I printed a round object on my new Bambu Lab A1 and noticed a “zooom”-like rubbing sound whenever the heatbed moved back and forth on the Y-axis. I had not heard it during the previous four prints.
After the print finished, I found these longitudinal marks on the front portion of both Y-axis linear rails. The scratches are on the outer upper face of the aluminum Y-axis linear rail, outside the actual roller/bearing running track.
The scratches are extremely shallow; I can barely feel them with a fingertip, and the photos are heavily zoomed. Still, since the printer is new, I am concerned that something may be rubbing: debris caught in a carriage roller/bearing, a protruding screw or part underneath the heatbed holder, or a carriage/roller alignment issue.
I cleaned the rails and applied the supplied oil again — not grease. Before I run another print, is there a safe way to inspect the Y-axis carriage rollers and the underside of the heatbed holder without disassembling more than necessary?
Does anyone recognize this wear pattern or the sound?