What is a Weld Crater?
At the end of the weld, you will generally get a crater due to the shrinkage of the metal while cooling from a molten to a solid state. This causes the weld not to be fully filled across the cross-section of the weld and leads to a weak spot in the weld
How to Prevent a Weld Crater?
This crater can be filled using the crater fill setting on the last point of the weld in the Beacon app. When performing the crater fill the robot will stop motion at the end of the weld and continue to weld for the amount of time specified in the app. During the crater-fill process, the robot commands the welding equipment to reduce the wire feed speed over the course of the crater-fill time effectively reducing the heat input into the weld and allowing the metal to cool and have enough excess metal so that when it finishes shrinking at the end of the weld the cross-section of the end of the weld is the same as the main portion of the weld.
Using the Crater Fill Settings in Beacon
In Beacon, the default crater fill time is 0.5 seconds. You can adjust this on each weld end point within a part or you can choose to have all of them be the same. You can also set-up your default settings as well as library entries to have the crater-fill time that best works with that combination of settings. To adjust the setting choose the point or points you want to adjust and change the setting in time up to 2 seconds long. If you need additional time you can also fill the crater using a tack weld where you have more control over the length of time the tack is held.
If you adjust the crater fill time in the memory location on the welding equipment you do introduce the chance that the system will continue to feed wire and weld AFTER an Emergency Stop is pressed. This is due to the fact that the robot will cease motion as required by the safety standard and cut off the trigger signal to the feeder but the feeder crater fill control will take over and perform the requested crater fill the same as if you were manually welding. It is NOT recommended to use the crater fill function on the welding equipment but rely solely on the crater fill settings in Beacon. This will lead to the system behaving as expected in the event of an Emergency Stop.