1、 Workpiece over cutting:
reason:
1. The tool strength is not too long or too small, causing the tool to snap.
2. Improper operation by the operator.
3. Uneven cutting allowance. (For example, 0.5 for the side of the curved surface and 0.15 for the bottom)
4. Improper cutting parameters (such as too large tolerance, SF setting too fast, etc.).
improve:
1. The principle of using a knife: big or small, short or long.
2. Add the corner cleaning procedure, and leave the allowance as uniform as possible (the allowance on the side and bottom shall be consistent).
3. Reasonably adjust the cutting parameters and round off the corners with large allowance.
4. Using the SF function of the machine tool, the operator can fine tune the speed to achieve the best cutting effect.
2、 Centering problem:
reason:
1. Inaccurate manual operation by the operator.
2. There are burrs around the mold.
3. The center splitter is magnetic.
4. The four sides of the mold are not vertical.
improve:
1. Manual operation shall be carefully checked repeatedly, and the points shall be at the same point and height as much as possible.
2. Use an oilstone or file to deburr the periphery of the mold, and then use a rag to clean it, and finally confirm it by hand.
3. Demagnetize the centering rod before centering the mold (ceramic centering rod or others can be used).
4. Check whether the four sides of the mold are vertical by calibration (if the perpendicularity error is large, review the plan with the fitter).
3、 Tool setting problem:
reason:
1. Inaccurate manual operation by the operator.
2. The tool is clamped incorrectly.
3. The blade on the flying knife is wrong (the flying knife itself has a certain error).
4. There are errors between knife R and flat bottom knife and flying knife.
improve:
1. The manual operation shall be carefully checked repeatedly, and the tool setting shall be at the same point as far as possible.
2. Use air gun or rag to clean the tool during clamping.
3. One blade can be used when the upper blade of the flying knife needs to measure the tool bar and smooth bottom surface.
4. A separate tool setting program can avoid the error between R flat knife and flying knife.
4、 Collision – programming:
reason:
1. The safety height is insufficient or not set (the tool or collet collides with the workpiece during rapid feed G00).
2. The tool on the program sheet is wrongly written with the actual program tool.
3. The tool length (blade length) on the program sheet and the actual processing depth are incorrectly written.
4. The depth Z-axis access and the actual Z-axis access on the program sheet are wrongly written.
5. Coordinate setting error during programming.
improve:
1. Accurate measurement of the height of the workpiece also ensures that the safe height is above the workpiece.
2. The tool on the program sheet shall be consistent with the actual program tool (try to use automatic program sheet or picture program sheet).
3. Measure the actual machining depth on the workpiece, and write down the tool length and blade length on the program sheet (generally, the tool clamp length is 2-3MM higher than the workpiece, and the blade length is 0.5-1.0MM).
4. The actual Z-axis data is taken from the workpiece and written clearly on the program sheet. (This operation is generally a manual operation, which shall be checked repeatedly).
5、 Collision – Operator:
reason:
1. Depth Z-axis tool setting error.
2. The number of hits and operands in the split is wrong (for example, there is no feed radius for unilateral access).
3. Wrong tool is used (e.g. D4 tool is processed with D10 tool).
4. The program goes wrong (e.g. A7.NC goes to A9.NC).
5. The handwheel is rotated in the wrong direction during manual operation.
6. Press the wrong direction during manual rapid feed (e.g. – X press+X).
improve:
1. In depth Z-axis tool setting, pay attention to the tool setting position. (Bottom surface, top surface, analysis surface, etc.).
2. Repeated inspection shall be carried out after the completion of split touch number and operation number.
3. The tool shall be installed after repeatedly checking with the program list and program.
4. The program should go one by one in order.
5. When using manual operation, the operator shall enhance the operation proficiency of the machine tool.
6. When moving quickly manually, you can first raise the Z axis to the workpiece and move it.
6、 Surface accuracy:
reason:
1. The cutting parameters are unreasonable, and the surface of the workpiece surface is rough.
2. The knife edge is not sharp.
3. The tool clamping is too long, and the blade avoidance is too long.
4. Chip removal, air blowing and oil flushing are not good.
5. Programming tool path mode (running milling can be considered as far as possible).
6. The workpiece has burrs.
improve:
1. The cutting parameters, tolerance, allowance and speed feed shall be set reasonably.
2. The operator is required to check and replace the tools irregularly.
3. When clamping the tool, the operator is required to clamp it as short as possible, and the blade should not be too long.
4. For the undercut of flat knife, R knife and round nose knife, the speed feed setting should be reasonable.
5. The workpiece has burrs: it is directly related to our machine tools, cutting tools and cutting methods. Therefore, we should understand the performance of the machine tool and repair the edge with burrs.