On Thursday, December 15, 2011 05:35:47 PM Richard Ray did opine: > On Thu, 15 Dec 2011, James Louis wrote: > > Dan, > > > > I don't know if you are going to get much discussion here on > > this fundamental topic. Your question is so complicated that > > it is usually answered in CNC classrooms or CNC books with > > lots of diagrams. A text based forum is a poor substitute for > > these. As far as You Tube is concerned, that is also not the > > place to learn the fundamentals of tool length compensation > > and cutter radius compensation and the relationships of CAM > > and CNC tool tables. That's why you can't touch an industrial > > CNC machine without a certification. At least not in a "for > > profit" shop. : ) It will only lead to frustration if you > > rely on these for your clear understanding of your tool > > "cribs". Also, a ballnose endmill is used for 3 axis > > contouring, and I would not even attempt that until I had a > > solid knowledge of 2 1/2 axis profiling, including tool table > > set-up in CAM and CNC. I don't know your background so please > > don't take this wrong, but I do know that there are better > > ways to get your questions answered than just asking questions > > in a forum. > > > > Good luck > > jim > > -----Original Message----- > > From: Dan Field [mailto:danfi...@roadrunner.com] > > Sent: Thursday, December 15, 2011 3:01 PM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] tool table definitions > > > > On 12/15/2011 6:27 AM, andy pugh wrote: > >> On 15 December 2011 14:06,<kqt4a...@gmail.com> wrote: > >>> For example how to define a 1/8" ball nose mill > >> > >> If you want to automatically compensate for the ball-radius then I am > >> afraid that you can't. EMC2 doesn't know enough about the material > >> shape to compensate for ball-nose (or V) cutters. All EMC2 knows > >> about is the cutter path, not what is being cut. That will always > >> have to be handled by the CAM package. > > > > I was or am hopeful there will be more discussion on this, I am in the > > same boat trying understand the Tool Crib ( and it's relationship to > > the CAM crib ) . So far I have got by but.... Now I thought the > > question was just how to enter or define a 1/8" Ball Nose in EMC2 not > > auto compensate. > > > > Agreed you set up your new tool in CAM. I sort of looked at any > > existing examples and copied what was there changing the diameter and > > a new Tool Number. I needed a 11/64 Ball Nose as that is what I > > had. There was a 6 mm Ball Nose already setup. > > > > I saw that for a Ball Nose, Flat Radius is zero, corner radius is > > half the tool diameter so that's what I did. Got a new tool number > > and sure enough EMC2 error msg, no Tool # 15. So into the EMC crib, > > I only told it Tool # 15, filled in Diameter and in comment what it > > was. That's it and it seems to work just fine. > > > > So now I wonder why there is even a Tool Crib in EMC? I assume if > > you are good enough to manually enter Gcode and run from there you > > need tools. > > > > That being said, I am using HeeksCNC for my CAM. There's not a lot of > > help for the noob so I watch any youtube vids I can find. This one > > mentions though I don't seem to have this option , EMC2 CRC and he > > calls it Cutter Compensation. I only have a choice built in of > > EMC2, and EMC2 Simplified ( using Simplified ) , no EMC2 CRC. I > > know if you know what you are doing you can teach Heekscnc any > > Postprocessor , don't know if this CRC is a Plug In or what. > > > > http://www.youtube.com/watch?v=TcMmKdtjX7w > > > > Hope this helps > > that's a bummer Well, consider the problems involved when using the ballnose when you have a certain surface roughness error budget to meet. That would mean that emc would have to keep a 3d profile of where that bit has been and already cut away, despite its being 300 lines of code since the bit was actually within the radii of that ball profiles volume the last time.
If such a requirement is presented, all of that fancy calculation needs to be done beforehand in the CAM program, by adjusting the step overs and what not that it would have to use to meet that finished surface tolerance profile. That is, simply, thousands of times more difficult than just driving the cutter over the g-codes pre-determined path. More experienced swarf makers will likely offer comments too, but that's my $0.02 worth of 1934 dollars. :) > ------------------------------------------------------------------------ > ------ 10 Tips for Better Server Consolidation > Server virtualization is being driven by many needs. > But none more important than the need to reduce IT complexity > while improving strategic productivity. Learn More! > http://www.accelacomm.com/jaw/sdnl/114/51507609/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> While money can't buy happiness, it certainly lets you choose your own form of misery. ------------------------------------------------------------------------------ 10 Tips for Better Server Consolidation Server virtualization is being driven by many needs. But none more important than the need to reduce IT complexity while improving strategic productivity. Learn More! http://www.accelacomm.com/jaw/sdnl/114/51507609/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
