That's what I did on my latest toon. That's the stuff I am constantly out of for all my crafting operations. I figured I'd use him to feed his own raw materials, and sell the left overs (yea right!).
My advice would be pick up:
Send companions mostly on UT missions, while slicing boxes in the world for credits and scavenging anything you can and selling those (along with your UT rewards) on the GTN.
Feel free to substitute Scavenging with Bioanalysis if those mats sell higher on your server. There's almost always a demand for all grades of scavenging and bio mats on the GTN.
Sending your companions off on Slicing missions at later grades also helps, but usually for the sliced tech parts and not the lockbox missions as the credits you get will often times be roughly the mission cost or sometimes even less. Slicing really shines as a money maker just opening all the open world nodes.