Generative Measurement Scenario for STEP-NC ISO AP238 Larry Maggiano Senior Systems Analyst Mitutoyo America Corporation CTLab 1 October 2008 Copyright Mitutoyo America Corp. 2008

AP238 Measurement Scenario AP238? Copyright Mitutoyo America Corp. 2008

Generative Measurement Scenario Can AP238 support generative measurement? AP238 defines four (4) Conformance Classes – CC1: Probe Points – CC2: CAD Nominal (AP203e1) and Probe Points – CC3: Parametric Measurement via: CAD Nominal (AP203e1) and linked Probe Points – CC4: Generative Measurement via: a)CAD Nominal & GD&T (AP203e2) b)CAD linked Probe Paths Copyright Mitutoyo America Corp. 2008

Measurement Scenario CC4 STEP Measurement Scenario – STEP with GD&T exists (AP203e2) – STEP with Probe Path doesn’t yet exist Scenario Steps 1.Create Curve (Probe Path) on CAD model 2.Read CAD model and Probe Path 3.Generate Measurement Program 4.Run Measurement Program Copyright Mitutoyo America Corp. 2008

Probe Path for In Process Measurement – Probe points along at 1 mm offset from blade edge – Skip leading and trailing edges Copyright Mitutoyo America Corp. 2008

Probe Path for Post Process Measurement Scanning CMM follows Curves, not Points Use same criteria for In Process Measurement – Scan Curve at 1 mm offset from blade edge – Skip leading and trailing edges Create “Curve on Surface” of Impeller Blade – Curve on Surface is CAD Entity, not data point set – Curve is associated with Surface of Blade – Defines precise Scanning Probe Path Copyright Mitutoyo America Corp. 2008

Create Curve for Probe Path Read Impeller (AP203e1) into SolidWorks™ Create 1 mm offset Curves on Surfaces of Blades Copyright Mitutoyo America Corp. 2008

Read CAD & Probe Path (~AP238) Copyright Mitutoyo America Corp. 2008

Pick Curve for Probe Path Copyright Mitutoyo America Corp. 2008

Define Start & End of Probe Path Copyright Mitutoyo America Corp. 2008

Define Additional Parameters Copyright Mitutoyo America Corp. 2008

Machine Independent Parameters Coordinate System & Datum Structure Label, Type and Tolerance of Features Label(s) of Curve(s) on Surfaces(s) Measurement Precision Maximum Path Deviation Start & End Points (or Start & Distance) Scan Data Pitch – Include Mapping to discrete Nominal Points Data output format – Tip Center or Surface Compensated – Points, Curves, or Both Copyright Mitutoyo America Corp. 2008

Machine Dependent Parameters Machine & Probe Configurations Move & Measure Speeds Approach & Retract Distances Probe Path Control – Curvature – Lean – Lead Rotary Table Angles Run In & Run Out Filtering Algorithms Copyright Mitutoyo America Corp. 2008

Generate Measurement Program Copyright Mitutoyo America Corp. 2008

Run Measurement Program Copyright Mitutoyo America Corp. 2008

Scan Probe Path as an AP238 Entity Created by STEP Tools for AP238 TC ENTITY curve_probing SUBTYPE OF (touch_probing) curve_to_be_measured: bounded_curve; start_position : OPTIONAL axis2_placement_3d; start_direction : OPTIONAL direction; distance : OPTIONAL length_measure; curve_axis : OPTIONAL bounded_curve as_measured_curve: OPTIONAL bounded_curve; as_measured_curve_normal: OPTIONAL bounded_curve; its_technology : OPTIONAL technology path_maximum_deviation: OPTIONAL bounded_curve; END_ENTITY; Copyright Mitutoyo America Corp. 2008

Scenario Test Results Probe Paths can be defined as CAD Curve – Curves are linked to Surfaces and Tolerances – Probe Paths (Curves) can have Parameters AP238 can include: – Measurement Plans expressed as: Probe Paths (CAD Curves on Surfaces) Probe Path Parameters (CAD attributes) AP238 CC4 Generative Measurement is: – Feasible – Relatively Simple Copyright Mitutoyo America Corp. 2008

Next Steps Cross-check to: – ISO 16792:2006 (ANSI Y ) – Digital Product Definition Data Practices Dimensional Metrology Standards Consortium – STEP is a normative DMIS 5.1 Reference – Submit Harmonization SIR – Next meeting is October 27-31, 2008 Copyright Mitutoyo America Corp. 2008

Thank you! AP238 Copyright Mitutoyo America Corp. 2008