Random-orbit sanders make the process easier, and with the right technique, more consistent.
They operate most efficiently when only the weight of the sander bears on the workpiece.
Applying excessive pressure not only slows the rotation of the pad (and thus, the sanding process) but can also cause swirl marks or elliptical thumbnail-scratch patterns.
Challenges within the application
Force control and feed speed are essential to achieve the wanted finish, which is technically difficult for human workers.
Process knowledge is essential: use of abrasive, steps of the process, quality inspection in between and at the end of the job.