Assembling model steam engines

[chunk07]

I model small steam engines. I'm having lots of problems with assembly and joints. Is there a tutorial that describes such an assembly and what types of joints are used where and why?

For example, I assemble the body with the crankshaft , the flywheel, and crank, add the crank pin and the animation works fine. Adding the connecting rod, piston and piston pin and the previous joints light up red. The crankshaft has a revolute joint with the body,, the Flywheel and crank are fixed to the crankshaft, and rotate with it, the crank pin is fixed to the crank, the connecting rod rotates on the crank pin as well as the piston pin. The piston pin is fixed to the piston, and the piston slides in the cylinder.

Each joint is working correctly when it is animated, but problems occur when the model is animated...

[davebYYPCU]

Tips and Tutorials, listed in this forum, second last orange title.

check your part alignments, joints won’t just fail, you may need offsets, between the Joint locations.  Revolute joints have to be axis accurate, whereas a cylindrical Joint will let you missalign to a degree.  

You will receive accurate assistance if your if your data is available.

Might help...

[sanket223.patil]

@chunk07 Hello , 

You can learn joints and assemblies from tutorials . I learned from (https://www.autodesk.com/products/fusion-360/get-started#) . And also some from you tube .

I have made an V8 engine just to practice joints and assemblies . If have any problem in joints , Do ask .

[jeff_strater]

@chunk07, the most common source of joint failures is, as @davebYYPCU said, inaccuracies in your geometry - things don't line up precisely.  Especially if you have a closed loop of constraints, the solver is not forgiving.  Unlike in real life, where you can sometimes force things to fit by bending them, Fusion can't handle that.  Sometimes you can fudge things a bit.  For instance, if you have Revolute joints for your connecting rod, try changing those to Cylindrical joints - this gives you an extra axis of freedom, and sometimes that is enough.

Most of all, as Dave said, share your design here.  There are lots of folks who want to help and will spend an unbelievable amount of time figuring out the problems and showing you how to fix them.

[chunk07]

Thank you, Dave and Sanket. I have decided to share the file I'm working with. Please critique and advise how to assemble. I get everything working except the slider joint between the piston and the cylinder portion of the standard. The file I have posted contains all the parts, but no joints.

I really don't want you or anyone to assemble it for me, I want to learn how to do it myself. Look and see if there are adjustments/changes to the parts that I can make to make assembling this engine easier/error free.

FYI, the specs for the parts come from original blueprints created in the 1940's and kindly shared with me by a descendent of the creator. Please don't share them outside this forum.

https://a360.co/2wwdx9G

 EDITED for clarification

[chunk07 · Accepted solution]

I finally got it! The joint between the crank and crankshaft, and the connecting rod and piston pin needed adjustment...