An operator has been complaining about erratic operation of a robotic stamping machine that runs on first shift only. The repair techs respond to the trouble calls but can't replicate the problem to troubleshoot it. Where should you begin?

The maintenance department is reacting to trouble calls instead of responding to them. Because the problem is recurring and intermittent, reaction isn't going to lead to a solution. The only way to solve this problem is to get out of reactionary mode. Begin by determining when this erratic operation is occurring.

If this erratic operation happens in the morning and then settles out as the day progresses:

  • Pull circuit boards out and look for moisture tracks. These could be anywhere, from the backs of the boards to the enclosure surfaces. Moisture remediation measures may require manufacturer approval.
  • Determine if the operator leaves the feedstock in the proper position when shutting down the machine for the day.
  • Compare the lubricants being used against the manufacturer's specifications. If a lubricant or its base is too heavy, then the machine may have to run and heat up before all points are actually lubricated. This would cause erratic operation.
  • Does other equipment starting on first shift create power anomalies? View your power monitoring logs, and use a portable power analyzer at the erratically operating equipment.

If this erratic operation happens mostly after the machine has run for a while:

  • Take thermographic images. Where there are hotspots, you’ll probably find the source of the erratic behavior.
  • Verify the feedstock has the proper alignment, correct feed rate, and (if applicable) correct tension.
  • Check lubricants. A light lubricant used in an application requiring a heavy one won’t keep mating surfaces apart. Erratic operation is possible, though outright failure is inevitable.