Help ! Cutting a cam.

[Brian Ulrick]

I have a flat 2d cam contour to cut and need some advise. I drew the cam using the rise and fall table provided . The rise and fall radius is at every two degrees. I used polar to create lines with the correct radius and angle, then added a point at each line end. I used create spline - automatic - picking the requested three points.

The contour supports a tool path , OK. Should I use the filter settings for the tool path and if so what is recommended to make the smoothest cut.

First time using spline,etc. Mill ver 8.1

 

Thanks in advance ! Brian

[Jack Mitchell]

Brian,

 

I suggest cutting the workpiece like it is.

Please try this method, add a false value of about .01" to the actual cutter diameter, then trial cut to a depth of .025"

Observe the profile to see if you’re happy with this.

Then, try the filter process as you have suggested.

Add .03" to the actual cutter diameter, then trial cut to a depth of .05"

Choose the one that you feel will perform best.

 

The cam developed at 2deg should be and likely is mathematically correct. The filtering will smooth its transition but this really a consideration of the actual cam size and application.

 

I had a similar experience with cutting a rather large cam for Russian built press (est. 24" diameter x 8" thick).

The developed cam drawing was one of the most amazing hand drawn drawings I have ever seen. I really regret not keeping this drawing - you just don’t see this type of artistry very often.

 

Regards, Jack

[Brian Ulrick]

Jack, Thanks for the quick reply. I'll give your advice a try. I still need to know more about the filter settings to see the results of a cut with filter on.

 

Thanks ! brian

[K Reed]

Hello, I'm new to this baord, but i'll give this a shot.

From what you say about the cam profile, I'm guessing you don't want to filter it so the profile get's to "choppy" around the spline. I recently had a problem with extremely choppy 3-d toolpaths and found that I had my postprocessor set to NOT support helix arc moves. When cutting say, a ball shape, the program would be HUGE ( not fitting in my machine memory, DNC time!!)because everything was point to point xy moves. I modified the post to accept helix arcs, and enabled filter arcs , VOILA. This might not be the same problem , because it's not a helix, but it could be a feasable try to copy your post, then go toy around in it a little bit. I hope I helped a little.

[Brian Ulrick]

Thanks for the help. The cam cut OK without filter

settings.

[McRae]

Nice Work Jack. Guess you do have some usefullness and are not here just to incite a roit with everyone else.

 

I have never used the filter arc for anything. As for the 3d arc filter problem, the arcs will only exist in the G17,G18 and G19 planes - live and breathe with the huge files and let the control do its job...

[MACHINEMASTERG]

when ever we cut cam profiles i would take the spline and do modify,break,many pick spline and set a line lenth of like .01 this will breakit into small .01 line lenthes for a nice smooth finish also delete splin be fore toolpathing so you only chain the lines hope that helps in the future???

[K Reed]

You can also break the spline into many less peices, and create arcs, for a smoother transition between the segements.

[Smit]

In the past I've had the best luck by breaking the spline into arcs. Makes a large program but has a better finish than using lines. I haven't programmed a cam since getting V9, however. Our Fadal has problems with this, (anytime a spline is broken into arcs) but it works well with all of our other machines.