AP-238 Testing for Closed-Loop Machining

On May 24-26, 2005, the OMAC STEP-NC Working Group held the latest AP-238 testing forum event at EASTEC 2005 in Springfield, MA. Representatives from Boeing, Unigraphics, NIST, Pratt and Whitney, and STEP Tools were present and Siemens graciously provided us with space in their booth.

This event focused on demonstrating closed-loop machining using touch trigger probes and cutter contact machining driven from STEP-NC. The following slides describe the complete closed-loop scenario. [PPT, 1.4M].

The scenario is to rough and finish a boss on the engine casing test part provided by Pratt and Whitney (see right). After roughing and semi-finishing, a probing operation is used to adjust a final finising pass. The finishing is done using cutter contact paths To further make things interesting, the roughing paths are created by one CAM system and the finishing paths by another.

The AP-203 CAD description of the entire part. [STP, 391k].
Stage 1 - AP-238 Roughing operation from UGS NX. [STP, 180k]. The corresponding siemens codes.
Stage 2 - AP-238 Probing operation from Mastercam. [STP, 37k]. The corresponding siemens codes.
Stage 3 - AP-238 from Stage 2 containing the probing results from the DMG run [STP, 39k]. The probing log data used to update the STEP-NC variables.
Stage 4 - AP-238 to change the CNC Tool diameter compensation [STP, 4k].
Stage 5 - AP-238 Finish operation from Mastercam. [STP, 31k]. The corresponding siemens codes.

The final product is an AP-238 data set containing the CAD geometry and all five workplans shown above. [STP, 616k].

The test piece. Machining and probing operations focus on the boss with five holes on the side.

Sid Venkatesh of Boeing and Martin Hardwick of STEP Tools both gave presentations at the Smart Machining & Job Shop Sessions