Hello everyone. This is Govardhanan. I am still a student, when mechanics is considered, so please tolerate my simple questions and pls do help me out.

I am trying to dispense some food from the container using a rack and a pinion, but was not successful in that, as the stepper motor I use doesnt give enough torque. So I need to know the torque I am supposed to generate to dispense the food. But I am not sure how to measure the force required to dispense the food. Please help me out in designing this. Thanks a ton in advance.

I have attached the rough explanation drawing and an image of what I have done already.

 

Given that you have hardware in front of you all ready, It is probably easiest to remove the motor and apply measure the force on the rack to achieve the flow rate you desire. Then you can design a gear train knowing the motor torque/speed performance.
To do this from first principles, you would need to know the viscosity of the food (probably non-newtonian) and run a CFD analysis to calculate flow rate as a function of force on the piston.

 

Don't worry, a 'successful' company, full of supposed professionals, managed to screw up pretty much the same problem. Look up Juicero.

I second Erich's suggestion, btw