Electronic CAD and Mechanical CAD integration plays a vital role in the modern world design.
It is also the most important part of the complete design cycle. The Mechanical CAD helps to create the concept in the 3 dimensional object while the Electronics CAD provides the logical information of electrical connectivity.
For example in a Wiring Harness assembly MCAD defines where and how connectors and fasteners will be packaged, and the ECAD defines what specific signal will flow from specific pin of a connector to the other connector over what type of wire.
In general practice of the Mechanical CAD can be structured as follows,
- Knowledge Base Engineering (KBE) design team and Product Design Office (PDO) defines the initial concept with Clay Models, Class A surface data etc.
- Advanced Concept Engineering (ACE) design team creates the fundamental envelop of the device components for the Space Claim
- Advanced Concept Engineering (ACE) design team also creates the overall packaging layout in the 3D virtual environment
- Once design feasibility and product is approved, the production design team as well as supplier design team is engaged to create the actual parametric 3D models of the device components
- Packaging/Design Release engineers/design team position the 3D CAD models of the components in the virtual environment to create subassemblies and assemblies to design the complete product
- Virtual Validation engineers compares the integrated assemblies and subassemblies for clash and clearance to avoid real time build issue
- Computer Aided ENgineering (CAE) engineers validate if the design is robust to stress, strain, crash, thermal and any other wear/tear related norms applying standard processes like Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), Multibody dynamics (MBD) etc. using Virtual Simulation tools like NASTRAN, HYPERMESH, ANSYS etc.
The ECAD design cycle starts almost in parallel with the MCAD design cycle.
In general practice of the Electronic CAD can be structured as follows,
- System engineers create the Functional Diagram to define the features and functionalities for the intended Electrical/Electronic system to be designed
- Device engineers defines the Component Device List (CDL) to accommodate these features and functions
- Device engineers specify the device requirements like current, load, fuse etc.
- Wiring system engineers defines the logical diagram (LD) to define the flow of signals to perform the functions based on the specifications provided by the device engineers
- Design engineers create the Schematic Diagram/Drawing (SD) to realize the wiring logical diagram into more engineering drawing with details like wire type, wire material, connector pin options, splicing etc.
- All of the above information is stored and managed using the Device Transmittal applications like Mentor Graphics, Zuken, AutoCAD electrical, VeSys etc.
- Once all the information is validated, netlist or wirelist is generated to feed to the MCAD model to complete the design.
ECAD MCAD Design Interoperability
Once the wirelist and complexity data is available following steps are normal practice in ECAD design cycle.
- Design Release engineer/Design team imports the wirelist into the MCAD model (3D wiring harness model)
- Each connectors and splices inside the wiring harness assembly models is mapped to the device connector ids
- Once the connectors are mapped, wiring harness assemblies are ready to compute the circuits to generate the wire bundles to reflect the accurate bundle size and other related attributes
- Additional value adds like protective covering (tape, scroll etc.), splice optimization can be further tuned based on the design environment
- Next step of the design cycle is to create the 2D formboard/splat drawing from the 3D model
- The 2D formbaord drawing is the final product to build/manufacture the wiring harnesses, it includes complete Bill of Materials (BOM), Circuit data, GD&T and other manufacturing standards and company trademark information