Six Steps for Injection Molding Machine Fault Repair
Injection molding machines combine mechanical, hydraulic, electrical, and special supporting parts. Even a local failure can cause the entire machine to shut down, directly affecting production. Following a systematic repair procedure ensures quick and effective troubleshooting.
Step 1: Symptom Analysis While Maintaining the Scene
Ask the Operator:
- What happened? Under what circumstances? When?
- How long has the machine been running?
- Was there any abnormal phenomenon before the failure? Sounds, alarm signals, smoke, strange smells?
- Is the control system operating normally? Has the operating procedure changed?
Observe the Overall Machine Status:
- Are there any obvious abnormalities? Parts stuck or damaged? Hydraulic system loose or leaking? Wires cracked, scratched, or burned?
- What changes have occurred in the operating parameters? Any obvious interference or damage signals?
Check Monitoring and Indicating Devices:
- Check all reading values including pressure gauges and oil level height.
- Check filters, alarms, interlocking devices, and motion outputs for normal operation.
Step 2: Inspect the Injection Molding Machine
Use Senses for Inspection:
- Look: Check plugs, sockets, motors, pumps, control positions, signs of arcing or burning, fuses, fluid leakage, lubrication paths.
- Touch: Check machine vibration, component heat, oil pipe temperature, mechanical movement state.
- Listen: Check for abnormal sounds.
- Smell: Check for burning smell, gas leak smell, or other strange odors.
- Check: Changes in workpiece shape and position, performance parameter changes, abnormal line inspection.
Evaluate Inspection Results:
Evaluate whether the fault judgment is correct, whether fault clues have been found, and whether the various inspection results are consistent.
Step 3: Determine the Fault Location
- Consult the machine manual and identify the structure, testing method, required testing means, test parameters, operating conditions, and safety measures.
- Adopt the most suitable technical testing for the system structure. Compare input and feedback results with normal values or performance standards to find suspicious locations.
Step 4: Repair or Replace
Repair:
Find the cause of the fault, repair the machine, and take preventive measures. Inspect related parts to prevent the fault from spreading.
Replace:
Correctly assemble, debug, and replace parts, and pay attention to related components. Repair or scrap the replaced parts.
Step 5: Conduct Performance Testing
- After assembly and debugging, start the machine manually first, then perform no-load and load measurements.
- Adjust load change speed from low to high, load from small to large. Maximum system pressure must not exceed 140 kg/cm2.
- Gradually expand the performance test range from local to system. If performance meets requirements, deliver for use; if not, re-determine the fault location.
Step 6: Record and Feedback
- Collect valuable data including time of failure, fault phenomenon, downtime, maintenance man-hours, repaired or replaced parts, repair effect, and settlement costs.
- Conduct statistical analysis of machine usage records and revise memo directories to find key measures for reducing maintenance operations.
- Report faults to the competent department and feed back to the machine manufacturer.
