Failure cause analysis and maintenance procedure o

2022-09-26
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Failure cause analysis and maintenance procedure of plastic injection molding machine

in case of failure of the injection molding machine, in order to ensure the quick and effective solution of failure analysis and troubleshooting, a certain procedure must be followed, which is roughly as follows

the first step is to conduct symptom analysis while maintaining the scene

1 Ask the operator

(1) what fault happened? Under what circumstances did it happen? When did it happen

(2) how long has the injection molding machine been running

(3) is there any abnormal phenomenon before the failure? What is the sound or sound light alarm signal? Is there smoke or odor? Is there any wrong operation? Pay attention to the way of inquiry

(4) is the control system operating 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

(1) whether there are obvious abnormalities? Is the part blocked or damaged? Is the hydraulic system loose or leaking? Are the wires broken, scratched or burned

(2) 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 indicating device

(1) check whether all readings are normal, including the readings of pressure gauge and other instruments, and the oil level

(2) check whether the filter, alarm and interlock, action output or display are normal

4. Jog the injection molding machine for inspection (under allowable conditions)

check the intermittent condition, lasting condition, fast forward or slow forward condition, and see whether these conditions 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 go deep into the process of classified observation of fatigue)

1 to see whether the plug and socket are abnormal, whether the operation of the motor or pump is normal, whether the control adjustment position is correct, whether there are signs of arcing or charring, whether the fuse is good or bad, liquid 3, whether the oil return valve is closed for leakage, whether the lubricating oil circuit is unblocked, etc

2 touch: the vibration of the injection molding machine, the heat of the components, the temperature of the oil pipe, and the state of mechanical movement

3 listen: whether there is abnormal sound

4 smell: whether there is burning smell, air leakage smell and other peculiar smell

5 check: changes in the shape and position of the workpiece, changes in the performance parameters of the injection molding machine, and abnormal circuit inspection

2. Evaluate the 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 instructions of the injection molding machine to identify which structure the injection molding machine is, what method to test, what test means are needed, what test parameters or performance parameters may be obtained, under what operating conditions to test, what safety measures must be observed, and whether an operation license is required

2. The system detection

adopts the technology detection of the most suitable digital display semi-automatic impact testing machine combined with the system structure. At the appropriate test point, according to the input and feedback results, compare with the normal value or performance standard to find out the suspicious position

step 4 repair or replace accessories

1 Repair

find out the cause of the failure, repair the failure of the injection molding machine and take preventive measures; Check the relevant parts to prevent the failure from spreading

2. Relying on the China Green Manufacturing Alliance to promote the cooperation of the whole industrial chain of green manufacturing to replace accessories

correctly assemble, debug and replace parts, and pay attention to relevant parts. Repair or scrap the replaced parts

step 5 performance measurement

1 Start the injection molding machine

after the assembly and commissioning of parts, start the injection molding machine manually (or inching), and then measure the no-load and load

2. Adjust the load change speed from low to high, and the load from small to large. The maximum system pressure cannot exceed 140kg/cm2. Measure the performance according to the specified standard

3. Expand the scope of performance test

gradually expand the scope of performance test from local to system as needed. Pay attention to the operation of the system in the non fault area. If the performance meets the requirements, it shall be delivered for use. If it does not meet the requirements, the fault location shall be determined again

step 6 record and feedback

1 Collect valuable information and data, such as the time of injection molding machine failure, failure phenomenon, downtime, repair hours, repair and replacement parts, repair effect, problems to be solved, settlement costs, etc., and store them in files according to the specified requirements

2. Statistical analysis

regularly analyze the use records of injection molding machines, analyze downtime losses, revise the memo directory, find key measures to reduce maintenance operations, study the failure mechanism, and propose improvement measures

3. Feed back relevant faults to the competent department according to the procedure, and feed back to the injection molding machine manufacturing unit or the injection molding machine equipment maintenance contractor

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