There are several aspects to assembly mates that I've learned to pay attention to:
1. Use subassemblies in the files. Build up subassembly models as you would actually put the parts together. This speeds things up a lot, reduces file size and complexity (the mates are MUCH easier to navigate!), creates reusable subassembly files, and makes other mating options available.
2. Mate surfaces/faces as they would actually touch each other rather than using a coincidental surface. For instance, mate the OD of a bearing to the ID of a bore rather than to the concentric OD of the part with the bore.
3. Features that mate, such as holes, should be created in the same way. If you are mating a 3-hole pattern in two parts by using a concentric mate on one hole pair and another concentric mate on another pair then those hole patterns should be defined in the same way. I had one part where the three holes were equally spaced on a bolt circle and it would not mate to the other part where the holes were defined with cartesian dimensions. The locations were identical as far as I could tell (as far as I bothered to look which was 4 decimal places), however, they weren't exactly the same. This was a bit frustrating, but has proven to be a well-learned lesson.
4. When encountering mates that conflict and you don't think they should, try suppressing the last mate and measureing the angles or distances of the features you have just picked. Sometimes you'll find they are off ever so slightly and they shouldn't be. (If you try make this a defining dimension it becomes a mate unless that would cause an over-defining condition.)
5. Sometimes when a mate chokes and pukes it is because you have constrained more begrees of freedom than necessary. Try moving one of the parts involved in the failed mate. This will help you see where it still has a degree of freedom. From this you can use a different mate that is more appropriate. A good example of this is making two cones coincident. This creates a concentric constraint and an axial constraint, leaving only a rotational freedom. If that is what you want then all the better, but if you have already constrained the cones axially then this could be a problem.
6. Use component patterns whenever you can. This is MUCH faster than having to insert a subassembly and applying several mates. This is beautiful too because the components in the pattern can be different configurations from each other and the original. I have a part with 16 configurations. I located the first one in an assembly and created a component pattern in 2 directions with 4 instances each. I then went to each instance and selected the configuration to use. Now I had a nice overview of all the parts without creating a ton of mates.
joec230, as I read your original posted problem I would suggest moving the parts to see where they still have some freedom and then making sure to apply an appropriate mate (#5, #4, #2). The other concern would be to make sure the geometry is defined the same (#3, #4).
- - -Dennyd
