What is cam displacement?

Cam displacement (lift) is how far the follower has moved from its lowest position (base circle) at a given cam rotation angle. It ranges from 0 at the start of the rise to the full stroke at the end of rise.

What is the difference between simple harmonic and cycloidal motion?

Simple harmonic motion (SHM) has infinite jerk at the endpoints, making it unsuitable for high-speed cams. Cycloidal motion has finite jerk everywhere, which greatly reduces vibration and wear at high speeds.

What does the velocity coefficient mean?

The velocity coefficient (v/ω·h) is the dimensionless ratio. Multiply it by the product of angular velocity (rad/s) and total lift (mm or inches) to get the actual follower velocity in consistent units.

What does the acceleration coefficient mean?

The acceleration coefficient (a/ω²·h) is dimensionless. Multiply by ω² × h to get the actual follower acceleration. Positive values indicate the follower is accelerating away from the cam center.

How do I use the results for follower force calculations?

Multiply the actual acceleration (a = a_coeff × ω² × h) by the follower mass to get inertia force. Add spring preload and spring rate × lift to get total contact force. Ensure it stays positive to avoid follower jump.

Cam Displacement Calculator

Name: Cam Displacement Calculator
Availability: InStock
Author: Nham Vu

Enter cam profile parameters to instantly compute follower lift, velocity, and acceleration at any cam angle.

Cam Parameters

Base Circle Radius

Radius of the base circle (minimum cam radius)

Total Lift (Stroke)

Maximum follower displacement from base circle

Rise Angle (β)

deg

Total cam rotation angle over which rise occurs

Current Cam Angle (θ)

deg

Angle at which to evaluate displacement (0 to β for rise)

Motion Profile

Equation governing follower motion during rise

Results at θ = 45°

Lift (y)

—

Velocity Coeff.

—

y' = v/(ω·h)

Accel. Coeff.

—

y'' = a/(ω²·h)

Phase: —

Cam Geometry

Base circle radius (r₀) —

Prime circle radius (r₀ + h) —

Follower radius at θ —

Normalized angle (θ/β) —

Displacement Curve (full rise segment)

Summary

Enter cam profile parameters to instantly compute follower lift, velocity, and acceleration at any cam angle.

How it works

Enter the base circle radius and total lift (stroke) of the cam.
Specify the total angle of the rise segment (typically 90–180°).
Choose a motion profile: simple harmonic, cycloidal, or constant velocity.
Enter the current cam angle to evaluate.
The calculator returns follower lift, velocity coefficient, and acceleration coefficient at that angle.

Use cases

Verify follower lift at a specific crankshaft angle during engine valve timing design.
Compare motion profiles to minimize impact and vibration in high-speed cams.
Compute peak velocity and acceleration for follower inertia load analysis.
Check displacement curves when designing automated machinery cams.
Validate hand calculations against known cam profile equations.
Teach cam kinematics concepts in mechanical engineering coursework.

Frequently Asked Questions

Last updated: 2026-06-10 · Reviewed by Nham Vu