ECAD-MCAD Co-Design Promotes Automotive First-Pass Success

Achieving first-pass success is the goal of every automotive design team, both electrical and mechanical, as it minimizes or even eliminates costly design iterations. In the automotive industry, first-pass success is more challenging than ever because of the increasing electro-mechanical complexity and density of modern vehicles. Most modern cars run their critical systems, such as the throttle and braking systems, electronically through computers and sensors. Most cars can also be equipped with an array of cabin amenities like infotainment systems, air conditioning, and heated seats. For high-end luxury cars the case is more extreme. According to Car and Driver (2016), the Bentley Bentayga contains greater than 100 million lines of software, 90 computers and control modules, and a wiring harness that weighs about 110 pounds.

Figure 1: A 3D rendering of a vehicle wiring system.      

The impact of electro-mechanical complexity and density on first-pass success can be significant. Failure to address issues early in the design cycle can delay the development of the product, causing increased cost and potentially missing the launch goal.

Given this impact, how do companies adjust their vehicle development process in order to achieve first-pass success? The optimal strategy is to use a system that allows for ECAD and MCAD design data to be exchanged incrementally throughout the design process. Incremental data exchange ensures that the ECAD and MCAD domains are compatible at each point in the design. This synchronization creates a steady line of communication between the electrical and mechanical engineers that increases productivity, reduces errors, and increases the chances of achieving first-pass success.

ECAD-MCAD co-design
Establishing such synchronization is easier said than done. The potential impediments to ECAD-MCAD collaboration are numerous. First and foremost is the traditional separation that has existed between the electrical and mechanical disciplines. Electrical and mechanical engineers typically work with completely different tool sets and have completely different vocabularies. Many times they even reside in different physical locations.

Because of these impediments, previous efforts to collaborate have met with limited success. Earlier ECAD-MCAD collaboration tools used everything from sticky notes and email to Excel spreadsheets. These approaches fell far short for obvious reasons. As a result, many automotive product development teams resorted to internally developed software and processes for collaboration that had to be tested and verified with each new release of the underlying ECAD and MCAD tool suites. These locally developed software and processes were costly to maintain and required dedicated in-house support.

True co-design: cross-probing
The electrical and mechanical design processes should be more connected, integrated, and collaborative than they are today. Seamless cross-probing between the two domains enables closer integration and collaboration by enabling the design in each domain to be completed with contextual information from the other (Figure 2).

Figure 2: An integrated ECAD-MCAD design flow allows for real-time cross probing

A key feature of such integration is replacing the cumbersome file-based exchange of previous methods. Integration used to depend on exporting a massive file of changes into a file system for the other engineers to retrieve and then import. This is no longer the case. Capital and NX support API level integration, where the two domains are directly connected to immediately update the design with changes or new information. Engineers no longer swap files but are truly integrated at the data level via a robust mechanism. For instance, a Capital designer may publish a bill of materials for the wiring which can then be seamlessly integrated into NX.

With this integration, the electrical system and wiring harness can be designed with explicit knowledge of the wet, hot, and noisy areas of the mechanical design. Doing so allows the ECAD designer to account for the impact on the electrical performance of these areas when designing the electrical system. On the mechanical side, space reservations can be made and the severity of bends in the harness can be adjusted to account for the wiring bundles that must route through the mechanical structures. With access to this contextual information from other domains, both electrical and mechanical engineers are able to quickly reconcile incompatibilities between the ECAD and MCAD designs.

Achieving first-pass success
ECAD-MCAD co-design has long been recognized as a potential enabler to increasing productivity and ensuring a robust design. With modern CAD tools designers are able to synchronize their data more efficiently and collaborate more effectively on critical design items between domains, thereby ensuring that the design intent is properly implemented.

During design, seamless cross-probing between the electrical and mechanical environments helps designers understand their counterpart’s domain. This enables incompatibilities to be identified and resolved early, reducing costly design iterations. ECAD-MCAD co-design provides a key enabler for design teams to increase the probability of achieving first-pass success.

For more information on ECAD-MCAD integration and how it improves engineering change order management, read our whitepaper: Automotive ECAD-MCAD Co-Design Leads to First-Pass Success