Closing object into solid

Hey there,
I’m very much of a beginner. I try to close the object flat from up and down. Next thing- making the edge round and eventually preapre for 3 D printing.

Screenshot 2024-05-11 175348
Screenshot 2024-05-11 175402

All help appreciated :slight_smile:

a_m_1.3dm (1.8 MB)

Hello - the main thing is, the helical surface is self-intersescting -