Getting Started Tutorials - MechDesigner > Tutorial 6: Cams: Flat, Barrel, Globoidal, 'Slot' > 6C: Barrel-Cams & Globoidal-Cams

GST-6C2-Sankyo-indexer

In the image, the:

•Pink-Axis is the axis of the Cam-Shaft (input-shaft).

•Red-Axis is the axis of the Follower-Part (output-shaft). It is also called a Turret, or a Star, because the Follower-Rollers radiate from the center of the Star.

•Green-Axes are the axes of the Follower-Rollers. Their axes are perpendicular(⊥) to the Red-Axis and they radiate from the Red-Axis.

•The Green-Axes and Pink-Axis lie on same Plane.

Commercial Globoidal Cams

Commercial Globoidal Cams are sealed, oil-filled, cam-boxes. The cam-boxes are usually cast, machined, and bored to accurately locate the bearings of the input and output-shafts. An eccentric can adjust the distance from the output-shaft to the input-shaft. Shims adjust the cam along its axis. The output is a shaft or a flange-plate. The output-shaft may also be hollow.

Dynamic Considerations

Connect the input-shaft and output-shafts to other parts of the machine with zero backlash, torsionally-stiff couplings. Shafts should be as short as possible. Connect a geared-motor directly to the input-shaft, or as near as possible to it.

The torque required to drive the input-shaft varies significantly as the output-shaft indexes. When referred to the motor, a high-ratio worm/wheel gear reduces the torque fluctuation significantly. Also, with efficient gearing, the motor behaves as a flywheel, which also reduces the speed variation of the input-shaft.

If the input-shaft does not rotate at constant-velocity, the motion-law of the output-shaft will also be distorted from the planned motion. When the input-shaft accelerates and it rotates faster than planned, the acceleration and speed of the output-shaft may far exceed that of the planned motion. When the speed of the input-shaft is faster than planned, it is called over-run. Over-run can damage the Cam, Follower, Follower-Rollers, bearings, and/or the machine-components that you connect to the output-shaft.

Input and Output motion exceptions

Usually, the output-shaft indexes one time as the input-shaft rotates one time. The output-shaft may also need to index two or even three times as the input-shaft rotates one time, particularly when the index-angle is small. Read the catalogs carefully.

A Cam from Destaco® North America.


Part Number: 110RGS 4H40-270©. See Catalog Page 14 (IN-RGS-14). – External link to Destaco Catalog.
110	Perpendicular distance (110mm) between the Input-Shaft (Cam-Shaft) and Output-Shaft (Follower Shaft)
RGD RGS	Roller Gear with Output Dial-Plate or Flange. Roller Gear with Output-Shaft.
4	Number-of-Stops - the Index-Angle = 360÷4 = 90º The Input-Shaft rotates 4× to rotate the Output-Shaft 4 × 90º
H32	Follower-Roller Diameter = Ø32/32 inches. = Ø1 inch (Ø25.4mm)
270 180	Index-Period = 270º. Dwell-Period = 90º. Index-Period = 180º. Dwell-Period = 180º.
MS MSC33	Modified Sine; Symmetrical. Modified Sine with a 33% Constant Velocity; Symmetrical.

In MechDesigner, a Globoidal-Cam is built on four Planes.

Cam-Shaft Part (Crank) - the rotating cam-shaft

Cam-Blank (Sketch) - the sketch that is the cross-section of the cam-blank.

Follower Plane - the indexing Follower turret

Follower-Roller Plane - the sketch of the Follower-Roller.

The elements on each Plane are easy to add. The skill you need is to add each Plane correctly.

Notes

1.The image is from SolidWorks®.

2.We export the 3D-Cam to SolidWorks®. We do not export the Follower, Follower-Roller or the Frame.

You must add the Follower, the Follower-Roller, and the frame to make the assembly. You can import the SLDPRT models into MechDesigner.

GST-6C2-101

STEP 1: Add the Cam-Shaft ( see example: Tutorial 1)

1.Model-Editor: Click Model toolbar > Add Mechanism-Editor | Click the Front Plane | Click in the Command-Manager

2.Mechanism-Editor: Edit the Base-Part.

3.Part-Editor: Geometry toolbar > Add Line. Drag from left to right.

4.Part-Editor: Constraints toolbar > Add Coincident | Click the Line's start-Point and Base-Part's X-axis | Do again, Line's start-Point and Base-Part Y-axis.

5.Part-Editor: Constraints toolbar > Add Horizontal | Click the Line.

6.Part-Editor: Geometry toolbar > Add Dimension | Click the Line . Dimension =100mm. Exit Part-Editor.

GST-6C2-102

continued...

1.Mechanism-Editor: Kinematic elements toolbar > Add Part | Edit the Part |

2.Part-Editor: Edit its length to 80mm. Exit the Part-Editor.

3.Mechanism-Editor: Kinematic elements toolbar > Add Pin-Joint | Click the start-Point of Part and start-Point of Line in the Base-Part (see STEP 1: 3 - 6

4.Mechanism-Editor: Kinematic FB toolbar > Add Motion-Dimension FB | Click the Pin-Joint , Line in the Base-Part , CAD-Line in Part, Click in the Command-Manager.

5.Mechanism-Editor: Edit the Motion-Dimension FB. Enter Base-Value = 0º .

6.Mechanism-Editor: Kinematic FB toolbar >Add Linear-Motion FB | and Add Gearing FB, connect wires between the Linear-Motion FB and Gearing FB, and Gearing FB and Motion-Dimension FB.

The Cam (input-shaft) must rotate by 4 × 360º = 1040º to rotate the Follower (output-shaft) by 9 × 90º = 360º.

7.Mechanism-Editor: Edit the Gearing FB | Enter Gearing-Ratio = 4

8.Rename the Mechanism-Editor to CAM-SHAFT, the Part to CAM-SHAFT, and the Plane you selected for the mechanism to CAM-SHAFT.

Mod-Sine and 33% Constant Velocity
Index-Period=180, Index-Angle=90

See FULL DETAILS : MotionDesigner Tutorials > Tutorial 1 : Indexing Motion

In MotionDesigner :

1.Click File toolbar > Add Motion - now you have two default motions. Use the instructions below to create two motions.

2.Right-Click a motion, and click Rename. Enter MS. Do again and enter MSC33.

3.Click Segment 4 (it is now the Selected-Segment): Click Blend-Point & Segment Editor toolbar > Delete Segment

4.Click Segment 3 (it is now the Selected-Segment): Click Blend-Point & Segment Editor toolbar > Delete Segment

5.Click Segment 2 (the last segment): Click Blend-Point & Segment Editor toolbar > Blend-Point Editor | X-Axis Values | X-Axis, = 270 if MS, or 180º if MSC33

6.Click Segment 1 (the first segment): Click Blend-Point & Segment Editor toolbar > Segment Editor | Segment Motion-Law | Modified-Sine (MS), or Sine-Constant-Cosine in the drop-down list-box

7.Continue : if SCCA Segment 1: Segment Editor | Segment Parameters | Enter Constant Fraction = 0, Sine Fraction = 1/6 (0.1666667) , Cosine Fraction = 0.5

8.Continue > Segment 1: Segment Editor | Y-axis Values | Enter Start Position = 0, end Position = 90

9.Click Segment Editor | Next Segment button at the top of dialog

10.Segment 2: Segment | Segment Motion-Law | Select Dwell in the drop-down list-box

Compare a Modified-Sine(MS) and a Modified-Sine with 33% Constant-Velocity (MSC33)

In the catalog page, the MSC33 and the MS motion-laws have an Index-Period(β) = 180º.

The image to the left show a:

•Modified-Sine ( Orange )

•Modified-Sine with 33% Constant-Velocity ( White )

They have an Index-Period = 180º, and an Index-Angle = 90º.

(β=180º)	MS	MS-CV33
Maximum Velocity :	~315º/s	~252º/s
Maximum Acceleration :	~2000º/s/s	~2382º/s/s
The maximum velocity of the MS-CV33 is less than that of the MS motion-law. The maximum acceleration of the MS is less than that of the MS-CV33. motion-law. The advantage of a smaller maximum velocity is a: •Smaller Pressure-Angle •Wider Cam-Ribs

Mod-Sine 180 and 270

When the Index-Angle is large, the Pressure-Angle can be high and the width of the rib between the cam flanks can be small. To increase the width of the rib, reduce the Follower-Roller diameter, or use a Cam Motion-Law with a low maximum velocity.

For information only:

Compare the Peak Velocity and Acceleration Values of a Modified Sine Index-Period(β) 180º with those values when the Index-Period is 270º

The image compares the two Modified-Sinusoid segments.

Orange : Index-Period(β) = 270º , Dwell-Period = 90º

Blue : Index-Period(β) = 180º , Dwell-Period = 180º

Peak-Velocity : Modified-Sine (β=180º)=~315º/s ; Modified-Sine (β=270º) = ~235º/s

Peak-Acceleration : Modified-Sine (β=180º)=~2200º/s/s ; Modified-Sine (β=270º)= ~980º/s/s.

Ratios are ~134% Peak-Velocity, ~225% Peak-Acceleration.

The output-shaft:

1.The output-shaft is on a different Plane and Mechanism-Editor

2.The axis of the output-shaft is offset from the input-shaft by 110mm.

3.The axis of the output-shaft is 90º, and perpendicular to the input-shaft (Cam-Shaft)

4.The Plane of the Follower-Rollers intersects with the axis-of rotation of the Cam-Shaft.

STEP 1: Add a Line to the Base-Part

1.Mechanism-Editor (Cam-Shaft) : Edit the Base-Part

2.Part-Editor: Geometry toolbar > Add Line

3.Part-Editor: Constraints toolbar > Add Coincident | Click start-Point of Line and X-axis

4.Part-Editor: Constraint-toolbar > Add Horizontal | Click the Line

5.Part-Editor: Geometry toolbar > Add Dimension | Start-Point of Line at (110,0). Exit Part-Editor

STEP 2: Add a Plane to the Line

1.Mechanism-Editor: Click Model-menu > Add Plane

2.Click the Line (see STEP 1)

In the Plane Parameters separator:

3.Edit Rotate around X-axis to –90º

The default direction of the Z-axis is vertical, down, in the –Y-axis direction.

We want the +Z-axis of the new Plane to be vertical, up, in the +Y-axis direction

4.Click in the Command-Manager.

Image of the new Plane - +Z-axis is up.

Plane

•+Z-axis : up, vertical, parallel with the +Y-axis of the active Mechanism-Editor.

•Origin (0,0) : start-Point of Line.

STEP 1: Add a Mechanism to the new Plane

1.Mechanism-Editor: Model-menu > Add Mechanism

2.Click the Plane

3.Click in the Command-Manager

You jump to the new Mechanism-Editor.

To see kinematic and sketch-elements in each Mechanism-Editor, you must:

1.Enable Visibility toolbar > Show other Kinematic and Sketch-Elements

AND in each Mechanism-Editor you want to see:

2.Right-Click a Mechanism name-tab at the top the graphics-area

3.Enable Show other Kinematic and Sketch-Elements

The elements in the image to the left are:

•Base-Part in the new Mechanism-Editor

•Base-Part and Cam-Shaft in Brown in the Cam-Shaft Mechanism-Editor.

STEP 4: Add the Follower to the new Mechanism-Editor (Follower)

1.Mechanism-Editor: Edit the Base-Part.

2.Part-Editor: Geometry toolbar > Add Line |

3.Part-Editor: Constraints toolbar > Add Horizontal, Add Coincident Click Line's start-Point and the Base-Part Y-axis and again, Base-Part X-axis. Exit the Part-Editor

4.Mechanism-Editor: Click Kinematic element toolbar > Add Part | Drag in the graphics-area

5.Mechanism-Editor: Click Kinematic-element > Add Pin-Joint. Click the start-Point of the CAD-Line and the start-Point of the horizontal Line in the Base-Part.

6.Mechanism-Editor: Click Kinematic FB toolbar > Add Motion-Dimension FB. | Click the Pin-Joint, the horizontal Line and the CAD-Line. Click in the Command-Manager.

7.Edit the Motion-Dimension FB | Enter Base-Value = -135º (=+225º)

STEP 5: Add Function-Blocks to control the Motion of the Follower

1.Click Kinematic FB toolbar > Add Linear-Motion FB , then click the graphics-area

2.Click Kinematic FB toolbar > Add Motion FB , then click the graphics-area

3.Click Kinematic FB toolbar > Add Gearing FB , then click the graphics-area

4.Connect a wire from the Linear-Motion FB to the Gearing FB, and then to the Motion FB and then to the Motion-Dimension FB (see STEP 3.5)

GST-6C2-Index-Mot-Dim-Negate-MotionValues

STEP 6: Edit the Motion-Dimension FB

The Follower (output-shaft) rotates 4 x 90º to rotate a total of 360º.

We want to move it in the negative direction.

1.Edit the Motion-Dimension FB | Directions | Negative Motion-Values.

2.Close the Motion-Dimension dialog

3.Edit the Gearing FB | Enter Gearing-Ratio = 4

4.Close the Gearing FB dialog

STEP 7: Edit the Motion FB

1.Open the Motion FB dialog

2.In the Select Motion box, select the Modified-Sine Constant-Velocity 33% motion: MSC33.

3.In the Output Option box, select Accumulate Output

STEP 8: Rename the three(3) elements to Follower:

•Rename the Plane

•Rename the Mechanism-Editor

•Rename the Part

If you duplicate an elements's name, we add for you a number to the end of the element's name. e.g.: Follower1, Follower2, Follower3, ...

Note: The Globoidal Indexer is a Body Closed Cam. During its dwell-period, two Follower-Rollers brace across the cam-flanks on the flanks of the cam, to give the Body-Closed construction. Also, a third Follower-Roller runs inside a groove during the dwell-period. Thus, a total of three Follower-Rollers are in contact with the cam during the dwell-period - which is over-constrained. The groove for the third Follower-Roller that runs in the middle of the cam may be cut wider than the Follower-Roller during the dwell-period. The L10 life of the Follower-Roller is longer and it will not scuff the cam surface as much, during the dwell.

This Follower-Part has eight Follower-Rollers. They are at equal angles around the Follower-Part as a dial, a turret, or a star.

We will see we need to add two 3D-Cams to the model. For this, we can add two Follower-Rollers, or we can design one 3D-Cam with one Follower-Roller, then edit the Base-Value of the Follower Part to add the other 3D-Cam with the same Follower-Roller.

It is easier to see with 2 × 3D-cams with two Follower-Rollers in one model at the same time.

We can use a Pattern to show the other 6 Follower-Rollers.

The axis-of-rotation of each Follower-Roller is normal(⊥) to the axis-of-rotation of the Follower.

To add 2 × Follower-Rollers, we must add 2 × Planes that are normal to the Follower Part. The Planes must at 45º to each other.

We will add Lines, and Planes to the Lines, and Mechanism-Editors to the Planes . We will then add the Follower-Rollers in these new Mechanism-Editors.

GST-6C2-108

STEP 1: Add 2 × Lines to the Follower (output-shaft) (See 3 above)

1.Mechanism-Editor: Edit the Follower Part

2.Part-Editor: Edit the Dimension of CAD-Line = 60mm (an estimate of the Pitch Circle Radius of the Follower-Rollers )

3.Part-Editor: Geometry toolbar > Add Line (long) | Add Angle Dimension = +45º between the long Line and the CAD-Line | Constraints toolbar > Add Equal (CAD-Line and long Line)

4.Part-Editor: Geometry toolbar > Add 2 × (short) Lines | Constraints toolbar > Add Coincident: select end-Points of 2 × long Lines, and start-Point of two short Lines.

5.Part-Editor: Constraints toolbar > Add Equal to 2 short Lines | Constraints toolbar > Add Perpendicular (between long Line and short Line (2 ×))

6.Part-Editor: Geometry toolbar : Add Dimension | Enter Dimension = 20mm to a short Line.

7.Exit the Part-Editor

GST-6C2-109

STEP 2: Add 2 × Planes to the short Lines

1.Mechanism-Editor: Click Model toolbar > Add Plane

2.Mechanism-Editor: Click, in the graphics-area, one of the short Lines

GST-6C2-Index-Rollers-RotatePlane

3.Plane dialog > Rotate around X-axis = -90

4.Click to close the Plane dialog

Rename the Plane to Follower-Roller-A

Do 1 - 4 again to Add Plane to the other short Line.

Rename the Plane to Follower-Roller-B

Note: Plane dialog: the order of the X,Y,Z parameter boxes can change!

GST-6C2-110

The Blue Z-axes of the two Planes on the short Lines will be towards the start-Point of the CAD-Line in the Follower Part.

The edges of the two Planes are in the image. The Planes are perpendicular to the Front-View (F3).

GST-6C2-111

STEP 3: Add 2 × Mechanism-Editors to the 2 × Planes

1.Mechanism-Editor: Click Model toolbar > Add Mechanism

2.Mechanism-Editor: Click Plane

3.Click in the Command-Manager

You jump to the new Mechanism Editor.

4.Click Follower Mechanism tab to make it the active Mechanism-Editor

5.Click Do 1 - 3 again to add a Mechanism-Editor to Plane

STEP 4: Rename elements

1.Rename the new Mechanism-Editor to Follower-Roller-A

2.Rename the new Mechanism-Editor to Follower-Roller-B

GST-6C2-112

Do STEPS 1, STEP 2 and STEP 3 in Mechanism-Editors Follower-Roller-A and Follower-Roller-B

STEP 1: Add a Circle and Profile

1.Mechanism-Editor: Edit the Base-Part

2.Part-Editor: Do Geometry toolbar > Add Circle

3.Part-Editor: Do Geometry toolbar > Add Dimension - Click the Circle and enter 12.7 as the radius of the circle. (1 inch)

4.Part-Editor: Do Constraints toolbar > Add Coincident - Click the center-Point of the Circle and the X-axis, of the Base-Part, then center-Point of the Circle and the Y-axis of the Base-Part

5.Exit the Part-Editor.

STEP 2: Add a Profile/Extrusion for the Follower-Roller

1.Mechanism-Editor: Solids toolbar > Add Profile.

2.Mechanism-Editor: Click the Circle

3.Mechanism-Editor: Click in the Command-Manager,

The default color of the Profile is Pink

STEP 3: Edit the Extrusion for the Follower-Roller

1.Mechanism-Editor: SHIFT+CLICK the Profile to show the Profile AND Extrusion in the Selection-Window

2.Selection-Window: Right-click the Extrusion, Click Edit element

3.Extrusion dialog : Enter Extrusion Depth = 15.875mm

The Follower-Roller is 0.625 inches (25.4 × 0.625 = 15.875mm)

4.Extrusion dialog : Enter Extrusion OFFSET = –15.875mm

5.Click to exit the Extrusion dialog

STEP 4: Do STEPS 1 -3 again to add the extrusion for Follower-Roller B

Notes

The Extrusion Depth is in the +Z-axis direction - normal to the Mechanism-Plane and Front-View (F3). The +Z-axis direction is to the center of the output-shaft. We want the end-plate of the Follower-Roller bearing at the end of the Follower Part. We use the Extrusion-Offset to move the Extrusion in an equal and opposite direction to the Extrusion-Depth to put the Follower-Roller in the correct position.

GST-6C2-113

GST-6C2-Index-Rollers-Extrusion

GST-6C2-114

To Display Elements

•Mechanism-Editor: Enable Visibility toolbar > Show Solids in Mechanism and Enable

•Mechanism-Editor: Disable Display toolbar > Display Planes to hide the Planes

•Mechanism-Editor: Enable Visibility toolbar > Show other Kinematic and Sketch-Elements

•Mechanism-Editor: Enable Show with other kinematic and sketch-elements Light-bulb :

A)Right-click each Mechanism name-tab

B)Enable Show with other Kinematic and Sketch-Elements

The elements in the image are:

Cam-Shaft Part (input-shaft)

Follower Part (output-shaft)

Follower-Roller-A Extrusion

Follower-Roller-B Extrusion

We must add a sketch for the Cam-Blank. The sketch is an approximation of the Cross-Section of the cam material immediately before you machine the Cams.

GST-6C2-Index-AddMech4Blank

STEP 1: Add a new Mechanism-Editor to the Top Plane

Click the Model name-tab

1.Model-Editor: Model toolbar > Add Mechanism

2.Model-Editor: Click the Top Plane in the graphics-area or the Assembly-Tree

3.Model-Editor: Click in the Command-Manager

You will jump to the new Mechanism-Editor.

Rename the Mechanism-Editor to Cam-Blank

GST-6C2-Index-AddMechBlank2

STEP 2: Edit the Base-Part to add the sketch of the Cam-Blank

1.Mechanism-Editor: Edit the Base-Part to add the sketch for the Cam-Blank.

<<< The image is the Front-View (F3) of the Mechanism-Editor BEFORE we add the sketch of the Cam-Blank.

Sketch of Cam-Blanki Part-Editor

Notes

The Cam-Blank must be a sketch-loop.

The Rotation-Axis of the Cam-Blank is a Line. It is collinear with the Y-axis.

•The center-Point of the Arc should be coincident with the center of the Follower (110,0).

•The radius of the arc should make sure the top of the Follower-Rollers are outside the surface of the cam-blank.

•The width of the cam-blank should engage with the sides of the Follower-Rollers in the dwell-period.

Cam-Blank in Mechanism-Editor

1.Exit the Part-Editor

2.Mechanism-Editor: Visibility-toolbar > Enable: Show Other Kinematic and Sketch-Elements

3.Mechanism-Editor: Visibility-toolbar > Enable Show Solids in Mechanism

4.Mechanism-Editor: Visibility toolbar> Enable Show all Solids in ALL Mechanisms

<< The image is the sketch of the Cam-Blank with the model and mechanism elements. The Master Machine Angle puts the Follower-Rollers at the end of one index motion cycle.

STEP 3: Add a Profile/Extrusion to the Cam-Blank

1.Mechanism-Editor: Solids toolbar > Add Profile.

2.Mechanism-Editor: Click the Cam-Blank sketch-loop

3.Mechanism-Editor: Click in the Command-Manager, The default color of the Profile is Pink

STEP 4: Edit the Extrusion for the Cam-Blank.

1.Mechanism-Editor: SHIFT+CLICK the Profile or Click the Extrusion

2.Selection-Window: Right-click the Extrusion and click Edit element

3.Extrusion dialog : Enter Extrusion Depth = 1mm

4.Extrusion dialog : Enter Extrusion OFFSET = –0.5mm

GST-6C2-117

The image is the model after we have add the Cam-Blank sketch and a Profile / Extrusion.

I have used my keyboard arrow-keys to spin the model.

The MMA is not at 0 to make it easier to see Cam-Shaft.

Note - Correct the angle of the Follower when the MMA=0.

Earlier, in the Follower Mechanism-Editor, we entered Motion-Dimension FB | Base-Value = –135

The Follower-Roller is in contact with the Cam-Blank when the Master-Machine-Angle = 0°.

It is better if the Follower-Roller is not in contact the Cam-Blank when the Master-Machine-Angle = 0°.

The first index should move the Follower to put the Follower-Roller in contact the Cam-Blank.

You should correct the error now:

1.Click the Mechanism-Editor : Follower

2.Edit the Motion-Dimension FB | Base-Value = –90

GST-6C2-118

The image shows the Follower in the correct position.

STEP 1: Before we do Add 3D-Cam

1.Click the Mechanism name-tab : Cam-Shaft

2.Prepare the view so that you can see all of the elements you need to select to add the 3D-Cam.

a)Enable Visibility toolbar > Show other Kinematic and Sketch-Elements

b)Right-click each Mechanism name-tab, and enable Show other kinematic and sketch-elements

c)Right-click each Mechanism name-tab to edit the Color of other kinematic and sketch-elements

d)Use the up/down; left/right keys on your keyboard to rotate the model-view.

e)Disable Display Filters toolbar > Display Planes

STEP 2: Click Machine elements toolbar > Add 3D-Cam

GST-6C2-2-Add3DCam-0

STEP 2: Machine-element toolbar > Add 3D-Cam

1.Click Machine-elements toolbar > Add 3D-Cam

The Command-Manager starts.

There are five selection-boxes for five elements.

The Command-Manager has five selection boxes.

GST-6C2-119

STEP 3: Select the elements to add 3D-Cam

1.Select the five elements in order.

Follower Part - Cyan

Follower-Roller Profile - Yellow or Pink

Cam-Shaft Part - Green

Cam-Blank Profile - Grey

Cam rotation axis Line - Grey

2.Click in the Command-Manager

The 3D-Cam is now in the Graphics-Area

GST-6C2-Index-Add3D-Cam01

Questions:

Q: Why is the 3D-Cam similar to a Worm-Cast (at low-tide on a beach)!

A: Because we calculate the 3D-Cam for one machine cycle.

The Cam-Shaft rotates 4 × 360 = 1440° in one machine-cycle.

To rotate it four times, we added a Gearing FB with a Gearing-Ratio=4 as the input to the Motion-Dimension FB.

The Follower also indexes 4 × 90 = 360°. Again, we added a Gearing FB with a Gearing-Ratio=4 as the input to the Motion FB.

Q: Why did we increase the rotations of the Cam-Shaft and the Follower by four?

A: Each Follower must index at least 3 time to move completely across the rotating Cam-Blank.

One(1) index-cycle is not enough. Two(2) may also not be enough. Three(3) is usually enough. Four(4) cycles is an insurance policy.

Q: How do we remove the data from the 3D-Cam that we do not need?

A: Use the 3D-Cam dialog > Cam tab > Flank-Length

STEP 1: Edit the 3D-Cam

1.Click the 3D-Cam element in the graphics-area or the Assembly-Tree

2.Right-click the 3D-Cam element in the Selection-Window

3.Click Edit element in the shortcut-menu

The 3D-Cam dialog opens.

The 3D-Cam dialog has three tabs:

Cam | Display | Export

GST-6C2-Index-3DCamDialog-Flank00

GST-6C2-Index-3DCamDialog-Flank01

STEP 2: Edit the Flank-Length

1.Click the Cam tab

2.Click the Flank-Length.

The Start-Angle and End-Angle limit the Master Machine Angle over which to calculate the 3D-Cam. Enter:

•Start Angle = ~15

•End Angle = ~125

GST-6C2-Index-Add3D-Flank01

TOP-TIP:

Add a Solid that is near to the shape of the Cam-Blank. - see the Green cylinder in the image

1.Edit the Cam-Shaft to add a Circle

2.Add a Profile / Extrusion to the Circle.

3.Edit the Extrusion. Edit the Extrusion Depth and Extrusion Offset parameters

When you edit the 3D-Cam > Cam tab > Flank-Length parameters, it is easier to see where the Follower-Roller enters and exits the Cam-Blank.

GST-6C2-Index-Add3D-Cam02

STEP 3: Add 3D-Cam 2

Prepare the View again :

1.Visibility toolbar > Disable Show Solids in Mechanism

2.Use the arrow-keys on your keyboard to rotate the model to see all 5 elements you must select to add the 3D-Cam.

Add 3D-Cam 2

3.Click Machine elements toolbar > Add 3D-Cam

4.Click again the 5 elements

5.Click in the Command-Manager.

GST-6C2-Index-Add3D-Cam03

STEP 4: Edit the 3D-Cam

6.Open the 3D-Cam dialog

In the 3D-Cam dialog:

7.Click Display tab : Display in Graphics-Area > color. Select different color for 3D-Cam-2 from 3D-Cam-1

8.Edit the Cam tab : Flank-Lengths.

•Start Angle = 30

•End-Angle =200

Experiment with the different parameters in the 3D-Cam dialog.

Close the 3D-Cam dialog or see below: 9: Export the 3D-Cam to SolidWorks

Start SOLIDWORKS®:

1.Start a new SLDPRT part document

2.Save the Part as an empty file.

In MechDesigner :

1.Edit 3D-Cam Cam-1 to open the 3D-Cam dialog.

2.In the Export tab: SolidWorks Data-Transfer > Send Cam-Blank

In SOLIDWORKS®:

The Cam-Blank should be in the SOLIDWORKS® part document

1.Save the Cam-Blank document as e.g. Cam-Blank.SLDPRT. Do not close it.

GST-6C2-SolidWorks-3D-Cam-Cam1

In MechDesigner :

Make sure you have entered the Parameters as required in the 3D-Cam-dialog

1.Click the Rebuild button, at the top of the dialog, to apply the latest parameter values

2.Click the Save button.

In the Windows® dialog:

3.Select Save as Type > STEP file-type, enter a file-name (e.g. Cam-1), click the Save button

4.Close the 3D-Cam dialog

Do 1 - 4 again. to edit and save Cam-2 as a STEP file-type.

In SOLIDWORKS®:

1.Do File menu > Open> STEP file-type > Cam-1 (see 5 above)

It may be necessary to:

a.In the Feature-Manager: Right-Click Cam-1

b.In the shortcut-menu, click Dissolve Feature , and Yes, break the link

c.In the Feature-Manager: Right-Click Surface-Imported1

d.In the shortcut-menu, click Import-Diagnostics, in the Import-Diagnostics Property-Manager click the Attempt to Heal All button, and then to close the Property-Manager.

2.Save Cam-1 document as Cam-1.SLDPRT file-type. Do not close it.

Do 1 and 2 again to save Cam-2 as Cam-2.SLDPRT. Do not close it.

GST-6C2-SolidWorks-3D-Cam-Cam2

GST-6C2-SolidWorks-3D-Cam-Cam1a2

In SOLIDWORKS®:

Return to the Cam-Blank SOLIDWORKS® part document. Then do:

1.Insert menu > Part... and select Cam-1 as the document

The 3D-Cam should be in the correct physical location. You should be able to:

2.Click to close the Property-Manager

3.Insert menu > Part... and select Cam-2 as the document

4.Click to close the Property Manager

GST-6C2-SolidWorks-3D-Cam

In SOLIDWORKS®:

1.Do Insert menu > Feature > Combine, and use subtract radio-button.

2.As the Main Body select Cam-Blank

3.As the Bodies to Combine select Cam-1 and Cam-2

You should now see the tracks of Cam-1 and Cam-2 in the Cam-Blank.

STEP 1.Open the 3D-Cam dialog and Edit the 3D-Cam settings:

To edit a 3D-Cam, we recommend you use this method:

1.Click the 3D-Cam element in the graphics-area or the Assembly-Tree

2.Right-click the 3D-Cam in the Selection-Window

3.Click Edit element in the shortcut-menu

The 3D-Cam dialog is now open.

3D-Cam dialog

Cam tab:

Cam Mesh Density Parameters

See 3D-Cam dialog: Cam Mesh Density

Roller Clearances

See 3D-Cam dialog: Roller Clearances

Flank Length

See 3D-Cam dialog: Flank Length Control

Display tab:

See 3D-Cam dialog: Display

Rebuild and Save buttons

Rebuild and Save 3D-Cam-Data

See 3D-Cam dialog: Rebuild and Save buttons

STEP 2.Send the Cam to SOLIDWORKS

See 3D-Cam dialog: Cam Transfer

6C2: Indexing-Follower Globoidal-Cam

6C2: Indexing-Follower Globoidal-Cam

Globoidal Cam with Indexing Output-Shaft

In this Tutorial we: