The cause of the abnormal treatment of treatment is hidden and the diagnosis is difficult. Today, I summed up the 4 main diagnostic principles and 5 diagnostic methods.
1. Causes of abnormal precision
Five main reasons: the unit of machine tools is modified or modified; ; A mechanical failure, like the screws, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the live, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, like the screw, Like the screw. In addition, preparing treatment procedures, selecting human tools and factors can also lead to abnormal treatment accuracy.
2. Principles of diagnosis of failure of the CNC machine
1. First, the internal CNC machine is a mechanical, hydraulic and electrical machine tool. Maintenance staff should be studied one by one by one to avoid opening and disassembly freely as much as possible.
2. In general, the electricity is generally easy to discover, while the diagnosis of failure of the CNC system is more difficult. Before defects, first pay attention to the elimination of mechanical failure, which can often make more efforts.
3. First cut, then move into the static state of the tool-tool. For destructive faults, you must first exclude danger before the power of power.
4. Simply and then complex. Often, after simple problems, the difficult problem can also be easier.
3. Diagnosis of diagnostic for defect of the CNC machine
1. Audio method: (looking at the question and cutting) – Machine failure, treatment state, etc. Soon.
2. Parameter verification method: The parameters are generally stored in the RAM. Check and related school parameters must be checked.
3. Isolation method: Some defects are difficult to distinguish if it is a CNC part, a servo system or a mechanical part, and is often used.
4. Similarly, the replacement of models suspected of defective models by the same function of the same function, or to exchange the same models or units of the same function.
5. Functional program test method writing all the instructions for the function of G, M, S and T to write a few small programs, and run these programs when diagnosing the failure to determine the lack of function.
4. Examples of diagnosis and treatment of abnormal accuracy of treatment of treatment accuracy
1. Mechanical failure causes abnormal treatment accuracy
Failure phenomenon: an SV-1000 vertical treatment center, using a frank system. During the treatment link mold, the Z axis proved to be abnormal, causing at least 1 mm of cutting errors (cutting the direction of Z).
Diagnosis of failure: During the investigation, the fault occurred suddenly. The machine tool moves. The following aspects must be checked one by one.
Check the treatment treatment segment when the tool-tool is abnormal, in particular the compensation for scale length, and the rereading and calculation of the treatment coordinate system (G54-G59).
In the way of moving, exercising the Z axis several times. Is more obvious. From this judgment, there may be hidden dangers in the machines.
Check the precision of the Z axis of the machine. Move the Z axis by hand with a hand-shaped pulse generator (fixed to a 1 × 100 gear, that is to say that each change stage, the engine is 0.1 mm) , and the movement of the Z axis is observed with the percentage table. Once the exercise has a roadway is normal, as a positive movement at the starting point, each stage of the impulse device changes, the real distance from the movement of the axis z of the machine d = d1 = D2 = D3 = … = 0.1 mm well. In terms of modifications to the real movement displacement of the machine tool, it can be divided into four stages: (1) Movement distance of the machine D1> D = 0.1 mm (the slope is greater than 1); (2) Watch D1 = 0.1 mm> D2> D3 (the slope is less than 1); (3) The establishment of the machine does not move, showing the most standard opposite difference; Values (the slope is equal to 1) to restore the normal movement of the machine tool. Whatever the way to compensate for the opposite difference, the characteristics are: with the exception of the compensation (3) of the step, other changes in each step always exist, in particular the (1) step seriously affects the treatment of the tool-machine. It is noted in compensation that the greater the gap compensation, the greater the distance between the movement at the stage.
Analysis of the above tests that there are several possible causes: first, the engine has anomalies, the other is the failure of the mechanics, and the third is that there is a difference in the screw. In order to further diagnose the defect, the engine and the screw are completely removed and the engine and the mechanical parts are verified. The results of the inspection were the engine normally; In normal circumstances, you should feel that the bearings move in an ordered and smooth movement.
Failure treatment: After disassembly examination, the bearings proved to be damaged and exceeded. The rear tool replacement is restored to normal.
2. The inappropriate control logic leads to an abnormal treatment accuracy
Failure phenomenon: The treatment center produced by a manufacturer of Shanghai machine tools, the system is frank. During the processing process, it was found that the precision of the X axis of the machine was abnormal. Diagnosis: During the examination, the tool-tool set up the coordinate system of part G54 according to the requirements. As part of the manual input data operation, run a program in the G54 coordinate system, “Goog90g54x60.oy70.of150; M30;”, the value of mechanical coordinates displayed on the standby display is in standby is (axis x) “1025.243”, the following value recorded. Then, manually, move the tool-tool to other positions and run the program segment as part of the manual input data operation. 1024.891 “At this time. The comparison of the latter’s values is 0.352 mm. According to the same method, the X axis moves to different positions and performs the segment several times, and the values displayed on the screen are different (unstable). Therefore, there are problems such as the network rule and the parameters of the system.
Defect processing: Modified the control program of the PLC logic of the machine tool, that is to say that the X axis is loose, the X axis can be loaded first, then the x axis is loosened. After setting the machine-tool defect to resolve.
3. Problem of the machine-tool causes abnormal treatment accuracy
Failure phenomenon: a CNC vertical grinding produced in Hangzhou, equipped with the KND-10M system in Beijing. During movement or treatment, the Z axis was abnormal.
Fault diagnosis: The examination revealed that the Z axis was moving unevenly and the noise, and there was a certain gap. When the engine begins, there is an unstable noise and force in the movement up of the Z axis under the movement method, and the sensation of the engine is relatively strong; But when the movement is moved, it is not so obvious; During treatment. The analysis considers that there are three reasons for failure: one is that the opposite space in the screw is very important; However, it should be noted that when stopping, it does not shake and the upper and lower exercise is unequal, so the problem of abnormal engine work can be excluded. Consequently, the mechanical part of the diagnosis is first diagnosed, and no abnormality is found during the diagnostic and test process in tolerance. Using the exclusion rules, the rest is only the belt problem. He?
Failure treatment: as long as the engine is reinstalled, intended for the angle, measured the distance (the engine bearing and the z axis), and the two sides of the belt (length) must be uniform. In this way, the Z axis moves unevenly and the noise and the jig, and the treatment of the Z axis returns to normal.
4. System parameters are not optimized and the engine operation is abnormal
The parameters of the precision treatment of treatment accuracy mainly include machine tools for units, zero biases, inverted gaps, etc. For example, the Frank CNC system has two types of feeders: the public and British system. During the repair of the machine tool, local treatment often affects changes in biases and gaps. The modifications must be modified accordingly to meet the requirements of the processing of the machine.
Failure phenomenon: a CNC vertical grinding produced in Hangzhou, equipped with the KND-10M system in Beijing. During the processing process, the precision of the X axis was abnormal.
Failure diagnosis: The inspection revealed that there is a certain gap in the X axis, and there is an unstable phenomenon in the engine. When you touch the X axis engine by hand, it believes that the engine is very powerful. The analysis considers that there are two causes of failure: one is that the reckless gap between the screw is very large; The other is that the engine of the X axis is abnormal.
Failure treatment: Use the KND-10M system settings to debug the engine. First compensate for the existence gap, then adjust the parameters of the Servo system and the impulse inhibitor function parameters.
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