Globoidal Cam with Indexing Output-Shaft

We can use Machine-Elements toolbar > Add 3D-Cam to model Globoidal Cams.

This tutorial adds the 5 elements you need in the model before we do Add 3D-Cam

Note: Globoidal Cams are also called Ferguson Cams or Roller Gear Drives.

This Tutorial:

1.Add the Cam-Shaft, the Cam-Follower Shaft, the Cam-Rollers, and Cam-Blank Parts and sketches to four different Mechanism-Editors and Planes.
2.Designs and compares the Modified Sine and Modified-Sine Constant-Velocity 33% motions
3.Adds the Globoidal Cam with Add 3D-Cam.
4.Uses the 3D-Cam dialog-box to configure the cam.
5.Exports the 3D-Cam to SOLIDWORKS®.
btn_delkeywordIndexing Globoidal Cams

Sankyo-indexer

Refer to the image:

Cam-Shaft: The input-shaft. It has a Pink-Axis
Cam-Follower: The output-shaft. It has a Red-Axis. It is also called a Turret, or a Star, because the Cam-Rollers radiate from the centre of the Star.
Cam-Rollers: They are each on a Green-Axis. The axes are perpendicular(⊥) to the Red-Axis and they radiate and intersect the Red-Axis
The Green-Axes are on a Plane. The Pink-Axis lies on the Plane that you can construct with the Green-Axes.

The six Green-Axes are the axes of the Cam-Rollers. They are normal (perpendicular) to the Red Axis

Commercial Indexing Cams: 'Indexers'

Commercial Cam Indexers are nearly always enclosed in sealed, oil-filled cam-boxes. Cam-boxes are often cast, and machined with a CNC machine tool to accurately locate the input and output shafts. There is often an eccentric to adjust the position of the output-shaft relative to the input-shaft. Also, there are shims, or other means, to move the cam along its axis to locate it correctly on its shaft. The output is either a shaft, or a flange-plate. The output-shaft or flange-plate may be hollow.


Dynamic Considerations

Backlash-free, torsionally-stiff couplings are used to connect the input and output-shafts to other parts of the machine. Often, the input-shaft is connected directly to a geared-motor. It is important the motor rotates at as near as possible to constant velocity.

This is not as easy as it sounds, because the input-torque varies considerably within each index-period. The torque fluctuations referred to the motor can be reduced significantly with a high gear-ratio worm/wheel gearing. With the gearing, the motor behaves as a flywheel. If the input-shaft cannot rotate at constant-velocity, the motion of the output-shaft will also not follow the indexing-motion exactly. If the motor input-speed is faster than planned, accelerations and speeds of the output-shaft may far exceed those of the original motion-design. When the speed of the input-shaft is faster than planned, it is called 'over-run'. This can cause damage to the Cam-Box, and/or damage to your machine.


Output Exceptions

Usually, the output-shaft moves one time (indexes) as the input-shaft rotates one time.  The output-shaft may need to index two times when it has many small angular movements to do one complete rotation. Read the catalogues carefully.


A Cam from Destaco® North America.

Click to Expand / Collapse Destaco catalogue
Click to Expand / Collapse
Destaco catalogue

Part Number: 110RGS 4H40-270©. See Catalogue Page 14 (IN-RGS-14). – External link to Destaco Catalogue.

110

 

Perpendicular distance (110mm) between the Input-Shaft (Cam-Shaft) and Output-Shaft (Cam-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 by 4 × 90º

H32

 

Cam 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.


btn_delkeywordReview of the Planes in the Globoidal-Cam

GloboidalCam-SW1

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

We add these elements to the Planes.

1r Cam-Shaft Part (Crank) - a rotating cam-shaft

2r Cam-Blank (Sketch) - a sketch that is the cross-section of the cam-blank.

3r Cam-Follower Plane -  an indexing cam-follower turret, or star

4r Cam-Roller Plane - a sketch of the cam-roller.

Thus, we can see that the elements on each Plane are easy to do. The skill you will need is to add each Plane correctly.

Notes:

1.The image shows the four planes, but in a 3D-Cam in SolidWorks®. In MechDesigner, we use the Mechanism name-tabs as the labels for each plane.
2.We only export the 3D-Cam to SolidWorks®. We must add the Cam-Follower, the Cam-Roller, and the frame-bracket in SolidWorks® to make an assembly. We can import these SLDPRT models into MechDesigner.
btn_delkeyword1: Add the Input-Shaft - the Cam-Shaft.

Add Cam-Shaft

GA-Index-CamShaft-AddLine

STEP 1: Add the Cam-Shaft ( see example: Tutorial 1)
1.Model-Editor: Click Model toolbar > Add Mechanism-Editor | Click the Front Plane | Click OK-tiny-11-15 in the Command-Manager
2.New Mechanism-Editor: Edit the Base-Part.
3.Part-Editor: Geometry toolbar > Add Line.
4.Part-Editor: Constraints toolbar > Add Coincident | Click new 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 | Geometry toolbar > Add Dimension to the Line. Make it ~100mm. Exit Part-Editor.
6.Mechanism-Editor: Kinematic elements toolbar > Add Part | Edit the Part | In Part-Editor: Edit its length to ~80mm. Exit the Part-Editor.
7.Mechanism-Editor: Kinematic elements toolbar > Add Pin-Joint | Click the start-Point of new Part and start-Point of Line at 0,0 of Base-Part (see STEP 1: 3-4)
8.Mechanism-Editor: Kinematic FB toolbar > Add Motion-Dimension FB | Click the Pin-Joint , Line in the Base-Part , CAD-Line in Part, Click OK-tiny-11-15 in the Command-Manager.
9.Mechanism-Editor: Edit the Motion-Dimension FBRed-14-1b, enter Base-Value = 0º .
10.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.

11.Mechanism-Editor: Edit the Gearing FBRed-14-2 | Enter Gearing-Ratio = 4

Note: We do not always need the follower to rotate 360. We can edit the Gearing-Ratio, again, if needed.

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

GA-Index-001

btn_delkeyword2: Motion of the Output-Shaft - Cam-Follower

GA-MT-SCCA-MSCV33

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

Summary : In MotionDesigner :

1.Click File toolbar > Add Motion - now you have two default motions. Use the instructions below to create two motions.
2.Click Edit toolbar > Active-Motion-Settings > Name tab > Motion Name | Motion Name: Enter MS. Do again and enter MSC33 . Remember, you MUST use the Enter key after you enter the Motion Name.
3.Click Segment 4 (the last segment): Click Blend-Point & Segment Editor toolbar > Delete Segment
4.Click Segment 3 (the last 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 (▶ ) top of dialog
10.Segment 2: Segment | Segment Motion-Law | Select Dwell in the drop-down list-box

 


<<< the image shows the motion with the MSC33 motion-law.


GA-Index-003

We can compare the Peak Velocity & Peak Acceleration of a Modified Sine & Modified Sine Constant-Velocity 33%

MODIFIED SINE CONSTANT VELOCITY 33% (MSC33)

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

<<< In the image shows the Modified Sine(MS) ( Orange ) and the MSC33 ( White ) with an Index-Period = 180º.

(β=180º) :

MS

MSC33

Peak Velocity :

~315º/s

~270º/s

Peak Acceleration :

~2000º/s/s

~2425º/s/s

The advantage of the MSC33 is its low peak velocity, NOT its high Peak acceleration!

An index motion with a Reduced Peak Velocity has a Reduced Peak Pressure-Angle.

GA-Index-002

Design Note: When there are a small Number-of-Stops, such as four, the Pressure-Angle can be high and the width of the rib between the cam flanks can be small.


For information only:

We will now compare the Peak Velocity and Peak Acceleration of a Modified Sine Index-Period(β) 180º and 270º


The image compares the two Modified-Sinusoid segments.

The Orange motion has a Index-Period(β) = 270º and a Dwell-Period = 90º

The Blue motion has an Index-Period(β) = 180º and a Dwell-Period = 180º

The Peak Velocity of the Modified-Sine (β=180º) is ~315º/s and for Modified-Sine (β=270º) is ~235º/s

The Peak Acceleration of the Modified-Sine (β=180º) is ~2200º/s/s and for Modified-Sine (β=270º) is ~980º/s/s.

That is, an index angle β=180º has ~20% higher peak velocity, and ~225% higher peak acceleration.

btn_delkeyword3: Add the Output-Shaft - the Cam-Follower Turret.

The output-shaft has these requirements:

1.The output-shaft is modelled on a different 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 to the input-shaft (Cam-Shaft)
4.The Plane of the Cam-Rollers intersects with the axis-of rotation of the cam-shaft

GA-Index-003A

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-PointRed-14-1b 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

GA-Index-AddPlane-PlaneParameters

STEP 2: Add a Plane to the Line
1.Mechanism-Editor: Click Model-menu > Add Plane

The Add Plane dialog-box opens.

2.Click the Line (see STEP 1)

In the  Plane Parameters  separator:

3.Edit Rotate around X-axis to –90º Red-14-1b

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

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

4.Click OK-tiny-11-15 in the Command-Manager.

GA-Index-004

PlaneRed-14-2 is now in the graphic-area

Its +Z-axisRed-14-3 is vertical and parallel with the +Y-axisRed-14-4 of the active Mechanism-Editor.
Its origin is at the start-Point of the Line.

STEP 3: Add a Mechanism to the new Plane
1.Mechanism-Editor: Model-menu > Add Mechanism
2.Click the PlaneRed-14-2 (see image above)
3.Click OK-tiny-11-15 in the Command-Manager

You jump to the new Mechanism-Editor.


The image shows the

Base-PartRed-14-1b in the new Mechanism-Editor and
Base-PartRed-14-2 and Cam-ShaftRed-14-3 in Pink in the Cam-Shaft Mechanism-Editor.

GA-Index-New MechanismEditor

GA-Index-AddCam-Follower

STEP 4: Add the Cam-Follower to the new Mechanism-Editor (Cam-Follower)
1.Edit the Base-Part. Add a Line. Add a Horizontal Constraint, and then Coincident Constraints between its start-Point and the Y-axis and then the X-axis. Exit the Part-Editor
2.Click Kinematic element toolbar > Add Part | Drag in the graphic-area to add the Part.
3.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.
4.Click Kinematic FB toolbar > Add Motion-Dimension FB. Click the Pin-Joint, the horizontal Line and the CAD-Line. Click OK-tiny-11-15 in the Command-Manager.
5.Edit the Motion-Dimension FBRed-14-1b | Enter Base-Value = -135º (=+225º)

GA-Index-CamFollower-FBs

STEP 5: Add Function-Blocks to plan the Motion of the Cam-Follower
1.Click Kinematic FB toolbar > Add Linear-Motion FB , then click the graphic-area
2.Click Kinematic FB toolbar > Add Motion FB , then click the graphic-area
3.Click Kinematic FB toolbar > Add Gearing FB , then click the graphic-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 FBRed-14-2 (see STEP 3.5)

 

GA-Index-Mot-Dim-Negate-MotionValues

STEP 6: Edit the Motion-Dimension FB

The Cam-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 FBRed-14-2 (see image above) | Directions | Negative Motion-ValuesRed-14-3.

GA-Index-MotionFB

STEP 7: Edit the Motion FB
1.Edit the Motion FB
2.In the Select Motion box , select the Modified-Sine Constant-Velocity 33% motion: MSC33.
3.In the Output Option box, select Accumulate OutputRed-14-4

 

STEP 8: Rename these three elements to Cam-Follower: the Plane, the Mechanism-Editor, and the Part

MechDesigner will add a number to the end of each new name each time you enter the New-Name. e.g.: Cam-Follower1, Cam-Follower2, Cam-Follower3, ...

btn_delkeyword4: Add the Cam-Roller Planes and Mechanism-Editors

Note: The Globoidal Indexer is a Body Closed Cam. During its dwell-period, two cam-rollers brace across the cam-flanks on the sides of the cam, to give the Body-Closed construction. Also, a third cam-roller runs inside a groove during the dwell-period This cam-roller is between the two cam-rollers that are across the two sides of the cam. Thus, a total of three cam-rollers are in contact with the cam during the dwell-period - which is over-constrained. The groove for the third-roller that runs in the groove may be cut wider than the roller during the dwell-period. The roller will not need to reverse its direction instantly when the index period begins. The L10 life of the roller is longer and it will not scuff the cam surface as much, during the dwell.


This cam-follower has eight cam-rollers. They are at equal angles around the cam-follower 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 rollers,  or we can design one 3D-Cam with one cam-roller, then move the Cam-Follower to do the other 3D-Cam with the same-cam-roller.

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

We can use a Pattern to show the other 6 cam-rollers.

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

To add 2 × Cam-Rollers, we must add 2 × Planes that are normal to the Cam-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 cam-rollers in these new Mechanism-Editors.

GA-Index-Sketcg4Rollers-01

STEP 1: Add 2 × Lines to the Cam-Follower (output-shaft) (See 3 above)
1.Mechanism-Editor: Edit the Cam-Follower Part
2.Part-Editor: Edit the Dimension of CAD-Line = 60mmRed-14-1b (an estimate of the Pitch Circle Radius of the Cam-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)Red-14-2 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.

<<< The sketch should be solved (Black sketch-elements)

7.Exit the Part-Editor

GA-Index-Sketcg4Rollers-02

STEP 2: Add 2 × Planes to the short Lines
1.Mechanism-Editor: Click Model toolbar > Add Plane
2.Mechanism-Editor: Click, in the graphic-area, one of the short LinesRed-14-3

 

 

GA-Index-Rollers-RotatePlane

3.In the Plane dialog-box >Red-14-4 Rotate around X-axis = -90

Note: The order of the Parameter boxes can change!

GA-Index-Rollers-RotatePlane-02a

4.Click OK-tiny-11-15 to close the Plane dialog-box
5.Rename the Plane to Cam-Roller-A
6.Do 1 - 4 again to Add Plane to the other short Line.
7.Rename the Plane to Cam-Roller-B

The Blue Z-axesRed-14-5 of the two Planes on the short Lines will be towards the origin Cam-Follower Part.

<<< The model after 5. The view shows the edge of the two Planes. They are perpendicular to the Front-View (F3)

GA-Index-Rollers-AddMech2Plane-01

STEP 3: Add 2 × Mechanism-Editors to the 2 × Planes
1.Mechanism-Editor: Click Model toolbar > Add Mechanism
2.Mechanism-Editor: Click PlaneRed-14-6
3.Click OK-tiny-11-15 in the Command-Manager

You jump to the new Mechanism Editor.

4.Rename the new Mechanism-Editor to Cam-Roller-A
5.Click Click Do 1 - 3 again to add a Mechanism-Editor to PlaneRed-14-7
6.Rename the new Mechanism-Editor to Cam-Roller-B
btn_delkeyword5: Add the Cam-Follower Rollers

GA-Index-Rollers-Roller

STEP 1: Add a Circle and Profile to Mechanism-Editors Cam-Roller A and Cam-Roller B
1.Click Mechanism-Editor name-tab : Cam-Roller-A to work in that to Cam-Roller-A
2.Mechanism-Editor: Edit the Base-Part
3.Part-Editor: Do Geometry toolbar > Add Circle
4.Part-Editor: Do Geometry toolbar > Add Dimension - Click the Circle and enter 12.7Red-14-1b as the radius of the circle. ( 1 inch)
5.Part-Editor: Do Constraints toolbar > Add Coincident - Click the centre-Point of the Circle and the X-axis, of the Base-Part, then centre-Point of the Circle and the Y-axis of the Base-Part
6.Exit the Part-Editor.
STEP 2: Add a Profile/Extrusion for the Cam-Roller
1.Mechanism-Editor: Solids toolbar > Add Profile.
2.Mechanism-Editor: Click the Circle
3.Mechanism-Editor: Click OK-tiny-11-15 in the Command-Manager, The default colour of the Profile is PinkRed-14-2
STEP 3: Edit the Extrusion for the Cam-Roller.
1.Mechanism-Editor: SHIFT+CLICK the Profile to show the Profile AND Extrusion in the Selection-Window
2.Mechanism-Editor: Right-click the Extrusion to open the Extrusion dialog-box
3.Extrusion dialog-box : Enter Extrusion Depth = 15.875mm

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

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

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 centre of the output-shaft. We want the end-plate of the Cam-Roller bearing at the end of the Cam-Follower indexing Part. We use the Extrusion-Offset to move the Extrusion in an equal and opposite direction to the Extrusion-Depth to put the cam-roller in the correct position.

We could also rotate the Cam-Roller-A Plane to which we add the Cam-Roller-A Mechanism-Editor.

5.Click OK-tiny-11-15 to exit the Extrusion dialog-box
STEP 4: Do STEPS 1 -3 again to add the extrusion for Cam-Roller B

 

GA-Index-Rollers-Profile

GA-Index-Rollers-Extrusion

GA-Index-Model-PreBlank-2

The Model status (Note: To edit the element colours, use: Application-Settings > Graphic tab > Display Colours > Background)

1.Mechanism-Editor: Visibility toolbar > Show Model in Mechanism Icon-ShowModelinMech24 and also Icon-ShowModelinAllME-24
2.Mechanism-Editor: Visibility toolbar > Show Other Mechanisms Icon-Visibility-Other Mech-SHOW-24
3.Mechanism-Editors: (New MD14.3) Turn on the Light-bulb in each Mechanism name-tab( Lightbulb-ShowMechanism ). 1: Right-click each Mechanism name-tab, 2: Click Show with background ...
4.Mechanism-Editor: Display toolbar > Show Planes to hide Planes

The image shows:

Red-14-1b The Cam-Shaft Part (input-shaft)

Red-14-2 The Cam-Follower Part (output-shaft)

Red-14-3 Cam-Roller Extrusion in Cam-Roller-A

Red-14-4 Cam-Roller Extrusion in Cam-Roller-A

btn_delkeyword6: Add the Cam Blank Sketch

We must add a sketch for the Cam-Blank. It is a sketch of the Cross-Section of the steel immediately before the Cams are cut in the steel.

In MechDesigner, the Cam-Blank does not move. We must add it to a new Mechanism-Editor. We will add it to the Top Plane, in the Model Editor

GA-Index-AddMech4Blank

STEP 1: Add a new Mechanism-Editor to the Top Plane
1.Click the Model-Editor name-tab
2.Model-Editor: Model toolbar > Add MechanismRed-14-1b
3.Model-Editor: Click the Top PlaneRed-14-2 in the Graphic-Area or the Assembly-Tree
4.Model-Editor: Click OK-tiny-11-15 in the Command-Manager

You will jump to the new Mechanism-Editor.

GA-Index-AddMechBlank2

STEP 2: Edit the Base-Part to add the Cam-Blank sketch
1.Mechanism-Editor: Visibility-toolbar > Show Other Mechanism - active

<<< The image shows the Front-View (F3) of the Mechanism-Editor (Cam-Blank).

2.Mechanism-Editor: Edit the Base-PartRed-14-1b to add the sketch for the Cam-Blank.

Notes:

Cam-Blank must be a sketch-loop.
Rotational-axis - you must add a Line to indicate the rotation-axisof the Cam-Blank.

The critical dimensions for the Cam-Blank:

A)The Arc should be concentric with the centre of the Cam-Follower.
B)The radius of the arc should makes sure the top of the cam-rollers are outside the surface of the cam-blank
C) The width of the cam-blank should engage with the sides of the cam-rollers in the dwell-period.

GA-Index-AddMechBlank3

3.Exit the Part-Editor
4.Mechanism-Editor: Visibility-toolbar > Show Other Mechanism elements active
5.Mechanism-Editor: Visibility-toolbar > Show Model in Mechanism: active (and Show All Mechanisms)

<< The image shows the sketch of the Cam-Blank with the model and mechanism elements. The Master Machine Angle is set to put the cam-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 OK-tiny-11-15 in the Command-Manager, The default colour of the Profile is PinkRed-14-2
STEP 4: Edit the Extrusion for the Cam-Blank.
4.Mechanism-Editor: SHIFT+CLICK the Profile to show the Profile AND Extrusion in the Selection-Window
5.Mechanism-Editor: Right-click the Extrusion to open the Extrusion dialog-box
6.Extrusion dialog-box : Enter Extrusion Depth = 1mm
7.Extrusion dialog-box : Enter Extrusion OFFSET = –0.5mm
8.Extrusion dialog-box : Enter Extrusion OFFSET = –0.5mm

GA-Index-AddMechBlank4

The image shows the model after we have added the Cam-Blank sketch and a Profile/Extrusion to the sketch.

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

The Cam-shaft Part is not at 0 to make it easier to see.

btn_delkeyword7: Add the 3D Cams

Add two 3D-Cams.

Note: I have made a mistake in the starting-position of the Cam-Follower.

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

At this angle, the Cam-Roller is in contact with the Cam-Blank when the Master-Machine-Angle is at 0°.

It is much better to edit the Base-Value so that the Cam-Roller moves to enter the Cam-Blank, and then also exit the Cam-Blank later in the machine-cycle.

We can correct the error now:

1.Click the Mechanism-Editor : Cam-Follower
2.Edit the Motion-Dimension FB | Base-Value = -90

GA-Index-Add3D-Cam

The image shows the Cam-Follower in the correct position.


You must select the Mechanism-Editor Cam-shaft.

STEP 1: Click the Mechanism name-tab : Cam-Shaft
STEP 2: Prepare the view so that you can see all of the elements you need to select to add the 3D-Cam.
Use the Visibility toolbar > Show other Mechanisms
Click in the Selection-Window, then use the up/down; left/right keys on your keyboard to rotate the model-view.

<< The view of the model should be similar to the image to the left.

Icon-Add3DCam

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

CM-Add3DCam-0

 

The Command-Manager needs you to select five elements:

Red-14-1b The Cam-Follower Part - in Pink

Red-14-2 The Cam-Roller Profile - in Pink (there are two Cam-Profiles in the model)

Red-14-3 The Cam-Shaft Part - in Green

Red-14-4 The Cam-Blank Profile - in Pink

Red-14-5 The Cam-Blank Rotation Axis - in Pink

 

 

GA-Index-Add3D-Cam

STEP 4: Add Cam-1: Make the Selections in order, 1 to 5.
1.Select the five elements in order.

Refer to the image to the left.

2.Click OK-tiny-11-15 in the Command-Manager
btn_delkeyword8: Settings in the 3D-Cam dialog

GA-Index-Add3D-Cam01

Q: Why is the 3D-Cam similar to a Worm-Cast?

A: It is similar to a Worm-Cast because we calculate the 3D-Cam (in the same way as 2D-Cams) for the full 360º of the Master-Machine-Angle (MMA)

The Cam-Shaft rotates 4 × 360 = 1440° in one Cycle of the MMA. To rotate it four times, we used a Gearing FB and entered Gearing-Ratio=4, as the input to the Motion-Dimension FB.

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

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

A: The Cam-Follower must index and move completely across the rotating face of the Cam-Blank.

One index cycle is not enough. Two may also not be enough. Three is likely to be enough. Four cycles is an insurance policy.

GA-Index-3DCamDialog-Flank00

Q: How do we remove the 3D-Cam data that we do not need to calculate the flanks of the 3D-Cam?

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

STEP 1: Edit the 3D-Cam
1.Click the 3D-Cam element in the graphic-area or the Assembly-Tree
2.Right-click the 3D-Cam element in the Selection-Window
3.Click Edit element in the contextual-menu

The 3D-Cam dialog-box will open.

The 3D-Cam dialog-box has three tabs:

Cam / Display / Export

GA-Index-3DCamDialog-Flank01

STEP 2: Click Cam tab: Flank-Length

The angles are the limits of Master Machine Angle over which we calculate the 3D-Cam

1.Start Angle
2.End Angle

 

GA-Index-Add3D-Flank01

TOP-TIP:

You can add a Profile/Extrusion that is a simplified shape of the Cam-Blank. Edit the Cam-Shaft to add an Circle and Profile / Extrusion.

OR - export the Cam-Blank to SolidWorks, and re-import the SLDPRT onto the CAD-Line of the Cam-Shaft.

When you add a simple extrusion, it is easier to see where the 3D-Cam-Track and Cam-Roller enters and exits the Cam-Blank.

<< here, there is a simplified Cam-Blank - an Extrusion of a Circle on the Cam-Shaft

Start Angle = 15

End-Angle =120

GA-Index-Add3D-Cam02

STEP 3: Add Cam 2

Prepare the View again :

1.Visibility toolbar > Show Model in Mechanism - to hide
2.Click the Selection-Window, then use the arrow-keys on your keyboard to rotate the model to see all 5 elements you must click 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 OK-tiny-11-15 in the Command-Manager.

GA-Index-Add3D-Cam03

3.Open the 3D-Cam dialog-box
4.Edit the Display tab : Display in Graphic-Area > Colour to choose a different colour for Cam-2
5.Edit the Cam tab : Flank-Lengths.

Start Angle = 30

End-Angle =200

Explore the different parameters in the 3D-Cam dialog-box.

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

btn_delkeyword9: Export the 3D-Cam to SOLIDWORKS

SolidWorks-3D-Cam-Blank

We recommend in MechDesigner 14.1 and later releases, you follow these instructions.


Start SOLIDWORKS®:

1.Start a new SLDPRT part document

In MechDesigner :

1.Edit 3D-Cam Cam-1 to open the 3D-Cam dialog-box.
2.In the Export tab: SolidWorks Data-Transfer > Send Cam-Blank

In SOLIDWORKS®:

The Cam-Blank should be in the SOLIDWORKS® part document ( see MechDesigner > 2)

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

SolidWorks-3D-Cam-Cam1

In MechDesigner : Make sure you have entered the Parameters as required in the 3D-Cam-dialog-box

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-box

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 contextual-menu, click Dissolve Feature , and Yes, break the link
c.In the Feature-Manager: Right-Click Surface-Imported1
d.In the contextual-menu, click Import-Diagnostics, in the Import-Diagnostics Property-Manager click the Attempt to Heal All button, and then OK-tiny-11-15 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.

SolidWorks-3D-Cam-Cam2

SolidWorks-3D-Cam-Cam1a2

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

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

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

2.Click OK-tiny-11-15 to close the Property-Manager
3.Insert menu > Part... and Cam-2 as the Insert Part document
4.Again,  click OK-tiny-11-15 to close the Insert-Part Property Manager

SolidWorks-3D-Cam

Finally:

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.


btn_delkeywordAlternative to STEP File: Export the 3D-Cam Mesh data
STEP 1.Open the 3D-Cam dialog-box and Edit the 3D-Cam settings:
1.Double-click the 3D-Cam in the graphic-area.

The 3D-Cam dialog-box should open.

If the 3D-Cam dialog-box does not open, then we recommend this method:

1.Click the 3D-Cam element in the graphic-area or the Assembly-Tree
2.Right-click the 3D-Cam in the Selection-Window
3.Click Edit element in the contextual-menu

The 3D-Cam dialog-box will open.


The 3D-Cam Separators

Cam tab:

Cam Mesh Density Parameters

See 3D-Cam dialog-box: Cam Mesh Density

Roller Clearances

See 3D-Cam dialog-box: Roller Clearances

Flank Length

See 3D-Cam dialog-box: Flank Length Control


Display tab:

See 3D-Cam dialog-box: Display


Rebuild and Save buttons

Rebuild and Save 3D-Cam-Data

See 3D-Cam dialog-box: Rebuild and Save buttons

STEP 2.Send the Cam to SOLIDWORKS

See 3D-Cam dialog-box: Cam Transfer

Tutorials and Reference Help Files for MechDesigner and MotionDesigner 14.2 + © Machine, Cam, Mechanism, and Motion Design Software by PSMotion Ltd