Tutorial 6: Cams: Flat, Barrel, Globoidal, 'Slot'

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Tutorial 6: Cams: Flat, Barrel, Globoidal, 'Slot'

Objective of these Tutorials:

To learn how to model different cam types.

To improve your modeling skills.

Please do tutorials 1,2,3, and 5 before Tutorial 6.

Motions of Cams and Followers

In machines, Cams impart motions to Followers.

The Cam usually has a simple motion, and the Follower has a more complex motion.

It is possible that the Cam or the Follower is stationary. Also, the Cam and the Follower may both have complex motions.

Packaging Machine with Cams. Courtesy of Lareka NL

Example of cams in a protected enclosure with forced oil feed, typical of a packaging machine.

GST-Icon-Add2DCam 2D-Cams and 3D-Cams

6A1: 2D-Cams – Rotating Cam & Circular Follower

6A2: 2D-Cams – Rotating Cam & Flat-faced Follower

6C : 3D-Cams – Barrel and Globoidal Cams

6D : 2D-Cams – A Stationary Linear 2D-Cam

6E : 2D-Cams – Design of Cams for a Cycloidal Gear Reducer - YouTube Tutorial

6F : 2D-Cams – Design of Cams for a Parallel-Indexer - YouTube Tutorial

Cam-Terminology:

Terms :

Definitions

Cam (or Cam-Part) :

The Part that supports the Cam-Profile shape. Its motion is the input to the Cam system.

Cam-Shaft :

The most common Cam-Part. It is rotating-Part (a shaft), to which you add the 2D-Cam (or 3D-Cam) as a Cam-Profile. A Cam-Shaft usually rotates with a constant angular-velocity.

Cam-Profile :

The curved surface of a 2D-Cam (or 3D-Cam) that imparts a motion to a Follower by point or line contact with the surface of a Follower-Profile.

Cam-Track :

A groove that is cut into a Cam-Blank with an Outer and an Inner Cam-Profile.

Follower (or Follower-Part) :

The Part that supports the Follower-Profile. Its motion is the output from the cam system.

Follower-Profile :

The surface of a machine component that is rigidly connected to the Follower-Part. The surface that is in continuous contact with the Cam-Profile.

Follower-Roller :

A common Follower-Profile that is cylindrical or barrel-shaped, and rigidly connected to the Follower-Part.

Flat-faced Follower : 

A Follower-Profile that is a flat surface that is rigidly connected to the Follower-Part.

Translating Follower :

A Follower-Part that moves along a straight axis.

Reciprocating :

A sliding-Part that has a motion that is non-progressive.

Rotating Follower :

A Follower-Part that rotates about a fixed axis with a progressive or non-progressive motion.

Oscillating :

A rotating-Part that has a motion that is non-progressive.

Progressive Motion :

A motion that moves the Follower-Part generally in one direction.

Non-Progressive Motion :

A motion that returns the Follower-Part 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.