Getting Started Tutorials - MechDesigner > Tutorial 6: Cams: Flat, Barrel, Globoidal, 'Slot' > 6A1: Cam-Shaft & Follower-Roller > Step 6A1.8: Plot the Cam's Pressure-Angle

Summary of this Step:

1.Add a Cam-Data FB and Graph FB

2.Link the Cam-Data FB to the 2D-Cam

3.Connect a wire from the Cam-Data FB to the Graph FB

4.Plot the Pressure Angle of the 2D-Cam with a Graph FB

Video

Add a Cam-Data FB

STEP 1: Add a Cam-Data FB to the graphic-area

1.Click Kinematics FB toolbar > Cam-Data FB

1.Click Add menu > Cam-Data FB

2.Click the graphic-area

The Cam Data FB is now in the graphic-area.

In the graphic-area, the Cam-Data FB is larger than other Function-Blocks.

We must link the Cam-Data FB to a 2D-Cam.

The Cam-Data FB has five output-connectors. After you link the Cam-Data FB to a 2D-Cam, one of the output-connectors is Pressure-Angle of the 2D-Cam.

See below : Cam-Analysis - Pressure-Angle

Link the Cam-Data FB to a 2D Cam

STEP 1: Open the Cam-Data FB

1.Double-click the Cam-Data FB

See How to open a Dialog

The Cam-Data dialog is open - see above.

Link the 2D-Cam to the Cam-Data FB.

STEP 2: Link the Cam-Data FB to the 2D-Cam

1.Click the 2D-Cam in the graphic-area.

The name of the 2D-Cam is in the Selected 2D-Cam box.

Note:

In this case, I have renamed the 2D-Cam to Blue !

This helps me identify the 2D-Cam in the graphic-area when there is more than one 2D-Cam in the model. I will use the 2D-Cam dialog to change the color of the 2D-Cam in the graphic-area to Blue of course.

STEP 3: Close the Cam-Data FB dialog

Click the at the top and right side to close the Cam-Data dialog.

Cam Analysis - Pressure Angle

Cam Data FB output-connectors
[Note: Entrainment-Velocity is available from R14+]

There are five(5) output-connectors from the Cam-Data FB.

To calculate the Contact-Force and Contact-Stress between the Cam-Profile and the Follower-Profile, the Parts in the Follower kinematic-chain must have mass and inertia properties. In this tutorial, we have not added mass or inertia to the Parts.

We can analyze the

•Pressure Angle

•Radius-of-Curvature

•Sliding Velocity

In this tutorial we will analyze the Pressure-Angle.

STEP 1: Add a Graph FB to the graphic-area.

1.Click Kinematics FB toolbar > Graph FB

1.Click Add menu > Graph FB

2.Click the graphic-area

STEP 2: Connect a wire from the Cam-Data FB to a Graph FB

1.Drag a wire from the Pressure-Angle output-connector of the Cam-Data FB (to the top input-connector of the Graph FB - see images

2.Drag a wire from the output-connector of a Linear-Motion FB to the bottom input-connector of the Graph FB.

The Pressure-Angle of a Cam is an important parameter to analyze. A high Pressure-Angle means that the force/torque is not transferred from the Cam-Part to Follower-Part efficiently. But, the Follower-Part does transfer Forces and Torque efficiently to the Cam-Shaft. This tends to increase the rotational-speed of the Cam-Shaft. The Pressure-Angle imposes extra forces on the machine elements in the Cam and the Follower kinematic-chains. The forces increase rapidly when the Pressure-Angle is greater than 40° (an arbitrary angle as it depends on what is being driven by the cam). Many designers aim to keep the Pressure-Angle between ±30°.

See Tutorial 7, Design-Set - where you reduce the Pressure-Angle to these limits.

See Tutorial Forces 13 for force analysis.