Video: 3 Tips for High Efficiency When Machining Composites

There's an increase in demand for composite materials due to their light weight, high strength and other desirable properties. Delamination, fibre breakage or pull-out and poor tool life are all common issues. In this film, we will outline three important tips that will help you secure high efficiency when machining composites.

Conventional milling is the preferred over-climb milling method when machining composites as it produces better surface finish and reduces delamination. An important adjustment here would be to rotate and feed the cutting tool in the direction of the surface composite fibres. This helps ensure a better surface finish and improves tool life. Cuts clean rather than forcing them to peel back into the workpiece.

In special cases a left-hand router may be used with an anti-clockwise spindle rotation. Another important tip for composite machining is to maximize cutting tool flute length utilization. Employing the complete flute length helps improve the tool life. This strategy requires up-front fixture considerations and creative machine programming. A practical strategy to increase cutting tool flute length utilization is to oscillate the tool while cutting. This will not only engage maximum cutting edge but will also help improve stability by introducing alternating forces.

To maintain maximum stiffness and minimal cutting tool deflection we suggest using the portion of the cutting tool nearest the shank. This helps to reduce bending and improve stability. During the multi-axis movements it is important to ensure that the cutting tool stays engaged in the workpiece. A pause in tool engagement may cause rubbing, resulting in negative wear patterns that reduce coating life. It may also cause surface finish blemishes that could result in an out-of-tolerance condition.