SolidWorks 2010 Bible

Chapter 13: Getting More from Mates

If you drag the assembly parts from the location shown in Figure 13.8, the performance varies.

This is because when you drag the handle parts, for every position of the handle, there is only one

solution for the rest of the parts. However, when dragging the plunger bar, for every position of

the plunger bar, there are two possible positions for both the links and the handle (one possibility

is as shown, and the other would be with the handle interfering with the base of the assembly).

This kind of ambiguity causes problems in SolidWorks assemblies such as assemblies that have

open degrees of freedom but will not move or only move in a jerky fashion.

Another example of difficulties related to open degrees of freedom and motion is shown in Figure

13.9. The grippers at the end of the arm move when the rest of the arm moves, but the grippers

cannot be independently controlled by dragging. To fix this problem, you may want to either use

the Fix/Float option (available through the RMB menu) or use configurations with mates suppressed

or unsuppressed. Fix the part that you want to remain stationary closest to the part you want to

move. Remember to Float the part when you are done. Be aware also that fixing a part may

over-define some mates. You can open this assembly from the CD-ROM, in the filename called

Chapter 13 Robot Assembly.sldasm.

FIGURE 13.9

A robot arm assembly with degree-of-freedom conflicts