What is a ʼMateʼ (Standard
Short Answer
A Mate in SolidWorks is an assembly relationship that controls how components align, touch, rotate, or move relative to each other. The most common professional method is using the Mate command in the Assembly tab to apply standard mates like Coincident, Concentric, or Distance. It only works correctly when references are stable and well-defined.
What You Need to Know Before
Warning: Mates can easily over-define an assembly if you stack multiple constraints on the same faces, edges, or axes. A very common failure is using temporary or changing geometry, which later breaks mates after part edits or feature rebuilds.
How to Create a Standard Mate
Command: Mate
Shortcut: [M]
Quick Steps:
- In an assembly, go to the CommandManager > Assembly tab > Mate, or press M.
- Select two references such as faces, edges, planes, or axes from the components you want to constrain.
- In the Mate PropertyManager, choose a standard mate type like Coincident, Concentric, Parallel, or Distance, then confirm with the green check.
Use the fastest professional method: preselect two valid references, then launch Mate for automatic mate suggestions.
Real option to check: enable or review Lock rotation when applying a Concentric mate if the component should not spin freely.
Variables & Settings
Key Setting: Lock rotation
Expert Setting: This option appears with concentric mates and controls whether a cylindrical part can rotate around its axis. In real assemblies, leaving rotation unlocked can cause unintended motion or unstable drag behavior during testing.
Why it Fails
Cause 1 (Geometry): The selected faces or edges are incompatible for the chosen mate type, such as trying to apply a concentric mate to non-cylindrical geometry.
Cause 2 (layers/Locks): One or more components may be Fixed instead of Float, preventing the expected movement needed to solve the mate correctly.
Cause 3 (Command/Logic): The assembly already has conflicting mates, causing over-definition or preventing the new standard mate from solving.
Quick Fix & Best Practice
Quick Fix: Right-click the component, choose Float if needed, then edit or suppress the conflicting mate in the FeatureManager before reapplying Mate.
Manager’s Verdict: Use standard mates first and keep them simple. In production assemblies, mate to planes, axes, and stable functional geometry instead of cosmetic faces whenever possible.
FAQ
What is the most common standard mate in SolidWorks?
Coincident mate is the most commonly used standard mate.
Why does a concentric mate still allow rotation?
Because Lock rotation is not enabled.
Can mates break after editing a part?
Yes, especially if the mate references changed or were deleted.
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