Using Multiple Mates

peter_cuthbert

Hi Folks

I am yet again in a 'hole' hemmed in my non operative Mates.  So I am seeking an expert to help me get going again and from whom I can hopefully learn some key skills to avoid crahing down again.

By experience I have learned that Fastened Mates are good for today, but probably not for tomorrow.  However, they seem good in that they do not seem to cause Overdefinition if heavily used. By comparison it seems that Revolute Mates like to be alone or perhaps in pairs.  Add more to the group and they seem to affect all other mates with Overdefinition.  Remove the 'one over' and the red wave disappears.  Slider and Cylindrical Mates appear to be less fussy but I have used them less which is probably why I have not hit their awkward side yet. However, I may just have done that. My drawing has become a mess of Overdefinition and I am really not sure where to begin with deleting Mates and finding less fussy substitutes.  The mess can be found here:

https://cad.onshape.com/documents/7bbfee06b5db98491f04bff8/w/de088e3b67ddbaf176be56ba/e/9ad793773033362f3f1ce757

In the early stages, or at least with the crank and base it was possible to have animation.  I fear that getting that back is a long way off.

As always, you advice is gratefully received.

Regards

Pete

NeilCooke

I really would like to help you, but you need to watch the assembly videos here: https://learn.onshape.com/catalog?labels=["Self-Paced Courses"]&values=["Assemblies"]

You don't even have a fixed part which is a dead giveaway that the above has not been reviewed. Let me know if you still have problems after going through the training.

dirk_van_der_vaart

I would like to help you, and normaly I would make a copy of your document and start making some changes, bur seeing this document I give up, Why the imported files? Why all the Part studio,s.
Make a Part studio for both cylinder,s with all the parts in it, Make Part studio for the Crankshaft.
Make a Part studio for the Housing.
Create an Assembly import the Housing and Fix the housing, next import the Crankshaft and give that a Rotational Mate and make sure the Crankshaft rotates and so on

eric_pesty

I'll second Neil's suggestion, however your main issue is that you are over-constraining many things: for example you connecting rods have a slider and a cylindrical, which both try to "lock" the rotation. Using two cylindrical solves that.
You also don't need the limits as these can end up fighting each other and the rotation and sliding will be limited once everything is mated.
Your last "fastened" was also trying to bring the two end plates out of alignment from each other as it wasn't mating the same way as the first one to the frame...

Using sub-assemblies and grouping things would help a lot (and renaming/putting mates in folders)...

Here's a slightly cleaned up assembly (at least it's working), still needs some more cleaning though...

https://cad.onshape.com/documents/94f09b8aae9ae1573dd8ff2c/w/3bb6eadb75c96d22ec1ac576/e/845ab6fe9797b5c1ec1f2a63