Troubleshooting of automated machine tools technology

Paper Keywords: CNC machine tool troubleshooting analysis

Abstract: CNC machine tools, electrical system failure investigation, analysis and diagnosis of the process is trouble-shooting process, once identified the reason, the failure will almost equal to the excluded. So the method of fault analysis and diagnosis is very important.



First, the failure investigation and analysis

This is the first stage of troubleshooting is a very critical stage, the main should be ready the following:
1, asked investigating the scene after receiving faulty machine demands the removal of information, the operator should be required first of all try to keep on-site fault condition, no treatment, so that is conducive to rapid and precise analysis of the problem.

2, on-site inspection to the scene, the first operator to verify the circumstances provided the accuracy, completeness, and thus to verify the accuracy of initial judgments. As the level of the operator, the ambiguous description of fault conditions or even inaccurate the example of the situation, so do not rush to the scene to approach even after the re-investigate all the circumstances carefully, so as not to damage the site, making troubleshooting more difficult.

3, failure analysis based on the known fault conditions described by the classification of fault type of fault to determine the troubleshooting principles. Since most of the fault is indicated, so under normal circumstances, the control of CNC machine tools supporting the diagnostic manual and instructions, can produce the failure of the various lists of possible causes.

4, determine the cause of the many possible reasons for the investigation to find out the real cause of this failure, this time for maintenance personnel is a familiarity with the tools, knowledge, practical experience and analytical ability of the comprehensive test.

5, troubleshooting for some troubleshooting method may be very simple, some failures are often more complex and need to do a series of preparations, such as tools for the preparation of instruments, local demolition, repair parts, components and even the procurement of troubleshooting steps in the development plan and so on.

The following commonly used in the diagnosis of electrical faults fully listed below.

(1) visual inspection method which is the beginning of failure analysis methods must be used, is the use of sensory examination.

�� ask site personnel asked in detail about the failure process of generating fault, fault and fault consequences of representation, and analysis to determine the whole process may be repeated inquiries.

�� visual part of the work overall view of the state machine is in normal state (for example, the axis position, axis status, knife, robot location, etc.), the electronic control devices (such as numerical control systems, temperature control equipment, lubrication equipment, etc.) have No alarm indicator, local see whether the insurance burning Duan, charred components, cracking, wire and cable loss, the operating components in the correct position or not and so on.

(2) Instrument test for the use of conventional electrical instruments, the group of AC and DC power supply, the relevant DC and pulse signals were measured in a search for possible failure. For example, the power supply with a multimeter to check the situation and some circuit boards signal state set on the measuring point related measurements, the pulse associated with the oscilloscope signal amplitude, phase, or even whether, with the PLC programmer to find parts of PLC program and the reasons for such failure.

(3) signal analysis and alarm indication
�� This refers to the hardware alarm indicator including CNC system, servo system, including the electronic, electrical devices of various status and fault indicators, with LED status and function of the corresponding instructions that can be informed of the content and cause of the malfunction and troubleshooting methods.

�� software alarm system software instructions mentioned above, PLC programs and processing procedures are usually equipped with fault alarm display, alarm display number according to the appropriate diagnostic manual control can be informed of possible causes and troubleshooting methods.

(4) interface state test for many modern numerical control system which will be integrated in the PLC, and a range of CNC and PLC interface signals between the Zeyi forms of mutual communication link. Some fault with the interface signals associated with errors or missing, these interface signals are can be in the corresponding interface board and input / output panel LED display, and some simple operations can be displayed on the CRT screen, and all the interface signals can be transferred out with the PLC programmer.

(5) Parameter Adjustment Act CNC, PLC and servo drive systems are set many parameters can be modified to adapt to different machines, different operating conditions of the request. These parameters not only make all electrical systems and specific Jichuang match, but also to make machine tools of various functions necessary to achieve the best. Therefore, any change in parameters (in particular, analog parameters) are not allowed even lost, but were caused by the bed long-running performance of the mechanical or electrical changes will break the initial state and optimal state match. such failure means more than one fault classification fault in the latter category, need to re-adjust one or more parameters related to only exclude.

(6) Spare parts replacement method when the results of failure analysis focused on a printed circuit board, due to the integrated circuit continues to expand and take on its failure to implement certain components of a region and it is very difficult, in order to shorten downtime, spare parts in the same condition can be replaced with the spare first, and then go check and repair faults board.

In view of the above conditions, the pull out before the new board replaced the old board must first carefully read the relevant information, understand the requirements and steps before getting to work so as not to cause more problems. Reposted elsewhere in the Research Papers Download http://www . hi138.com (7) cross-conversion method when the board found fault or failure can not determine whether the board but there is no case of spare parts can be the same or compatible system board swap the two checks, for example, two coordinates instruction plate or servo board from the exchange board or failure to determine fault location. This cross-conversion law should pay particular attention to not only the correct exchange of the hardware connection, but also the corresponding parameters of a series of exchange, or not achieving its purpose, but will result in failure to generate new thinking, confusion, be sure to advance thoughtful, well designed software and hardware exchange programs, exchange of accurate re-examination.

(8) special treatment method today has entered the PC-based CNC system, opening stage of development, including software, more and more rich content, a system software, machine tool manufacturer software, and even user's own software, the software logic the design of some of the problems inevitably will make no analysis of some fault condition, such as backing out. For this failure phenomenon can take special measures to deal with, such as machine power, a pause and then start, sometimes it may eliminate the fault. maintenance staff can explore their own long-term practice of its laws or other effective methods.


Second, electrical maintenance and trouble-shooting

Electrical failure analysis process is a trouble-shooting process, so an electrical fault of some commonly used exclusion methods in the analysis of the previous section has introduced a comprehensive, this section lists several common electrical failure is a brief introduction, for the maintenance of reference.

1, power supply maintenance system is working properly and the whole machine energy source, and its failure or malfunction light who will lose data, resulting in downtime. Severe cases, partial or all of the system will be destroyed. Western countries, because of sufficient power, power quality, so The electrical system design considerations less power, which China has a greater volatility and for the high harmonics of the power supply network is to slightly less than, together with some human factors, will inevitably lead to power caused by the failure.

2, position loop numerical control system failure
�� position loop alarm. May be open circuit position measurement, measurement component damage, the position control signal does not exist to establish such an interface.

�� axis case in the absence of instruction in motion. May be too large drift, position or velocity loop are connected to form a positive feedback loop, feedback wiring open circuit, measuring cell damage.

3, the machine can not find the zero coordinates. May be zero in the direction away from zero, the encoder wiring is damaged or open, the grating zero marked shift back to zero deceleration switch failure.

4, the dynamic characteristics of machine deterioration, decline in the quality workpiece, and even occur in a certain speed machine tool vibration. Which is very possible that mechanical transmission gap is too large or badly worn or rail lubrication or wear caused by inadequate , for electrical control systems may be a speed loop and position loop parameters and the best matching state longer should be the basic rule out mechanical failure after the re-optimization.

5, the occasional downtime. There are two possible situations: one is mentioned above related to software design problems caused in the operation and function of specific combinations of the shutdown operation, under normal circumstances Machine will disappear again after power off, and the other is caused by environmental conditions, such as strong interference (power or peripheral devices), high temperature or humidity and so on. that environmental factors are often neglected by people, such as ordinary machine placed in the southern region near the plant or even open the door near the door panels for a long time to run, near a large number of dust, metal chips or water spray equipment and so on. These factors not only result in failure, serious damage will systems and tools, be sure to pay attention to improvement. Links http://www.hi138.com Research Papers Download