STEP-NC - History

History

STEP-NC is not the first attempt at providing better quality information to a CNC. The EIA 494 Basic Control Language (BCL) defined a control language that was portable and had toolpaths independent of machine geometry, but did not contain any of the other product model information found in STEP-NC.

The core of STEP-NC is the ISO 14649 model for CNC control developed by European ESPRIT and IMS STEP-NC projects begun in 1999. These were led by Siemens with contributions from the University of Aachen and the University of Stuttgart in Germany, Komatsu and FANUC in Japan, Heidenhain in Switzerland, and the Pohang University of Science and Technology in Korea. Models for the control of CNC milling and turning machines were published in 2005, and draft models exist for EDM and contour cutting.

Integration of the CNC model into STEP to produce ISO 10303-238 was done in the United States, under the NIST ATP Model Driven Intelligent Control of Manufacturing project, led by STEP Tools, Inc. with an industrial review board (IRB) consisting of Fortune 500 companies, CAD and CAM software developers, machine tool manufacturers, job shops and industry experts. STEP-NC AP238 was published in 2007.

In 2005 the OMAC STEP-NC Working Group hosted an AP238 testing forum in Orlando to demonstrate 5-axis parts machined using AP238 CC1 machine independent toolpaths. Four CAD/CAM systems produced AP238 machining programs for milling a 5-axis test part (an NAS 979 circle/diamond/square with an inverted NAS 979 cone test in the center). Each run on a pair of CNCs configured for completely different machine geometries (AB tool tilt vs. BC table tilt). In addition, Boeing cut parts on a variety of machines at their Tulsa facility and a machine at NIST in Gaithersburg.

In June 2006, a live 5-axis STEP-NC machining demonstration was hosted by Airbus at the Université Paul Sabatier Laboratoire de Génie mécanique in Toulouse. Further machining and measurement demonstrations were conducted in Ibusuki Japan in 2007.

On March 10–12, 2008, the STEP Manufacturing team (ISO TC184 SC4 WG3 T24) met in Sandviken and Stockholm, Sweden to demonstrate use of STEP-NC for feed and speed optimization, high-speed machining, tolerance-driven tool compensation and traceability. The participants in the demonstrations included Airbus/Univ. Bordeaux, Boeing, Eurostep, KTH Royal Institute of Technology, NIST, Sandvik Coromant, Scania, STEP Tools, and Univ. of Vigo.

On October 1–2, 2008, the STEP Manufacturing team met at the Connecticut Center for Advanced Technology, in Hartford, Connecticut to demonstrate closed-loop machining, feed optimization, and measurement using STEP-NC. The highlight of the meeting was the live 5-axis machining of a titanium impeller. Participants in the machining demonstration and other activities included Boeing, Connecticut Center for Advanced Technology, Concepts NRec, DMG, KTH Royal Institute of Technology, Mitutoyo, NIST, Sandvik Coromant, Scania, Siemens, and STEP Tools.

These participants and others continue to hold STEP-NC international implementation and testing events on a roughly six-month cycle. The demonstrations in 2009 focused on machining a Mold part at multiple sites from the same AP238 data including one part machined on a FANUC-developed STEP-NC control. At a meeting in Seattle the parts were then measured for accuracy using a CMM probe and a laser scanner.

In the first half of 2010, the testing activity focused on tool wear management and machining a part in multiple setups with multiple alternate machining plans for 3, 4 and 5-axis machining. The new test part was a gear box that must be machined on all six sides. The tool wear and consequent machine loads were predicted from the STEP-NC data and verified using a dynamometer. In the second half of 2010, the testing forum applied STEP-NC to setup compensation with on-machine measurement of part and fixture datums using a FaroArm portable measurement device.