Instant Measurement System Selection Tool
Enter the part size and tolerance band, select an IMAGE 3 model, and see whether the part fits the measuring range plus how the tolerance compares with the stated repeatability.
Calculator
Formula and applicable conditions
| Range check | part length ≤ range X and part width ≤ range YBased on the measuring range stated in the IMAGE 3 datasheet. |
|---|---|
| Tolerance / repeatability ratio | ratio = tolerance band (µm) / repeatability (µm)A larger ratio means more margin. This is a screening indicator, not a full gauging capability study. |
Parameter definitions
| Part length / width | Outer dimensions of the workpiece in mm. |
|---|---|
| Measuring range | Stated measuring range of the selected IMAGE 3 model (high-precision mode and wide-field mode differ). |
| Tolerance band | Width of the tolerance zone of the dimension to be measured, in mm. |
| Repeatability | Stated repeatability of the device, not its accuracy. |
Worked example
- Part 20 × 20 mm on IMAGE 3 (high-precision range 18 × 18 mm): the part does not fit — choose IMAGE 3 PLUS (118 × 118 mm) or larger.
- IMAGE 3 MAX 2: high-precision range 206 × 106 mm, repeatability ±0.25 µm.
- A tolerance band of 20 µm against ±0.25 µm repeatability gives a ratio of 40 — comfortable, but the final capability still has to be confirmed with MPE, uncertainty and the decision rule used in your process.
Frequently asked questions
Is repeatability the same as measurement accuracy?
No. Repeatability describes the spread of repeated measurements. Accuracy or MPE describes closeness to the true value and includes systematic effects. Do not replace one with the other.
What is a gauging capability ratio?
It compares the tolerance with the measurement uncertainty (or with the device capability). Common practice requires the measurement uncertainty to be a small fraction of the tolerance. This tool only gives a first screening ratio using repeatability.
Why are there two measuring ranges?
IMAGE 3 models offer a high-precision mode with a smaller field and a wide-field mode with a larger field. The stated accuracy and repeatability differ between the modes.
What else must I confirm?
Fixturing, part surface and edge definition, lighting, program settings, thermal conditions and the calibration artefact. A sample-part study is the reliable way to confirm capability.
Request a POMEAS lens recommendation
Submit the parameters and the calculation result below. The form posts to the existing POMEAS contact interface; nothing is sent automatically and no data is shared with third parties.