The Best Catch of the Month!
Image of the Month: Graphite Fishing Rod – August 2014
The Best Catch of Month!
Anyone who is an avid fisherman/fisherwoman will know that a majority of fishing rods are made of graphite or a combination of carbon fiber and resins. There is a lot of science that goes into creating fishing rods so that there is a balance of proper bending without breaking. Fortunately for Micro Photonics (unfortunatly for Brandon Walters), one of his graphite poles broke as he was trying to reel in a snagged log. This gave us the perfect opportunity to investigate the structure of a graphite rod using our SkyScan 1172 system.
A fishing rod is typically tapered with laminations of graphite fibers. Each layer of fibers is called a ply and multiple layers are added to provide strength during flexion of the rod. There are various layering techniques but typical ply orientation is parallel to the axis of the rod with other plies oriented at different angles from the axis. The reason for angled plies is to provide maximum strength during flexing, reduce the number of plies, and minimize the weight of the rod.
The basic manufacturing of a graphite rod is done by first cuting a large sheet of graphite into a triangular shape. The large triangular sheet of graphite is then dipped into a liquid plastic resin and rolled onto a tapered mandrel (steel rod). As the sheet is rolled it is squeezed between two heated rollers. Once the entire graphite sheet is wrapped around the mandrel, a polymer layer of cellophane or polyester is applied and heated to apply pressure on the resin as it cools. After cooling, the polymer layer and mandrel are removed. Light sanding is done and paint or protective coatings are applied to finish the rod 1, 2. Steps can vary slightly depending on the quality of the rod but a good how to video is available by Clicking Here.
A section of the broken graphite fishing rod was scanned in our SkyScan 1172 microCT system. As you can see in Figure 1, the graphite fiber plies and resin of the scanned fishing rod are visible. The white areas are the bundles of graphite fibers and the dark gray regions between the fibers are the resin. Looking at the 3D image (watch the video below), fiber bundles in the cross-thatch pattern consist of a single ply. There are a total of five plies in the construction of this fishing rod (See Figure 1).
Figure 1. Axial slice image showing graphite fiber bundles, resin and plies.
Further investigation shows that each of the plies is wrapped concentrically around the axis, with none of the plies oriented at different angles. As mentioned earlier, the angled plies add to the strength of the rod. Since I know the rod was inexpensive, it is not a surprise that the plies are wrapped in a simple pattern and hence were more prone to failure during rod flexion. Overall, the log put up a good fight but the best catch was the microCT images!
SkyScan 1172 Micro-CT
NRecon, DataViewer, CTvox
Micro Photonics Imaging Laboratory, Allentown, PA
Brandon Walters, Micro Photonics, Laboratory Manager