Geometric Dimensioning and Tolerancing (GD&T) links design, production and metrology, but ambiguous interpretation can produce conflicting measurements, scrap and repeated exchanges between teams. Metrologic DCS says the risk is growing as product manufacturing information (PMI) is increasingly embedded in CAD files and standards continue to evolve.
The company outlines four measures intended to make inspection workflows more reliable, from reading design intent to delivering reports to the shop floor.
Start with PMI and avoid manual re-entry
Metrologic DCS recommends using software that takes PMI as its starting point rather than requiring users to re-enter tolerances. Features and evaluations can then be generated from the part’s digital definition. The company says this avoids re-keying, reduces interpretation gaps and saves time at the beginning of program preparation.
Automate the datum reference frame
The datum reference frame (DRF) defines where measurements are taken and which degrees of freedom are constrained. According to Metrologic DCS, building it in the wrong order or selecting degrees of freedom poorly can lead the same part to be judged conforming or non-conforming depending on the operator. It recommends automating the step so the DRF and degrees of freedom follow the drawing definition. In its Metrolog software, the company says the DRF is created automatically when a GD&T is evaluated.
Reuse CAD-defined references and tailor reports
Metrologic DCS also advises reusing DRFs imported from PMI instead of recreating reference features A, B and C by hand. It says this limits discrepancies and rework when definitions change, while Scan GDT assigns status to decoded PMI so users can validate decoding and measurement. For reporting, the company recommends formats suited to the reader: numerical tables for quality control, go/no-go reports for quick decisions and decomposition analysis for operators. Metrolog splits a feature’s defect into form, size, position and orientation alongside the global defect, which the company says helps identify what to correct first.