Analyze machining finish using weighted roughness benchmarks. Track Ra, Rq, Rz, waviness, and drift clearly. Make smarter finishing decisions using visual results and exports.
This single-page tool uses a responsive grid: three columns on large screens, two on tablets, and one on mobile devices.
Use this example to understand a typical roughness study for a precision-machined shaft.
| Component | Process | Ra (µm) | Rq (µm) | Rz (µm) | Rt (µm) | Wa (µm) | Target Ra (µm) | Target Rz (µm) |
|---|---|---|---|---|---|---|---|---|
| Hydraulic Spool | Finish Grinding | 0.42 | 0.54 | 2.90 | 4.10 | 0.22 | 0.50 | 3.20 |
| Valve Seat | Superfinishing | 0.18 | 0.23 | 1.40 | 2.00 | 0.09 | 0.20 | 1.60 |
| Bearing Journal | Fine Turning | 0.85 | 1.05 | 5.20 | 6.80 | 0.48 | 1.00 | 6.30 |
This calculator creates a normalized engineering index. It is useful for screening and comparison, but it does not replace a formal surface metrology standard or a certified inspection report.
ni = Measuredi / Targeti
Each roughness parameter is divided by its selected limit so different metrics can be combined on the same basis.
Weighted Ratio = Σ(wi × ni) / Σwi
User-defined weights let you prioritize Ra, Rq, Rz, Rt, or waviness according to functional surface needs.
Texture Penalty = 1 + |Rsk|/20 + |Rku − 3|/20
The index increases when skewness or kurtosis moves away from a more balanced reference texture.
Sampling Factor = clip( √((Le / λc) / 5), 0.90, 1.10 )
This lightly adjusts the result around a five-cutoff evaluation, which is a common inspection setup.
SRI = Weighted Ratio × Texture Penalty × Sampling Factor × 100
An SRI near 100 is close to the chosen target band. Lower values are smoother and stronger. Higher values indicate rougher, less compliant surfaces.
It combines several measured roughness parameters into one normalized engineering score. The index helps compare finish quality, tolerance alignment, and texture balance on a single view.
For this model, yes. Lower values mean the measured profile stays further below the selected targets. Values near 100 are close to the target boundary.
Different parts care about different roughness features. A sealing surface may emphasize Ra and waviness, while a load-bearing surface may care more about Rz and Rt.
They describe texture shape, not only amplitude. A surface can meet amplitude targets yet still have peak-heavy or abnormal peak distributions that affect performance.
Yes. Choose microinches in the unit menu. The calculator converts values internally and returns the summary table using your selected unit.
No. It is a decision-support model for screening, comparison, and reporting. Final release should still follow your drawing notes, standards, and inspection procedure.
You can still use the calculator, but the index becomes stronger when more profile metrics are entered with realistic targets and weights.
Start with any bar above 1.00. Those metrics exceed the target and contribute most directly to a poor finish score or a corrective action warning.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.