Edit the Design-Set.

The objectives are to edit the Design-Set to:

Make the radius-of-curvature of the two cams have a minimum value of 20mm
Make the radius-of-curvature of the two cams to have equal maximum values.

Tut07-DesignSet-Graph

Measure the Cam Radii of Curvature

1.Add two Cam-Data Function-Blocks1s-red2s to the graphic-area.
2.Add one Graph FB 3s
3.Link the Cam-Data Function-Blocks to the 2D-Cams with the rollers on the left and the right.
4.Connect the Cam Radius-of-Curvature output from the two Cam-Data Function-Blocks to two different input-connectors of the Graph FB
5.To indicate to which Cam/Roller the Cam-Data FB is linked, rename the Cam-Data FBs to Left-Roller and Right-Roller.

Note: You can also use a Measurement FB and measure between the centre of the cam and the cam contact-points.


Display the Graph:

1.Double-click the Graph FB icon in the graphic-area. The Graph-Plot opens.
2.Select the correct Radius-of-Curvature [1 or2] for the the two cams with the Y-axis data-channel drop-down boxes [to the right-side of the graph-plot area].

Important Notes:

Each 2D-Cam has two Cams: Cam 1 and Cam 2. Thus, you can also plot, Radius-of-Curvature 1, and Radius-of-Curvature 2.

For each Cam, use the Y-axis data-channel drop-down [to the right-side of the graph-plot area] to select which Radius of Curvature you want to plot - RoC1 or RoC2?

For this model, with two different cams, there is a small '2' next to their contact-points. Thus, we want to plot the Radius-of-Curvature 2 for the two cams.


To read the radius-of-curvature values in the graph-plot

2.Move your mouse-pointer to the graph-plot area
3.Drag your mouse in the graph-plot area

As you drag in the graph area...

the Vertical Bar moves with your mouse-pointer
the MMA updates so that it equals the Red Vertical Pointer and the kinematic-chains follow the MMA - of course
The DRO 5s shows the exact value[s] of the graphed variable at the red cursor

You can edit the Minimum and Maximum graph-plot values in the Graph Settings dialog-box.

I have changed the maximum and minimum of the two graphs to ±100.

Measure the Minimum and Maximum Radius of Cam Radii of Curvature

1.Drag the Cursor Pointer to put the kinematic-chain in the Dwell Segment of the motion at the maximum or minimum radius of the cam.
2.Read the Radii-of-Curvature from the DROs

Do Steps 1 and 2 again for the other Dwell Segment

Tut07-DesignSet-CamDS

Edit the Design-Set

1.Double-Click the Design-Set in the Assembly-Tree or graphic-area
2.Make sure the Design-Set is LOCKED.

Edit the dimensions to make the Radii-of-Curvature equal.

1.In the Design-Set dialog-box, click the Element Row with the dimension you want to change, to make it the active Element-Row.
2.Edit the values - with the Spin-Box tool

The model updates as you edit the dimension in the Design-Set.

If it does not, then click the Rebuild icon in the Design-Set.

3.Experiment. You will find many solutions for the design objectives.

Note, it is best to put the Number-of-Steps parameter in the Machine-Settings dialog-box to ~100.

See Edit menu > Machine Settings > Cycling Parameters > No-of-Steps.

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