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Time to Push for Step and Other Open Standards

Kristen Letelier
By Kristen Letelier Senior Manager Operations Program Management, Raytheon Space and Airborne Systems

In the age of Industry 4.0 and the digital thread, computer-aided design (CAD) data exchange should be open and seamless because it happens daily in a multi-tiered supplier ecosystem and so much interoperability depends on it. But we are not there yet. Proprietary solutions continue to dominate the market and evolve without support for open data exchange among manufacturers that must support many customers and programs with a diverse universe of CAD formats.

Data-exchange incompatibility leads to time delays, finger-pointing and even voice-raising disputes among suppliers and is estimated to cost industry billions.

Engineers focus on CAD design capabilities when they buy software, but more emphasis should be placed on data-exchange competencies. These expensive solutions should address business challenges like design-to-manufacture cost, increased product configurations, first-time quality and, most importantly, integration of the supply chain. Usually, major subcontractors, partners and sub-tier suppliers use different CAD platforms. Sometimes, CAD formats are not even compatible among major upgrades from the same CAD vendor and CAD software can even develop several major versions during the life of an aircraft program. Given this environment, it is incredible that manufacturers have not demanded more support for open CAD exchange formats from CAD vendors. Instead, it appears as though CAD vendors are closing their solutions when industry requires more open solutions to realize a cohesive business system.

The two options to exchange CAD information between different systems are to export to a neutral file exchange format or to translate one proprietary CAD format to the other. Some CAD systems have direct translators that generate kernel transmission files using algorithms that are imported into other software. But depending on this method can be unreliable and limited due to the proprietary nature of CAD geometric modeling kernels and the number of CAD systems available.

Some companies rely on third-party translation services like Elysium, International TechneGroup and Anark for CAD data-interoperability solutions. They can eliminate what engineers have notoriously done manually—but with a hefty price tag.

Theoretically, the most cost-effective method is neutral file exchange. Many neutral-file solutions for CAD exchange have emerged, including STEP, DXF, VDA-FS, IGES, JT, and 3D PDF. STEP, the Standard for the Exchange of Product model data, is the informal name for ISO 10303. It is the most comprehensive and may be the backbone of CAD interoperability. The STEP data exchange package has proven to be effective in handling data transmission during many phases of the product lifecycle. But it has limitations. STEP works well in traditional design, assembly and manufacturing environments and can protect proprietary information of how a part is made while still providing GD&T information, color, topology, texture and material specifications, finish requirements, process notes and welding symbols.

The evolution of the STEP format has proven that it can adapt to the changing needs of the industry. Case in point: the many application protocols (APs) that have been added to the standard, such as AP 203 (configuration-controlled 3D designs of mechanical parts/assemblies), AP 242 (management model-based 3D engineering), AP 209 (composite metallic structural analysis) and AP 210 (electronic assembly, interconnect and packaging design). Most major CAD/CAM systems have a module to read and write data defined by one of the STEP APs.

While STEP has provided universal usability for data exchange, some argue that more CAD-intensive future applications like 3D simulation, augmented reality and 3D-centric collaboration will require the native CAD file format. For example, a Critical Design Review among different partners in the value chain should be devoid of PowerPoint slides and instead use 3D CAD model-derived visuals.

And on the shop floor, technicians use CAD model data coupled with non-destructive inspection techniques to visualize the as-built product condition and make repairs in real time. With all of these new digital mockup and simulation capabilities depending on the CAD model, platforms will need to seamlessly share 3D models in virtual and augmented reality.

Based upon usage scenarios of new and old CAD systems, the STEP format will never be a panacea. Third-party companies will always have niches in the data-exchange market. However, the open standard will have staying power if it continues to evolve and if industry embraces it.

Adoption of standards like STEP, by major manufacturers and CAD vendors, is the only hope to reach the vision of the digitally connected enterprise and cyber-physical ambitions
for Industry 4.0.

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