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swept cut that's not perpedicular to trajectory

kschubert

New member
I've been working on this for 3 weeks now, I have a cam and a follower, pretty straight forward, what I'd like to do is have a slot in the cam and a post on the follower so that I can have the follower rotate 90 degrees. to get the rotation the post is .1061 offset from the center of the follower. The problem is that a swept cut is always normal to the trajectory, the post is actually offset from the tangent point. Does this makes sense?



the cam is split into 4 quadrants, radius .25 and .344 on opposite sides connected by a spline (rho=.4) for the translations. I need to rotate my follower 90 degrees in the radiused sections.... I'm at my whits end of trying this and that (enough so that I finally shelled out the money for a pro. membership to this site)



Thanks in advance!!!

Keith
 

Brian_Adkins

Moderator
With a variable section sweep, you can have a swept cut that is not normal to the trajectory. You must still specify something for it to be normal to however. That reference could be a datum plane, or even a different curve (perhaps a plain old circular curve)



-Brian Adkins
 

kschubert

New member
Still can't seem to understand what to do or get it to come out correctly. Download the file at http://home1.gte.net/res05cgq/pro-e/cam.zip



(it's a pro/e 2001 file)



You'll see that I've taken a few snapshots of the post location with the pattern. If I made an infinite pattern it would be close. but how can I get a cut to do the same thing in a nice clean feature?



Keith
 

bem

New member
I took a look at your model, and I can definitely say there is a better way.



As for design intent, does the slot for the post have the same profile as the cam itself (i.e. uniform depth?) The curves for the slot profile are not on the surface of the cam which is confusing. Also, rho is not a parameter for a spline (that I know of), but a conic.



What version (and date code ) are you working on so I can tailor a response
 

kschubert

New member
bem, The cam follower centerline is tangent through the transition area. Because the post is offset (to get the rotation) the base of the post (diameter .065 x .065 long) is not directly on the cam... I spent a day and a half coming up with the equations for the trajectory of the transition curves and verifying them. Have I answered your questions? Oh and yes rho is for a conic, not a spline... my miss statement.



I have a better model now with a patter of cuts that shows the post position every 5 degrees... but that was just to help me try and visuallize what I need.



Your help is greatly appreciated



Keith
 

bem

New member
First, Let me apologize for taking so long... it kinda fell off my radar screen.



Second, I still don't understand your equations. I think they are more complicated than need be



The attached file is my interpretation of your design intent. I used a variable section sweep and a sketch relation to do the follower rotation. i used a regular sweep for the straight sections. The only reason I used VSS was to access the variable trajpar to drive the relation. (why doesn't trajpar work with regular sweeps?) I think the sweep should be normal to the origin tajectory(like an end mill ) but you could pivot it in any direction as Brian has said.



You can do the entire cut in one feature, but the nested IF ELSE ENDIF statements in the relations would be confusing.



Hope this helps (oh yeah 2001 datecode 2002430)
 

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