diff --git a/slice_test.html b/slice_test.html
index 418d42b..2160d7f 100644
--- a/slice_test.html
+++ b/slice_test.html
@@ -44,7 +44,6 @@ var printer = new D3D.Printer({
 	"printer.heatup.enabled": true, 
 	"printer.heatup.temperature": 180, 
 	"printer.retraction.amount": 3, 
-	"printer.retraction.enabled": false, 
 	"printer.retraction.minDistance": 5, 
 	"printer.retraction.speed": 50, 
 	"printer.screenToMillimeterScale": 0.3, //????
@@ -54,6 +53,7 @@ var printer = new D3D.Printer({
 	"printer.type": "ultimaker", 
 	"printer.useSubLayers": true, //wat is dit?
 
+	"printer.retraction.enabled": true, 
 	"printer.speed": 50, 
 	"printer.wallThickness": 0.4, //nozzle
 	"printer.layerHeight": 0.3, 
diff --git a/src/box.js b/src/box.js
index 520db93..6a5751e 100644
--- a/src/box.js
+++ b/src/box.js
@@ -16,9 +16,8 @@ D3D.Box = function (localIp) {
 	"use strict";
 	var self = this;
 
-	this.batchSize = 1024 * 10;					//10kb
-	this.maxBufferSize = 1024 * 1024 * 2;		//2mb
-	this.bytesSend = 0;
+	this.batchSize = 512;
+	this.maxBufferedLines = 4096;
 
 	this.localIp = localIp;
 	this.api = "http://" + localIp + "/d3dapi/";
@@ -61,7 +60,7 @@ D3D.Box.prototype.update = function () {
 	//Bij error wordt gelijk zelfde data opnieuw gestuurd
 	//Als DoodleBox ontkoppeld wordt komt er een error in de loop waardoor pagina breekt en ververst moet worden
 
-	if (this.printBatches.length > 0 && (this.status["buffered_lines"]*30 + this.batchSize) <= this.maxBufferSize) {
+	if (this.printBatches.length > 0 && (this.status["buffered_lines"] + this.batchSize) <= this.maxBufferedLines) {
 	//if (this.printBatches.length > 0 ) {
 		this.printBatch();
 	}
@@ -89,9 +88,12 @@ D3D.Box.prototype.print = function (gcode) {
 
 	this.currentBatch = 0;
 
+	//clone gcode to remove array links
+	gcode = gcode.clone();
+
 	//gcode split in batches
-	for (var i = 0; i < gcode.length; i += this.batchSize) {
-		var gcodeBatch = gcode.substring(i, Math.min(i + this.batchSize, gcode.length));
+	while (gcode.length > 0) {
+		var gcodeBatch = gcode.splice(0, Math.min(this.batchSize, gcode.length));
 		this.printBatches.push(gcodeBatch);
 	}
 
@@ -106,7 +108,7 @@ D3D.Box.prototype.printBatch = function () {
 	this.setPrinterPrint({
 		"start": ((this.currentBatch === 0) ? true : false), 
 		"first": ((this.currentBatch === 0) ? true : false), 
-		"gcode": gcode
+		"gcode": gcode.join("\n")
 	}, function (data) {
 		console.log("batch sent: " + self.currentBatch, data);
 
diff --git a/src/printer.js b/src/printer.js
index 98e3885..a3bdfd1 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -29,7 +29,7 @@ D3D.Printer.prototype.getStartCode = function () {
 	var gcode = this.config["printer.startcode"];
 	gcode = this.subsituteVariables(gcode);
 
-	return gcode;
+	return gcode.split("\n");
 };
 D3D.Printer.prototype.getEndCode = function () {
 	"use strict";
@@ -37,7 +37,7 @@ D3D.Printer.prototype.getEndCode = function () {
 	var gcode = this.config["printer.endcode"];
 	gcode = this.subsituteVariables(gcode);
 
-	return gcode;
+	return gcode.split("\n");
 };
 D3D.Printer.prototype.subsituteVariables = function (gcode) {
 	"use strict";
diff --git a/src/slicer.js b/src/slicer.js
index 5dce187..343700c 100644
--- a/src/slicer.js
+++ b/src/slicer.js
@@ -431,8 +431,8 @@ D3D.Slicer.prototype.dataToGcode = function (data, printer) {
 					}
 				}
 				else {
-					var a = new THREE.Vector2().set(point.X, point.Y);
-					var b = new THREE.Vector2().set(previousPoint.X, previousPoint.Y);
+					var a = new THREE.Vector2(point.X, point.Y);
+					var b = new THREE.Vector2(previousPoint.X, previousPoint.Y);
 					var lineLength = a.distanceTo(b);
 
 					extruder += lineLength * wallThickness * layerHeight / filamentSurfaceArea * flowRate;
@@ -452,7 +452,7 @@ D3D.Slicer.prototype.dataToGcode = function (data, printer) {
 		return gcode;
 	}
 
-	var gcode = printer.getStartCode().split("\n");
+	var gcode = printer.getStartCode();
 
 	var extruder = 0.0;
 	var speed = firstLayerSlow ? (bottomSpeed*60).toFixed(3) : (normalSpeed*60).toFixed(3);
@@ -480,7 +480,9 @@ D3D.Slicer.prototype.dataToGcode = function (data, printer) {
 		}
 	}
 
-	return gcode.join("\n") + "\n" + printer.getEndCode();
+	gcode = gcode.concat(printer.getEndCode());
+
+	return gcode;
 };
 //only for debug purposes
 D3D.Slicer.prototype.drawPaths = function (printer, min, max) {
diff --git a/src/utils.js b/src/utils.js
index d4bc3bf..74dae39 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -68,4 +68,15 @@ function downloadFile (file, data) {
 	button.download = file;
 	button.href = window.URL.createObjectURL(blob);
 	button.click();
+}
+
+Array.prototype.clone = function () {
+	"use strict";
+	var array = [];
+
+	for (var i = 0; i < this.length; i ++) {
+		array[i] = this[i];
+	}
+
+	return array;
 }
\ No newline at end of file