It is a classic problem in printed circuit board (PCB) design: how to reconcile the electrical engineer’s vision with the mechanical engineer’s realities. And with today’s marketplace demanding ever smaller and thinner electronics products — requiring mechanical designers to continually shrink product size — the conundrum has become more pronounced.
“Handheld devices are shrinking, and product development cycles are doing the same,” says Jim Barrett-Smith, MCAD product manager at PTC. “So mechanical engineers need higher design definition when converting 2D ECAD designs into 3D MCAD models via IDF (Intermediate Data Format).”
Engineers can save time by using Pro/ENGINEER ECAD functionality and a simple add-on module.
Facing the challenge with Pro/ENGINEER ECAD functionality. You probably know the drill: A 2D electrical PCB design must be represented within the 3D virtual prototype. There are many ways you can transfer information: import DXF files, manually recreate the PCB using a 3D modeling application, or use an intermediate file such as IDF.
IDF files are electronic, and therefore help minimize errors and can save time.
Pro/ENGINEER contains core ECAD functionality, which can import PCB information from any EDA tool that supports IDF. Using the ECAD functionality in Pro/ENGINEER is easy because it essentially works straight out of the box.
Let’s take a simple scenario: You’re an MCAD engineer designing a small electronic handheld device. You design a new part based on the outline of the device’s PCB, then send the board information to the EDA tool using IDF. The ECAD engineer can then import the IDF file into the EDA tool and use the MCAD information to populate the board with all electrical information.
Once the ECAD engineer has designed the electrical aspect of the PCB, all the new information can then be sent back to you via a new IDF file. When you import the new IDF file, a new assembly is created, including the updated board, which is automatically populated with all electronic information defined by the electrical engineer, such as components and pin holes.
Tailoring ECAD functionality for optimal performance. To configure ECAD functionality for optimal performance, you need to understand the IDF file that is transferred between the EDA and MCAD tool. In reality, two files are generated: an EMN and an EMP. Both files provide the basic information to generate a simple version of the PCB. The EMN file contains information about the PCB’s shape (including keep-out and keep-in areas, drilled holes, and more), as well as each component’s location and orientation. The EMP file contains information describing each component’s 2D size, height and shape.
A key challenge is to use the files’ information to create accurate representations for each component. How, for example, can mechanical engineers work with the exact PCB geometry before the first circuit board is manufactured, minimizing the iterative loop between ECAD and MCAD, while optimizing design constraints such as size? That increased accuracy can minimize costly tooling errors and the need for multiple models and prototypes.
The mechanism to accomplish this task is an ecad_hint.map file. When the IDF file is imported, the ECAD functionality searches the ecad_hint.map file for a matching component called out in the EMN file. If the ECAD functionality finds a component, it will replace the out-of-the-box block geometry with a 3D library part that accurately represents the real-life component.
As a result of all this, Barrett-Smith says, “The PCB can be optimized, allowing the released product to be smaller, thinner, and sleeker.”
Saving time: the simple solution. Simplified Solutions — a Pro/ENGINEER linked tool from Simplified Solutions Inc.— is a web based tool that allows mechanical engineers to use IDF files to automatically generate the required hint map file in a fraction of the time it would take to do so manually. You can also download accurate representation of common electrical components from the extensive Simplified Solutions library.
“You just go to the Simplified Solutions website, download and start working right away,” says Keith Richman, president of Simplified Solutions Inc. and creator of the solution.
The result is a much more comprehensive and accurate rendering of components within a given housing, allowing mechanical engineers to design to a space with a much finer degree of precision.
The Simplified Solutions tool follows a three-step process and is extremely easy to use, says Richman.
“Just upload the IDF files from your ECAD application, search the Simplified Solutions online library for 3D components that replace each of the files and, using the new 3D components, generate a map file that links ECAD and Pro/ENGINEER components,” he says.
Now, with the ECAD functionality in Pro/ENGINEER and Simplified Solutions, electrical and mechanical designers can sit at one workstation, with the mechanical engineer demonstrating issues in real time with a fully defined digital mockup. And the two engineers can rectify problems on the spot.
That not only makes for a sleeker product, but for a smoother working environment as well.
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