Cam issue

[g00eY]

Hey everyone. I'm a newbie at SolidWorks and I've encountered a problem. I'm trying to make this ramp start in an up position and end in a down position. There will be an air cylinder pushing from the bottom of the ramp and will travel in the same horizontal direction as the straight cam guide. However, every time I try to cam mate the ramp to the curved guide I encounter an error that reads:

 

The selected faces do not form a closed and continuous cam extruded from a single profile.

 

I have no idea what the issue is. I've tried redrawing the cam guide with spline and different sized circles, but the only time it ever worked was a physically impossible model.

 

Here's a screenshot of what I'm trying to accomplish:

 

[g00eY]

I think I solved the issue. I ended up just drawing two sets of straight lines and using sketch fillet to get the curve. But... how come it doesn't seem to work with circles and splines?

 

Also, when I try to mate the pegs on to the guide as "aligned", it works fine, but after I run a simulation or two it either always gets stuck in the start position or one of the pegs un-aligns itself with my cam guide. Does anyone know the solution to this?

[shift1313]

im going to guess that it was an issue with your geometry and not the sketch method. Did you create one curve then use offset for the next? did you have tangnet constraints on the ends? If you can post the model here we may be of more help

[g00eY]

I drew two circles for the start and end points. Then I drew the bottom curve with spline. After that I drew 4-5 tangent lines at the spline points, all 4 mm long (the diameter of the circles) and basically played connect the dots. When all was said and done I just used trim and deleted all the extraneous lines.

 

Here is a link to the version I made with the spline and the one I made with the sketch fillet. The sketch fillet is fine except I can't seem to get the cam mates to stay aligned to the inside of the guide.

 

Just kidding... it's not letting me post the link. Is there another way I can my files up?

[shift1313]

are you applying a mechanical mate in the assembly file or are you working in a motion simulation?

 

i think there is a post limit to adding links and uploading files, idont remember what the post count is , 5 or 10

[g00eY]

I'm applying the cam mate in the assembly.

 

Yea, that was the message it was giving me. Darn.

[shift1313]

how are you determining your arc path? do you only have start/end constraints that you want you mechanism to have or does this arc path need to be specific?

[shift1313]

i just drew something similar and it worked okay for me. I uploaded a short avi of it.

 

I drew my horizontal slot first. then i drew a reference line 1" long from the start and end of that slot(center point) and drew circles at the end of these reference lines. then i drew an arc between those circles and offset that arc two directions the radius of my circle. When applying the cam mate make sure you select the entire set of faces of your groove, it needs to be a closed loop, and then select your follower.

camfollower23.zip

[g00eY]

Ahhhhh I get it. I should have used that offset feature... doh! I'm still trying to get the hang of SolidWorks, so thanks a bunch for you help!

[shift1313]

no problem. SW is pretty good about telling you whats wrong. The tip off was "closed and continuous". That points to a geometry problem.

 

Did you get the mates to work out after re-doing the curve?

[g00eY]

Yup, everything is working great now. Thanks again!