Abstract:
In Nigeria, the Computer Numerical Control (CNC) milling machines in most of our indigenous industries and research institutes usually ended up as waste. There are no identified efforts towards testing and diagnosing of the CNC milling machine for various defects. These defects were attributed to many factors including maintenance, lack of the technical know-how or complex protocol involved in restoring the machine working condition. The collection and inspection of the component parts of the CNC Milling machine as well as the working diagnostic data have formed the bases for developing strategies for the maintenance of a defective CNC milling machine in the Federal University of Technology, Akure (FUTA)’s Mechanical workshop. The maintenance strategies were developed through identified sources of defects/faults. The defective components namely electrical main supply, electrical cabinet of the machine, spindle motor, table motor, the processor cabinet, the processor unit, coolant pipe and servo, programming and display unit, lighting system and mechanical faulty were established using testing instruments such as magnifying glass, signal generator, avometer, and line tester. The components were corrected by carrying out repair and replacement maintenance strategies on them. The restored components were re-tested and found to be functioning according to specification of the CNC milling machine except the display unit which was blinking and did not display fully. The maintenance effectiveness of the machine was estimated to be 85 %. This indicate a success in the research carried out. Replacement of the display unit called processor will bring the machine to full operable condition .Findings showed the local potential at restoring defective imported CNC milling machine to operable condition with available spare parts. Although the spare parts are not readily available. The total time expended on the maintenance of this machine was 47 hours and an estimated cost of ₦116,000 ( one hundred sixteen thousand naira only) was spent on the maintenance of the machine
