STEP's Future in Manufacturing

Manufacturing Engineering, Apr 2007

SOFTWARE

Jack R. Harris is director, advanced manufacturing technology, for avionics supplier Rockwell Collins Inc. (Cedar Rapids, IA), and also the new general manager for PDES Inc. (Charleston, SC), a global consortium of manufacturers, government, and academic members working to advance the development and implementation of STEP (STandard for the Exchange of Product model data) protocols, which are under the ISO 10303 umbrella.

Manufacturing Engineering: What is the current status of the STEP ISO standard used by manufacturers?

Jack Harris: The major usage of STEP today is with AP203, which is a robust standard at this point. It was initially approved in the mid-1990s, and it's used by a number of the commercial and aerospace companies to move information between CAD systems. It more or less replaced IGES. We give our suppliers a couple of options, but we really like to have them use STEP AP203 for any of the mechanical parts that we have fabricated. In some cases, there may be small shops that still deal with IGES, but for the most part, AP203 has taken its place. There are a number of other STEP protocols that have a foundation on 203, but 203 is probably the one that gets the most interest and, in fact, is most used. There are a lot of companies that use it transparently. When people say they use STEP to do this or that, it's typically AP203 to move information between design systems and CAM systems. AP203 and many of the other APs are applied worldwide.

ME: How can STEP help today's manufacturers avoid the pitfalls of poor CAD interoperability, as evidenced by the highly publicized problems with Airbus?

Harris: The important thing today is that everybody is dealing with disparate systems-whether it's within your four walls, or whether it's within your supply chain. So from the standpoint of effectiveness and efficiency, the ability to take standard information to go between systems is essential. If you're going between MCAD and CAM, there are model changes to make. This results in an opportunity for introducing errors into that CAM model, which requires rework downstream. The focus we've had for developing these product-model protocols is to deal with the interoperability question between like and unlike domains.

ME: How has STEP evolved and matured for use on the factory floor today?

Harris: AP203 Edition 1 has been used successfully with AP238 to support Design to Manufacturing. AP 238 is a mapping of design to the NC language, and is considered STEP NC. It maps geometry to numerically controlled manufacturing fabrication features. It's fair to say that so much work has gone into completing the standards. Industry is now they're in a position of implementation. Again, I would say that the product model standard flagship is AP203, and it is being used by lots companies like Boeing, Lockheed Martin, and others to successfully fabricate mechanical parts. In addition, electronic companies are now starting to use the AP210 protocol, to deal with designs. It's very important in electronics to have interoperability between mechanical and electrical tools. AP210 Edition 2 is in the ISO approval process now.

ME: What are some of the technical differences between the STEP AP203 standard for geometry and the more recent STEP AP238 standard for manufacturing?

Harris: It's the mapping of geometry from AP203 to NC machining features, so it's taking circles and lines and translating them to holes in the machine language. It actually allows you to take the AP203 information and drive your NC machine tools. Otherwise, manufacturers take the take the design model and recreate a CAM model. STEP AP238 will be used by automotive, aerospace, and commercial applications, allowing manufacturers to map geometry to interpretable machining features.

ME: What are some good examples of STEP being used today by manufacturers such as Boeing, which has specified that its parts be STEPcompliant, and other organizations, including NASA and US government agencies and foreign governments, that are getting interested in STEP?

Harris: Lockheed Martin, Boeing, Raytheon Missile Systems, Rockwell Collins, and other similar aerospace companies are adopting many of the APs, specifically AP203, 209, and 210. In general, most of us don't make our own machined parts or sheetmetal parts; we'll have somebody else do that. Clearly our supply chain takes that information and makes the parts that we ask them to make using that data. If I was a common supplier to companies like Boeing, Lockheed Martin, or Raytheon Missile Systems, I'd want information in a standard form. STEP allows information in the standard form, reducing the need to have duplicative tools to deal with native CAD formats. Boeing has created a position that basically says: 'You're going to have to be STEP-complaint if you're going to do business with us.' They've adopted 203 as the primary means for exchanging CAD data with their suppliers, and that's probably getting into the F-35 as well as other programs. I'll also refer to a joint commanders' letter generated a few years ago that basically says: 'If you're not STEP-compliant, your ability to bid on DoD programs is at risk.' That is a powerful letter. We are also seeing testing of STEP protocols as a solution to long-term data retention and archival by the National Archives and Records Administration, and the National Nuclear Security Administration.