Trying to farm for Materials is more tedious than it actually is.
As of right now, I don't have access to the higher missions, but trying to get into the 7-1 and above missions are nothing more than a hassle because of the material spawn frequency, it's definitely a challenge. It probably is the material drop rate IMO.
I've been stuck trying to access the missions, 7-1 and up, for a good few hours now.
I personally think there should be a heat generator and a Material merchant. As i said in another topic, we're here to test for bugs and errors, not grind again.