A poorly structured CAD model can be as fragile as a house of cards when modifications are needed. To instill best practices in our junior engineers, we provide them with a comprehensive CAD standard. While this document was specifically written for SolidWorks, its core principles apply to other CAD systems as well. Do you have a CAD standard in place? If not, feel free to use ours as a foundation.
Part
Begin all parts with a start part template.
Fully define all sketch entities. Defined entities are black; undefined entities are blue by default.
Ensure all features regenerate properly(no brown features!).
Rebuild heavily modified models to reflect final design intent.
When uncertain, use default planes as parent references.
Avoid covering undesired geometry with new features—correct the original issue.
Use Hole Wizard for all holes, tapped and untapped. Avoid 3D sketches unless necessary. To start a 2D sketch, first select the placement surface before clicking Hole Wizard.
Position parts with default planes at the center, using“Mid Plane” extrudes or symmetric sketches.
For molded parts, add draft as the second-to-last feature set. Use draft within cuts and protrusions only if a standalone Draft feature won’t work.
Add fillets last.
Use the“Draft Analysis” tool after applying drafts.
Create robust models by modifying base feature dimensions to check for failures.
Design slots, internal radii, and fillets to match standard milling cutters and drills.
Use sketch relations to convey design intent.
Avoid using mirrored or patterned features as parent references.
Break and redefine all external references before finalizing a project or handing it off.
Verify CAD models of critical commercial parts by cross-referencing datasheet dimensions with actual measurements.
Create all sheet metal parts using sheet metal functionality.
Do not leave suppressed features unless required for a configuration.
Assembly
Start all assemblies using the designated start assembly template from the project directory. Each project has specific start assemblies.
Fix the first component to the origin or default planes.
Ensure all parts and mates regenerate properly(no red parts or broken mates!).
Do not leave components in a“Floating” state.
Include all fasteners and organize them into a component folder.
Apply color only at the part level.
Perform interference checks to identify conflicts.
Avoid designing components with line-to-line fits; account for tolerances in the model.
Assemble components as they would be in real life. Use screw holes rather than default planes as assembly references.
Do not leave suppressed components unless required for a configuration.
Ensure parts move as they would in the real assembly. If movement is limited, apply limit mates(Advanced Mates).
Drawing
Start all drawings using the designated template from the project directory. Each project has specific drawing templates.
Enter all drawing format data in the design table(in the part or assembly). Do not input data directly into the title block.
Do not create unassociated dimensions or tolerances.
Ensure all required dimensions and tolerances for manufacturing are included.
Verify there are no redundant dimensions.
Mark critical dimensions and denote inspection dimensions with an oval outline. Include a note defining its meaning.
Each drawing must contain at least one inspection dimension.
Confirm the inspection level(upper left of the drawing format) is correct.
Ensure dimension decimal places accurately represent the intended tolerance.
Use section views to dimension internal features. Do not dimension to hidden lines.
Include item number bubbles for all parts in assembly drawings.
Use unique section lines for each part in assembly section views.
Avoid placing dimensions over drawing entities unless it is the clearest way to show details.
When dimensioning drafted parts, define“+draft” and“-draft” according to Figure 1.
Figure 1: Defines the standard on how to dimension drafted parts.
