CAM AND FOLLOWER: DEFINITION, TYPES, WORKING & USES [PDF]

A cam and follower is a mechanical linkage used to convert rotary motion into reciprocating or oscillating motion. It consists of two main components: the cam and the follower.

Table of Contents

Cam: The cam is a specially shaped mechanical component typically mounted on a rotating shaft. It has a profile that determines the motion of the follower. The shape of the cam may vary, but common types include the cylindrical cam, plate cam, and the grooved or contour cam.
Follower: The follower is the component that rides along the surface of the cam, following its shape. It can be a lever, roller, or any other mechanism that maintains contact with the cam. The follower’s motion is dictated by the shape of the cam, which can result in linear or curvilinear motion.

The primary purpose of a cam and follower system is to control the motion of the follower based on the desired output motion. The shape of the cam determines the follower’s displacement, velocity, and acceleration throughout the motion cycle. This makes cam and follower systems useful in various applications, such as engine valve mechanisms, printing presses, and automated manufacturing systems.

Different types of followers can be used depending on the specific requirements of the system. Some common follower designs include knife-edge followers, roller followers, and flat-faced followers. Each type has its advantages and disadvantages in terms of friction, wear, and stability.

Cam and follower systems can provide precise control over motion, allowing for complex motion profiles and automation. They are widely used in industries where controlled reciprocating or oscillating motion is required.

Cam and Follower Nomenclature

When discussing cam and follower systems, there are specific terms used to describe different elements and characteristics. Here are some common nomenclature terms associated with cam and follower systems:

Camshaft: The camshaft is the rotating shaft that carries the cam or multiple cams. It is responsible for driving the motion of the follower(s).
Cam Profile: The cam profile refers to the shape or contour of the cam’s surface. It determines the specific motion and displacement experienced by the follower.
Base Circle: The base circle is the smallest circle that can be drawn around the cam profile. It represents the portion of the cam where there is no lift or displacement of the follower.
Cam Lift: Cam lift refers to the maximum displacement or distance traveled by the follower during one complete rotation or cycle of the cam.
Dwell: Dwell refers to the period during the cam rotation where there is no motion or displacement of the follower. The follower remains stationary during this phase.
Lift Curve: The lift curve is a graphical representation of the follower’s displacement or motion over one complete rotation of the cam. It shows how the follower’s position changes with respect to the cam angle.
Follower Travel: Follower travel refers to the overall distance traveled by the follower during one complete rotation of the cam. It includes the lift and any additional movement such as dwell or return.
Follower Return: Follower return refers to the motion of the follower as it returns to its initial position after the lifting or displacement phase. It is the reverse motion from the rise or lift of the follower.
Follower Drop: Follower drop refers to the sudden decrease or drop in the displacement of the follower as it transitions from the lifted position to the returning or dwell phase.
Pitch Circle: The pitch circle is the theoretical circle that represents the average contact between the cam and the follower. It is derived based on the contact point or line between the two components.
Pressure Angle: The pressure angle is the angle between the line of action or the direction of the follower movement and the normal to the pitch curve at the contact point. It affects the force and pressure exerted on the follower and can impact system efficiency.

These nomenclature terms help in describing and analyzing the different aspects of cam and follower systems, facilitating communication and understanding within the field of mechanical engineering and related disciplines.

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what is cam ?

A cam is a mechanical component that is typically in the form of a rotating or sliding disc or cylinder with a specially shaped profile. It is used in various mechanical systems to convert rotary motion into reciprocating or oscillating motion.

The shape of the cam determines the motion of the follower, which is a component that rides along the surface of the cam. As the cam rotates or slides, the follower follows the contour of the cam’s profile, resulting in a specific motion.

types of cam

Certainly! Here are detailed explanations of each type of cam based on their shapes:

Wedge or Flat Cam: A wedge or flat cam has a flat or slightly curved profile. It is the simplest form of cam and provides basic reciprocating or oscillating motion to the follower. The motion is typically linear, with the follower moving in a straight line or along a simple curve.
Disk or Plate Cam: Disk or plate cams are flat discs with one or more slots or grooves cut into them. The follower rides inside these slots or grooves, resulting in various motion patterns. The shape and arrangement of the slots determine the specific motion characteristics of the follower.
Spiral Cam: Spiral cams have a spiral-shaped profile, often wrapped around a cylindrical core. As the cam rotates, the follower experiences a continuously changing motion due to the varying radius of the spiral. This can result in linear, curvilinear, or even non-uniform motion of the follower.
Cylindrical Cam: Cylindrical cams have a cylindrical shape with a profile cut into their surface. The follower’s motion is determined by the shape of the profile, which can be linear or curvilinear. As the cam rotates, the follower moves in a reciprocating or oscillating manner, following the contour of the cylindrical profile.
Heart-shaped Cam: Heart-shaped cams have a profile resembling a heart or an asymmetric figure-eight shape. The follower’s motion generated by a heart-shaped cam is non-uniform, with varying velocities and accelerations throughout the motion cycle. This type of cam is often used when a specific motion pattern is desired, such as in certain valve mechanisms.
Translating Cam: Translating cams have a translating or sliding motion instead of rotational motion. The cam itself moves linearly, and the follower responds accordingly. This type of cam is used when linear motion is required instead of rotary motion.
Snail Drop Cam: Snail drop cams have a spiral-shaped profile similar to a snail’s shell. As the cam rotates, the follower experiences a motion that resembles the descending and ascending path of a snail shell. This type of cam is used when a smooth and gradual change in motion is desired.
Conjugate Cam: Conjugate cams consist of two or more profiles that work in combination to create complex motion patterns. These profiles are designed to interact with different followers, enabling synchronized and coordinated motion. Conjugate cams are used in applications where multiple motions need to be precisely controlled and synchronized.
Globoidal Cam: Globoidal cams have a spherical or globular shape. They produce complex motions with multiple rises, falls, and curves. The shape of the cam allows for precise control over the follower’s motion, making them suitable for applications where intricate and intricate motion patterns are required.
Spherical Cam: Spherical cams have a curved profile that resembles a portion of a sphere. They are designed to generate precise and controlled motion, often with high-speed applications. Spherical cams can produce linear, curvilinear, or intermittent motion, depending on their specific design.

Each type of cam offers unique motion characteristics, and the choice of cam shape depends on the desired motion pattern and the requirements of the application.

what is a follower ?

A follower, in the context of cam and follower systems, refers to a mechanical component that rides along the surface of a cam. It is responsible for translating the motion of the cam into a corresponding motion or displacement.

The follower is typically in contact with the cam through a point or a line, depending on the specific design. As the cam rotates or moves, the follower follows the contour or profile of the cam, resulting in a specific motion.

types of follower

Certainly! Here are detailed explanations of each type of follower based on their shape, movement, and line of movement:

Roller Follower: A roller follower is a type of follower that utilizes a rolling element, such as a cylindrical or spherical roller, to maintain contact with the cam’s surface. The roller reduces friction and allows for smooth motion between the cam and the follower. Roller followers are commonly used when low friction, high precision, and reduced wear are required. They find applications in various industries, including automotive, manufacturing, and robotics.
Knife Edge Follower: A knife edge follower has a sharp, pointed edge that makes contact with the cam. It is designed for high precision and minimal friction. The knife edge follower provides a line contact with the cam’s profile, allowing for precise motion transmission. This type of follower is commonly used in applications that require accurate positioning, such as in measuring instruments, optical devices, and high-precision machinery.
Flat-Faced Follower: A flat-faced follower has a flat surface that directly contacts the cam’s profile. This type of follower provides a larger contact area compared to other types, which helps distribute the load and reduces wear. Flat-faced followers are versatile and find applications in various systems where controlled motion is required, such as in automotive engines, printing presses, and industrial automation.
Spherical Follower: A spherical follower has a spherical shape and makes contact with the cam through its curved surface. The spherical shape allows for multi-directional motion and provides flexibility in different orientations. Spherical followers are often used in mechanisms where the follower needs to adapt to varying cam profiles or where the motion needs to occur in multiple planes.

According to the movement of the follower:

Reciprocating Follower: A reciprocating follower moves back and forth in a straight line. The motion of the follower is typically parallel to the axis of rotation of the cam. This type of follower is commonly used in applications where linear motion is required, such as in pumps, compressors, and certain types of engines.
Oscillating Follower: An oscillating follower moves in an arc or curved path rather than a straight line. The follower’s motion is rotational or angular, oscillating about a fixed point. Oscillating followers are often used in applications where rotational or swinging motion is required, such as in pendulum clocks or certain types of linkages.

According to the line of movement of the follower:

Radial Follower: A radial follower moves along a path that is perpendicular to the axis of rotation of the cam. The follower moves inward or outward, maintaining a fixed distance from the center of the cam. Radial followers are commonly used in applications such as camshaft-driven mechanisms in engines or in systems that require radial motion.
Offset Follower: An offset follower moves along a path that is not directly aligned with the center of rotation of the cam. The follower’s motion has a lateral component, deviating from a purely radial path. Offset followers are often used to generate complex motion patterns or to achieve specific mechanical actions in applications like cam-based mechanisms or machinery.

The selection of the follower type depends on factors such as the desired motion, the load requirements, the need for precision, and the specific application’s constraints. Each type of follower offers advantages and limitations, and the appropriate choice is determined by the specific requirements of the system.

Cam and Follower Working Principle

The working principle of a cam and follower system involves the conversion of rotary motion from the cam into reciprocating or oscillating motion of the follower. Here’s a general overview of the working principle:

Cam Rotation: The cam, typically mounted on a rotating shaft such as a camshaft, undergoes rotational motion. As the cam rotates, its profile interacts with the follower, initiating motion transfer.
Follower Contact: The follower, which can be a lever, roller, or other mechanism, remains in contact with the cam’s surface. The type of follower determines the nature of contact, such as a point, line, or surface contact.
Cam Profile: The shape or contour of the cam profile determines the specific motion imparted to the follower. The profile can be designed to produce various motion patterns, such as linear motion, curvilinear motion, or a combination of both.
Follower Motion: As the cam rotates, the follower moves in response to the cam profile. The follower can experience rise or lift, where it moves away from the base circle, and return or drop, where it returns to the base circle or its original position. Additional motion phases like dwell, where the follower remains stationary, may also be incorporated depending on the cam design.
Output Motion: The motion of the follower is the desired output motion of the system. This motion can be used to actuate other mechanical components or perform specific tasks, depending on the application.

By controlling the shape and contour of the cam profile, the cam and follower system allows for precise control over the follower’s motion. The follower follows the cam’s profile, faithfully replicating its shape and producing the desired displacement, velocity, and acceleration characteristics.

The working principle of a cam and follower system enables the conversion of rotary motion into a wide range of reciprocating or oscillating motions. This makes it a versatile mechanism used in numerous applications, including engine valve mechanisms, printing presses, packaging machinery, robotics, and more.

application of cam and follower

Cam and follower systems find applications in various industries and devices where controlled motion is required. Here are some common applications of cam and follower systems:

Engine Valve Mechanisms: Cam and follower systems are widely used in internal combustion engines to control the opening and closing of valves. The camshaft rotates, and the cam lobes actuate the valve lifters, allowing fuel and air intake or exhaust gases to flow in and out of the cylinders.
Printing Presses: Cam and follower systems are extensively utilized in printing presses to control the movement of printing plates, ink rollers, and other components involved in the printing process. The cam profiles determine the precise timing and coordination of these movements, ensuring accurate and consistent printing.
Industrial Automation: Cam and follower systems play a vital role in automated manufacturing processes. They are employed to control the movement of robotic arms, conveyors, assembly lines, and other machinery, enabling precise and synchronized motion required for manufacturing operations.
Packaging Machinery: Cam and follower systems are commonly used in packaging machinery to control the movement of conveyor belts, packaging materials, and sealing mechanisms. They ensure precise and synchronized motion for efficient and reliable packaging operations.
Textile Machinery: In textile manufacturing, cam and follower systems are employed in various machines, such as looms and knitting machines. They control the movement of the warp and weft threads, enabling precise weaving or knitting patterns to be created.
Automotive Applications: Cam and follower systems are used in automotive systems such as fuel injection systems, throttle control mechanisms, and automatic transmission systems. They control the movement of various components, ensuring efficient and reliable operation of these systems.
Robotics: Cam and follower systems are utilized in robotics for controlling the movement of robot arms, grippers, and other robotic mechanisms. They enable precise and coordinated motion required for performing tasks in industries such as assembly, pick-and-place operations, and material handling.
Packaging and Bottling Equipment: Cam and follower systems are commonly employed in packaging and bottling equipment to control the movement of containers, filling mechanisms, capping devices, and labeling systems. They ensure accurate and synchronized motion, facilitating efficient packaging and bottling processes.

These are just a few examples of the wide range of applications where cam and follower systems are utilized. Their ability to provide precise and controlled motion makes them valuable in industries where repetitive or complex motion patterns are required for mechanical operations.

advantages of cam and follower

Cam and follower systems offer several advantages in various applications. Here are some of the key advantages:

Precise Control: Cam and follower systems provide precise control over motion. The shape of the cam determines the follower’s displacement, velocity, and acceleration throughout the motion cycle. This level of control allows for accurate positioning, timing, and synchronization of mechanical components, ensuring reliable and consistent performance.
Versatility: Cam and follower systems can be designed to achieve a wide range of motion profiles. The shape and contour of the cam can be customized to generate complex motion patterns, such as linear, curvilinear, or intermittent motion. This versatility makes cam and follower systems suitable for diverse applications and allows for the implementation of various mechanical actions.
Compact Design: Cam and follower systems can be designed to occupy relatively small space compared to other mechanisms. The compact design is particularly advantageous in applications where space is limited, such as in automotive engines, machinery, or robotic systems.
Efficiency: Cam and follower systems can provide efficient motion transmission. They minimize energy losses through friction, allowing for smooth and efficient transfer of motion from the cam to the follower. This efficiency contributes to overall system performance, reducing energy consumption and enhancing productivity.
Reliability: Cam and follower systems are known for their reliability. With proper design and maintenance, they can operate with minimal wear and have long service lives. Their robustness and stability make them suitable for demanding industrial applications that require consistent and dependable motion control.
Automation Capabilities: Cam and follower systems are often used in automation processes. They can be integrated into automated machinery, allowing for repetitive and precise motion without the need for constant human intervention. This automation capability enhances productivity, reduces human error, and enables high-speed and consistent operation.
Cost-Effectiveness: Cam and follower systems can be cost-effective solutions for motion control compared to alternative mechanisms. They are relatively simple in design and construction, resulting in lower manufacturing and maintenance costs. Additionally, their reliability and efficiency contribute to overall cost savings in terms of operation and system longevity.
Customizability: Cam and follower systems offer a high level of customizability to meet specific requirements. The shape, size, and profile of the cam can be tailored to achieve the desired motion characteristics, allowing for precise adaptation to different applications and operational needs.

These advantages highlight the benefits of cam and follower systems in achieving controlled motion, enhancing efficiency, and enabling reliable performance in various industries and mechanical systems.

disadvantages of cam and follower

While cam and follower systems offer several advantages, they also have some potential disadvantages to consider:

Limited Flexibility: Cam and follower systems are designed to follow a specific cam profile, resulting in a predetermined motion pattern. Changing the motion requires modifying the cam profile, which can be complex and time-consuming. This limited flexibility may not be suitable for applications that require frequent changes in motion or adjustable motion profiles.
Wear and Friction: The contact between the cam and follower can lead to wear and friction over time, especially in high-speed or high-load applications. This can result in increased maintenance requirements, the need for regular lubrication, and potential for system inefficiencies. Adequate lubrication and periodic maintenance are necessary to mitigate these effects.
Noise and Vibration: Cam and follower systems can generate noise and vibration during operation, particularly at higher speeds or with irregular cam profiles. This can be undesirable in applications that require quiet operation or where excessive vibration may affect the accuracy or stability of other components.
Limited Range of Motion: Cam and follower systems have a limited range of motion determined by the cam profile. They may not be suitable for applications that require continuous or unrestricted motion, such as in some robotic systems or mechanisms requiring extensive articulation.
Complex Design and Manufacturing: Designing and manufacturing cam and follower systems can be complex, especially when intricate cam profiles or specialized followers are required. The design process may involve detailed analysis and precision machining, which can increase manufacturing costs and complexity.
Potential for Impact and Jerky Motion: In certain cases, depending on the cam profile and follower design, cam and follower systems may exhibit impact or jerky motion during the transition between different sections of the cam profile. This can result in sudden changes in velocity or acceleration, potentially affecting the smoothness and stability of the overall motion.
Sensitivity to Misalignment: Cam and follower systems are sensitive to misalignment between the cam and follower. Misalignment can result in increased wear, excessive friction, or even binding between the components. Proper alignment and regular maintenance are necessary to ensure optimal performance and longevity.
Size and Space Requirements: Depending on the specific application, cam and follower systems may require a certain amount of space due to the size of the cam and follower components. This can limit their suitability in applications with tight spatial constraints.

It’s important to consider these potential disadvantages alongside the advantages when evaluating the suitability of cam and follower systems for a particular application. Each system should be carefully designed, maintained, and monitored to address and mitigate these potential limitations.

Reference : http://vlabs.iitkgp.ac.in/mr/exp8/index.html