Are you seeing any error or alarm messages in the Console window when your laser stops? If so, please share them here - you can either copy and paste them or share a screenshot.
The behavior you’re describing is usually caused by your laser’s controller disconnecting/resetting partway (you may see an ‘Alarm 3’ message if this is the case).
That could be due to a loose USB connection, static discharge causing the controller to reset, or insufficient power supply leading to a brown out condition.
Check your USB connection, and try a new, high quality, shielded USB cable. Route your USB so that it avoids the stepper motors or anything else that could cause electrical interference. Make sure that your machine is properly grounded. Make sure there are no devices on the same circuit as your laser that could be causing a power drop or brown out.
Here are some resources to help you troubleshoot these issues:
