When drilling composite material, the speed (RPM) of the drill motor is affected by which factor?

The speed (RPM) of the drill motor when drilling composite materials is significantly affected by the size of the drill bit used. Larger drill bits typically require lower RPMs to effectively cut through materials without causing damage, such as delamination, which is particularly critical in composite materials. This is due to the increased contact area and resistance that larger bits encounter. Conversely, smaller drill bits can operate at higher RPMs because they have a smaller cutting area, allowing for quicker penetration through the material.

Choosing the appropriate drill bit size is crucial to ensure efficient drilling while minimizing the risk of overheating or damaging the composite structure. The selection of RPM in conjunction with the bit size aids in optimizing both the performance and the integrity of the composite being drilled.