Wire-Covering Machine: Serving Animation, Lay and Coverage Calculator

Posted by Robbie Dickson on

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A serving spindle wraps one or more yarn ends helically around a translating wire. This calculator evaluates ideal lay geometry and an inverse target-coverage construction.

Wire Serving Lay Length and Coverage Calculator

Enter line speed, spindle speed, diameter under serving, yarn dimensions, end count and target coverage. Results are geometric estimates—not finished-layer validation.

Use this as a geometry check, not a production guarantee. Soft yarn can flatten, stretch, compress, slip, or change width with tension. Confirm the finished construction by measuring lay, outside diameter, coverage, and any electrical or mechanical properties required by your specification.

Measured conductor speed through the serving head.
One spindle revolution is treated as one yarn turn.
Use the measured diameter immediately before this layer.
Width across the yarn after tension and flattening.
Used to locate the mean yarn centerline diameter.
Count only ends laid together by this serving head.
This is surface geometry, not dielectric performance.
0°

Actual lay length
--
Lay angle from wire axis
--
Estimated coverage
--
Wrap density
--
Lay needed for target
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Line speed for target
--

Enter valid positive values to calculate.

Equations used

L=1000v/N; Dm=D+t; A=atan(pi Dm/L); C=100nw/(L sin A); target L=nw pi Dm/sqrt(q^2(pi Dm)^2-(nw)^2). Dm = Du + t    and    A = arctan(πDm / L) C = 100Ew / (L sin A)
  • Line and spindle speeds are steady.
  • Mean diameter is diameter under serving plus yarn thickness.
  • Yarn width is an entered effective projected width and is held constant; deformation is not predicted.
  • All ends are evenly phased and follow identical helices.
  • Tension, compression, gaps, slip and manufacturing tolerances are omitted.
FIRGELLI Automations - Interactive Mechanism Calculators
Same mechanism and inputs as the interactive calculator.

Ideal Serving Geometry

The animation shows one ideal helix advancing by the calculated lay length on the entered mean diameter.

What This Calculator Represents

Steady helical geometry and an inverse target-coverage construction only.

Serving Geometry Equations

L=1000v/N
A=atan(pi Dm/L)
C=100nw/(L sin A)

Worked Scenario

The default values evaluate the displayed advance, helix angle and ideal coverage; a sample must confirm the finished layer.

Model Boundary

No yarn deformation, tension, compaction, abrasion, thermal behavior or quality acceptance is calculated.

Frequently Asked Questions

Can coverage exceed 100%?

The raw geometry can indicate overlap; display coverage is capped.

Is yarn flattening included?

No.

Is tension predicted?

No.

Does pitch guarantee coverage?

No; verify a sample.

Are multiple ends phased?

Even phasing is assumed.

Can this set a production machine?

Only as an initial geometric reference.

References

Building or designing a mechanism like this?

Explore the precision-engineered motion control hardware used by mechanical engineers, makers, and product designers.

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