If you need to joint composites or make some kind of hatch in a composite structural element, you will encounter the fact that you need to drill, mill or cut the composite material. Drilling, milling and cutting significantly reduce strength of reinforced composite in vicinity of the machined edge. The strength can drop down several times! So, the machining is actually killing the idea of reinforced composites application.
Avoid drilling, milling and cutting reinforced composites! They do not like it!