Skip to main content
T
23-Emerald IV
TomU23-Emerald IV
23-Emerald IV
March 28, 2012
Question

Barrel Cam Modeling

  • March 28, 2012
  • 24 replies
  • 48651 views

I'm looking for ideas on how to properly model the slot in a barrel cam. I have attempted multipe techniques and I'm starting to spin my wheels. I have an idea that what I want to do can probably be done with the variable section sweep, but that feature is definitely not my area of expertise.


I've worked through the "wave washer" suggested technique on PTC's site (http://www.ptc.com/appserver/wcms/standards/freefull_cskdb.jsp?&im_dbkey=88651&icg_dbkey=900). The problem with this exampl is that the part is not a constant thickness (whereas my cam slot needs to be). To get a constant thickness, I changed the sketch profile to a single line, which created a single wavy surface, and then thickened it. Problem is, the sides are no longer vertical. To get around that, I lengthend the VSS section to include some extra on each end, then extruded inner and outer cylinder surfaces, merged everything together, and solidified. This succeeded in creating a constant thickness washer with straight sides.(See attached PDF.)


Problem is, thistechnique does not transfer well to the cam. The centersurface won't offset nearly as far as it would need to. Creating inner and outer curves and building boundary blends didn't work either.


Tom


This thread is inactive and closed by the PTC Community Management Team. If you would like to provide a reply and re-open this thread, please notify the moderator and reference the thread. You may also use "Start a topic" button to ask a new question. Please be sure to include what version of the PTC product you are using so another community member knowledgeable about your version may be able to assist.

24 replies

Show previous replies
T
TimMcLellan12-Amethyst
12-Amethyst
March 30, 2012
Sorry, everyone. After I sent the last file I noticed a small error with
the cutting tool in the assembly.



Please download the latest example which includes Tom's part updated and an
assembly where you can simulate the tool cutting (mechanism).



Have a great weekend,



Tim McLellan
Mobius Innovation and Development, Inc.
T
23-Emerald IV
TomU23-Emerald IVAuthor
23-Emerald IV
April 2, 2012
For those who are following this thread, here is a cam that was cut like it would be in real life. There are revolved cuts (804 of them to be exact) normal to the outer cylinder surface, tracking the desired trajectory around all the way around. Doing this clearly shows the off-axis gouging that occurs from the cutter's tip as well as what happens when the slot is so wide that the offset becomes sharp in areas. If only there were only some way to get Proe/Creo to properly create clean surfaces representing this roller surface (not the gouging necessarily, but at least the partially sharp corner area).

[cid:image001.png@01CD10EF.4AB88FD0]

[cid:image002.png@01CD10EF.C4458150]

M
mjenkins10-Marble
10-Marble
April 5, 2012

I created an angled offset axis and revolved the profile around it.


But I think this may not be what you are calling a barrel cam.

In Reply to Tom Uminn:



I'm looking for ideas on how to properly model the slot in a barrel cam. I have attempted multipe techniques and I'm starting to spin my wheels. I have an idea that what I want to do can probably be done with the variable section sweep, but that feature is definitely not my area of expertise.


I've worked through the "wave washer" suggested technique on PTC's site (http://www.ptc.com/appserver/wcms/standards/freefull_cskdb.jsp?&im_dbkey=88651&icg_dbkey=900). The problem with this exampl is that the part is not a constant thickness (whereas my cam slot needs to be). To get a constant thickness, I changed the sketch profile to a single line, which created a single wavy surface, and then thickened it. Problem is, the sides are no longer vertical. To get around that, I lengthend the VSS section to include some extra on each end, then extruded inner and outer cylinder surfaces, merged everything together, and solidified. This succeeded in creating a constant thickness washer with straight sides.(See attached PDF.)


Problem is, thistechnique does not transfer well to the cam. The centersurface won't offset nearly as far as it would need to. Creating inner and outer curves and building boundary blends didn't work either.


Tom







T
23-Emerald IV
TomU23-Emerald IVAuthor
23-Emerald IV
April 5, 2012
This works because the follower is a ball. Once the follower becomes a cylinder, things get much more interesting.
Terms & ConditionsAccessibility statement