Multi-discipline universal CAD library

Details Multi-discipline universal CAD library Multi-discipline universal CAD library

2001-05-21

2004-04-13

Picard, Leo (Department: 2121)

Data processing: generic control systems or specific application

Specific application, apparatus or process

Product assembly or manufacturing

C700S095000, C700S098000, C700S182000, C345S960000, C706S919000

Reexamination Certificate

active

06721614

ABSTRACT:

BACKGROUND
The present invention relates to a web-based system for facilitating computer-aided design activities, and more particularly, the present invention relates to a web-based system for facilitating multi-disciplinary collaboration activities related to computer-aided design (CAD) processes.
Coordinating the engineering processes involving multiple CAD disciplines requires much planning. For example, in a typical electromechanical product design system, engineering processes are separately carried out in parallel by electrical and mechanical engineering disciplines—often in different organizations and/or geographic locations. Various software tools are available with which these engineers can design a product or component; however, these tools are primarily point solutions directed toward a single discipline (e.g., electrical, or mechanical design) and are not compatible with one another. The software required for each discipline varies dramatically due to the unique skills required and data utilized by each discipline. As a result, electrical engineers and mechanical engineers working on the same component are unable to effectively exchange information or collaborate on these designs utilizing existing tools. For example, the electrical designer of circuit assemblies is responsible for determining placement of components on a circuit board in the most desirable and effective manner. Electrical engineers are also responsible for design decisions affecting signal clarity, timing, input/output interfaces, and cooling/heat matters. Thus, ECAD software must address these functions. The mechanical or packaging engineer, on the other hand, is concerned with the physical size and shape of the circuit card, method and area required to mount the card within an enclosure or assembly, related connectors for the card, optimum airflow determinations for the card and system cooling. Thus, MCAD software on the market is designed to assist with these unique mechanical design functions.
Another reason why the two disciplines have been unable to share information is because of the lack of neutral data formats utilized by these disciplines; that is, the data stored by each discipline is defined by that discipline in its unique software format and stored in that discipline group's database or directory/environment accordingly. The mechanical designers using a common design system are able to communicate and collaborate amongst themselves, but it is difficult for them to make their data available to others due to uncommon units of measurements, naming conventions, etc. This impacts the activities of the electrical designers who also define the data they use in a format or convention not recognized by the same disciplines and/or other disciplines. In some cases, the transition of data from one area to another is done by paper drawings which requires total reentry of the data. The reentry increases costs, as it requires time to complete. The reentry process also provides the opportunity for error insertion during the transcription. This leads to increased product development cycle time for new and modified designs.
To date, there are several de-facto, industry, national and international standards available which provide some point solutions. De-facto standards such as AutoCAD Drawing Exchange Format (DXF) and Gerber Plotter data format facilitate some geometric data exchange. There are also industry standards such as those from the Institute of Interconnecting and Packaging Electronic Circuits (IPC) and Electronics Industries Alliance (EIA) which provide some discipline dependent data interchange. National standards such as Initial Graphics Exchange Specification (IGES), a United States CAD/CAM data exchange standard; Intermediate Data Format (IDF), an electrical card/board exchange standard; and Vereinung Deutsche Automobilindustrie Flachen Schnittstelle (VDAFS), a German neutral file format for the exchange of surface geometry, broaden the scope of data exchange to more than geometry. There are international standards such as Standard Generalized Markup Language (SGML), Electronic Data Interchange Format (EDIF), and the ISO Standard for the Exchange of Product (STEP) model data which increase the data scope and the audience even further.
However, the problem with these standards is that they are point solutions and solve only part of the problem. For example, geometric data standards allow for the transfer of geometry between disciplines, but many properties and annotation get lost. Drawing exchange allows for the transfer of more information, but still the picture is incomplete. EDIF, IPC and EIA are electrical design-centric solutions which cause loss of analysis, product data management (PDM), and mechanical information. IDF covers MCAD and ECAD functions but does not provide communication and issue tracking structures required for collaboration and offers little PDM.
As a result of these disparities, current practices for manufacturing enterprises which deal in electrical and mechanical design of circuit boards and other electronic components typically involve a ‘ping pong’ approach in which one or more engineering groups transfer a product in design stage back and forth amongst one another. For example, a typical design scenario may be described as follows:
An electrical card/printed circuit board (PCB) design starts in the mechanical CAD system where the overall size and shape are modeled. The board outline is modeled and critical components (such as LED's that must be aligned with a hole in a casing or board edge connectors or connector footprints) are pre-placed.
The mechanical designer may also define technology rules and electrical placement constraints which are represented by the functional areas such as placement or routing areas, keep in and keep out areas based on the physical constraints of the enclosure (the printed circuit board (PCB) designer can also define or modify the restrictions).
The board is then transferred to the PCB layout editor which performs placement of the components indicated by the MCAD designer and all remaining components. Changes can be made over the areas which support electrical information. Routing is done to convert the logical net list to a physical wiring of the net list. The design is then passed back to the mechanical system, where 3D modeling of the board is performed and definitions of the annotations for electrical references are provided.
This completed PCB design is used to check for alignment with a slot connector, as well as to perform interference analysis in order to see if the board and its components fit with the casing and/or adjacent PCBs.
After interference or fit analysis, modifications of the board may be necessary. In order to correct interferences, the mechanical engineer may either modify or create a placement keep out height and pass this information back to the PCB designer or may directly move the components in agreement with the design. A check is performed by mechanical engineering to determine the level of design integrity before the design is transferred back to the PCB environment where a revised placement and routing process will be performed, and so on.
While a product design project is being transferred back and forth between electrical and mechanical engineering groups, providing accurate data exchange is critical. Many different types and forms of data are utilized in the design process which creates a burden on inter-disciplinary design functions. For example, some types of circuit cards can be populated with components on either side of the card, and in some cases, on both sides of the card. It is quite often the case that when both sides of the card are used, each side of the card will provide different design criteria (e.g., keep outs, connectors, etc.). The main areas of inter-disciplinary data exchange typical in the electromechanical design process include: board outline, card thickness, airflow analysis, mounting hole locations, connector footprint, restricted areas, cooling recommendations,

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