I. Establish an Overhaul Trigger Mechanism Based on Equipment Status
Overhauls are not performed periodically, but rather determined based on the actual operating performance of the equipment and the condition of core components. An overhaul should be initiated when the following situations occur:
Persistent Color Registration Inaccuracy: Even after repeated calibration of the alignment system, the accuracy cannot be stabilized within ±0.2mm, resulting in frequent pattern misalignment and ghosting, directly impacting the yield.
Forced Reduction in Printing Speed: The machine, which could previously operate stably at over 700 pieces/hour, is now forced to reduce its speed to below 500 pieces/hour to maintain quality, resulting in a production efficiency decrease of over 30%.
Increased Abnormal Noise and Vibration: Metallic friction sounds, impact sounds, or noticeable vibrations occur during operation, especially during station changes or acceleration phases, indicating wear or loosening in the transmission system.
Frequent Stop Alarms: The PLC control system frequently reports errors such as "servo out of sync," "insufficient air pressure," and "positioning timeout," and these errors are triggered again shortly after a reset.
These phenomena indicate that the equipment has exceeded the scope of repair achievable through routine maintenance and requires in-depth overhaul.
II. Establish Overhaul Cycles Based on Industry Standards
Overhaul cycles should be comprehensively determined based on equipment type, usage intensity, and maintenance level. According to the planned preventive maintenance system, the equipment overhaul cycle refers to the working time of the machine between two consecutive major overhauls. For oval printing machines, the following is recommended:
Regular Overhaul Cycle: A comprehensive overhaul should be performed every 5–8 years. The specific cycle can be adjusted according to the equipment's usage intensity and maintenance level.
High-Load Equipment: Equipment operating for more than 10 hours per day experiences accelerated wear; it is recommended to schedule a major overhaul in the 5th–6th year.
Preventive Overhaul: Equipment used for more than 8 years without a major overhaul history, even if it appears to be operating normally on the surface, has accumulated internal fatigue; it is recommended to proactively schedule a preventive overhaul.
III. Develop a Precision Component Inspection Plan
The core of overhaul lies in the in-depth inspection and repair of critical components. Recommendations:
Transmission System: Disassemble and inspect the linkage mechanism, gear meshing clearance, and synchronous belt tension; replace the entire transmission module if necessary.
Guide Rails and Bearings: Inspect guide rails for scratches, pitting, or operational obstructions; grind or replace as necessary.
Pneumatic and Electrical Systems: Conduct a comprehensive inspection of the entire pneumatic circuit and control cabinet; replace aging components.
Print Head Assembly: Disassemble and calibrate the scraper holder, lifting mechanism, and wire frame clamping mechanism; replace critical components as necessary.
IV. Develop a Spare Parts Inventory Management Plan: Overhauls require a large number of spare parts. Recommendations:
Create a Spare Parts List: List all spare parts required for the overhaul, including transmission components, guide rails, bearings, pneumatic components, electrical components, and print head assemblies.
Establish a Safety Stock: Establish a reasonable safety stock based on equipment usage intensity and maintenance level to ensure sufficient spare parts during overhauls.
Establish a Spare Parts Replacement Record: Record spare parts replacements during each overhaul for future maintenance.
V. Develop a Time Quota Plan: Overhauls require a large number of man-hours. Recommendations:
Develop Time Quotas: Develop reasonable time quotas based on equipment type, usage intensity, and maintenance level.
[Details of the plan are not provided in the original text.] Develop a work schedule: Based on the overhaul plan, reasonably arrange the work hours to ensure that the overhaul is completed on time.
