Assembly Replicate Behavior - Need to replicate multiple components & maintain constraints

VinceHaley_SkillCoach

I'm looking to replicate in the same feature a set of fastener components that have constraints applied to them already. There are two variables I have to account for, bracket thickness and housing thickness. These thicknesses will change as I iterate the design so I want the constraints in my assembly to update automatically.

The required constraints:

• face of Slotted-post co-planar (mated) with bracket top face
• top face of Bushing co-planar with Bracket bottom face
• bottom face of Bushing co-planar with Housing top face
• face of Chicago Screw co-planar with Housing bottom face
• Slotted-post axial with each hole in the Housing
  

I've been able to replicate the component group. Unfortunately, the "Mate to be matched" section only allows for choosing a single mate as opposed to a collection of mates.

To fully constrain the assembly as desired, I've had to manually add additional constraints to each member of the replicate. I'm hoping there is a way to avoid needing to do this. Any advice is appreciated.

https://cad.onshape.com/documents/8c0cd47f7af0e232f9556479/w/f84b663a5fadd2db8b0b65ed/e/051d99a112ebf60ad5602830

eric_pesty

I had a quick look and it seems you had too many different mates so simplifying helps a bit... Replicate can't quite handle this directly but here are a couple way to handle it.

The two screws have to bottom out against each other (otherwise they will loosen) so if you change your thickenesses you will need to change screw lengths so I'm not sure it makes sense to have the top screw follow the bracket face.

For items on both sides of the housing, I find the "quick and dirty" way to handle that is to just create several replicate features. Otherwise your can use an offset in your mate that matches the thickness, which is not a bad option if you can use a variable to drive it.

Another option would be to create a sub-assembly with the stack of fasteners and replicate that. You could use a sketch or something to set the spacing in there so that it would update automatically, this simple to implement and scales well...

See the three examples: assemblies: https://cad.onshape.com/documents/12139a066dce89184a85c452/w/5349afa3c00acb8366f323ff/e/9acf3350477293948f103d9d

Hope that helps...

VinceHaley_SkillCoach

@eric_pesty thank you for taking a look at this. I'll review your examples shortly.

VinceHaley_SkillCoach

@eric_pesty Nice examples! I've got plenty of options now. I frequently use variables in part studio, but have not in assemblies. Variable studios is the ticket. I've gleaned from your example how to incorporate variable studios. Thanks again!

eric_pesty

Glad to help. The only downside with the variable studio is that you have to drive it from there so can't make an extrude "up to" something which can be a bit limiting.
The fastener stack assembly driven by the helper sketch works well as a an alternative, the only downside there being you have to hide the sketches in the assembly...