A barrel cam guides a follower through rise, dwell and return as a grooved cylinder rotates. Allocate those phases within one revolution and calculate their mean speeds and dwell time.
Barrel-Cam Timing Calculator
Enter lift, rise/top-dwell/return angles and cycle time. The worksheet reports mean segment speeds and signed remaining low-dwell angle; it does not define a detailed cam law, pressure angle, forces or safe speed.
Equation Used
- The cam completes one revolution in the entered cycle time.
- Entered rise, top-dwell and return angles are nonnegative.
- A nonnegative remaining angle is assigned to low dwell.
- Follower size, groove width, curvature, pressure angle, contact force, inertia, backlash and wear are excluded.
Each phase occupies a share of the 360-degree revolution. The calculator checks the remaining low-dwell angle and gives mean rise and return speeds at the entered cycle time.
Cylindrical groove and translating follower
A barrel cam carries a groove around a cylinder. A follower engaged in that groove is guided axially as the barrel rotates. Portions of the groove with no axial change create dwell; sloped portions create rise or return.
The animation uses piecewise linear displacement only to make the entered angle schedule visible. It is not a manufactured cam profile.
An angle-budget and mean-speed worksheet
Use the calculator to verify that entered phases fit one revolution and to convert phase shares into elapsed time. Actual cam design requires a motion law, geometry, loads and contact analysis.
Constant-driver timing
The signed low-dwell remainder must be zero or positive for a complete non-overlapping schedule. A negative value flags over-allocation.
Angle-budget example
For 25 mm lift, 90-degree rise, 120-degree top dwell, 90-degree return and an 8 s revolution, mean rise speed is +12.5 mm/s, top dwell lasts 2.67 s, mean return speed is -12.5 mm/s and 60 degrees remain for low dwell.
Mean speed is not instantaneous velocity
A real cam motion law controls displacement, velocity, acceleration and jerk throughout the segment. Patents likewise show that the groove shape is selected for the desired mode of movement and that follower/groove engagement details affect backlash and accuracy.
Barrel-cam timing questions
What does a negative low-dwell remainder mean?
The entered rise, top dwell and return exceed one revolution and the schedule is invalid.
Are the displayed speeds peak speeds?
No. They are signed segment means.
Does the worksheet generate a machinable groove?
No.
Cam and follower references
- EP1895342B1, Cam drive mechanism: rotating cylinder, cam groove, follower and linear drive topology.
- EP1413387B1, Linear drive mechanism with cam and followers: cylindrical cam groove shaped for constant or intermittent follower motion.
- EP1750880A2, Rotary-to-reciprocating motion attachment: barrel-cam groove and follower converting rotation to reciprocation.
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