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. as the angle of the Follower. At this angle, the Follower-Roller contacts the Cam-Blank when the MMA = 0°.

However, it is usually better that the Follower-Roller does not contact Cam-Blank when the MMA = 0°. The first index motion should move the Follower and Follower-Roller towards the Cam-Blank.

You can edit the Base-Value 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. You must select 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 sections of 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.

IMPORTANT NOTE:

You should machine the flanks of Globoidal Cams, with a milling tool that has a diameter as near to possible to the diameter of the Follower-Roller.

Tools with a diameter that is smaller than Follower-Roller have a machining error. The larger the difference in diameters, the larger the error between the 'true cam' as provided by MechDesigner, and the cam that you will actually machine.

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: