Objective  The objective of this research was to investigate the difference of medium density fiberboard (MDF) cutting characteristics between spherical cone grit and pentagonal pyramid grit and study the action mechanism of cutting edges on fibrous material removal in sanding process. This research is going to provide some theory basis to fulfill highly efficient sanding.

  Method  Spherical cone grit and pentagonal pyramid grit were used to conduct the cutting experiments through a wedge-style scratching method. High-speed camera, three-dimensional dynamometer and 3D profiler were applied to record and measure the dynamic cutting process, the cutting force variation and the sanded surface morphological profile.

  Result  Spherical cone grit caused more material pile-up on both sides of the groove, where the initial surface integrity was better. For nearly the same groove volume, more chips formed in the pentagonal pyramid grit cutting, where the relative moment of chip formation was earlier for a single scratch with more evident chip flowing from the two rake faces. For a single scratch, the pentagonal pyramid grit presented less time to reach the peak value of tangential cutting force. The two kinds of abrasive grits when cutting MDF showed a quadratic increasing trend between cutting force and cutting depth. And the force ratio of the pentagonal pyramid grit was greater. There was a quadratic variation that first decreased and then increased between the specific grinding energy and the groove volume for the two kinds of abrasive grits. And there existed a turning point that was the critical groove volume (a critical cutting depth). When the groove volume was basically the same, the actual specific energy of spherical cone grit was greater than that of the pentagonal pyramid grit.

  Conclusion  The pentagonal pyramid grit which was with evident cutting edges presented better cutting performances, specifically higher material removal rate and energy utilization rate, which shows that cutting edge plays a key role in removing fibrous material during sanding processes.