CNC Machine Tool Troubleshooting and Classification
Computer Numerical Control (CNC) machine tools are widely used in the manufacturing industry for their precise and repeatable control of movements. The fundamental principles of CNC machine tool control operations can be applied to any machine tool. Therefore, troubleshooting and classification of CNC machine tools is similar to those of non-CNC machine tools.
Troubleshooting CNC machine tools involve the inspection and resolution of erroneous digital signals, communication and interfacing, drive and positioning systems, digital machining operations and other related mechanical systems. This article outlines the troubleshooting and classification of CNC machine tools.
Digital Signals
Erroneous digital signals may be caused by wrong/faulty code, numerical control or machine tool errors, power interruption and control cabinet failure. Faulty code includes invalid ASCII Characters and invalid block numbers in an NC program. Numerical control errors involve incorrect codings, stops, m-codes, missing G-codes and parameters, jump codes and incomplete coding in conjunction with related hardware failure. Power interruption discrepancies will involve system that have already been programmed with the requirement for regular maintenance. Control cabinet failure requires immediate inspection and repairs as any errors may lead to erratic control of movements, lost memory and erratic operations.
Communication & Interfacing
Communication and interfacing errors involve leadscrew and spindle malfunction, improper port configurations and system wiring errors. Leadscrew and spindle malfunctions can be corrected by ensuring the lubrication of the leadscrews is regularly performed and by checking the spindle run-out and speed. Improper port configuration problems can be resolved by setting the appropriate baud rate, type of connection and addressing the parity errors. System wiring errors involve incorrect extraneous signals such as feedback encoder signals or loss of signals like resolution signals or servo amplifier signals.
Drive & Positioning
Drive and positioning malfunctions involve errors in the servo systems and control problems. Servo systems contain needs, servo motors and amplifier motors which are all essential components of positioning and drive machines. These components also require regular lubrication and proper maintenance. Control problems stem from the malfunction of the system software and halo. The severity of the questions should be ascertained in order to whether it is required to upgrade the system software and halo. Depending on the machine tool, it may be necessary to upgrade the machining control to an NC programmable machine tool for more effective control operations.
Digital Machining Operations
Incorrect machining operations include errors in the bores machined, parts being cut too thin, cuts being too deep, variations in the dimensions machined and no cornering cuts when required. These errors can be resolved by setting the correct number of codes in the program, checking the speeds and feeds, retracting the tool far enough to ensure that the bores machined are parallel and ensuring that the cutting tool has enough clearance.
Other related mechanical systems
Errors in other related mechanical systems such as belt pulleys, counterweights and clutch assemblies will also require immediate action. Belt pulley alignment and tension require correcting using a V-belt or serpentine belt adaptor. Counterweights require replacement whilst clutch assemblies should be inspected as they are integral to ensuring smooth machine operation.
Conclusion
Troubleshooting and classifying CNC machine tools involves a variety of processes and procedures. As the actual manufacturing industry has become more automated, the number of CNC machine tools deployed has grown exponentially, making it essential for operators to carry out effective troubleshooting and classification in order to minimise downtime and maximise job outputs.
