2D-Cam 'Elements and Dialog-Boxes'

2D-Cams have a number of elements, function-blocks and dialog-boxes that are related to each other. The Process-Map [below] shows how they are related.

2D-Cam Process-Map:

STEP 1A

Add 2D-Cam

Select a:

Part: the Cam-Part
Profile: the Cam-Follower

... optional ...

 

STEP 1B

Open: Cam Display and Properties dialog-box

Display Cam1, Pitch-Circle, Cam2
Display Cam as Profile, Pressure Angle, Contact-Force*, ...
Display Colour

Note: Make sure *material-properties are correct.

 

 

STEP 2A

Add Cam-Data FB

STEP 2B

Edit Cam-Data FB to open Cam-Coordinates dialog-box

Select the 2D-Cam

Do STEP 3B immediately, or

Do STEP 3A, then STEP 3B


STEP 3A

Cam-Analysis [with Graph FB]

Output-Connectors are:

Contact-Force*
Contact-Shear-Stress*
Radius-of-Curvature
Pressure-Angle
Entrainment Velocity

*Note: You MUST do Configure Power Source to see Contact-Stress

STEP 3B

Calculate Cam-Coordinates as Points or Biarcs

Save as DXF, TXT, STEP
Transfer cams directly to SOLIDWORKS
Save As Points, Biarcs

*Force analysis only: Configure Power Source, Mass Properties of Parts

2D-Cam-Data Function-Block (FB)

Add CamData FB

Kinematics FB toolbar > Cam-Data FB - [right of Graphic-Area >>]

Menu:

Add menu > Add Cam-Data FB

What for:

To analyse 2D-cams - see below: Cam Analysis

To calculate 2D-cam coordinates

See also: Add 2d-Cam

Cam-Data FB in Graphic-Area

Cam-Data FB in Graphic-Area

STEP 1.Add the Cam-Data FB to the graphic area
1.Click Kinematics Function-Block toolbar > Add Cam-Data FB
2.Click in the graphic-area

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

Double-click FB to open the dialog-box

STEP 2.Edit the Cam-Data FB to open the Cam-Coordinates dialog-box
1.Double-click the Cam-Data FB to open the Cam-Coordinates dialog-box

-or -

Dialog-CamCoordiantes-Open

Cam-Coordinates Data dialog-box opens immediately.

You must now select a 2D-Cam.

MD-2DCam-Element-GA-1click

STEP 2.Link a 2D-Cam to the Cam-Coordinates dialog-box
1.Click a 2D-Cam in the graphic-area

Dialog-CamCoordiantes-Selected

The 2D-Cam becomes linked to the Cam-Data FB and shows as the: 'Selected Cam-Track'.

You can use the Cam-Coordinates dialog-box to calculate the cam coordinates, or close it, and open it again, later.

Cam Analysis data is available at the output-connectors of the Cam-Data FB.

GA-FB-CamData

Cam Analysis from the Cam-Data FB output-connectors.

After the Cam-Data FB is linked to a 2D-Cam, you can connect wires from the Cam-Data FB to a Graph FB or Stats FB.

It is best to add the same number of Cam-Data FB as there are 2D-Cams in your model.

Also, add the same number of Graph FB to plot the data.


Top tip: Connect the same output-connector [parameter] from different Cam-Data FBs [and 2D-Cams] to the same Graph FB.

For example, connect the Pressure-Angle from each Cam-Data FB to the same Graph FB. Then, you can more easily compare the 2D-Cams


tog_minusCam Analysis Parameters

The Cam Analysis parameters that are available at the output-connectors of the Cam-Data FB [to plot with a Graph FB] are:

F : Cam Contact Force. See Note 1

Ԏ: Maximum Shear Stress. See Note 2

ρ : Radius-of-Curvature. See Note 3

μ : Pressure Angle. See Note 4

Drag wires from the output-connectors of the Cam-Data FB to a Graph FB or a Statistics FB

In the Graph FB, make sure you select the correct cam [Cam 1 or Cam 2] in the Y–axis display option .


Make sure you have Configured the Power Source. Select the Kinematic-chain with the Cam-Follower, and select the 2D-Cam as its Power Source.

Note 1:

If Force does not show in the Graph FB, even with the Power Source Configured Correctly, try the changing the Cam: Cam 1 or Cam 2.

Note 2:

If Shear-Stress does not show in the Graph FB, even with the Power Source Configured Correctly, try the changing the Cam: Cam 1 or Cam 2.

The Maximum Shear Stress happens to be below the Cam Surface. You must enter the correct material properties for the Cam and the Cam-Follower in the Cam Display and Properties dialog. Also, there are many assumptions. The most significant assumption is that there is no lubrication, and, for sliding cam-followers, is that there is no friction between the Cam and the Cam-Follower.


Note 3: The Radius-of-Curvature [ROC] of the Cam-Follower is assumed to be 'positive'. If the cam conforms to the cam-follower roller [wraps around], the cam has a 'negative' ROC. If the cam is convex to the cam-follower roller, the cam has a 'positive' ROC.

Radius-of-Curvature of the Pitch-Curve is not available. If you need to know the Radius-of-Curvature of the Pitch-Curve, export the Radius-of-Curvature of Cam 1 and Cam 2 to Excel, and then calculate the average. Also, it is easy to forget which cam is in the Graph plot. Make sure you use the Y–axis Display drop-down box to select the correct Cam.


Note 4:

1.The Pressure Angle is through the Centre of the Cam-Follower. There are also two other Pressure Angles available: the Contact Pressure Angle of Cam 1 and Cam 2.
2.We cannot calculate Pressure Angle for a Stationary Cam. You must add a line to the Cam-Follower that is perpendicular to the movement of the Cam-Follower. Add an 'Angle' measurement with the Cam Contact Point and the Line that gives the motion direction of Cam-Follower Roller. Please email for more information.

Cam-Coordinates dialog-box

Dialog-CamCoordinates2

See Cam-Coordinates dialog-box

Delimiters

You can select a 'delimiter' to add between each column of data at each cam value 'index'.

Top-Tip: To 'paste' data directly into Excel®,

1.Select the 'Tab' delimiter.
2.Calculate the Data with the 'Recalculate button
3.Click the 'Copy all data to the Clipboard
4.In excel, Paste Special'

The data will show in different columns.

Cam Contact-Force

There are four ways to show and plot the Contact-Force between the Cam and the Cam-Follower.

In all four cases, you must do Configure Power Source to calculate Contact-Force and Contact Shear-Stress correctly.

Display in the Graphic-Area:

1.Display Force Vectors button. This shows two equal and opposite vectors:
the force vector that ACTS-ON the Cam-follower Part, and
the force vector that ACTS-ON the Cam-Part.

You must analyse whether the force between the cam and the follower is active or not.

2.Use: Cam Display and Properties dialog > Cam Display Options > Contact-Force.
The Force remains at zero when the active force is less than zero.

Use a Graph-FB:

3.Use a Force-Data FB, select the Cam as the Force element, plot with a Graph FB.

You must analyse whether the force between the cam and the follower is active or not.

The Force is always 'positive'.

4.Use the Cam-Data FB and the Contact Force output-connector to plot with a Graph FB.

Contact-Force is = '0' if Contact-Force '0'.

This is the preferred option if you need to know whether the Cam-Force becomes less than zero.

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd