NOTE: Your grade for this week is for attendance. If you show up on time with your group at your scheduled time slot with both cams ready for testing, you get full credit.

OBJECTIVES:

• Test output motion of follower for flat-faced and roller follower cams
• View and discuss high-speed video clips of engine valves driven by cams

HARDWARE:
The cam tester we will be using is similar to the slider-crank/scotch-yoke lab we did in Lab 2. A controller determines the speed at which the cams rotate and an LCD displays the RPMs. Both cams can be tested simultaneously, which should make testing very quick. By looking at the tester, it should be very obvious which is the roller follower and which is the flat-faced follower. Place your cams beneath the corresponding followers by unscrewing the knob that covers the drive shaft, sliding the cams on to the appropriate shaft, and replacing the knobs. Since the followers are spring loaded, you will have to hold them up while putting the cams on.  Just as in the slider-crank lab, flip the controller switch to "Enable" to run the motor.  The dial controls the speed of the motor.  Adjust the speed until the LCD reads 60 RPM.

SOFTWARE:

1. Before running the Cam software, you should reset (zero) the system as outlined in the Cart Lab (Lab 2).
2. Open the "Cam" folder from the desktop and run the "Cam-Tester" LabVIEW program. 
3. Choose the "cam.vi" from the list.
4. In the text box for entering the location to save the file, type "U:\<filename>.xls".  Make sure to add the ".xls" file extension to your filename. If the U: drive is unavailable, use the C: drive.
5. Run the cam tester at 60 RPM if you haven't done so already.
6. Click the white arrow at the top left to start running the program.
7. Click and hold down momentarily the button that says, "Press to START Saving Data."  Once you click this, it will record 2000 data points in one second.  So, if you are running the motor at 60 RPM, you will have recorded exactly 360 degrees of data.
8. Press and hold down momentarily the "Stop" button to save this data to disc (or the file you specified in step 3).
9. Open the file you just saved.
10. This first column has the position data (in inches) for the flat-faced follower; the second column has the same information for the roller follower.
11. If necessary, save the file to a flash drive.

NOW WHAT?
Now that you've designed, cut and tested your two cams, you are ready to write your report.  See the HMWK 7 write-up for the requirements and due date.

To compare the cam tester data to the designed motion profile, one option is to export your motion profile from MathCad and import it into Excel to plot along with the tester data. See the cam cutting Lab write-up for information on how to do this. Alternatively, you can import the tester data into MathCAD. To do this, first save each column of data to separate text files. Then import each file into MathCAD using the "Importing Data from a Data File" procedure in the MathCAD Help system. To find this, hit F1 or select "MathCAD Help" under the Help menu and search for "importing data".

ADDITIONAL RESOURCES:

• Cam tester setup
• high-speed video clips of engine valves driven by cams