# How to calculate the pull force of scissors?

i want to use a stepper motor to move a brush to a industrial scissor machine to cut material of brushes.

The stepper motor will use a worm gear box to increase torque and smooth movement. The stepper motor will produce a torque about 0,4Nm and the gear box a torque of 20Nm. The distance is 0,15m. And the brushes with other stuff are about 1kg. For my calculation i must know how much pull force is produced by scissors.

How can i solve it?

• Welcome to Robotics, user8886193. At the moment, it's not clear what you're asking. There is not diagram and no description of how the system is arragned. You give a torque (rotational force) and a linear distance, then ask about a linear force. It's also not clear if you're asking how to find the current force (the force required to pull the scissors) or a hypothetical output force (how much force you're capable of applying to the scissors). Please edit your question with drawings of how your system is arranged and more details regarding what you're trying to calculate. – Chuck Dec 15 '17 at 16:27
• Thank you for your comment. I added a picture of it. The lenght of .15m are the arm length. While cutting the brush the scissors will try to pull the brush (Force Fp). – user8886193 Dec 15 '17 at 17:53