Add the Stationary Cam

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We will not design the tool. We will only add the Rocker to the sliding-part.
STEP 1: | Edit the sliding-part |
STEP 2: | Add a vertical Line |
See the image to the left.
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See the image to the left
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STEP 5: | Add a Motion-Dimension FB so that the Part is now a Rocker |
STEP 6: | The angle of the Rocker relative to the vertical Line is 135º. |
STEP 7: | Rename this Part to Follower. |
We now want to synchronize the Motion of the Follower with the Motion of the sliding-Part.
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We want a Slot Cam to rotate the Cam-Follower.
We must add a sketch and Profile to represent the Cam-Roller Follower
STEP 8: | Edit the Rocker, renamed as Follower. |
STEP 9: | Add a Line and Circle, as indicate to the left. |
STEP 10: | Close the Part-Editor |
STEP 11: | Add a Profile. Use the Circle. |
We can rename the Circle Profile to Cam-Roller Follower.
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Plan the motion for the Slot Cam
First: What do we want the Stationary Cam to look like?

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The image to the left shows the design we want. It has a Slot Cam . To remind us, ....
... the Angle of the Rocker is a function of the motion of the Sliding-Part, NOT the MMA.
What is the difference between Design 1, 6D1, and this Design 2, 6D2?
Design 1: We can get the motion of the Sliding-Part directly. Its motion is the output from the .
Design 2: We do not know the motion of the Sliding-Part directly. The Sliding-Part is one Part in an R-R-P Dyad.
Note: the Motion of a Part includes its Position, Velocity, and Acceleration motion-values.
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This is the Motion for the Rocker that we have prepared.
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Q: How can we get the motion of the sliding-part?
A1: METHOD 1
Use a Measurement FB to measure the position (and motion) of the sliding-part
A2: METHOD 2
Use a Point-Data FB to give the position (and motion) of the sliding-part relative to the origin of the Base-Part.
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A Measurement FB measures the distance between
In this case, we will measure the distance from a stationary sketch-element in the Base-Part to a moving sketch-element in the sliding-part.
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STEP 1: | Add a sketch-element to the Base-Part |
2. | Part-Editor: Add a vertical Line |
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STEP 2: | Add a Line to the sliding-part : |
2. | Part-Editor: Add a vertical Line |
The Line is vertical, from the start-Point of the sliding-part.
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STEP 3: | Add a Measurement FB to measure the perpendicular distance between the two Lines |
2. | Mechanism-Editor: Click the Point at the top of the Line in the Sliding-Part. |
3. | Mechanism-Editor: Click the Line in the Base-Part |
4. | Mechanism-Editor: Click the graphic-area |
The two Lines should not move past each other as you cycle the model. If they do, move the Line in the Base-Part more to the left.
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STEP 4: | Add a Graph FB to find the range of the motion. |
1. | Click | then click the Graphic-Area. |
2. | Mechanism-Editor: Connect a wire from the Measurement FB to a Y-input of the Graph FB |
The Measurement range in my model is: Minimum = 20.000mm; Maximum = 221.44mm
You can see the and values if you open the from the Graph FB.
Graph Settings dialogs Y-axis | and values.
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1. | Click | then click the graphic-area. |
2. | Edit the Motion FB to open the Motion FB dialog-box |
3. | Click the Select-Motion drop-down arrow and select the Rocker motion in MotionDesigner |
4. | Close the Motion FB dialog-box |
5. | Connect a wire from the output-connector of the Measurement FB to the Motion FB. |
In the image, the Red lines/arrows indicate the range of output from the Measurement FB (20 up to 220 down to 20). This is also the input, or X-axis, to the Motion FB. Thus, the output from the Motion FB is limited to those values in Blue on the Y-axis.
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STEP 6: | Connect the Function-Blocks |
1. | Connect a wire from the output-connector of the Motion FB to the input-connector of the Motion-Dimension FB (Rocker). |
Note: The motion-units from the Measurement FB are NOT important. It is the number value provided to the Motion FB that are important.
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3. | Click the Follower Roller |
MechDesigner adds the 2D-Cam to the Base-Part / Machine Frame.
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Notes:
• | If the X-axis motion of the Slot Cam has a range greater than 360 units, then edit the motion in MotionDesigner to increase the X-axis to be greater than 360. Remember, the units of the Motion FB X-axis are dimensionless. |
• | It is best to make sure the Measurement FB does not output a negative value. |
• | You can use a Gearing FB to 'scale' or 'shift' the output of the Measurement FB to suit the motion and the requirements of the Stationary Cam. |
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