SolidWorks 2011 Assemblies Bible - Matt Lombard [51]
The red circle containing the X is a failed mate. This mate is in conflict and is invalid. If it is also a Coincident mate, then the two Coincident entities are not coincident.
Troubleshooting warnings and errors
SolidWorks distinguishes between errors and warnings. Errors are situations where a condition is not satisfied, such as a coincident mate where the selected entities are not coincident. Errors are marked with a red symbol. Warnings are symbols that mark situations where a conflict exists, but otherwise all conditions are met. For example, both a coincident and a perpendicular mate use the same faces. One mate will have an error and the other a warning, because one can be satisfied, but not both.
You can use the following troubleshooting techniques to work with assemblies where errors or warnings exist:
• Last in first out. When a mate is added that causes warning and error signs to appear throughout the design tree, you can usually correct the problem by removing this last mate.
• Single elimination. If you are sure that the last mate added is correct, then you may want to go backward up the tree starting at the bottom, suppressing individual mates until you find one that causes the warning and error signs to disappear from the tree.
• Single addition. It may be easier to take the opposite approach, by suppressing all but the mates that you are sure of, and then gradually unsuppressing mates until the conflict reappears.
• Suppress a part. With all the mates active, try suppressing an individual part to see whether this makes a difference. If it does, then unsuppress the part and look at the mates for that part in the Mates folder under the part.
• MateXpert. The MateXpert is an automated routine that creates subsets of groups of conflicting mates. Each subset of mates has one mate that is not satisfied because of the conflict. This may help you to find the cause of the conflict. Figure 5.22 shows the MateXpert interface. You can access the MateXpert from the RMB menu on mates with errors.
FIGURE 5.22
The Mate Xpert interface
Examining Mate Options
The Options pane of the Mate PropertyManager is shown in Figure 5.23. Most of the options are self-explanatory, except for Use for positioning only. This option positions a part but does not apply a parametric mate. Some users select this option often for various applications where they need the part located precisely, but do not need or want a mate feature in the tree. One example of using this option is to position a part for Animator animations where the part does not move according to a mate.
FIGURE 5.23
The 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, or even a bad idea. As a result, you should apply the following recommendations carefully. Don't take best practices too seriously, but at the same time you should not disregard them altogether. Some companies use best practice recommendations as modeling standards. The less experience your SolidWorks team has, the more you need standards of this sort. Every situation has a different need for best practice, and probably even a need for a set of rules that are different from the ones laid out here. You can think of this set of mate best practices as a starting point for the discussion at your own company.
• 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.
• 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.
• Do not mate to time-dependent features in the assembly tree, or to in-context features in parts. This can create circular references