A manufacturing company has supplied us with a timing diagram and extreme-position specifications for a pick and place mechanism to load parts into the conveyor of an automatic assembly machine. The attached figures show the desired arrangement. A small plastic part is advanced along a feed rail and presented to the gripper jaws of the mechanism. The pneumatic gripper jaws close at point A in the figures and grab the part. The gripper then moves vertically to pluck the part out of the feed rail at point B. The gripper then moves horizontally to place the part over the receiving nest on the stopped conveyor at point C. The gripper then moves down vertically to insert the part in the nest at point D. The gripper jaws open and the gripper moves horizontally back to the feed rail to pick up the next part at F.

    The station distance from nest to nest on the conveyor is 5 inches. The conveyor sprockets are 10 inch diameter and the conveyor belt is 10 feet long center to center. Note the gripper displacement dimensions in the figures. This manufacturer has cam blanks available in both 8 inch and 10 inch diameter and prefers to use 1.25 inch diameter roller followers. The goal is to manufacture at least 100 parts per minute.

    There are three main sub-tasks within this project:

1 Design a cam-driven index mechanism to move the conveyor using a ratchet and pawl mechanism.

2 Design a cam-driven mechanism to perform the vertical motion of the gripper.

3 Design a cam-driven mechanism to perform the horizontal motion of the gripper.

    These tasks are interrelated and interdependent. An overall design is needed to integrate the three sub tasks. The timing of each event should be as defined in the attached timing chart but there may be tradeoffs in respect to the cycle time allotted for each event. Your team will have to work out those conflicts including modification of the timing chart if necessary. The team should assign its resources as appropriate to cover all aspects of the problem. We suggest that definite tasks be assigned to each team member. You are expected to integrate the designs of your cam-follower mechanisms such that they package in a reasonable size and are all driven by a common motor in proper time phase.

    As with any design problem, there is an infinity of solutions possible. You are expected to come up with the best solution you can design. To do so you will have to try out many alternate designs and iterate to your 'best' solution. You should expect to typically go through at least ten iterations before arriving at an acceptable one. Some measures of "better" designs will be: lower peak accelerations, smoother jerk, smaller physical cam size, good pressure angles and reasonable follower size. You may use either a flat faced or roller follower on any cam (but note manufacturer’s preference above). You are required to compute the s, v, a, j functions, the pressure angles and radii of curvature of the entire cam(s) and draw the cam profile. All of these tasks can be accomplished with program Dynacam.

    You are also required to document your solution in a professional engineering report which adheres to the Project Report Specifications document previously distributed. This report will document the process by which you iterated to your final design as well as the design itself. Do not just describe the final result. Rather show us how you arrived at it, including the failures encountered along the way. This will demonstrate to us that you understand the engineering concepts and the relevant course material. Note that unreferenced and undiscussed computer or other illustrations will be considered to be report "filler" and be ignored. Do not put anything in the report unless you discuss its meaning. NO model of your design is required. But, please do include a computer disk with your DYNACAM solution files on it.

    For this project, no specific background research is required beyond reading your textbook and asking questions of our resident manufacturing and cam design experts. See Chapters 9 and 17 and Section 2-15.

    You may begin your report with the goal statement and task specifications followed by the design description phase of the design process. You may also include background research information if you wish, as an option. The report must include the following figures for each cam IN THE ORDER LISTED!

-    The timing diagram for the whole cycle showing all events including the conveyor motion.

-    S-V-A-J diagrams in one plot for each sub task

-    separate S, V, A, J plots (4 figures) for each sub task

-    pressure angle plot for each sub task

-    radius of curvature plot for each sub task

-    the (3) boundary condition tables for each of your segments that use polynomials, for each sub task

-    a cam profile for each sub task

-    multi-view sketches of your cam-follower trains for each sub task

-    any other data you think necessary

IMPORTANT! IMPORTANT!