ShenyangDoosan CMV920 machining center overhaul

Before Improvement: Damaged and obsolete machine tool that cannot operate normally

After Improvement: High internal precision, high appearance quality

Overhauling a Doosan CMV920 machining center is a complex and meticulous process involving inspections and repairs in multiple aspects. The following is a detailed analysis of the Doosan CMV920 machining center overhaul:

### I. Overview of Overhaul

Machining center overhauls typically involve comprehensive inspections and repairs of mechanical, electrical, hydraulic, and control systems, as well as the replacement and upgrading of key components. The purpose of the overhaul is to ensure that the performance and accuracy of the machining center reach their optimal state, thereby ensuring production safety and extending the service life of the equipment.

### II. Pre-Overhaul Preparations

1. **Equipment Inspection and Assessment**: Conduct a comprehensive inspection of the Doosan CMV920 machining center to assess the degree of wear and performance of each component and determine the items and content requiring overhaul.

2. **Develop an Overhaul Plan**: Based on the results of the equipment inspection and assessment, develop a detailed overhaul plan and schedule, including the repair process, required resources, and repair personnel allocation.

3. **Prepare Tools and Spare Parts**: Prepare the necessary repair tools and measuring instruments, as well as spare parts that need to be replaced, to ensure the smooth progress of the overhaul work.

### III. Overhaul Content

1. **Mechanical Parts**:

* Spindle System: Check the wear condition of the spindle bearings; if replacement is needed, use appropriate bearings; adjust the bearing preload to ensure spindle stability and accuracy; replace spindle seals; conduct spindle dynamic balance testing and adjustment.

* Guide Rail System: Clean the guide rail surface, check the guide rail wear; repair or replace worn guide rails; check the working status of the guide rail lubrication system to ensure normal lubrication; check the integrity of the guide rail protection device and replace it if damaged.

* Transmission System: Check the wear condition of gears, bearings, and other components in the gearbox and perform necessary repairs or replacements; check the wear and deformation of the transmission shaft and use a suitable new transmission shaft if replacement is needed; check the wear condition of the transmission belts and chains and use suitable new belts or chains if replacement is needed.

2. **Hydraulic and Pneumatic Systems**:

* Check the working status of pumps, valves, cylinders, and other components in the hydraulic system and replace them if damaged.

* Regularly replace hydraulic oil and filter it to ensure the cleanliness of the hydraulic oil.

* Check the working status of valves, cylinders, and other components in the pneumatic system and replace them if damaged; regularly clean and maintain the pneumatic lines to ensure the smooth flow of the pneumatic lines and the normal operation of the components.

3. **Control System**:

* Inspect the hardware devices of the control system, including lines, interfaces, and power supplies.

* Update and maintain the control system software and back up the software.

* Adjust and optimize the parameters of the control system according to the working needs of the machining center.

* Check the safety protection devices of the control system to ensure that they can work normally in emergencies.

### IV. Post-Overhaul Inspection and Debugging

1. **Appearance Inspection**: Check if all fasteners are tightened and there is no loosening; check if the equipment appearance is intact and there is no obvious damage or rust.

2. **Oil Circuit System Inspection**: Check if the oil circuit system is unobstructed and there is no blockage or leakage.

3. **Electrical System Inspection**: Check if the electrical system is normal and there are no short circuits, open circuits, or poor contacts.

4. **Functional Test**: Test key performance indicators such as spindle speed, feed system stability, and cutting accuracy; perform thermal error compensation and workpiece coordinate system calibration.

### V. Overhaul Precautions

1. **Safety First**: Before performing maintenance, turn off the main power of the machining center and ensure that all moving parts have stopped running to prevent accidents.

2. **Professional Maintenance**: Ensure that maintenance personnel have received professional training, are familiar with the structure and working principles of the machining center, and have the necessary