# Finding accelerations of a cam follower using motion analysis

Question asked by Jacob Murray on Apr 24, 2017

I have a uni assignment where we are to design a cam and a spring follower arrangement and I would like to simulate the setup in Solidworks. I have designed my cam and am trying to test it in Solidworks to make sure I am getting the correct displacement, velocity and acceleration of the follower before I move onto designing the rest, however I simply cannot get the motion analysis add-in to play ball.

I have calculated that this cam should produce a linear acceleration of approximately 51m/s^2 with a flat faced follower at the point where the base circle meets the first flank arc, when rotated clockwise. If you open the sketch you will see there is a sketch point at the very bottom of the sketch - the first flank is found by drawing an arc with a radius that is the length between that point and the very top of the cam. This arc goes tangent from the large base circle (basically the top of the sketch) to the nose circle/arc to the very left.

I have simulated the motion of this cam with a dummy flat faced follower with as light a weight as possible but have been having a lot of issue and I can't get acceleration values anything close to my calculated one. I have played around with the solid body contacts, the accuracy settings, different spring values etc. but Soldiworks is just doing things that don't make any sense (bodies penetrating each other, spring values affecting that penetration and acceleration plots that oscillate wildly). The acceleration max values sometimes double with the smallest changes.

This process shouldn't be this complex and I am wondering if someone could show me how to create a sensor or an actual follower with the correct motion settings that give the same answer as my calculations (51m/s^2 for the first rise). I have checked my calculations with teaching staff and everything is fine there so it is just a matter of getting Solidworks to do the same.