Troubleshooting steps for six injection molding machines

Both imported and domestic injection molding machines have the following characteristics:
A. The injection molding machine has large fixed assets investment, large production scale, large consumption of raw materials, high labor productivity and large output value. It is a form of production organization with high labor efficiency.
B. The injection molding machine is composed of machinery, hydraulic pressure, electrical appliances, special accessories, etc., which are organically combined according to the needs of injection molding processing technology, with high degree of automation and close correlation; The injection molding machine can operate continuously for 24 hours in 3 shifts. If a component of the injection molding machine fails, it will lead to shutdown.
C. Although the operation of the injection molding machine is simple and there are few workers, the management and maintenance of the injection molding machine is highly technical and the workload is also large. Therefore, to ensure that the injection molding machine is always in good condition, it is necessary to strengthen the management of the injection molding machine and strictly control the failure of the injection molding machine.
In order to reduce the failure rate, reduce maintenance costs and extend the service life. Injection molding machine failure generally refers to the event or phenomenon that the injection molding machine or system loses or reduces its specified function in use. The injection molding machine is equipped by enterprises to meet the requirements of the production process of injection molding products.
The function of the injection molding machine reflects its value in the production of injection molding products and the degree of assurance for injection molding production. In the production of modern injection molding machines, due to the complex structure of the injection molding machine, the high degree of automation, and the close connection of hydraulic, electric and mechanical, the failure of the injection molding machine, even if it is a partial failure, will cause the shutdown of the entire injection molding machine. The failure of injection molding machine directly affects the quantity and quality of injection molding products.
To ensure fast and effective fault analysis and troubleshooting, certain procedures must be followed, which are roughly as follows:
The first step is to conduct symptom analysis while maintaining the scene
1. Ask the operator
What happened? Under what circumstances did it happen? When did it happen?
How long has the injection molding machine been running?
Is there any abnormality before the fault occurs? What is the audible or visual alarm signal? Is there smoke or odor? Is there any wrong operation (pay attention to the inquiry method)?
Does the control system operate normally? Are there any changes in the operating procedures? Is there any special difficulty or abnormality during operation?
2. Observe the condition of the whole machine and various operating parameters
Is there any obvious abnormality? Are the parts jammed or damaged? Is the hydraulic system loose or leaking? Are the wires broken, scratched or burned?
What are the changes in the operating parameters of the injection molding machine? Is there any obvious interference signal? Is there any obvious damage signal?
3. Check the monitoring and indication device
Check whether all readings are normal, including the readings of pressure gauge and other instruments, and the oil level.
Check whether the filter, alarm and interlock device, action output or display are normal.
4. Inching injection molding machine inspection (under allowable conditions)
Check the intermittent, persistent, fast-forward or slow-forward conditions to see if they affect the output and may cause damage or other hazards.
Step 2 Check the injection molding machine (including parts, components and circuits)
1. Use sensory inspection (continue to observe the process in depth)
A. Check whether the plug and socket are abnormal, whether the motor or pump operates normally, whether the control adjustment position is correct, whether there is arcing or burning trace, whether the fuse is good or not, whether there is liquid leakage, whether the lubricating oil circuit is smooth, etc.
B. Touch: the vibration of the injection molding machine, the heat of the element (assembly), the temperature of the oil pipe, and the state of mechanical movement.
C. Listen: whether there is abnormal sound.
D. Smell: whether there is burnt smell, air leakage smell and other peculiar smell.
E. Check: change of the shape and position of the workpiece, change of the performance parameters of the injection molding machine, and abnormal line inspection.
2. Evaluation of inspection results
Evaluate whether the fault judgment is correct, whether the fault clue is found, and whether the inspection results are consistent.
Step 3 Determination of fault location
1. Identify the system structure and determine the test method
Refer to the injection molding machine manual to identify the structure of the injection molding machine, the method used for testing, the test means required, the test parameters or performance parameters that may be obtained, the operating conditions under which the test is conducted, the safety measures that must be followed, and whether the operation license is required.
2. System detection
Use the technology most suitable for the system structure. At the appropriate test point, compare the results obtained from input and feedback with the normal value or performance standard to find out the suspicious position.
Step 4 Repair or replace
1. Repair
Find out the cause of the failure, repair the injection molding machine failure and take preventive measures; Check the relevant parts to prevent the fault from spreading.
2. Replace
Correctly assemble, debug and replace parts, and pay attention to relevant parts. The replaced parts shall be repaired or scrapped.
Step 5 Conduct performance measurement
1. Start the injection molding machine
After assembly and commissioning of parts, start the injection molding machine, first manually (or jog), and then carry out no-load and load measurement.
2. Adjust the load change speed from low to high, the load from small to large, and the maximum system pressure shall not exceed 140kg/cm2, and the performance shall be measured according to the specified standard.
3. Expand the scope of performance test
Gradually expand the scope of performance test from local to system as required. Pay attention to the system operation in the non-fault area. If the performance meets the requirements, it will be delivered for use. If it does not meet the requirements, the fault location will be determined again.
Step 6 Record and feedback
1. Collect valuable information and data
For example, the time of injection molding machine failure, failure phenomenon, downtime, repair time, parts replacement, repair effect, problems to be solved, settlement costs, etc., shall be stored in the file according to the specified requirements.
2. Statistical analysis
Regularly analyze the use records of the injection molding machine, analyze the shutdown loss, revise the memo directory, find out the key measures to reduce maintenance work, study the failure mechanism, and propose improvement measures.
3. Feed back relevant faults according to the procedure and report to the competent department, and feed back to the injection molding machine manufacturing unit.