Mechanical Design Deliverables: CAD, Drawings, BOM and Simulation Reports Explained
Quick Answer The standard deliverables in mechanical design are: a 3D CAD model, 2D manufacturing drawings with tolerances, a bill of materials (BOM), and simulation reports when FEA or CFD analysis is performed. Each serves a distinct practical purpose in getting a design from an engineers screen to a factory floor. |
If you are new to working with mechanical engineers, the list of deliverables in a project proposal can read like jargon. Each one serves a distinct, practical purpose - here is what each actually means and why you need it.
3D CAD Model
This is the digital, three-dimensional geometry of a part or assembly. It is the master source of truth for the design - everything else (drawings, analysis, prototypes) is derived from it. You typically receive this in a native or neutral format (such as STEP) so you or your manufacturer can open and use it.
2D Manufacturing Drawings
While the CAD model shows what the part looks like, manufacturing drawings specify exactly how it must be made: dimensions, tolerances, surface finish requirements, and material callouts. A manufacturer quotes and produces parts based on these drawings - this is the document that removes ambiguity from production.
Bill of Materials (BOM)
For any assembly with more than one part, a BOM lists every component - custom-made and purchased - along with quantities, material specifications, and part numbers where applicable. It is essential for procurement, costing, and assembly instructions.
Simulation Reports (FEA/CFD)
When structural or fluid analysis is performed, a simulation report documents the methodology, assumptions, boundary conditions, results, and engineering recommendations. This is the evidence that supports design decisions - useful for internal review and, in regulated industries, often required for design history documentation.
How These Deliverables Work Together
The CAD model is the design itself
Drawings translate the design into manufacturing instructions
The BOM organizes everything needed to procure and assemble it
Simulation reports justify that the design will actually perform as intended
FAQ
Do I need all of these deliverables for every project?
Not necessarily - a simple part might only need a CAD model and drawing. Simulation reports and a full BOM become relevant as complexity or assembly count increases.
What file format should I request for the CAD model?
STEP is a widely supported neutral format that most CAD software can open. If you use a specific platform like SolidWorks, you can also request the native file format directly.
Can a BOM include both custom and off-the-shelf parts?
Yes - a complete BOM typically lists both, since an assembler needs to know everything required to build the full assembly.
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