I'm not a system programmer and don't have the mathamatics background to know exactly what the formulas and algorithams are required to explain this properly, so this is probably an oversimplification. If anyone can explain it bettter, 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 (ie. SmatCAM) 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 I 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 intirum 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] ======================================================================
