The guy asked me to introduce myself. Then he also introduced himself. He started to ask many technical questions and they were quite hard. He first asked me some general questions about the mechanical design, then he gradually increase the hard level. After interviews, I wanted to send him an email to express my gratitude. Unfortunately, this company doesn’t allow me to do so. I sent the email to HR and he passed my thank you email to the interviewer. Anyway, very strange and disappointed.

The interview process was straightforward and very technical-question focused. The second round after the initial HR phone call is a technical exam online and the third is an interview with a technical recruiter. After this, there's a panel interview on-site.