Robotics News & Insights

Spotting Robot Performance Issues Before They Happen

Written by Aaron Barnes | Jun 9, 2015 9:28:38 AM

Just like with a car, performance issues with an industrial robot are often a sign of more costly trouble ahead. But what if you had a way to know of a potential problem with your robot before any visible signs of trouble? Even when everything seems to be running right, one way to get ahead of unwanted surprises is to analyze the grease that's used to lubricate each axis of your robot.

Cars need oil, and robots need grease. Keeping your axes well-lubricated can help control friction, vibration and heat. Even if you faithfully re-grease through regularly scheduled PMs, you may not be seeing the whole picture. Taking a closer look at what's inside your grease can detect potential drive-related failures before they become costly.


A grease analysis reads the amount of iron present in the grease, and the rate that the iron level is increasing in each axis. Some buildup of iron naturally happens over time. Under normal operation, routine grease changes will keep iron levels within a safe operating range.

The red flag comes when there's a spike in the iron content of one or more axes. If a drive is misaligned, for example, the iron levels for that axis will rise at a higher rate than the others. In this sample readout, s multi-axis grease analysis summary shows abnormal iron levels for the L-axis, indicating potential wear on the drive. If left alone, high iron content not only serves as a symptom, it also becomes a factor that can degrade the drive at an exponential rate.

Gathering grease samples for analysis is simple, quick, and does not require an onsite service call. At Yaskawa, we offer our customers a kit to draw their own grease samples and send them to us for analysis.

The results of a multi-axis grease analysis can help you determine the proper countermeasure. When the result is beyond the safe operating range for the gear reducer, we recommend the following diagnostic steps:

Diagnostic data helps determine next steps.
  1. Verify that the axis is operating properly. Ensure that it moves freely and does not have vibration. You may need further vibration testing at this point.
  2. Replenish grease by purging all old grease out and replacing with new. Take a grease sample of the axis within 90 days of the previous test. If the axis shows it is now operating within the safe range, continue with preventive measures recommended by the manufacturer.
  3. An axis with iron content beyond the safe range could indicate potential drive failure. A closer evaluation of the drive is in order.
  4. At this point, parts for replacement and planned downtime should be scheduled.

Yaskawa Motoman's Customer Satisfaction Group is on hand to help guide you through the entire process.