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Cavity Mill _ corner control slowdown help!!

Cavity Mill _ corner control slowdown help!!

Cavity Mill _ corner control slowdown help!!

(OP)
I wanted to know if anyone has had success with the corner control slowdown on a cavity mill operation. Is there a way to make every pass on walls to slowdown in the corners? So far I have noticed that slowdowns will work randomly in corners.  We have a older cnc machine that cannot make 90 degree turns over 40 ipm without keeping material on part.  So basically if i want to rough out a square pocket at 200 ipm but want the passes on the wall to slow down to 40 ipm in the corners, I keep seeing a inconsistent feedrate. Any comments would be appreciated. Hopefully I gave enough information.

RE: Cavity Mill _ corner control slowdown help!!

Could you program a short dwell in each corner?  This is usually done with a G04 command, followed by a dwell time in seconds or parts of a second - usually expressed as a P or F code.

Software For Metalworking
http://mrainey.freeservers.com

RE: Cavity Mill _ corner control slowdown help!!

Are you using a CAM software package?? Many CAM programs have some feature that will accomplish this for you.

If you are writing your own code by hand you could do something like this:

G1X8.F200.
G1X8.5F40.
G3X9.0Y0.5I8.5Y0.5F40.
G1Y1.0F40.
G1Y8.0F200.
G1Y8.5F40.
G2X8.5Y9.0I8.5J8.5F40.
G1X8.0F40.
G1X0.5F200.
ETC...
ETC...
ETC...

Effectively what you are doing is slowing it down in the corners yourself. Notice that there is a short linear move at the 40 IPM feedrate. This will allow for deceleration of your table and a true 40 IPM feedrate through the corners.

With a G91 incremental Z move and a looping command you could write the entire code to any depth in about a dozen lines.

RE: Cavity Mill _ corner control slowdown help!!

(OP)
Well I know how to write the code by hand but what I am really trying to find out is how to make the Cavity Mill operation do it.  I have been trying a few things out like using Circular Feedrate Compensation.  It seems to work a bit better but still it is missing some slowdowns.  I tried to change the percent of tool dia. slowdown and also the amount of steps.  I guess Cavity just isnt perfect but I have to believe there is a way to have more control over it.  Thanks for all the input so far though guys.

RE: Cavity Mill _ corner control slowdown help!!

Kyleb77,

What is Cavity Mill? Is it a feature in a CAM software package?? If so, which program.  

RE: Cavity Mill _ corner control slowdown help!!

(OP)
Ya I should have mentioned that important fact from the beginning.  UG NX2  :)

RE: Cavity Mill _ corner control slowdown help!!

Quote (kyleb77 ):

Ya I should have mentioned that important fact from the beginning.  UG NX2  :)

Well, in that case I can't help you a bit....

But, here's something to think about. Is UG primarily a CAD package or a CAM package???

Me thinks its a CAD package. That being said, the functionality of any CAM add on should be an interesting proposition indeed.

Good Luck!!!

RE: Cavity Mill _ corner control slowdown help!!

UG is a CAx package.  It has an integrated CAM application, and its arguably the best out there. :) Corner slowdowns are sometimes quirky.  Its hard to help without seeing your tool path.  That being said, can you post your part so I could give it a shot?  Plus, you'll get alot more help from the UG forum on this site, plus the UGS BBS.
-Derek

RE: Cavity Mill _ corner control slowdown help!!

(OP)
Well I cannot show you the part I am sure you know why.  Nice try though :)

RE: Cavity Mill _ corner control slowdown help!!

I understand, we're kind of in the same boat here as well.  Anyways, it looks like there is 2 Problem Reports open that are related to your issue.  These can be found at http://www.uganswer.com                     
[PR-05539290]                    
[PR-02074263]

RE: Cavity Mill _ corner control slowdown help!!

Quote (hdrl1935 ):

UG is a CAx package.  It has an integrated CAM application, and its arguably the best out there. :)

noevil mmmmmmmmKay, if you say so... noevil

RE: Cavity Mill _ corner control slowdown help!!

One way of getting around it is to customise your postprocessor. For instance you could write an ude/mom procedure that triggers a different feed when the angle between two linear elements exceeds a certain amount.

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