Mates and cylindrical parts
Mates and cylindrical parts
(OP)
When mating cylindrical parts that only require 2 mates, do you leave off the third mate? Out of 19 SolidWorks users here, we have only one person defining all 3 mates for dowels, washers and screws. He says he does this because he can look down the tree of a 500-part assembly and tell if all required parts are fully mated. We cannot tell the difference between a washer and a relay by looking at the part number in the tree. Some of the persons that do not define all 3 mates for cylindrical parts complain that someone is moving their parts into space. I was wondering if any of you complain of others moving your parts? I think that not mating all 3 mates is linked to parts moving in space, but cannot prove it. Because, they miss defining a critical part location I think that if someone moves a part in a subassembly, could move other parts, which are not fully defined.
Bradley






RE: Mates and cylindrical parts
With that said, I usually use 3 mates for rotational parts, but make good use of small sub-asseblies. Some people complain about assembly problems where there are too many mates, but usually I only see this when they have large (~250 parts) sub-assemblies.
"The attempt and not the deed confounds us."
RE: Mates and cylindrical parts
BBJT CSWP
RE: Mates and cylindrical parts
But if there is some angular relation between the cilindrical part and other parts I use a third mate.
I normally use a third mate for fasteners, so they can have the proper appearence in the drawings (otherwise the heads will show in strange angles).
Regards
RE: Mates and cylindrical parts
BBJT CSWP
RE: Mates and cylindrical parts
I most all cases that I have been in, my assemblies never exceeded 100-200 parts. My preference is to full define everything whether its an assembly or sketch. It helps to keep things from moving later, unless thats what your after.
It comes down to the users design intent and overall preference. If you don't use the proper mates for your assemblies you will see some freaky things happen when you move a component in an assembly. Which maybe what your seeing Bradley.
In real life when we as designers and engineers design our ideas, we design them theoretically perfect. In the perfect world there is no fastner that will ever strip, you only have to tighten it once and it lines up with all the others perfectly.
That was the first thing I was taught in college "everything is drawn theoretically perfect".
Best Regards,
Scott Baugh, CSWP

3DVision Technologies
http://www.3dvisiontech.com
http://www.3dmca.com
FAQ731-376
When in doubt, always check the help
RE: Mates and cylindrical parts
Again, this argument fails if you want dynamic assembly motion. To get around that, I try to use a dimension driven mate (i.e. distance or angle) to drive my different assembly position configs.
RE: Mates and cylindrical parts
Naming mates, feature, and configurations will help during collaboration, after memory failure, or after the creator is gone. Using planes and axes for mating will allow greater flexibility when changes need to be made, and simplify repair when things go bad.
RE: Mates and cylindrical parts
RE: Mates and cylindrical parts
Have any of the moving parts been modelled in the part file at a location away from the origin and then later moved to the origin?
If so, parts that are truely mated will retain the desired position in the assembly. Parts that are inserted and then have their position fixed will move.
RE: Mates and cylindrical parts
That, and ever since SW 2001-plus came out and "cancelled" any overdefining mates my co-workers created in previous versions, I have a feeling that someday they may "require" everything to be fully mated and defined. I don't want to go through ALL that again.
Mr. Pickles