MechDesigner Reference & User Interface > 2.2 Mechanism-Editor: > Machine elements

2D-Cam

Add 2D-Cam and Degrees of Freedom

Add 2D-Cam does NOT remove a degree-of-freedom.

Terminology:

Terms :	Definitions
Cam :	The Part that supports the Cam-Profile shape. Its motion is the input to the Cam system.
Cam-Shaft :	A rotating-Part (the shaft) onto which you fix a 2D-Cam (or 3D-Cam). The shaft usually rotates with constant angular-velocity.
Cam-Profile :	The surface of a 2D-Cam that is in continuous contact with the Follower-Profile.
Cam-Track :	A groove that is cut into a Cam-Blank with an Outer and an Inner Cam-Profile.
Follower :	The Part that supports the Follower-Profile. Its motion is the output from the cam system.
Follower-Profile :	The surface that interacts with the Cam-Profile.
Follower-Roller :	A Follower-Profile that is cylindrical or barrel-shaped.
Flat-faced Follower :	A Follower-Profile that is a flat surface.
Translating Follower :	A Follower that moves along a straight axis.
Reciprocating :	A sliding-Part that has a non-progressive motion.
Rotating Follower :	A Follower that rotates about a fixed axis with a progressive or non-progressive motion.
Oscillating :	A rotating-Part that has a non-progressive motion.
Progressive Motion :	A motion that moves the Follower in one direction.
Non-Progressive Motion :	A motion that returns the Follower to its original position after each machine cycle.
Indexing :	A progressive, usually rotating motion.
Indexer :	A device whose input is a constant-speed Cam-Shaft and output is a rotating shaft with a progressive motion. After the cam-shaft rotates fully a number of times, the output shaft rotates by 360º.
Cam-Blank :	The material that you need before you cut the shape of the Cam-Profile.

2D-Cam: Work-flow

1.Add a 2D-Cam - see Machine elements toolbar > Add 2D-Cam

If the new 2D-Cam is one from a pair of Conjugate-Cams, or it is one flank of a Groove-Cam

1.a. Add a Conjugate-Cam FB - see Machine elements toolbar > Add Conjugate Cam FB

1.b. Edit the Conjugate-Cam FB to select least two 2D-Cams - see Conjugate-Cam dialog.

2.Select a 2D-Cam or a Conjugate-Cam FB as the Power Source for the Follower - see Configure-Power Source

3.Review the 2D-Cam : Display, Properties, Roller-Life, Cam-Life, ... - see 2D-Cam dialog

4.Add a Cam-Data FB - see Kinematic FBs > Add Cam-Data FB

5.Edit the Cam-Data FB to link it to the 2D-Cam- - see Cam-Data dialog : Cam Analysis

6.Connect wires from the Cam-Data FB to a Graph FB to analyze 5 parameters - see Cam-Data dialog : Cam Analysis

7.Edit the Cam-Data FB again to calculate the Cam's Coordinates - see Cam-Data dialog : Cam-Coordinates

Prepare to Add 2D-Cam (typical):

Preparation for Add 2D-Cam

The elements you need in the model before you do Add 2D-Cam:

Cam - any Part that is kinematically-defined

Follower - any other Part that is also kinematically-defined

Follower-Profile - a Profile in the Follower-Part

The Cam usually moves, but it may be stationary.

The Follower usually moves, but it may be stationary.

The Cam and the Follower must move relative to each other.

The Cam-Part and Follower are usually in different kinematic-chains, but this is not necessary.

Do Add 2D-Cam:

STEP 1: Click Add 2D-Cam

1.Mechanism-Editor: Add menu > Mechanism menu > Add 2D-Cam

1.Mechanism-Editor: Machine-elements toolbar > Add 2D-Cam

The command-manager indicates you need to select two elements.

STEP 2: Select the two elements

Element 1 is the Part to which you want to add the 2D-Cam.

1.Click the Part-Outline in the graphic-area, or the Part element in the Assembly-Tree

Element 2 is the Follower-Profile in the Follower.

2.Click the Profile in the graphic-area or the Profile element in the Assembly-Tree

STEP 3: Complete the Command

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

Result :

Graphic-Area

The Inner and Outer 2D-Cams show in the graphic-area.

Result :

Assembly-Tree

A Cam-Plate as a child to the Part to which you add 2D-Cam Red-14-3 .

The 2D-Cam is a child to the Cam-Plate.

The icon for the 2D-Cam in the Assembly-Tree provides a warning that it may be “Bad Cam”!

We base the warning for you on the Cam's Radius-of-Curvature as a percentage of the radius of the Follower-Roller. You can set the warning limit.

The default warning limit is specified in the Application Settings - see here

You can specify a warning limit for each 2D-Cam - see 2D-Cam dialog

YOU must make sure the cam is suitable for your needs, even if it is a “Good Cam”.

“Good Cam”

“Bad Cam”

Next Steps:

If Force analysis is important

Configure the Power-Source and select the 2D-Cam - see Configure Power-Source

Add Mass-Properties to the important Parts in the model - see CAD-Line dialog

Add a Force Data FB to plot Torques, Forces over a machine-cycle - see Force-Data FB, Add Spring FB

If the Cam-Part is actually a Cam-Shaft, then you can select a servo-motor and gearbox - see Servo-motor and Gearbox

Edit the 2D-Cam

Select and edit the 2D-Cam to open the 2D-Cam dialog.

You can display its Pitch-Curve, edit its color, the thickness of the cam-profile, ...

You can estimate the Roller-Life and Cam-Life.

Analyze the Cam over a Machine-Cycle

Add and edit a Cam-Data FB and link it to the 2D-Cam you want to analyze - see Add Cam-Data FB and Cam-Data FB dialog : Cam Analysis

Analysis parameters include: Maximum Shear-Stress, Contact-Force, Radius-of-Curvature, Pressure-Angle, Sliding-Velocity

Calculate and export the Cam-Coordinates in different formats

Add and edit a Cam-Data FB to link it to the 2D-Cam for which you want the Cam-Coordinates - - see Add Cam-Data FB and Cam-Data FB dialog Cam-Coordinates

Calculate the Cam Coordinates as XY-Points or BiArcs.

Export the Cam Coordinates as TXT, DXF, STEP, or export the XY-Points or BiArcs directly to SolidWorks.

Add 2D-Cam