敬业 担当 同创 共享
May 2024
HVM90MSA compressor analysis
and corrective action report
敬业 担当 同创 共享
敬业 担当 同创 共享
Serial No ：
HVM90MSa23091100739
Assembled DEC 23 Service Call JAN 24 Service Check : LOCK
R&D Check : NO RESISTANCE Compressor Condition:
1. Wire connector broken
2. Discharge line welding is not perfect
1. Tear down analysis and Main problems
敬业 担当 同创 共享
HVM90MSa23091101538
Assembled NOV 23 Service Call MAR 24 Service Check : LOCK R&D Check : LOCK Compressor Condition:
1. Carbon deposite on Valve
2. Connecting Rod lock with Crankshaft
1. Tear down analysis and Main problems
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• 1 EA winding connector broken
• 1 EA Carbon deposite
2. Failure type
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Robot holds mechanical part
Moves to the above of lower
shell
Loosens the
robot claw Puts mechanical part into the shell.
1. Measure the motor winding without resistance value, open the shell found that the winding lead connector is broken, resulting in enameled winding break.
2. The mechanical part is automatically entered into the shell by the robot. The height of mechanical part into the shell is above the edge of the lower shell. During the process under mechanical part, the winding connector is stuck on the edge of the stop of the lower shell, generating a pulling force, resulting in the damage and cracking of the lead hardness (winding connector), and finally the breakage of the enameled winding.
3. Winding connector installation staff failed to find damage defects, resulting in defective products flow out of factory.
3. Cause analysis- winding connector broken
敬业 担当 同创 共享
Before improvement
1. The previous robot operation process: the robot holds the mechanical part/pumping body, moves to the above of lower shell, loosens the robot claw, and puts the mechanical part into the shell.
2. The height of the claw is 5mm, and the depth of the mechanical part into the shell is insufficient.
3. There is no guide block.
After improvement
1.Improve the robot operation process: reduce the height of the mechanical part into the shell:
the robot holds mechanical part, moves to the above of lower shell, loosens the robot claw, and puts mechanical part into the shell.
2. Increase the height of the claw to 10mm, increase the depth of mechanical part into the shell.
3. Adding the guide block, the lead harness (winding connector)of motor can enter the shell smoothly, and will not get stuck at the edge of the lower shell (Improvement date :January 2024)
Improved video: Lead harness
smoothly slide in lower shell
4. Corrective action-Winding connector broken
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1.We have added the tooling board blocker on the welding post of the inner discharge pipe. During welding, the compressor must be guaranteed to be stopped for welding. Finish date: September , 2023
2. We have reinforced training for welding staff again and strictly control welding time within 1-2s, The welding residence time does not exceed 3 seconds; Finish date: September , 2023
3. In July 2024, our company will promote high-frequency welding instead of manual welding, reduce personnel welding errors, improve the stability of welding, and ensure welding quality stable. （ Finish in July 2024） .
After improved: High- frequency welding Before improve :
welding by manual
5. Corrective action-Discharge tube welding
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1. There is micro/slight leak in the piping of the refrigerator system, so that the refrigerant leaks, While the air can continuously enter the system.
2. The system is not vacuumized properly, causing residual air in the compressor.
3. When the compressor is running, a steady stream of air is drawn into the cylinder and compressed, causing the temperature and pressure of the cylinder head to be much higher than when compressing refrigerant .
4. In the case of high temperature and air， moisture ，the compressor refrigeration oil is gradually oxidized. And then form carbon deposits (gels, carbides) on the valve valve and other parts.
5. 因为阀组高温积碳，润滑油逐步被劣解、变质，润滑油粘度下降，油膜被破坏，造成机械部件磨损严重，曲轴和连杆之间磨 损卡死
System leak
Oil
O2
Long time
Short time
high temper
ature Obvious carbon deposit
Oil plug
In the compressor use, maintenance and other processes to avoid moisture, air residual and refrigerator system leakage caused the compressor oil oxidative deterioration.
6. Carbon deposit on Valve plate
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1. The HVM70MTa compressor is installed with the BCD-301W refrigerator, and a hole/leak point is opened on suction/return pipe of the refrigerators.
2. No Vacuum , don’t add refrigerant, only add a small amount of nitrogen, the refrigerator at room temperature, 4500 speed no-load operation.
3. Check the appearance of the compressor muffler, valve group, and oil after the refrigerator runs for 12 hours.
Test verification
The return/suction pipe is leaking
6. Carbon deposit on Valve plate
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The return/suction pipe is leaking, the refrigerant oil is seriously carbonized, the silencer port is melted, and the valve group is carbon deposited
