean the fluid tank and water tank, and replace the working fluid.

10. Observe whether the discharge state is stable and whether the short circuit fallback occurs during repair—— If there is a short circuit during repair, the UHP value can be increased by 1~2.

11. If the discharge current and voltage are normal during repair, but the speed is very low—— You can reduce the relative offset.

12. The flushing state is not good, and the standard flushing pressure and jet shape cannot be reached—— Check whether the upper and lower nozzles are damaged. If damaged, replace them in time.

13. The wire tension is unstable—— Calibrate the thread speed and tension.

4、 The surface is not polished

1. The relative offset is too small—— Increase the relative offset appropriately.

2. Uneven cutting speed caused by workpiece material deformation during trimming—— Reasonably arrange the process to reduce material deformation.

3. The quality of electrode wire is poor. Original consumables are recommended.

4. The guide wire is too dirty—— Maintain the guide wire part.

5. The conductive block is seriously worn. Rotate or replace the conductive block.

6. Wrong selection of process parameters—— Correctly input relevant processing requirements and generate reasonable process documents.

7. The flushing state is not good, and the standard flushing pressure and jet shape cannot be reached—— Check whether the upper and lower nozzles are damaged. If damaged, replace them in time.

5、 Large cutting shape error

1. When cutting corners, the lagging of electrode wire will cause corner collapse—— For workpieces requiring high corner accuracy, parameters with corner strategy shall be selected.

2. In order to reduce the deformation of large workpieces during processing, the processing technology can be improved:

(1) Die:

Make two main cuts. First, increase the compensation of the main cut by 0.1mm~0.2mm on one side to make the first main cut, release the stress, and then make the second main cut with the standard offset.

(2) Punch:

1) Two or more temporary reserves shall be reserved, and open machining shall be adopted during programming.

2) Arrange reasonable cutting position and support position. Punch holes as far as possible to avoid cutting directly from the outside of the material.

3. The wire is not vertical—— Conduct wire correction again.

4. The external environment of the machine tool is harsh and the vibration is large—— Improve the external environment of the machine tool.

5. Quality problems of electrode wire and workpiece materials—— It is recommended to use original consumables and materials without quality problems.

6. The distance between the workpiece clamping position and the upper and lower nozzles is too large—— Adjust the clamping method.

7. The thread speed or tension is unstable—— Adjust or calibrate the thread speed and tension.

8. The flushing conditions have changed significantly, resulting in large wire vibration—— Check the upper and lower nozzles. If the nozzles are damaged, replace them in time.

9. Whether the shaft and upper and lower arms of the machine tool collide, causing changes in mechanical accuracy—— If the shaft or upper and lower arms collide, causing abnormal accuracy, the service personnel shall be contacted in time for maintenance.

6、 Concave center or bulge of workpiece

1. Concave center in the middle of the workpiece: it can reduce the Ssoll value of the main cutting and repair cutting parameters, increase the wire speed and tension, increase the constant speed cutting speed of the last cutter, and increase the relative offset between repair 1 and the main cutting.

2. Bulging in the middle of the workpiece: it is opposite to the method of processing the concave center of the workpiece.

7、 Straight workpiece reducer

1. The quality of electrode wire is poor—— Original consumables are recommended.

2. Optimize parameters.

1) Increase the wire speed and slightly increase the wire tension.

2) Adjust parameter CCON.

3) During programming, taper compensation is added to the program.

8、 Thread mark at the feed of female die

1. Arc cut in arc cut out mode is adopted. During programming, the mode of arc cut in – arc cut out is adopted, and the arc size is 0.5mm.

2. The cut in/cut out point separation mode is adopted. During programming, set each feed point at a different position to avoid feeding and withdrawing from the same point.