Abstract: In recent years, in the process of maintaining imported numerical control equipment, some fault laws of numerical control system have been gradually understood and mastered.
Sort out the rules and rapid diagnosis methods. The purpose is to provide reference for the use and maintenance of CNC equipment.
Keywords: CNC machine tools; Diagnosis and maintenance; way
With the continuous introduction of advanced technology and equipment in developed countries
It is inevitable that the maintenance of our equipment maintenance personnel will become more and more difficult.
The fact of denial. But how to adapt and master as soon as possible is what we should do.
The topics that should be discussed seriously and urgently need to be solved are as follows.
Personal maintenance experience.
Hitachi Seiki VA-65 and HC- 1 introduced by the author in recent years.
800 two machining centers, not only AC servo drive, four-axis connection.
Dynamic function, with full closed-loop position feedback and automatic measurement of magnetic grating.
Quantity, automatic cutting monitoring system, its numerical control was the first in the world at that time.
In FANUC- 1 1M system. Run 1 1 year, although with
With the increase of service life, some parts are aging, and the failure period is coming.
In recent years, especially with the increase of processing tasks, the equipment has been running 24 hours a day.
Operation, almost every week there is a phenomenon of fault alarm. if it were not for
In order to ensure the completion of the task on time, we have not received training at home and abroad.
And the drawings are incomplete. In many maintenance tests,
Carefully analyze the failure law, continuously accumulate relevant data, and gradually master the dimension.
Maintenance points, try to find out the fault point in the shortest time, and use the fastest one.
Speed repair adjustment completed. The following is a discussion of rapid diagnosis and
Maintenance methods of numerical control equipment:
1 Observe and inquire before handling.
Look at the alarm information first, because most CNC systems now
With perfect self-diagnosis function, it can be known immediately through prompt information.
Road fault area, narrow the detection range. It's like a HC-800 bedroom.
50 10 # spindle drive unit appears in the operational machining center.
Call the police, call the police, and we will check it in order according to the prompt information immediately.
Spindle motor and its executive components, spindle control panel, find out overcurrent and open circuit.
/kloc-it only takes 20 minutes to return to normal after 0/0. But according to our experience,
There are also examples of being misled by alarm information, so it can be said that it can be based on but
You can't rely on it
If there is no alarm information after the fault occurs, it needs to be further used.
For an official, the most important thing to know the equipment status is to ask the operator.
Causes and consequences of failure. The same device, once it
When the protective cover is not opened, the APC system suddenly rotates the B axis.
The shield has never been scratched before. Be us
Inquire about the operation process carefully on site to find out the fault course: original operation.
Personnel first input M60 instruction to make _bPm_? APC system program running (more
In the turntable), when the actuator is out of control and stops halfway, re-enter.
Perform single-step instruction operation in manual state. At that time, M60 was not yet available.
Deleted, and continue the original program after the actuator returns to normal.
Work. After careful understanding and analysis, we immediately deleted all
The original set of instructions, to detect and replace out-of-control parts, to avoid bigger.
The occurrence of a fault. According to the alarm information and the equipment state before the failure,
Determine the fault area and strive for maintenance time.
2 Follow the principle of maintenance from the outside to the inside, from the shallow to the deep.
According to the author's years of maintenance experience in machining centers, most of them
The root causes of failures are all external components because they are influenced by external factors.
Great influence, such as mechanical collision and wear, coolant corrosion, excessive dust accumulation,
Poor lubrication, etc. , make these disrepair parts in poor condition,
Unreliable state has become the biggest hidden danger of equipment failure. Just like every axis meridian
Overtravel alarm, zero reset error and no feedback of position signal often occur.
And so on, all caused by some kind of magnetic or mechanical switch failure. There are others.
Frequently retractable solenoid valves, motors and cables will also fail.
B-axis like HC-800 does not rotate properly, or sometimes it does not rotate at all.
Rotation failure, the alarm prompt is: feed shaft failure (APC com2
Mand), it seems to have something to do with orders. But according to the fault phenomenon,
Or decisively check the travel limit of axis B, and sure enough there is a bulge.
The switch contact is not good, and it is normal after adjustment. This avoids aimlessness.
Spend a lot of energy to check the whole CNC system, focusing on the outside first.
In the department.
This is actually an empirical diagnosis. If we have it,
If there is a principle wiring diagram, it should be compared according to the drawings.
Find and test potentials and waveforms in sequence and learn from them.
Realize something theoretical. It is precisely because there is no such condition,
Therefore, we follow the principle of "from outside to inside, from people to outside" in maintenance.
To the system, from the shallow to the deep principle, which greatly shortened the design.
Standby downtime.
3 Make full use of PC diagram to find the fault point
According to the alarm information, bring up the PC diagram related to it for analysis.
Examination is also a convenient diagnostic method. A VA-65 from
After the manipulator for moving and replacing tools is in place, it will not execute the command of grabbing tools, and we will make adjustments immediately.
The PC diagram shows the switching signal from each command to each forward, backward, loosening and tightening action.
Check the signals one by one, and finally find out the signal to which the manipulator rotates.
The number was not issued because the magnetic proximity switch was loose and moved backward.
It doesn't work, so that the next knife grasping action can't be carried out, and it will be restored after adjustment.
Normal.
It seems more convenient and intuitive to check the fault point with PC diagram, but if
I don't know its internal working principle and working procedure, so to speak.
Looking for a needle in a haystack, there is no way to start. Especially without electrical schematic diagram, it is even more difficult.
To judge, each output action can only be filled with dozens of switching conditions.
That's enough. It really takes a lot of effort to understand and master it gradually. we
Is to rely on the usual long-term maintenance, in constant understanding and transportation.
Use it.
4. Detection, analysis and quick treatment of difficult faults
Some parts of these two machining centers have been aging for a long time, which makes their parameters change with temperature.
Or current changes, and can automatically recover after a fault.
The phenomenon of instant good and bad is what we scratch our heads most. because
Maintenance workers know that broken parts are easy to detect, not abnormal.
It is difficult to judge whether the components are broken or the lines are in poor contact.
Reason, because normal signal detection can't be done. Such as b-axis operation
Taiwan Province transposition; The knife inlet of the tool magazine automatically opens; Clamping and loosening of B-axis bedplate
Fault and other faults, its executive component is a solid-state relay that accepts instructions.
After the signal is connected, the solenoid valve is driven to act. There may be no difference when testing.
Often everything may be normal after the start, and then stop after several consecutive actions.
Machine alarm. According to the fault phenomenon and repeated cycle, we should judge that it is
Due to the decline of the performance of the actuator, due to unclear drawings and unclear identification, only
Can be associated with a set of actuators under normal and abnormal conditions.
Without testing, after repeated testing, we finally got more than 30 relay components.
Found and replaced degraded components.
HC-800 B axis origin reset is out of control, giving instructions.
After rotating, there is no alarm message. After on-site understanding and analysis, firstly,
Determine that it should be the fault of the B-axis zero detection system, which is composed of
The magnetic proximity switch sends out a position signal to control the actuator to descend.
Stop the car. We immediately tested the line of this signal, and as a result,
No signal is sent. If a signal is set in place artificially, it will stop accurately.
Car, confirm that there is a fault between the detection switch and the set signal point. but
If the proximity switch is to be detected directly, the B-axis and must be turned off.
The axis adjustment of the joint is disassembled because this switch is installed on the B-axis workbench.
Such a large structure has never been demolished and repaired before. Measure the workload.
It takes half a month, and more than a dozen of them should be carefully controlled.
It is difficult to ensure the disassembly and repair of cables and dozens of oil pipes.
After the accuracy of each part, but in order to solve the problem, it must also be revealed.
Switches for testing and maintenance. You can use a simple method
After repeated discussions, the workload of disassembly and assembly can be saved and the detection switch can be taken out.
After verification, I finally came up with a bracket that only removed the B-axis end cover and the axis adjusting magnetic ruler.
How to take out this switch. Despite the disassembly and testing by electrical maintenance personnel.
It is very difficult, but it ensures that the countertop does not disintegrate and reduces the influence of future troubles.
Minimize. After the actual test, the switch is in the original position.
After installation, the B-axis reset function is restored, but it will also affect.
The position error of axis adjustment and the positioning fault of axis B are compensated and adjusted.
After everything is normal, the goods will be delivered in three days, which ensures the trial production.
Handle the completion of the task.
5 conclusion
In a word, how to open our minds and make progress as soon as possible in the process of dealing with faults.
The root cause of entering the state, narrowing the detection range and direct contact with the fault is the maintenance technician.
The key to the level of employees. Seemingly simple facts are full of
All aspects are also the crystallization of maintenance personnel's efforts for many years. I
It is under the pressure of this high-frequency fault that scientists have overcome many difficulties.
Difficult, try to solve the problem in a short time and reduce the downtime of the equipment.
It has made our due contribution to the trial production of the vehicle model.
[References]
[1] Li, Long Zeming, Han. Crawling problem of CNC machine tools
Analysis and research [J]. Modular machine tools and automatic machining technology,
2006 , ( 10) :76~78.
[2] Jordis. Numerical control technology and application [M]. Beijing: national defense industry.
Press, 1997.