Inputs
- Adhesive thickness
- Flow factor
- Pressure factor
- Opening clearance
- Registration tolerance
FPC / PCB Engineering Calculator
Coverlay Adhesive Overflow Calculator
Estimate adhesive overflow risk from adhesive thickness, opening clearance and flow factor.
How to use the Coverlay Adhesive Overflow Calculator
Coverlay adhesive overflow can contaminate pads, reduce solderability or create cosmetic defects. This calculator estimates overflow risk from adhesive thickness, flow behavior and opening clearance.
Adhesive overflow risk estimate
Formula: Overflow = adhesive thickness x flow factor x pressure factor
- Adhesive thickness: nominal adhesive layer thickness.
- Flow factor: empirical lateral flow multiplier.
- Pressure factor: lamination pressure and temperature effect.
- Available margin: opening clearance minus registration tolerance.
Formula Basis
- Formula basis: empirical adhesive-flow risk model using adhesive thickness and process multipliers.
- Engineering note: flow factor should be calibrated from lamination recipe, coverlay material and inspection data.
Example
0.025 mm adhesive with 2x flow factor and 1.2x pressure factor gives an estimated 0.06 mm overflow.
Outputs
- Estimated adhesive overflow
- Available margin
- Remaining clearance
- Pass / warning indication
Engineering Notes
- Adhesive flow depends on coverlay material, lamination recipe, pad density and opening shape.
- Fine-pitch connector pads need tighter control than large exposed pads.
- Use cross-section or visual inspection data to tune the flow factor.
Validation Checks
- Pad contamination risk
- Coverlay opening margin
- Lamination condition
- Fine-pitch solderability
Related Manufacturing Process
- Lamination - Lamination thickness, adhesive squeeze-out, registration, CTE mismatch
- Coverlay / Solder Mask - Opening compensation, bridge width, pad exposure, alignment tolerance
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FAQ
Why use a flow factor?
Adhesive flow is strongly process-dependent. A factor lets you tune the calculator to your factory data later.
Should this be linked with coverlay opening?
Yes. Coverlay opening and adhesive overflow are related checks and should be reviewed together for fine-pitch areas.