system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 why do tattoo machines not cut your skin?

I see it all the time in videos. The tattoo artist pulls a line on the skin, but the needle part needs to be deep into the skin to deposit the ink, so how does it keep pulling the line without cutting the skin?
gpt
Welp im a tattoo artist so i guess i better weigh in here

Technically you are "cutting" (puntcuring is more accurate) the skin every time you tattoo, tattoos are really just fancy wounds with ink deposits when you think you about it. However i get the premise of your question, why doesnt the needle cut the skin like a knife through butter in a line, well the simple answer is, the needle is moving up and down at a fast pace, the needle needs to puntcure the outer layer of skin and insert the ink BUT not go too deep. You arent cutting, you're puncturing.

Basically this is the process

Needle up

needle down

puncture skin

Insert ink

Repeat process 

All at a rapid pace, it may look like a line but its really just dots of ink all being connected drop by drop (or more accurately puncture by puncture)

It is VERY possible for someone to get cut or hurt with tattoo needles, which is one of the million reasons why you should ALWAYS get a tattoo done by a professional.