i projected a curve onto a cylinder. when i sweep cut a rectangular profile, it rotates the profile. i need it to stay in the same orientation as the start location for the entire length of the curve.
the curve is a cam path projected onto a cylinder the profile is a rectangle shape
Mike
A scroll cam huh. Don't even bother with a sweep. Make a sheet metal flat pattern, roll it up, and fill up the spaces. This is better in several ways. It's easiesr, more mathematically accurate, and you have the flat pattern for programming the CNC.
Most CNC controls support "A axis mapping". This is a method where the cam profile is programmed as if it were flat (unwrapped). A special line of code is used to "wrap" the program onto a cylinder of a given diameter. This method produces much better results, than four axis contouring, for things like cams.
Regards
Mark
Muggs,
The method I use is kinda backwards from what I posted...(sorry).
What I usually do extrude a circle of less than 360 deg. (359.9 or so) as a thin feature. I apply a thickness to it equal to the depth of the acutal cam features. Then I "unroll" it by applying a sheetmetal feature using one of the the edges on the seam (.1deg gap).
After I flatten it out I apply the cam features. For instance, a 30 deg slot will equal a 30 deg helix etc. I save it in this form as a machining configuration. Then I'll switch back to the default config., roll it back up, and finish detailing the part for the assembly.
Regards
Mark
Muggs,
The method I use is kinda backwards from what I posted...(sorry).
What I usually do extrude a circle of less than 360 deg. (359.9 or so) as a thin feature. I apply a thickness to it equal to the depth of the acutal cam features. Then I "unroll" it by applying a sheetmetal feature using one of the the edges on the seam (.1deg gap).
After I flatten it out I apply the cam features. For instance, a 30 deg slot will equal a 30 deg helix etc. I save it in this form as a machining configuration. Then I'll switch back to the default config., roll it back up, and finish detailing the part for the assembly.
Regards
Mark
"Muggs" wrote in news: snipped-for-privacy@enews2.newsguy.com:
Here are examples of that method. It's easiest if the cam is cut into the end of a cylinder. Making it in the middle kind of complicates this process a bit.
Thank You Mark,
That works pretty nice!
Muggs
Matt,
Both good questions. Using a "K" factor of 1 makes the edge of the flattened circle equal to the circumfrence.
As for the second part. I haven't had many occaisions where the cam went all the way around, but in those cases I use a method similar to your example. You want to make sure you put the gap in an area where it's continuation is a straight line. I'll import the flat pattern with the gap, and just extend the cut beyond it.
Regards
Mark
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