Natural fiber composites (NFCs) have strong potential to replace glass fiber-reinforced plastics. An
instrumental operation in machining composite structures is hole making which facilitates assembly
of parts. Understanding the effects of drilling process parameters on feature properties of NFCs has
great benefits. In this regard, to make a good quality and accurate hole in composite structures,
appropriate selection of drill bit and cutting parameters is important. This paper investigates delamination behavior and hole quality of flax/epoxy composite laminates in response to feed, spindle speed,
and three different types of drill bit. As indicated by analysis of variance results, drill bit type and feed
have greater influences on the thrust force. It appeared that delamination factor and surface roughness
were significantly influenced by drill bit, but not by feed and spindle speed. The choice of drill bit has
great impact on the delamination factor (67.27%) and surface roughness (74.44%), respectively.