Bari, The 5 axis tool path for the machine I describe is point to point motion. CAM generates XYZAB and a feedrate (G93) for every line of motion.
5 axis CDC uses the A and B command to create a target vector. In essence I use the AB values to recreate the tool axis vector the CAM system used to create the AB values. The XYZ point and the tool axis vector describe a plane where the programmed target tool position is. I use the plane to calculate the corrected target XYZ point. The values of A and B don't change. The only thing changed are the XYZ values needed to move the edge of the tool to the desired location. This in conjunction with 5 axis tool length correction allows the 5 axis tool path to be (from the operator stand point) no different from a 2D path. Change the tool, reset the TLO, reset the diameter(or radius) value and you are off and making chips again. You need to account for cutting pressure or tool wear to tweak a workpiece dimension? TLO or CDC to the rescue as in 2D work. In the 80s (1980s) Cincinnati Machine Works engineers claimed we would never see 5 axis TLO as it was impossible to calculate from the values in the program. A thought provoking IMTS booth conversation with Willie (the programmer in a wheel chair at MPM and my shop) enabled Cincinnati to announce (about 6 months later) a NEW USD10,000.00 software/hardware upgrade to the control allowing 5 axis TLO. Processor speed development had allowed the calculation in real time. I used NCL (a CAM package I use) to help me verify the calculations of plane and correction values. When I was able to calculate the same values NCL output I knew I was correct. After I had developed my algorithm I saw a Fanuc manual describing how they calculate 5 axis CDC. They use EXACTLY the same process. This is what I want to have available in LinuxCNC. Something else to add to my desire for 5 axis TLO and CDC is the application of the changes during the running of the program. If you change the value of either I would like it to be applied to the next line of code in the program. The control would finish the current commanded positioning and then use the new values to calculate the next line position correction. Bari - I sounds to me like you are wanting to develop an open verification application. That would be a very nice addition to the open source tool kit. thanks Stuart On Thu, Apr 15, 2021 at 12:24 AM Bari <bari00...@gmail.com> wrote: > On 4/14/21 11:49 PM, Stuart Stevenson wrote: > > > Gentlemen, > > My current attention to the project is driven by my desire to have 5 > axis > > cutter diameter compensation in LinuxCNC. > > > > On a more serious note I'd like to see what you have thought up. I am > starting to work on an open 5-axis CAM application for FreeCAD Paths. > I'm going to use a physics engine to prevent collisions between the > tools and the parts. I thought of how this might even be used within > LCNC to preflight programs. > > > -Bari > > > > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers > -- Addressee is the intended audience. If you are not the addressee then my consent is not given for you to read this email furthermore it is my wish you would close this without saving or reading, and cease and desist from saving or opening my private correspondence. Thank you for honoring my wish. _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
