I interviewed on campus, didn't hear back for 2 weeks, and then got placed with a different hiring team that ended up being a better fit. For the on-campus interview, I was asked product design questions such as how you would manufacture a perfect sphere, how I would redesign Apple device components, what components they showed me were made of and how they were made, how I would redesign a project I had already completed. I brought a portfolio which I think helped my case, though they tore me apart on every decision I made in past projects. Overall it was a very intense experience with 7 interviews back to back culminating in a presentation of their design challenge, where they really grilled me. If you don't know the answer, say "I don't know." Don't BS Apple interviewers otherwise you'll talk yourself into a hole. With most of their questions, they just want to "see how you think," as they say. Also, study your basics of material science and heat transfer. And know the stress-strain curve by heart.