What is the recommended included angle for a drill bit used for drilling composites?

The recommended included angle for a drill bit used for drilling composites is typically 135 degrees. This angle is ideal because it provides a balance between cutting efficiency and the reduction of delamination or damage to the composite material. A sharper angle can create more cutting edges that may lead to excessive heat generation and increased risk of damaging the laminate layers of composites. Conversely, angles that are too obtuse can lead to poor cutting performance and potential tearing of the material rather than a clean cut.

In the context of drilling composites, the 135-degree drill bit helps in maintaining proper chip removal, minimizing friction and heat, and ensuring cleaner holes. This aspect is particularly important in composites where preserving the integrity of the material is critical during machining processes. Using a drill bit with this recommended angle helps ensure optimal performance when working with sensitive materials like fiberglass or carbon fiber composites.

Other angles, whether larger or smaller, do not provide the same balance of cutting performance and material preservation. This crucial aspect of angled design specifically caters to the unique properties of composite materials, which can behave differently compared to metals.