Phone screening -> All day on sight interview with a tour and wrap up interview: The phone screening was difficult and caught me off guard. I then interviewed in Corvallis where they told me I would be applying to several different jobs at once. I interviewed in 30-minute increments with 5-6 different people with a lunch and tour in the middle of the day. Most of the questions were technical and a majority of the staff was friendly.
Some of the technical questions were challenging and related to problems they were working on. They would ask "we have this issue going on. Here is the data/equipment we are using. What kind of information or patterns can you draw from this?" Or "How would you MFG this product and its different pieces if you needed to build X amount of them a year?"
I can't give a specific thing to study up on because it was super broad in what they asked. As a mechanical engineer, they asked me mostly general things (heat transfer, mechanics of materials, dynamics, material selection, physics, etc.) that I knew most of. I would just say to be well rested before you go in for the all day interview and order a light lunch. By the end of the day, around 430pm, I had my last interview and my brain was totally fried.
In the end, they did tell me I didn't get the position which was nice but I asked for feedback and they didn't respond. It seems like they are trying to help young engineers get connected in the company and in the area but if you are looking for a hip scene Corvallis doesn't have much to offer.
The campus is HUGE and really nice. Overall the process was positive and a good experience even though nothing came of it.