Non-circular boring. (Linuxcnc fun)

[skunkworks]

First couple tries in plastic. (painfully slow - just testing) (and the hole size should be way closer to the inscribed polygon diameter...)

Definitely an interesting use of a boring tool. Care to share the code for generating the toolpath?

This is the hal component for linuxcnc... WIP use at your own risk.

//   This is a component for Linuxcnc HAL
//   Copyright 2020 Sam Sokolik <samcoinc@gmail.com>
//
//   This program is free software; you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation; either version 2 of the License, or
//   (at your option) any later version.
//
//   This program is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//   GNU General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program; if not, write to the Free Software
//   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
component polygon "Create a spindle synced motion that carves a polygon using eoffset inputs.  Assumes positive rotation.";
 
pin in bit enable;
pin in unsigned numsides=3 "Number of sides in the polygon";
pin in float inscribedradius=1 "inscribed radius of the polygon";
pin in float cutterdiam "cutter diameter";
pin in float eoffsetscale "scale that eoffset is set to.";
pin in float toolang "angle difference between index and actual tool poition";
pin in float spindlepos "Spindle position scaled to 1 per rev";
pin out float spindlerad "Spindle postion in radians";
pin out float polyradius "radious of the polygon at given spindle position";
pin out float xoffset "x offset to send to offset componant";
pin out float yoffset "y offset to send to the offset componant";
pin out signed xeoffset "x eoffset output";
pin out signed yeoffset "y eoffset output";
pin out bit isindex "set index enable only once";
pin io bit indexenable "hooked to index enable of encoder";
 
function _;
license "GPL";
;;
#include  <rtapi_math.h>
#define  PI 3.14159265358979323846
float spinang;
float scale;
float spinangoffset;
 
    if (!enable) {
        xoffset=0;
        yoffset=0;
        xeoffset=0;
        yeoffset=0;
        isindex = false;
        return;
    }
 
// only set index enable once
    if (enable && !isindex) {
    isindex = true;
    indexenable = true;
        return;
    }
 
// wait for spindle index before actually enabling
    if (enable && isindex && indexenable){
        return;
    }
 
//convert spinangoffset to ratio.. for adding to spindle pos - plus a couple rotations
//so the spindle position isn't negative
spinangoffset = (toolang/360)+2;
 
//formual I found is for circumscribed - convert to inscribed - makes more sense.
scale=inscribedradius/cos(PI/numsides);
 
spinang = ((spindlepos + spinangoffset) - (int)(spindlepos + spinangoffset))*2*PI;
polyradius = (cos(PI/numsides)/cos((fmod(spinang, (2*PI/numsides))-PI/numsides)))*scale-cutterdiam/2;
 
//actual offsets applied - could be used for offset componant.
xoffset = cos(spinang)*polyradius * -1;
yoffset = sin(spinang)*polyradius;
 
//counts for use with eoffset functionality
xeoffset = xoffset / eoffsetscale;
yeoffset = yoffset / eoffsetscale;
 
spindlerad = spinang;