Generate G-code for trochoid toolpath on X-axis

xtrochoid.js

// usage: cscript xtrochoid.js //Nologo > myFile.nc
// alter the below variables to taste!
// based on code from https://gist.github.com/r24y/48285ef648803d195740
//
// program will output trochoidal cut in +X direction
// creating D shapes from -120 to 105 degrees
// feed to MAXFEED outside of arc

var TOOLDIA = 0.375; // Tool diameter
var STEPOVER = 0.0375; // Stepover (try 10% of tool diameter)
var CUTFEED = 54.3; // Cutting feed
var MAXFEED = 150.; // Feed for positioning moves
var LL = [-0.06,-0.93]; // slot lower left corner
var UR = [24.2,-0.075]; // slot upper right corner
var DEC_PLACES=4; // number of decimal places (for rounding)

// CODE STARTS HERE

// Display settings
WScript.Echo("(" + WScript.ScriptName + " Settings:) ");
WScript.Echo("(TOOLDIA = " + TOOLDIA + ") ");
WScript.Echo("(STEPOVER = " + STEPOVER + ") ");
WScript.Echo("(CUTFEED = " + CUTFEED + ") ");
WScript.Echo("(LL = [" + LL[0] + "," + LL[1] + "]) ");
WScript.Echo("(UR = [" + UR[0] + "," + UR[1] + "]) ");
WScript.Echo("(DEC_PLACES = " + DEC_PLACES + ") ");

// Timestamp -- from https://stackoverflow.com/questions/10632346/how-to-format-a-date-in-mm-dd-yyyy-hhmmss-format-in-javascript
Number.prototype.padLeft = function(base,chr){
    var  len = (String(base || 10).length - String(this).length)+1;
    return len > 0? new Array(len).join(chr || '0')+this : this;
}
// usage
//=> 3..padLeft() => '03'
//=> 3..padLeft(100,'-') => '--3' 
var d = new Date,
    dformat = [d.getFullYear(),
			   (d.getMonth()+1).padLeft(),
               (d.getDate()).padLeft()].join('-')+' '+
              [d.getHours().padLeft(),
               d.getMinutes().padLeft(),
               d.getSeconds().padLeft()].join(':');			   
WScript.Echo("(" + dformat + ")");

// WScript.Echo("RAD = " + RAD); // DEBUG
// WScript.Echo("ORIGIN = (" + ORIGIN[0].toFixed(DEC_PLACES) + "," + ORIGIN[1].toFixed(DEC_PLACES) + ")"); // DEBUG

// WScript.Echo("0°: (" + Math.cos(0).toFixed(DEC_PLACES) + ", " + Math.sin(0).toFixed(DEC_PLACES) + ")" ); // DEBUG
// WScript.Echo("90°: (" + Math.cos(90/360*2*Math.PI).toFixed(DEC_PLACES) + ", " + Math.sin(90/360*2*Math.PI).toFixed(DEC_PLACES) + ")" ); // DEBUG
// WScript.Echo("180°: (" + Math.cos(180/360*2*Math.PI).toFixed(DEC_PLACES) + ", " + Math.sin(180/360*2*Math.PI).toFixed(DEC_PLACES) + ")" ); // DEBUG
// WScript.Echo("270°: (" + Math.cos(270/360*2*Math.PI).toFixed(DEC_PLACES) + ", " + Math.sin(270/360*2*Math.PI).toFixed(DEC_PLACES) + ")" ); // DEBUG

var RAD = (UR[1]-LL[1]-TOOLDIA)/2;
var ORIGIN = [LL[0]-RAD,(LL[1]+UR[1])/2];
var theta, x, y, start, end;

start = -2*Math.PI/3; // -120 deg
end = 7*Math.PI/12; // 105 deg

for(;ORIGIN[0]<=(UR[0]+STEPOVER);ORIGIN[0]+=STEPOVER) {
	// WScript.Echo("ORIGIN = (" + ORIGIN[0].toFixed(DEC_PLACES) + "," + ORIGIN[1].toFixed(DEC_PLACES) + ")"); // DEBUG
	theta = start;
	x = ORIGIN[0]+Math.cos(theta)*RAD;
	y = ORIGIN[1]+Math.sin(theta)*RAD;
	WScript.Echo(
		"G01 X"+x.toFixed(DEC_PLACES).replace(/0+$/, "")
		+" Y"+y.toFixed(DEC_PLACES).replace(/0+$/, "")
		+" F"+MAXFEED.toFixed(DEC_PLACES).replace(/0+$/, "")+" "
	);
	
	theta = end;
	x = ORIGIN[0]+Math.cos(theta)*RAD;
	y = ORIGIN[1]+Math.sin(theta)*RAD;
	WScript.Echo(
		"G03 X"+x.toFixed(DEC_PLACES).replace(/0+$/, "")
		+" Y"+y.toFixed(DEC_PLACES).replace(/0+$/, "")
		+" I"+ORIGIN[0].toFixed(DEC_PLACES).replace(/0+$/, "")
		+" J"+ORIGIN[1].toFixed(DEC_PLACES).replace(/0+$/, "")
		+" F"+CUTFEED.toFixed(DEC_PLACES).replace(/0+$/, "")+" "
	);
}
WScript.Echo("(End " + WScript.ScriptName + ") ");