Chuck, Several thoughts on 3D cutter comp situations in Freeform: 1. In 3D milling think tangency point of the ball cutter "at all contact points" and the part surface, not center of the tool. 2. Smartcam tool diameters can be changed (like for reground tools) and the program re-coded to do what cutter comp does. 3. "Finish Stock" amounts can also accomplish the same thing, the amount of Finish Stock can either be Positive or Negative entries. Hope this helps, Michael
"Glawe, Chuck" wrote: > Please ignore the first 2 (the send button got in the way of the spell > checker, too early in the morning I guess). > > I'm not a system programmer and don't have the mathematics background to > know exactly what the formulas and algorithms are required to explain this > properly, so this is probably an oversimplification. If anyone can explain > it better, please correct me. > > 3D cutter comp requires 3 additional coordinates (I,J,K) on the same line as > the X,Y,Z location of the cutter. These have nothing to do with arc radii in > this context, they define a vector that points away from the contact point > of the cutter on the surface, through the center of the ball, so the machine > knows which direction (in 3D space) to move the cutter. This is the simplest > form of comp, core type surface (convex) with a ball cutter. If you have a > cavity (concave) surface with scallops and a cutter that is too big for the > smallest radius, then you have 2 or more contact points, and there has to be > an averaging to determine the proper offset. All of this is done in the > computer software (i.e.. SmartCAM) when the cutter path is calculated. All > that is needed is for the programmers of the software to make that > information available to the code generator/postprocessor so it can add the > I,J,K coord to the G-code (not always as simple as it may sound). The > restriction that Kevin stated about programming to the center of the ball, > if you use a program that is to the bottom of the ball, the I,J,K vector is > no longer in line with the contact point of the cutter and the surface, so > the offset direction would be incorrect. > > As far as only being able to use ball cutters, yes, to use a flat or bull > end cutter you would need to add an additional offset (2D) to get from the > center of the radius, or sharp corner, to the center of the end ot the > cutter. > > As far as Mazak's promises, there weren't any to us. We needed some machines > in a short time, and this feature was already on the control. At the time I > inquired to SmartCAM about getting the proper output, and they said it may > be in a future release, this was when SmartCAM was still Point Control. We > buy Mazaks for reasons too extensive to go into here (politics), but mainly > for the conversational programming (2D) on the machine for our mold base > work. We are now looking into other machines to do the type of work that > Kevin was talking about (one being Bostomatic). > > I have since found out that SDRC can output the I,J,K for 3D comp but > haven't looked into what level of software options are required, or if my > copy of IDEAS 8 is at that level. We haven't been using IDEAS, we have > Surfcam as a interim measure to our move to solids machining (we use > Solidworks for mold design). > > This got longer than I intended. Again, if anyone out there can explain it > better, or I'm all wet :-), please jump in. (Gene Bowen comes to mind). My > knowledge is purely from the school of hard knocks in duplicating, language > based programming, CAD/CAM and now solids. > > Sincerely, > Chuck Glawe > Courtesy Corporation > Mold & Tool Div. > [EMAIL PROTECTED] > www.courtesycorp.com > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, May 16, 2001 2:59 PM > To: Glawe, Chuck > Subject: Re: [mfg-smartcam] RE: 3D Comp. > > Kevin; > > > > >We are looking into this right now as well. We have 2 Mazaks with 3D cutter > > >comp, and the powers that be are coming down on us for new cutter > purchases. > > > > I am not familiar with 3D cutter comp. > Is 3D cutter comp used only on ball mills? > If not what other types of tools? > > What did Mazak promise? How could someone purchase machinery without > checking to see if the existing CAM software supported it? > > Tom > > ====================================================================== > To find out more about this mailing list including how to unsubscribe, > send the message "info mfg-smartcam" to [EMAIL PROTECTED] > ====================================================================== -- Visit our Programming website at http://www.microsystemsgeorgia.com/toc.htm Email mailto:[EMAIL PROTECTED] ====================================================================== To find out more about this mailing list including how to unsubscribe, send the message "info mfg-smartcam" to [EMAIL PROTECTED] ======================================================================
