Years ago, I read a series of books about humans trying to survive in a universe being flooded with robots. The first book I read started on a planet where people were scouting, while they had to watch out for robots, which collected their memories. The people had implants in their head with the memories of deceased friends. As soon as someone was killed, they had to get their memories, so not all knowledge was lost. If they were too late, the brain would be destroyed by the robot getting the memories.
In one of the books there was something about some aliens using a cosmic string to cut a hole in a planet through which liquid iron from the core of the planet would spray. One of the characters would get into the belly of one of those aliens IIRC.
The Dutch translation had something like "mech wars series" on the cover, but that was not part of the title.