Cam Synthesis for Project 8-1 from Norton Design of Machinery
Problem Statement & Information
Approach to Solution
I started out by drawing my own plot and determining the different beta’s of each cycle. I then started to analysis the rise and fall motions of the cam, in an attempt to determine which motion program to use. Based on the problem statement I need little to no velocity at B (end of cycle 2) and a low enough velocity at C (end of cycle 3) so that it won’t bend the filament. Next, I used the student addition of DYNACAM which came with our textbook to design a cam that would meet the requirements of the project. I entered all my motion information and chose the motion programs for each Beta as seen below (Figure 1).
After several hours of trying many different types of motion programs and analyzing their Displacement (S)-Velocity (S)-Acceleration (A)-Jerk (J) graphs, as shown below (Figure 2); I narrowed my choices to two motion programs which I thought would work the best.
The Modified Sinusoidal had the lowest peak velocity and the Modified Trapezoidal which has the lowest peak acceleration as pictured below in Table 8-3 from our textbook. I chose to use the Modified Sinusoidal for the first rise (Beta2) because it offered zero velocity at point B and I chose the Modified Trapezoidal motion program for the rest of the rise and fall actions since it offered a relatively low peek velocity and the lowest peak acceleration.
After deciding on my motion programs, I then proceeded to size the Cam. The problem didn’t specify any specific requirements for the dimensions of the cam. I decided on using the following dimension shown below in (Figure 3): Prime Radius-15mm, Follower Radius-2mm and an Offset-2mm. I chose to use a radial cam with a translating motion and a roller follower in order to allow my cam to be as compact as possible.