What kind of industry category and function category does the screen printing machine belong to?

There is no industry, it belongs to the printing industry. But a small part of the printing.

This job is generally difficult to find and easily overlooked. However, the market demand is great. So you can still find a job. But it is not a promising and promising job. After all, it is not very technical. What you can do, others can do. So it's a question of opportunity.