Chapter 13: Getting More from Mates
FIGURE 13.23The Options pane of the Mate PropertyManager
Reviewing Mate Best Practices
Sometimes best practice recommendations can contradict one another, and for each best practice
recommendation that you find, there are likely several specific situations where the recommendation
is invalid. As a result, you should apply the following recommendations carefully.l Each assembly should have at least one part that is either fixed or fully mated to the
standard planes of the assembly so that it cannot move relative to the assembly.
l You should use fixed parts sparingly. One part that serves as a “ground” for the assembly
should be fixed. Other than that, the parts of imported assemblies are sometimes fixed to
keep them from being moved accidentally.l (^) Do not mate to time-dependent features in the assembly tree, or to in-context features in
parts. You may want to refer to Chapter 12 for a refresher on time-dependent features
in the assembly tree. This can create circular references where the assembly must be
rebuilt multiple times to fully resolve the positions of all parts and sketches.
l (^) When possible, it is best to mate all parts to the “ground” part. Creating daisy-chain mates
(where A mates to B, which mates to C, and so on) forces the mates to be solved in a
particular order, which may take more time to solve than otherwise. If all the mates relate
to established assembly references, the mates may be more stable. Chapter 11 describes
using a skeleton in a part to make sketch and feature relations. A similar concept can be
applied in an assembly, by mating parts to an assembly sketch.
l (^) When possible, leave part positions fully defined, especially when other geometry is
dependent upon the position of parts. Some examples include in-context features, assembly
features, or assembly-level reference geometry, which are dependent on part geometry.
l Constraining the rotational degree of freedom for components such as screws, washers,
and nuts is usually considered excessive. At times, too many open degrees of freedom may
cause problems with complex motion, such as a gripper on the end of a robotic arm.
SolidWorks functions well when there is a single, well-defined path between two points,
but when there are multiple options, the software may become confused.
l (^) Do not leave errors unresolved in the tree.