Composite Laminate Cutting

The Basics of Composite Laminate Cutting

Cutting composites is uniquely difficult when compared to cutting wood, metal, or other more traditional building materials. There are a several reasons for this, but there are three primary factors which impact tool selection when cutting laminates.

First, reinforcement fibers are abrasive. Since carbon fiber, fiberglass, and Kevlar® fibers can be abrasive, tools with traditional cutting edges dull quickly, effectively shortening tool life. In addition to wearing out your tools quickly, cutting composites with dull tools increases the likelihood that you will damage the material while also increasing the severity of overheating, our second factor of consideration.

Composites do not typically transfer heat very well. Resin and cut fibers carry away relatively little heat, unlike metal chips, and overheating can melt resin or prematurely dull your tool. When resin melts, it can also clog your cutting tool or damage the finish of your part. In severe instances, there can be enough heat build-up near the edges of a laminate to sacrifice the structural integrity of a part.

Lastly, composites can delaminate when cut. Delamination varies from minor edge chipping (burrs and fibers showing on poorly drilled holes/poorly trimmed edges) to major stress fractures due to poor bonding of resin to reinforcement.

Each of these factors affects your tool selection and determines how you cut composites. There are a variety of methods available, including 5-axis CNC machines, waterjets, and laser jetting. We often use CNC machines for fine machining.

Before we get started, it should be noted that while carbon fiber and fiberglass dust is not toxic, it is a mild irritant to the skin, eyes, and lungs. We strongly recommend that you wear a dust mask and eye protection to minimize any itching or irritation, especially when cutting or sanding in quantity. Edges can be very sharp, so gloves are also critical to avoid cuts and slivers. Check out our safety supplies to find all of the products needed to ensure you are cutting composite laminates safely and correctly.