SolidWorks

CircuitWorks – Electro Meets Mechanical, Part 1 (Solid Thinking SolidWorks Tutorial)

1 Sep, 2008 By: Richard Doyle

Software bridges the divide between electrical and mechanical, allowing you to automatically create accurate, fully populated models from ECAD data.


Editor's note: This tutorial courtesy of SolidWorks.

Printed circuit board (PCB) design has really evolved in the last 25 years. In the early days, PCB designers used sheets of Mylar, colored pencils, and crepe tape to lay out components and circuitry. With the advent of PCB design software, those days are long gone. One similarity to days gone by is the gap between the electronics designer and the mechanical or packaging designer. Integrating PCBs into a mechanical design often means re-modeling circuit boards from scratch, leading to possible errors and costly rework. CircuitWorks bridges the divide between electrical and mechanical, allowing you to automatically create accurate, fully populated models from electrical computer-aided design (ECAD) data. CircuitWorks was developed by Priware, a company recently acquired by SolidWorks. CircuitWorks is now available as part of the SolidWorks Office Premium package.

CircuitWorks Stand-Alone
As a stand-alone product, CircuitWorks is an intuitive tool for viewing, editing, and translating files created by ECAD systems. CircuitWorks reads and writes industry standard IDF (v2, 3, and 4) and PADS (.ASC). CircuitWorks can display the board outline, components, holes (plated and non-plated), keep-out and keep-in areas, as well as notes from the ECAD data. With IDF v4, even pads, filled areas, and traces are shown.

Once the ECAD data is open in CircuitWorks, changes to the data can be made. Components may be moved, filtered out, and features such as reference designators can be edited if necessary. Changes made to the imported file can be saved out in the IDF format for use in the original PCB design software.

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CircuitWorks Interface.

CircuitWorks for SolidWorks
CircuitWorks for SolidWorks provides extra functionality, adding a bi-directional link between CircuitWorks and SolidWorks. Using this capability, you can produce an accurate, fully featured assembly model of the circuit board. Board outlines, keep-out (and keep-in) areas, holes and components are created in SolidWorks. With the option to Show Part Creation in SolidWorks turned on, this happens literally right before your eyes.

Building the model in SolidWorks starts by importing the IDF file into CircuitWorks. A preview of the PCB is created with information about the assembly in a tree-view structure that SolidWorks users will find very familiar. Expanding the plus symbols in the tree provides a complete look at the various entities — the board outline, plated and non-plated holes, and information for every single component from the IDF file.

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The Preview Window and Component Tree.

The tree view also has information about each component. Right-click and select Properties to access the Component Instance Properties dialog box that contains information such as part number, the reference designator, rotation, the side of the board where the component is placed, and its position relative to the 0,0 origin. The component highlights in the preview window when you click the description in the tree.

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Component Properties.

Before using CircuitWorks to create the model in SolidWorks, consider how you would like the model created. How much detail do you really need? Filtering allows you to choose whether or not certain geometry will be created in SolidWorks. If the ECAD file is IDF v4, even pads and traces can be created. This could result in a very large SolidWorks model, and it will take more time to create. From the CircuitWorks Tools menu, select the items you want to filter — components, plated holes, and more.

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Setting the Filters.

Once your filters are set, click on Build Model on the SolidWorks toolbar in CircuitWorks. If the ECAD file contains any components that do not have a z height value, a warning will display. You can continue to create the model, but the components will be modeled in SolidWorks as a simple sketch. If you choose to cancel, you can edit the component in the CircuitWorks library to add a height. To edit a component in the CircuitWorks library, click the Library icon. A list of parts in the library will be displayed. Locate the affected components in the tree, and right-click and select Edit Component. Add a value to the Component Height box and click the green checkbox to close and save the component. Close the component library window and re-start the Build Model process.

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Editing Components.

Most models take just a few seconds to build in SolidWorks.

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The SolidWorks Assembly File.

Bi-directional Capabilities of CircuitWorks
CircuitWorks and SolidWorks are seamlessly integrated and provide bi-directional capabilities that allow changes made in either program to update the other. In the example file we just created, the mechanical designer may need to add some mounting holes, components (such as connectors), and possibly some new keep-out areas. CircuitWorks has explicit rules that are set up to make the transfer possible. Certain features, sketches, and components must be named properly in the SolidWorks file in order for CircuitWorks to recognize them. A simple example is mounting holes. The holes must be created as simple extruded cuts (CircuitWorks does not recognize hole wizard holes), and the feature must be renamed (PTH for Plated Thru Holes, and NPTH for Non-Plated Thru Holes) in order for CircuitWorks to recognize the feature. The figure below shows the mounting holes added to the PCB assembly.

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Mounting Holes Added in SolidWorks.

After creating the mounting holes, select Export to CircuitWorks from the CircuitWorks toolbar. The figure below shows the new PCB (left) in CircuitWorks compared to the original file.

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The Updated CircuitWorks File. (Click image for larger version)

In addition to the rules for holes, CircuitWorks requires other rules in order to recognize components and board outlines, even via holes and silkscreen keep-out areas can be defined in Solidworks and exported back to the CircuitWorks file.

Summary
We've only scratched the surface of the capabilities of CircuitWorks for Solidworks. Next month in part two of this article we'll look at the component library in-depth, including information on adding to the CircuitWorks library, customizing components, and creating your own set of electro-mechanical components that you can use with CircuitWorks.


About the Author: Richard Doyle


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