Submitted job application to HR. Within one week, a hiring manager sent me an email, including five design/manufacturing issues and asked me for solutions. After I gave her my best solutions, she bounced back more questions (8 in total) and asked me more technical details and explanation. After I gave her what she was looking for, I was invited for on-site interview. On-site interview started with a written test, then was focused on technical/manufacturing solutions, a lot of questions about design/processing/testing. After nearly 3 hours interview, I finally realized the hiring manager was not interested in me as a job applicant. What she really wanted was solutions for her products, processing, and design. 2 days after that interview, she sent me 7 more technical questions and asked my answers (which was annoying and ridiculous). I never answered her email again. Ironically, two weeks later, HR called me and would like to offer me the position.