Mating vs instances

Vashaus

I am coming across assemblies that are combined with instances. I am confused to the reason the person would not be mating the parts together. I am not oblivious to the fact that I am very stupid so I’m wondering what I am missing to understand why someone would make assemblies that just come apart so easily?

Vashaus

Please be kind to me.

glen_dewsbury

I can think of a few reasons why that might be done.

1. The assembly looks exactly like the parts studio so all is inserted a the same time but provides a BOM. Better to use insert part studio as rigid. and fix one of the parts so that nothing moves.
2. Once any moving parts are added then mates must be used to keep the rest in place and animate functions. Looks odd if the gear box rotates around a gear.
3. Assembly is done quickly for display/sample and mates can be done later.
4. There are some that don't understand what mates are so they are not using them. If one of or all of parts are left loose they can be moved by accident and can be a bit confusing to put back in place. Best option is the learning center and some study time. You can get away with this for simple arrangements but once the assembly size grows or multiple instances of the same part are needed in one assembly it will become a huge problem. Moving parts in an assembly are impossible without mate. If fix is not applied to one of the parts the whole assembly can be displaced.

jelte_steur814

extra possibility: (i have this regularly)

5. The assembly was made by Onshape upon importing a STEP/parasolid/other file. maybe a group constraint was added at the top level of the assembly, but all subassemblies below are not constrained.

Vashaus

thanks

Vashaus

Vashaus

thanks