In case you have to punch a hole.

Blanking and punching are both shearing operation. The difference is only in the scrap. In blanking what you cut out is of interest.
In punching what you cut from is of interest.


For example: You cut a hole in a sheet metal. If you are interested in the disc that is cut out, then the process is called blanking. The sheet metal with a hole through it is the scrap. If you are interested in the sheet metal that now has a hole through it, then the process is called punching. The disc is the scrap.

Physical mate :)

Your working gas steel main and you need to know if the main has any gas in it. So you punch a hole in it to see if it has any gas in it, I need a procedure in punching a hole in asteel main of natural gas.

To perforate something is to make a hole in it. It can imply the use of force to create the hole, such as pricking or punching a hole through something.