Metrologic DCS has outlined four practices for reducing interpretation gaps in geometric dimensioning and tolerancing (GD&T), from product manufacturing information (PMI) in CAD files to reports delivered to the shop floor. The company says GD&T connects design, production and metrology, but manual handling of PMI and datum references can lead to conflicting measurements, scrap and repeated exchanges between teams.
Start with PMI, not re-entry
The first recommendation is to decode design intent directly from PMI: the targeted feature, references and tolerance. Metrologic DCS says manual entry is prone to copied values or misunderstood references, which can cause a part to be inspected against the wrong requirement. Its Metrolog software is presented as using PMI as the starting point, creating features and evaluations from the digital part definition rather than requiring tolerances to be re-keyed.
Automate datum reference frames
The second and third tips concern datum reference frames (DRFs). A DRF defines the reference features A, B and C and constrains the degrees of freedom used in evaluation. Metrologic DCS warns that rebuilding a DRF by hand, or selecting degrees of freedom poorly, can make the same part appear conforming or non-conforming depending on the operator. It says Metrolog creates the DRF automatically when a GD&T is evaluated and selects degrees of freedom from the drawing definition. The company also recommends reusing DRFs imported from PMI to avoid duplicate work and discrepancies when definitions change; its Scan GDT function assigns status to decoded annotations so users can check both decoding and measurement.
Report by reader
The fourth tip is to tailor reports to their users. Metrologic DCS argues that a pass/fail-only report does not tell an operator what to correct, while numerical tables suit quality control and Go/No-Go reports support quick decisions. Metrolog splits an evaluated feature's defect into form, size, position and orientation, alongside the global defect, so the dominant type can be identified first. The company says this approach can reduce scrap and speed corrective action.