John Kasunich wrote: > > One thing to keep in mind when considering the tapered end mill idea > is chatter. > > The existing stepped design limits the depth of cut (width of cutting > edge engaged) to the height of one step. If you use a tapered end > mill, the cutting edge will be engaged in the cut over its full > length. You are much more likely to get chatter in that case. A high > helix cutter will help, as will ensuring that the finish cut isn't too > deep. > It seems logical that this would be a problem, but my sample of one test making an ill-fated mold cavity with one was that something in the dynamics of the taper reduces the chatter. Of course, the taper makes the shank end stiffer, which is good, but the buildup of resonances is a major factor in chatter, too. I think the differing diameters seems to prevent these resonances. But, then I only did this one time, so I may not have explored the range of possibilities much. > Another chatter risk is cutting inside radii with a cutter that is the > same as (or very close to) the finished radius. If the cutter radius > is close to the part radius, then the path of the tool centerline has > a sharp or nearly sharp corner. Just before the tool reaches that > corner, the amount of tool perimeter engaged in the cut increases > dramatically. (Hard to explain in words - see the attached sketch. > The heavy red line is the portion of the tool perimeter that is > cutting.) The result can easily be chatter and a crappy surface finish. > My project was a round, tapered bore, so I didn't create that condition. You can always program the radius to avoid this.
Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
