Carbon fiber ply cutting

General Composites Discussions Equipment Talk
#1

Hi guys,

I have started building a carbonfiber speedbar for my hangglider. The first layer is a hand layup without vacuum to reïnforce the foamcore before applying vacuum forces. I am now finishing this layer in preparation for the next layers which I will vacuum bag and cure in a hotbox.

Laminating the first layer was my first experience with the laminating process. I have encountered most difficulties defining the best contour of the ply to stretch and conform around the complex shapes. Also, it had a tendency to unraffle at the edges.

Does anyone have some basic information on cutting contours for complex shapes? Corner relief, overlap, flat patterns, ply dropoff or general tips & tricks for making the layers conform to complex shapes? A book or publication maybe?

Thank, André

p.s. I will use different weaves (UD, 0/90, +/- 45 and twill as a top layer) of dry fabric, nót prepreg.

#2

Masking tape …

Cover the area you need the cloth to lay on with masking tape … Use a pencil on the tape to define the shape. Remove the masking tape ( I normally use lots of smaller pieces to create overlaps) trim on your pencil outline and there you have a stencil.
If the tape is still sticky, you can lay it on a board to make a stiffer template , trace around cut out

#3

Another option is to draw you ply out on plastic film. Cut a slightly over sized piece of cloth and wet it out. Then lay the fun over the top and cut out the ply. It also helps keep the ply the shape you intended. Then pull the film after placing the ply.