UT Scan Coverage Calculator

This calculator models coverage on a rectangular surface using parallel scan lines. Each scan line covers a swath equal to the probe coverage width (Pw). Adjacent lines are separated by the scan index step (S).

• Computed step from overlap: S = Pw × (1 − O/100)
• Achieved overlap from step: O = 100 × (1 − S/Pw)
• Scan lines across width: N = ceil((W − Pw)/S) + 1
• Covered width estimate: Union ≈ min(W, Pw + (N−1)×S) when S ≤ Pw
• Width coverage: Cw = 100 × Union/W
• Total scan distance: D = N × L × passes × sides
• Scan time: Tscan = D / speed
• Estimated labor cost: Cost = (Ttotal minutes) × (rate per minute)

The model is intended for planning and reporting scope, not acceptance criteria.

1. Measure the accessible surface length and width for scanning.
2. Enter the probe coverage width that your setup achieves.
3. Select a spacing method: enter index step or desired overlap.
4. Add edge exclusions if clamps or geometry limit scanning.
5. Set passes and sides to match your planned technique.
6. Enter scan speed, setup time, reporting time, and labor rate.
7. Press Calculate and review coverage, distance, time, and cost.
8. Download CSV or PDF to attach to your package.

These examples illustrate planning scenarios and sensitivity to spacing.

Example outputs are approximate, and assume full-length scan lines.

Coverage planning helps align UT effort with inspection objectives, site access, and reporting needs. Many teams define coverage using scanned surface percentage, scan lines, and repeat passes. Overlap matters because real scanning includes hand motion, couplant variation, and geometry effects.

Tightening the index step increases overlap and reduces missed indications. The tradeoff is higher scan distance and longer inspection time. When step exceeds probe coverage width, gaps can appear and coverage drops quickly.

Use the exports to document assumptions, parameters, and scope for your work pack.

1) Meaning of UT scan coverage

UT scan coverage is the planned fraction of an accessible surface that is swept by the probe footprint during scanning. It is often reported as coverage across width and coverage by area, supporting clear scope definition for weld inspection work.

2) Establish the effective scan window

Field access rarely matches drawing dimensions. Clamps, coatings, heat zones, or geometry can create no-scan margins. By subtracting edge exclusions from both sides and both ends, the calculator models an effective window that matches site reality.

3) Swath width data and spacing inputs

The probe swath is the lateral width covered by one scan line under your setup. Line spacing is entered as an index step, or you can enter a desired overlap to compute the step from swath × (1 − overlap). For a given effective width W, swath Pw, and step S, the scan line count is estimated as N ≈ ceil((W − Pw)/S) + 1.

4) Overlap versus gaps

When index step is less than or equal to swath, adjacent lines overlap and width coverage approaches 100%. If step exceeds swath, gaps appear between scan lines and coverage falls quickly. Overlap also buffers hand-motion variability and couplant thickness changes that can narrow the effective swath.

5) Passes and two-side scanning

Passes represent repeated scanning of the same window, commonly used to change direction or improve detection confidence. If access allows, scanning from both sides can reduce shadowing in complex weld geometry. The calculator multiplies travel by passes and by sides to reflect effort.

6) Time estimation from scan speed

Total scan distance divided by scan speed yields scan time. Setup and reporting minutes are added to estimate end-to-end effort. Using realistic speed data from prior jobs makes planning consistent across crews and reduces schedule surprises. If you track production, compare distance-per-hour outputs by component type and adjust inputs to match each work package.

7) Cost planning and traceability

Labor cost is computed from total minutes and a supplied rate, enabling fast what-if comparisons between spacing and overlap choices. Exporting results to CSV or PDF preserves inputs and outputs, helping justify scope, budget, and change control decisions.

8) Quality checks before mobilizing

Verify that swath width reflects the probe, wedge, and surface condition you will use. Confirm that exclusions match access limits. If coverage is low, reduce spacing or select a wider probe. Strong planning supports reliable coverage and clean documentation.

1) What is the difference between width coverage and area coverage?

Width coverage measures how completely scan lines span the effective width. Area coverage multiplies the covered width by the effective length, assuming each line runs the full length. Both are useful for documenting scope.

2) How do I choose a good overlap percentage?

Many teams plan 10–30% overlap to reduce missed zones from hand variation and couplant changes. Use your procedure, weld geometry, and acceptance requirements to decide. Higher overlap increases time and cost.

3) Why does the calculator warn about gaps?

If index step is larger than probe swath, adjacent scan lines do not touch. That creates unscanned bands between lines and reduces coverage. Reduce the step or use a wider effective swath to remove gaps.

4) What should I enter for probe swath width?

Enter the practical footprint you can maintain on the surface with your probe, wedge, and coupling. If unsure, measure a test sweep on representative material and use the average value you can repeat reliably.

5) When should I use multiple passes?

Use multiple passes when you need repeated scanning for confidence, changed direction, or different technique coverage. Passes increase total travel and time. Document the reason for extra passes in your report.

6) How is scan time calculated?

The calculator divides total scan distance by the scan speed you enter, then adds setup and reporting minutes. For best results, use speed and adders based on your crew’s recent production data.

7) Can this tool replace an approved inspection procedure?

No. It supports planning and reporting of scan scope. Always follow your approved procedure for equipment settings, calibration, sensitivity, and acceptance criteria. Use the exports to document assumptions and scope.