How to solve the problem of wire cutting in the middle of the wire? Handling of broken wires, threaded holes and deviations

1. Broken wire

 

1) Poor quality of molybdenum wire-choose a good quality molybdenum wire.

 

2) The selection of processing parameters is unreasonable-choose suitable processing parameters for different materials and workpiece thicknesses. Please note that the wire is likely to break when the current is large.

 

3) The conductive block wears out of the groove and the wire is clamped off-adjust the conductive block to a new position, and replace the conductive block if necessary.

 

4) The concentration of the cutting fluid is not appropriate-keep the concentration of the cutting fluid at 11-12.5%.

 

5) Molybdenum wire is clamped off due to deformation of the workpiece: material cutting deformation is avoided: material heat treatment technology is reasonable; pre-processing wire holes; pre-cutting to relieve stress; optimizing the cutting path.

 

6) There are non-conductive impurities in the workpiece material or non-conductive oxides on the surface of the workpiece-replace the material; remove the non-conductive impurities and then cut.

 

7) The flushing fluid is too small to effectively penetrate into the slit, and the discharge conditions are severe, causing wire breakage-set a reasonable flushing fluid size; regularly check whether the cutting fluid is sufficient and the circulation channel is unblocked.

 

8) The accuracy of the guide wheel (especially the support guide wheel)-the bearing should be replaced regularly in strict accordance with the machine maintenance instructions, and the guide wheel or bearing should be replaced when necessary.

 

9) The tension provided by the counterweight is too large-2 counterweights for 0.2mm molybdenum wire; 1 counterweight for 0.18mm molybdenum wire; 0.15-0.12mm wire does not need to be equipped.

 

10) The molybdenum wire was not replaced in time after a lot of wear and tear——replace the molybdenum wire in time. 

2. Surface roughness becomes worse

 

1) The cutting fluid has been used for a long time and the concentration is not appropriate-keep the coolant concentration at 11-12.5%, and replace the cutting fluid if necessary.

 

2) The capstan and bearing wear-observe whether the electrode wire is jittery, and listen to whether there are abnormal noises in the bearings of each part, so as to determine whether to replace the bearing or the guide wheel, and replace it if necessary.

 

3) The trimming process is wrong ---- Correct selection of trimming condition number and offset.

 

4) Workpiece deformation---avoid material cutting deformation: material heat treatment technology is reasonable; pre-processed wire holes; pre-cutting to relieve stress; optimizing the cutting path.

 

5) Molybdenum wire wears a lot-replace with a new molybdenum wire.

 

6) The organizational structure of materials-different materials have different processing effects.

 

7) The state of the machine tool is not good-check whether the lubrication of each guide wheel, wire barrel, conductive block, and each screw guide is in the best condition.

 

3. Low processing efficiency

 

1) The selection of processing parameters is unreasonable-choose suitable processing parameters for different materials and workpiece thicknesses. Please note that the processing efficiency is low when the current is small.

 

2) The concentration of the cutting fluid is inappropriate-keep the concentration of the cutting fluid at 11-12.5%.

 

3) Deformation of the workpiece leads to unstable discharge state during machining, especially trimming-----control deformation.

 

4) The trimming speed is slow-the relative processing volume of each cut can be reduced a bit. If the trimming speed is increased, the offset of the main cutting can be reduced by 0.01mm-0.02mm.

 

4. Maintenance and replacement of cutting fluid concentration

 

1) The water-to-water ratio for the initial preparation of water-based cutting fluid is 1:5.5, and then the concentration is checked to maintain the concentration. After each water replenishment, it is checked to determine whether it needs to be refilled.

 

2) Water should be replenished every shift and the concentration of the working fluid should be tested. Use a hand-held refractometer with a concentration detector for detection. Under normal circumstances, the concentration reading should be maintained between 11.0 and 12.5. When the concentration is exceeded, it should be filled with water, and when it is lower, the concentration should be filled with fluid.

 

3) During the processing, the color of the working fluid will gradually become darker, or even brownish-black, which is a normal phenomenon. As long as the effective filtration is ensured, the performance will not be affected.

 

4) The best effect is to use pure water.

 

5) Water-based cutting fluid is prone to produce a large amount of foam during use. At this time, it is necessary to spray some defoamer at the location of the working fluid tank and the water tank and the water outlet of the fluid tank to solve it.

 

6) When the cutting fluid is very dirty, replace all the cutting fluid and clean the cutting fluid tank.

 

5. Problems related to taper processing

 

1) The influence of the change of the tangent point of the guide wheel on the processing size, resulting in trapezoidal error-----In order to reduce this error, the graph can be rotated by 45°, and the X and Y axes can be linked, and the error can be greatly reduced; Another method is to add transition circles at the corners when the workpiece allows.

 

2) Overcut is formed due to the existence of a small transition circle, and an alarm of "overcut or arc radius too large" appears during cutting-the taper cutting parameter of "workpiece thickness" can be changed artificially.

 

3) After cutting some taper parts, it is found that one end is cut ----- When taper programming, the "retract length" should be changed to be greater than or equal to the length of the feed line.

 

6. Treatment of the deviation of the threaded hole during multi-hole processing

 

If the position of the threading hole is found to be offset, there is a deviation from the coordinate position in the program. The processing method is to move the XY axis and thread the molybdenum wire into the threading hole to ensure that there is no short circuit (the voltmeter indicates 5V). Without terminating the current processing program, use "manual processing" to the threading point of the current hole of the program At the coordinates, close the "Manual Machining" window and move the X or Y axis of the machine tool with a movement greater than 0.001mm. Then click the pause point in the electrical discharge machining interface and press the green machining button on the manual control box to start machining.

 

7. The trace display does not match the actual program

 

The cursor position is not on the contour line during normal processing or simulation-Uo and Vo are not cleared after the molybdenum wire is vertical in the processing preparation stage. In the spark alignment window, clear Uo and Vo to zero, and set the user coordinates U and V to the reference 0 point at the same time.

 

8. "The arc and the arc are connected incorrectly" alarm

 

Increase or decrease the arc I or J value in the alarm program line by 0.001.

 

After the modification, process the file modification, from the original three decimal places to four decimal places. The specific steps are:

1) Find the Metalcam folder of the FIKUS installation file, double-click to find the Fikusvisualcam folder;

2) Find the post folder, double-click to find the cfg folder;

3) Find the post-processing file edmAGIE-FW-G61.cfg, and change Max. digits for fractional part 3 to 4.

 

9. Unqualified workpiece size

 

1) The molybdenum wire is in a non-vertical state-----calibrate the molybdenum wire with a wire calibrator.

 

2) Inappropriate offset-first try cutting, and correct the offset according to the actual size.

 

3) Loss of molybdenum wire----replace the electrode wire in time or correct the offset in time.

 

4) The condition of the machine tool is not good ---- Whether the lubrication of each guide wheel, wire barrel, conductive block, and each screw guide is in the best condition.

 

5) Workpiece deformation-avoid material cutting deformation: material heat treatment technology is reasonable; pre-processed wire holes; pre-cutting to relieve stress; optimizing the cutting path.

 

10. How to reduce the wear of conductive block when processing aluminum

 

1) Reasonable selection of pulse electrical parameters.

 

2) The cutting fluid has good fluidity and washing properties and guarantees a good filtering effect.

 

3) A thin steel plate can be added on the upper and lower surfaces of the processed aluminum parts, which can reduce the adhesion of alumina or particles with alumina on the surface on the electrode wire.