Machine tool maintenance engineer years of work experience
        1. Electrical components of the mechanical problems
        In addition to having a good mechanical properties, but also inseparable from the sound and reasonable electrical principle of the design and configuration of the original electrical installation and use of the device. In the process of electrical maintenance of electrical equipment often occurs in the mechanical failure of the original device.

        Case is as follows: 

        ① a X52K milling machine in the processing of parts, the table X positive and negative directions are not working in both directions, the inspection found that the work table X direction of the trip switch between the normally open contacts and normally closed contacts Of the spring, for a long time in continuous operation due to positive and negative direction of the two repeatedly press the change; coupled with the vibration of the machine will be fixed spring screws to shake off, resulting in spring off; trip switch contact point broken off can not be normal use , Resulting in equipment table X positive and negative both directions are not working properly. After re-installing the new limit switch, the device is operating normally.

        ② There is a lathe CM6125 at work when the spindle motor is only buzzing boot, the motor can not rotate properly, resulting in the spindle can not turn, can not be cutting. This is the motor running single-phase symptoms, check the main switch circuit breaker intact, three-phase AC 380V power supply phase is not the lack of phase, the switches and insurance are intact, check the AC contactor on the interface three-phase voltage, AC contactor Coil 36V pull is also normal. For safety reasons, the device power switch off the power to check, will control the single-phase spindle AC contactor normally open contact with a screwdriver from the top down, with a multimeter to measure the contact resistance of the normally open contact is off. The inspection found that two-phase contact conduction, one phase does not turn, which is the single-phase motor to run the main reason.
        Why is the AC contactor normally open with a lot of power down the button can not turn it? After the contactor is removed from the distribution box after the inspection found that the contactor due to contact copper thin, poor quality, long-time over-current heating, the contacts burned deformation upturned, coupled with the internal spring has been burned annealing And the loss of flexibility, the card often can not touch the fixed contact contacts, so the motor phase failure caused the motor can not work. After the replacement of the new AC contactor equipment is operating normally.
        We can not ignore the electrical equipment in the process of maintenance and installation of the mechanical problems inherent in the device itself, even if a new electrical original devices, but also to check whether the mechanical structure of its flexible, reliable, the electrical aspects of attention to the original device The size of the load current and voltage level is consistent with the original design requirements. When it is required to install again when debugging to prevent problems after installation, maintenance work to bring unnecessary trouble.


        2. Electrical problems related to the machine

        Our electrical maintenance process equipment, often only concerned about the electrical circuit equipment, but ignores the electrical machinery associated with the problem.
        (1) Case 1: We have a vertical machining center imported from Russia, the system has been updated to Fanuc 0i-MC. Equipment in the work of the spindle when the tool is not allowed to locate the problem, there is no alarm. We first adjust the parameters of the positioning of the machine the necessary adjustments and modifications, boot restart, the return of each mechanical axis reference point to work properly, and then the spindle spindle orientation tool change. The first spindle tool change positioning accuracy, when the second time the spindle tool change positioning, the spindle tool change position appeared a dozen degrees of deviation. After repeatedly modifying the parameter values and spindle tool change positioning, there are different degrees of spindle angular deviation, can not correctly align the robot tool change position.
        Where does the problem lie? We take to the robot tool change process distribution of working principle analysis: ① analysis of electrical lines and the system is no problem on the grounds that each change of different parameters, the spindle motor rotation is working properly. The encoder attached to the spindle head correctly executes the computer send and return commands. ② related to the mechanical part of the inspection, analysis that: there may be a spindle on the spindle and the encoder between the soft coupling out of the question. We will remove the encoder on the spindle to find the soft coupling has been broken, the encoder and the spindle soft coupling due to infinitive friction displacement, leading to spindle positioning tool change inaccurate angle deviation. After the replacement of the new spindle and the encoder between the soft couplings after the equipment location tool change is accurate, working properly.
        (2) Case 2: My unit has a Swiss horizontal machining center, in the exchange of workstations often appear halfway to stop for Taiwan failure, check did not find that after the sensor and switch problems, the computer system is working properly, all hydraulic valves, electromagnetic Valve and relief valve work is normal, that is, the exchange of workstations, when the exchange of hydraulic piston retractor to the bench when the machine does not stop the implementation of the next command, and an alarm. We did a single inspection of all of the electrical parts of our exchange workbench and found no problems.
        Since the electrical problems and causes can not be found, we work on the exchange stage work step by step to check the mechanical part. When the T-hook is extended from the piston cylinder to the T-shaped groove below the table in the spindle direction, the position of the T-hook on the piston is opposite to the position of the T-shaped groove of the table. Deviation of 0.4mm, resulting in a change table when the piston hook does not extend into the workbench below the slot, and withstand the table does not move, resulting in the exchange table when the shutdown alarm failure.
        The problem is found, we will work on the T-shaped slot removed, with the milling machine to the left side of the deviation of the excess side mill 1.5mm. Installed on the table, the first manual mode after the switch table, the piston on the T-shaped hook can be very well into the table below the hanging slot, and then automatic table exchange, everything is normal.
        Some seemingly electrical equipment failure, in fact, the problem with the machinery itself are interrelated, to conduct a comprehensive mechanical and electrical part of the inspection, in order to find the problem.
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