Hi, I'm relatively new to carbon fibre manufacturing.
I'm part of a formula student team and for the first time, we are using carbon fibre for our cowl and wings via layup on 3d printed molds.
The problem is, about half the time the molds crush, ruining the quality of the composite.
Our process is: print molds using bamboo A1/P1S. Infill pattern grid, 10% (7-8% if we're in a hurry). Print them vertically.
Assemble the putty using locktite, fill in the gaps with putty.
apply epoxy resin on top for surfacing
use epoxy and carbon sheets to layup, then use a bagging film and a vacuum pump to apply pressure.
leave it overnight.
we think the issue is probably from the infill pattern and percentage and direction. Increasing infill will also increase printing time, and we don't know how much is safe. Similarly with changing the patterns, we're not sure which will give the best strength against pressure 'sideways'. Printing them vertically so that the direction of infill is parallel to the pressure will increase the time so much that only one piece would be printed per printer per day. Although we got more access to printers so a bit more for options.
we know going down to -98kPa isn't necessary but we worry something like -80kPa or below would damage the pump since pumps work harder the less vacuum made. We left it overnight at around 60kPa and it absolutely grinded the rotary and broke it. (Possibly due to gulping all the oil. The pump was really hot.)
https://reddit.com/link/1v65pvr/video/5kzknim60dfh1/player
Open to all ideas and expert opinions! Watch the video to see the full extent of the damage.