How Does the Robot Determine an Arc has Started
This message is sent by the robot when it cannot successfully initiate the arc at the beginning of the welding process. The robot monitors the arc amperage for a maximum of 2 seconds and checks whether it stays above a certain threshold for 0.1 seconds. If the amperage drops below the threshold, the robot restarts the timer and continues trying for up to 2 seconds. If the amperage remains above the threshold for 0.1 seconds continuously, the robot determines that the arc has been successfully initiated and proceeds with welding.
Reasons for the Error Message
There are a couple of reasons that you could see this message pop up broken up into intermittent issues and continuous issues.
Common Intermittent Issues
The liner is worn or damaged causing the wire to not feed smoothly, this can keep interrupting the weld cycle at the start of the weld and cause the timer to keep resetting. Changing the liner generally solves this issue.
Drive rolls are loose, if the drive rolls are loose the wire will not feed smoothly causing the weld to be interrupted and causing the timer to keep resetting. Check your drive roll tension, you want it tight enough to push the wire against some resistance but not so tight as to smash the wire out of round.
Clips in the drive roll door have not been moved to the correct spot so no drive roll pressure is being applied by the tension adjustment knobs. The clips ship from Miller installed in the Push-Pull welding slots.
Starting the weld on the end of a previous weld or a tack can result in trying to start the weld on silica glass on the surface of the weld. This acts as an insulator and will prevent the wire from grounding. Try moving the weld start off of the previous weld.
Adjust your pre/post flow settings to ensure they are within the recommended settings.
Common Continuous Issues
The feeder is out of wire, load more wire
The wire is welded to the end of the contact tip, free wire or replace the contact tip
If the welder is not outputting amperage to the robot it cannot measure the amperage, you can monitor for this on the IO screen of the robot teach pendant. You are looking for a signal when welding at Analog Input 0. It should read 0V when not welding and 1/100 of a V for each amp output by the welder. For instance, 140 amps would be 1.4V displayed on the robot teach pendant.
Analog input failure at the robot. If there has been a spike in amperage it is possible the input in the robot cabinet has been damaged and will require repair with a new SCB assembly from UR.
If you are seeing the arc start failure be continuous then we can help you diagnose the issue as either the robot controller or the weld equipment. Please contact Hirebotics for further help with this issue.