A feed wheel advances material through contact with its rotating surface. An opposing roller or support holds the material against the driven wheel. Enter effective wheel diameter, number of turns and an assumed slip percentage to compare ideal travel, net travel and lost feed.
Feed Wheel Interactive Calculator
Vary the effective wheel diameter, rotations, and slip to see feed length, net travel, and lost motion in the roller nip.
Equation Used
The wheel advances material by one circumference per revolution. Use the effective rolling diameter at the nip, not an unloaded outside diameter. The slip input reduces the ideal travel to estimate real net feed when grip is imperfect.
- D is the effective rolling diameter at the material contact line.
- N is the commanded wheel rotation in revolutions.
- Slip is treated as a simple percentage loss of ideal travel.
- Material stretch and acceleration effects are neglected.
From wheel rotation to material travel
With no slip, one wheel revolution advances the material by one circumference, πD. For a 100 mm effective diameter that is about 314.16 mm per turn. The driven roller supplies motion, the backing roller supplies contact, and guides keep the material aligned.
Effective rolling diameter refers to the diameter relevant to the loaded contact, which can differ from the unloaded outside diameter of a compliant roller. Surface condition, deformation and slip affect measured travel. The calculator treats diameter and slip as independent inputs; it does not infer them from material or contact force.
The animation illustrates the roller nip and feed direction. It does not specify roller coatings, bearing tolerances or a suitable pressure setting.
Where a feed wheel is useful
Roller feeds can advance strip, wire, paper or other continuous material toward a downstream operation. The required feed may be continuous or indexed, depending on how the machine works.
Use this tool to compare travel for a known wheel diameter and rotation. To check a real feeder, measure delivered length over several turns under its working conditions. Do not enter a slip value already included in an experimentally calibrated effective diameter, because that would count the same travel loss twice.
Wheel travel with an assumed slip loss
For effective diameter D in millimetres and N revolutions, ideal travel is Lideal = πDN. Travel per revolution is πD.
With slip entered as a percentage s, net travel is Lnet = πDN(1 − s/100). Slip loss is Lideal − Lnet. The percentage is prescribed by the user and is not a prediction of roller traction.
The calculation does not include material stretch, acceleration, intermittent grip or changes in slip during the cycle.
Example: ten turns of a 100 mm wheel
Enter D = 100 mm and N = 10. Ideal travel is π × 100 × 10 = 3,141.59 mm. At zero slip, net travel is also 3,141.59 mm and loss is zero.
At an assumed 1% slip, net travel becomes 3,110.18 mm and lost travel is 31.42 mm. At 2%, net travel is 3,078.76 mm and loss is 62.83 mm.
These results show the accumulated effect of a specified percentage. They do not establish what slip a particular material, roller surface or production speed will produce.
Contact feed and positive engagement
A friction-driven wheel can maintain continuous contact with material, but its shaft position does not by itself prove material position. A belt feed also relies on contact, while a gripper or locating feature can constrain material differently. The appropriate arrangement depends on the stock and process.
Increasing contact pressure may improve grip but can deform or mark the stock. Roller material, alignment and pressure must be selected for the actual application. This calculator gives no universal pressure, hardness, accuracy or service interval.
Frequently asked questions
Does a 100 mm wheel advance material 100 mm per turn?
No. With a 100 mm effective diameter and no slip, one revolution advances π × 100 = 314.16 mm.
How do I choose the slip percentage?
Use measurements under the intended operating conditions, or treat the value as a sensitivity comparison. The calculator cannot predict traction from diameter and rotation alone.
Why is net travel less than ideal travel?
The entered slip percentage subtracts that fraction of the ideal circumference-based travel. At 1% slip, net travel is 99% of ideal travel.
Does this give feed speed?
No. N is the number of revolutions, not revolutions per minute. The outputs are distances. Feed speed also requires a rotation rate or elapsed time.
Can this identify the cause of a feed error?
No. A travel discrepancy can involve grip, rolling diameter, material stretch or drive motion. Compare measured material travel with measured roller rotation before drawing conclusions.
References & Further Reading
- Wikipedia contributors. Roller (mechanical). Wikipedia
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