Last week over spring break I stuck around campus and completed the prototype for our support section. This prototype was made of a thin 10 layers of fiberglass prepreg. Prior to layup, we coated the steel tooling with a special polymer mold release to allow the part to come off the tool once cured.
We began the layup with 10 plies of a reinforcing strip, and then alternated between two different patterns (5 plies each) to obtain the necessary thickness. The following picture shows the reinforcing strips applied under the first main layer.
Once all of the plies were applied, thin steel caul plates were attached to help give a smooth finish on the outside surfaces.
Next, the part was vacuum bagged and was made ready to go in the autoclave (basically a big pressure cooker).
After the part cured and the processing materials were removed, this is what we got:
We used the previously installed air fitting on the tool to pop the part off about 4 inches, but this was not enough. It was determined that we may not have incorporated quite enough draft into the tooling to allow it to come off easily, and our solution to this will be shown in a future post. In the meantime, to get this part off we had to slit one of the corners a few inches,and here is the resulting part:
Being only 10 plies thick (about 0.1"), the part is fairly flimsy and has a feel similar to cardboard. Holes were then drilled both to mount it to the truck and to the winch, and here is the result:
And finally, with the winch installed:
We were all surprised that such a flimsy structure was able to hold such a heavy winch on its own. Once it was bolted up to the truck's frame, it really stiffened up the whole part and made it quite strong. ']
Next episode: tooling modifications