All of us who use assemblies in SOLIDWORKS know that mating can be fun (in SOLIDWORKS, of course). As a result, one can have a natural tendency to get carried away,which I’ll show you in SOLIDWORKS Mate Best Practice #4: Don’t Mate Too Much.
When adding a lot of mates there is a danger that can creep in. You can end up creating an over-defined assembly, you can make redundant mates that will give you grief when you try to delete them or modify something. Sometimes the problem appears right away, but in the example I’m about to show you, it can remain buried until a design change causes problems to arise suddenly:
Here is Rule #4: Don’t Mate Too Much:
Wow, scary stuff. Good thing SOLIDWORKS has some safeguards built in to stop me from getting carried away.
Of course, that was just with 3 parts to prove how simple an assembly can be and still get over-mated. It’s easy to spot the problem and follow the rule for such a simple assembly, but what about when your assembly contains 400 parts and over 1000 mates? Generally speaking, it’s still pretty simple. Just imagine that all the fully defined parts are one complex part. Then, ignore all the floating parts that you’re not mating anything to. Now your assembly looks a lot simpler. If you want to mate to part of this complex mess of mated parts, look at the one part you want to mate to and examine its mates. This will tell you the design intent of that part’s role within the assembly (yes, assemblies have design intent as well).