what is the solution for losing connection?
Losing a USB connection can be caused several different ways.
One of the most valuable clues is the message from the Console window in LightBurn. Please copy and paste any alert or error message from the Console into a reply here. Another clue that’s really helpful is the welcome message when the engraver connects. There’s usually a version number and a date (or some variation on that theme). This will show us how old the Firmware is and if there are any known problems that the manufacturer has addressed.
Other points to consider are the power saving modes for your Microsoft Surface. USB connections are powered down into standby modes by the operating system and these are invisible and easy to overlook.
Other known causes are Static electricity and stray radio frequency (RF) noise (from a spinning electric motor - like an egg beater, exhaust fan or a compressor motor in a freezer or refridgerator.
I’ll move your post to its own thread in an effort to get more focus on what you’re observing.
It’s also incredibly helpful to share some history of your experience with your engraver. Have you tested it with a different computer or the manufacturer’s software? Is this a new out of the box problem or an emerging problem as files get larger?
This may be worth review: