Mechanical Noise Or Dissonance - ABB IRB 920 Product Manual

7 Troubleshooting

7.3 Mechanical noise or dissonance

7.3 Mechanical noise or dissonance
Description
Mechanical noise or dissonance that has not been observed before can indicate
problems in bearings, motors, gearboxes, or similar. Be observant of changes over
time.
A faulty bearing often emits scraping, grinding, or clicking noises shortly before
failing.
A humming resonance sound can occur without being an error. Mechanical
resonance sound is a physical phenomenon in mechanical structures. It has no
impact on product performance or lifetime. Adjusting the robot movement speed
out of the range that causes the resonance will eliminate the sound.
Consequences
Failing bearings cause the path accuracy to become inconsistent, and in severe
cases, the joint can seize completely.
Possible causes
The symptom can be caused by:
If the noise is emitted from a gearbox, the following can also apply:
Recommended actions
The following actions are recommended:
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• Worn bearings.
• Contaminations have entered the bearing grooves.
• Loss of lubrication in bearings.
• Loss of lubrication in ball screw.
• Loose heat sinks, fans, or metal parts.
• Overheating.
Action
CAUTION
Allow hot parts to cool down.
Verify that the service is done according to
the maintenance schedule.
If a bearing is emitting the noise, determine
which one and make sure that it has suffi-
cient lubrication.
If possible, disassemble the joint and meas-
ure the clearance.
Bearings inside motors are not to be re-
placed individually, but the complete motor
is replaced.
Make sure the bearings are fitted correctly.
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Information
Product manual - IRB 920
3HAC075721-001 Revision: C