How to deal with problems in CNC machining

Here are six problems during in CNC machining, Danke tells you how to deal with these problems in CNC machining.

一．Overcutting of the workpiece:

Reason:

1. Bouncing knife, the tool strength is not too long or too small, causing the tool to bouncing off.

2. Improper operation by the operator.

3. Uneven cutting allowance. (For example: leave 0.5 on the side of the curved surface and 0.15 on the bottom)

4. Improper cutting parameters (such as too large tolerance, SF setting too fast, etc.).

Improve methods:

1. The principle of knife use: can be big but not small, short but not long.

2. Add the corner cleaning program, and keep the margin as even as possible (the side and bottom margins are the same).

3. Reasonably adjust the cutting parameters, and round the corners with large margins.

4. Using the SF function of the machine tool, the operator fine-tunes the speed to achieve the best cutting effect.

二．Question of dividing:

Reason:

1. The operator is not accurate during manual operation.

2. There are burrs around the mold.

3. The center rod has magnetism.

4. The four sides of the mold are not vertical.

Improve methods:

1. Manual operation should be carefully checked repeatedly, and the points should be at the same height as possible.

2. Deburring around the mold with oilstone or a file, wipe it clean with a rag, and finally confirm it by hand.

3. Demagnetize the centering rod before centering the mold (ceramic centering rod or others can be used).

4. Calibrate to check whether the four sides of the mold are vertical, (large vertical error requires reviewing the plan with the fitter).

三．Problem of knife setting:

Reason:

1. The operator is not accurate during manual operation.

2. The tool clamping is wrong.

3. The blade on the flying knife is wrong (the flying knife itself has a certain error).

4. There is an error between the R knife and the flat-bottom knife and the flying knife.

Improve methods:

1. Manual operation should be carefully checked repeatedly, and the tool setting should be at the same point as much as possible.

2. When the tool is clamped, blow it with an air gun or wipe it with a rag.

3. One blade can be used when the upper blade of the flying knife needs to measure the tool shaft and the smooth bottom surface.

4. A separate tool setting program can avoid the error between R knife, flat knife and flying knife.

四．Collision-programming

Reason:

1. The safety height is insufficient or not set (the tool or the chuck hits the workpiece when the rapid feed is G00).

2. The tool on the program sheet and the actual program tool are written incorrectly.

3. The tool length (blade length) and the actual machining depth on the program sheet are wrong.

4. The depth Z-axis access and actual Z-axis access on the program sheet are incorrectly written.

5. The coordinates are set incorrectly during programming.

Improve methods:

1. Accurate measurement of the height of the workpiece also ensures that the safety height is above the workpiece.

2. The tool on the program list must be consistent with the actual program tool (try to use the automatic program list or the picture to list the program list).

3. Measure the actual machining depth on the workpiece, and write clearly the length and blade length of the tool on the program sheet (generally, the length of the tool holder is 2-3MM higher than the workpiece, and the blade length is 0.5-1.0MM).

4. Take the actual number of Z axis on the workpiece and write it clearly on the program sheet. (This operation is generally written manually and needs to be checked repeatedly).

五．Collision-operator

Reason:

1. The depth Z axis tool setting error.

2. The number of hits and operations in the division are wrong (such as: there is no feed radius in the unilateral reading, etc.).

3. Use the wrong tool (for example: D4 tool is used for processing with D10 tool).

4. The program went wrong (for example: A7.NC went A9.NC).

5. The handwheel is turned in the wrong direction during manual operation.

6. Press the wrong direction during manual rapid feed (for example: -X press +X).

Improve methods:

1. Be sure to pay attention to the position of the depth Z-axis tool setting. (Bottom surface, top surface, analysis surface, etc.).

2. Check repeatedly after the count and the operation are completed.

3. When clamping the tool, check it repeatedly with the program list and the program before loading it.

4. The program should go one by one in order.

5. When using manual operation, the operator himself must strengthen the operation proficiency of the machine tool.

6. In manual rapid traverse, you can first raise the Z axis to the workpiece before moving.

六．Surface accuracy

Reason:

1. Unreasonable cutting parameters and rough surface of the workpiece.

2. The cutting edge of the tool is not sharp.

3. The tool clamping is too long, and the blade is too long to avoid the air.

4. Chip removal, air blowing, oil flushing is not good.

5. Programming the way of cutting tool, (you can consider down milling as much as possible).

6. The workpiece has burrs.

Improve methods:

1. Cutting parameters, tolerances, margins, and speed feed settings should be reasonable.

2. The tool requires the operator to inspect and replace it irregularly.

3. When clamping the tool, the operator is required to clamp as short as possible, and the cutting edge should not be too long.

4. For the down-cutting 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. So we have to understand the performance of the machine tool and make up the edges with burrs.