diff --git a/FlatCAMApp.py b/FlatCAMApp.py
index 9189e8f8..36c06ba9 100644
--- a/FlatCAMApp.py
+++ b/FlatCAMApp.py
@@ -1001,7 +1001,7 @@ class App(QtCore.QObject):
                                           'box, center_x, center_y, columns, combine, connect, contour, default, '
                                           'depthperpass, dia, diatol, dist, drilled_dias, drillz, dwelltime, '
                                           'extracut_length, '
-                                          'feedrate_z, grbl_11, grbl_laser, gridoffsety, gridx, gridy, has_offset, '
+                                          'feedrate_z, grbl_11, GRBL_laser, gridoffsety, gridx, gridy, has_offset, '
                                           'holes, hpgl, iso_type, line_xyz, margin, marlin, method, milled_dias, '
                                           'minoffset, name, offset, opt_type, order, outname, overlap, '
                                           'passes, postamble, pp, ppname_e, ppname_g, preamble, radius, ref, rest, '
@@ -1290,7 +1290,7 @@ class App(QtCore.QObject):
             # Excellon Options
             "excellon_drillz": self.ui.excellon_defaults_form.excellon_opt_group.cutz_entry,
             "excellon_travelz": self.ui.excellon_defaults_form.excellon_opt_group.travelz_entry,
-            "excellon_endz": self.ui.excellon_defaults_form.excellon_opt_group.eendz_entry,
+            "excellon_endz": self.ui.excellon_defaults_form.excellon_opt_group.endz_entry,
             "excellon_feedrate": self.ui.excellon_defaults_form.excellon_opt_group.feedrate_z_entry,
             "excellon_spindlespeed": self.ui.excellon_defaults_form.excellon_opt_group.spindlespeed_entry,
             "excellon_dwell": self.ui.excellon_defaults_form.excellon_opt_group.dwell_cb,
@@ -1368,14 +1368,14 @@ class App(QtCore.QObject):
             "geometry_ppname_g": self.ui.geometry_defaults_form.geometry_opt_group.pp_geometry_name_cb,
             "geometry_toolchange": self.ui.geometry_defaults_form.geometry_opt_group.toolchange_cb,
             "geometry_toolchangez": self.ui.geometry_defaults_form.geometry_opt_group.toolchangez_entry,
-            "geometry_endz": self.ui.geometry_defaults_form.geometry_opt_group.gendz_entry,
+            "geometry_endz": self.ui.geometry_defaults_form.geometry_opt_group.endz_entry,
             "geometry_depthperpass": self.ui.geometry_defaults_form.geometry_opt_group.depthperpass_entry,
             "geometry_multidepth": self.ui.geometry_defaults_form.geometry_opt_group.multidepth_cb,
 
             # Geometry Advanced Options
             "geometry_toolchangexy": self.ui.geometry_defaults_form.geometry_adv_opt_group.toolchangexy_entry,
             "geometry_startz": self.ui.geometry_defaults_form.geometry_adv_opt_group.gstartz_entry,
-            "geometry_feedrate_rapid": self.ui.geometry_defaults_form.geometry_adv_opt_group.cncfeedrate_rapid_entry,
+            "geometry_feedrate_rapid": self.ui.geometry_defaults_form.geometry_adv_opt_group.feedrate_rapid_entry,
             "geometry_extracut": self.ui.geometry_defaults_form.geometry_adv_opt_group.extracut_cb,
             "geometry_extracut_length": self.ui.geometry_defaults_form.geometry_adv_opt_group.e_cut_entry,
             "geometry_z_pdepth": self.ui.geometry_defaults_form.geometry_adv_opt_group.pdepth_entry,
@@ -2263,7 +2263,7 @@ class App(QtCore.QObject):
                                  'box', 'center_x', 'center_y', 'columns', 'combine', 'connect', 'contour', 'default',
                                  'depthperpass', 'dia', 'diatol', 'dist', 'drilled_dias', 'drillz',
                                  'dwelltime', 'extracut_length',
-                                 'feedrate_z', 'grbl_11', 'grbl_laser', 'gridoffsety', 'gridx', 'gridy',
+                                 'feedrate_z', 'grbl_11', 'GRBL_laser', 'gridoffsety', 'gridx', 'gridy',
                                  'has_offset', 'holes', 'hpgl', 'iso_type', 'line_xyz', 'margin', 'marlin', 'method',
                                  'milled_dias', 'minoffset', 'name', 'offset', 'opt_type', 'order',
                                  'outname', 'overlap', 'passes', 'postamble', 'pp', 'ppname_e', 'ppname_g',
diff --git a/FlatCAMObj.py b/FlatCAMObj.py
index fdc45475..f7faf045 100644
--- a/FlatCAMObj.py
+++ b/FlatCAMObj.py
@@ -2814,7 +2814,7 @@ class FlatCAMExcellon(FlatCAMObj, Excellon):
             "dwell": self.ui.dwell_cb,
             "dwelltime": self.ui.dwelltime_entry,
             "startz": self.ui.estartz_entry,
-            "endz": self.ui.eendz_entry,
+            "endz": self.ui.endz_entry,
             "ppname_e": self.ui.pp_excellon_name_cb,
             "z_pdepth": self.ui.pdepth_entry,
             "feedrate_probe": self.ui.feedrate_probe_entry,
@@ -3475,13 +3475,23 @@ class FlatCAMExcellon(FlatCAMObj, Excellon):
             except AttributeError:
                 pass
 
-            self.ui.travelzlabel.setText('%s:' % _("Focus Z"))
+            if 'marlin' in current_pp.lower():
+                self.ui.travelzlabel.setText('%s:' % _("Focus Z"))
+                self.ui.endz_label.show()
+                self.ui.endz_entry.show()
+            else:
+                self.ui.travelzlabel.hide()
+                self.ui.travelz_entry.hide()
+
+                self.ui.endz_label.hide()
+                self.ui.endz_entry.hide()
 
             try:
                 self.ui.frzlabel.hide()
                 self.ui.feedrate_z_entry.hide()
             except AttributeError:
                 pass
+
             self.ui.dwell_cb.hide()
             self.ui.dwelltime_entry.hide()
 
@@ -3503,6 +3513,12 @@ class FlatCAMExcellon(FlatCAMObj, Excellon):
 
             self.ui.travelzlabel.setText('%s:' % _('Travel Z'))
 
+            self.ui.travelzlabel.show()
+            self.ui.travelz_entry.show()
+
+            self.ui.endz_label.show()
+            self.ui.endz_entry.show()
+
             try:
                 self.ui.frzlabel.show()
                 self.ui.feedrate_z_entry.show()
@@ -4082,7 +4098,7 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             "travelz": self.ui.travelz_entry,
             "feedrate": self.ui.cncfeedrate_entry,
             "feedrate_z": self.ui.feedrate_z_entry,
-            "feedrate_rapid": self.ui.cncfeedrate_rapid_entry,
+            "feedrate_rapid": self.ui.feedrate_rapid_entry,
             "spindlespeed": self.ui.cncspindlespeed_entry,
             "dwell": self.ui.dwell_cb,
             "dwelltime": self.ui.dwelltime_entry,
@@ -4095,7 +4111,7 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             "extracut_length": self.ui.e_cut_entry,
             "toolchange": self.ui.toolchangeg_cb,
             "toolchangez": self.ui.toolchangez_entry,
-            "endz": self.ui.gendz_entry,
+            "endz": self.ui.endz_entry,
             "cnctooldia": self.ui.addtool_entry
         })
 
@@ -4225,10 +4241,10 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             self.ui.addtool_btn.hide()
             self.ui.copytool_btn.hide()
             self.ui.deltool_btn.hide()
-            # self.ui.endzlabel.hide()
-            # self.ui.gendz_entry.hide()
+            # self.ui.endz_label.hide()
+            # self.ui.endz_entry.hide()
             self.ui.fr_rapidlabel.hide()
-            self.ui.cncfeedrate_rapid_entry.hide()
+            self.ui.feedrate_rapid_entry.hide()
             self.ui.extracut_cb.hide()
             self.ui.e_cut_entry.hide()
             self.ui.pdepth_label.hide()
@@ -5228,10 +5244,10 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
 
         if 'marlin' in current_pp.lower() or 'custom' in current_pp.lower():
             self.ui.fr_rapidlabel.show()
-            self.ui.cncfeedrate_rapid_entry.show()
+            self.ui.feedrate_rapid_entry.show()
         else:
             self.ui.fr_rapidlabel.hide()
-            self.ui.cncfeedrate_rapid_entry.hide()
+            self.ui.feedrate_rapid_entry.hide()
 
         if 'laser' in current_pp.lower():
             self.ui.cutzlabel.hide()
@@ -5242,13 +5258,23 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             except AttributeError:
                 pass
 
-            self.ui.travelzlabel.setText('%s:' % _("Focus Z"))
+            if 'marlin' in current_pp.lower():
+                self.ui.travelzlabel.setText('%s:' % _("Focus Z"))
+                self.ui.endz_label.show()
+                self.ui.endz_entry.show()
+            else:
+                self.ui.travelzlabel.hide()
+                self.ui.travelz_entry.hide()
+
+                self.ui.endz_label.hide()
+                self.ui.endz_entry.hide()
 
             try:
                 self.ui.frzlabel.hide()
                 self.ui.feedrate_z_entry.hide()
             except AttributeError:
                 pass
+
             self.ui.dwell_cb.hide()
             self.ui.dwelltime_entry.hide()
 
@@ -5270,6 +5296,12 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
 
             self.ui.travelzlabel.setText('%s:' % _('Travel Z'))
 
+            self.ui.travelzlabel.show()
+            self.ui.travelz_entry.show()
+
+            self.ui.endz_label.show()
+            self.ui.endz_entry.show()
+
             try:
                 self.ui.frzlabel.show()
                 self.ui.feedrate_z_entry.show()
diff --git a/README.md b/README.md
index 38b752bc..f727c607 100644
--- a/README.md
+++ b/README.md
@@ -11,8 +11,9 @@ CAD program, and create G-Code for Isolation routing.
 
 8.02.2020
 
-- added a new preprocessor for using laser on a Marlin 3D printer named 'Marlin_laser'
+- added a new preprocessor for using laser on a Marlin 3D printer named 'Marlin_laser_use_Spindle_pin'
 - modified the Geometry UI when using laser preprocessors
+- added a new preprocessor file for using laser on a Marlin motion controller but with the laser connected to one of the FAN pins, named 'Marlin_laser_use_FAN_pin'
 
 5.02.2020
 
@@ -2772,7 +2773,7 @@ CAD program, and create G-Code for Isolation routing.
 - added options for trace segmentation that can be useful for auto-levelling (code snippet from Lei Zheng from a rejected pull request on FlatCAM https://bitbucket.org/realthunder/ )
 - added shortcut key 'L' for creating 'New Excellon' 
 - added shortcut key combo 'SHIFT+S' for Running a Script.
-- modified grbl_laser postprocessor file so it includes a Sxxxx command on the line with M03 (laser active) whenever a value is enter in the Spindlespeed entry field
+- modified GRBL_laser postprocessor file so it includes a Sxxxx command on the line with M03 (laser active) whenever a value is enter in the Spindlespeed entry field
 - remade the EDIT -> PREFERENCES window, the Excellon and Gerber sections. Created a new section named TOOLS
 
 26.01.2019
@@ -2780,7 +2781,7 @@ CAD program, and create G-Code for Isolation routing.
 - fixed grbl_11 postprocessor in linear_code() function
 - added icons to the Project Tab context menu
 - added new entries to the Canvas context menu (Copy, Delete, Edit/Save, Move, New Excellon, New Geometry, New Project)
-- fixed grbl_laser postprocessor file
+- fixed GRBL_laser postprocessor file
 - updated function for copy of an Excellon object for the case when the object has slots
 - updated FlatCAMExcellon.merge() function to work in case some (or all) of the merged objects have slots  
 
@@ -2800,8 +2801,8 @@ CAD program, and create G-Code for Isolation routing.
 - added the Copy entry to the Project context menu
 - made the functions behind Disable and Enable project context menu entries, non-threaded to fix a possible issue
 - added multiple object selection on Open ... and Import ... (idea and code snippet came from Travers Carter, BitBucket user https://bitbucket.org/travc/)
-- fixed 'grbl_laser' postprocessor bugs (missing functions)
-- fixed display geometry for 'grbl_laser' postprocessor
+- fixed 'GRBL_laser' postprocessor bugs (missing functions)
+- fixed display geometry for 'GRBL_laser' postprocessor
 - Excellon Editor - added possibility to create an linear drill array rotated at an custom angle
 - added the Edit and Properties entries to the Project context menu
 
diff --git a/camlib.py b/camlib.py
index 217e3ef5..e3002d8a 100644
--- a/camlib.py
+++ b/camlib.py
@@ -4067,6 +4067,13 @@ class CNCjob(Geometry):
                     command['Z'] = 1
                 else:
                     command['Z'] = 0
+
+            match_lsr_pos_2 = re.search(r"^(M10[6|7])", gline)
+            if match_lsr_pos_2:
+                if 'M107' in match_lsr_pos_2.group(1):
+                    command['Z'] = 1
+                else:
+                    command['Z'] = 0
         elif self.pp_solderpaste_name is not None:
             if 'Paste' in self.pp_solderpaste_name:
                 match_paste = re.search(r"X([\+-]?\d+.[\+-]?\d+)\s*Y([\+-]?\d+.[\+-]?\d+)", gline)
diff --git a/flatcamGUI/ObjectUI.py b/flatcamGUI/ObjectUI.py
index 0a08d60b..1bac450d 100644
--- a/flatcamGUI/ObjectUI.py
+++ b/flatcamGUI/ObjectUI.py
@@ -992,23 +992,23 @@ class ExcellonObjectUI(ObjectUI):
         self.grid3.addWidget(self.estartz_entry, 9, 1)
 
         # End move Z:
-        self.eendz_label = QtWidgets.QLabel('%s:' % _("End move Z"))
-        self.eendz_label.setToolTip(
+        self.endz_label = QtWidgets.QLabel('%s:' % _("End move Z"))
+        self.endz_label.setToolTip(
             _("Height of the tool after\n"
               "the last move at the end of the job.")
         )
-        self.eendz_entry = FCDoubleSpinner(callback=self.confirmation_message)
-        self.eendz_entry.set_precision(self.decimals)
+        self.endz_entry = FCDoubleSpinner(callback=self.confirmation_message)
+        self.endz_entry.set_precision(self.decimals)
 
         if machinist_setting == 0:
-            self.eendz_entry.set_range(0.0, 9999.9999)
+            self.endz_entry.set_range(0.0, 9999.9999)
         else:
-            self.eendz_entry.set_range(-9999.9999, 9999.9999)
+            self.endz_entry.set_range(-9999.9999, 9999.9999)
 
-        self.eendz_entry.setSingleStep(0.1)
+        self.endz_entry.setSingleStep(0.1)
 
-        self.grid3.addWidget(self.eendz_label, 11, 0)
-        self.grid3.addWidget(self.eendz_entry, 11, 1)
+        self.grid3.addWidget(self.endz_label, 11, 0)
+        self.grid3.addWidget(self.endz_entry, 11, 1)
 
         # Feedrate X-Y
         self.frxylabel = QtWidgets.QLabel('%s:' % _('Feedrate X-Y'))
@@ -1748,23 +1748,23 @@ class GeometryObjectUI(ObjectUI):
         # self.grid3.addWidget(self.gstartz_entry, 8, 1)
 
         # The Z value for the end move
-        self.endzlabel = QtWidgets.QLabel('%s:' % _('End move Z'))
-        self.endzlabel.setToolTip(
+        self.endz_label = QtWidgets.QLabel('%s:' % _('End move Z'))
+        self.endz_label.setToolTip(
             _("Height of the tool after\n"
               "the last move at the end of the job.")
         )
-        self.gendz_entry = FCDoubleSpinner(callback=self.confirmation_message)
-        self.gendz_entry.set_precision(self.decimals)
+        self.endz_entry = FCDoubleSpinner(callback=self.confirmation_message)
+        self.endz_entry.set_precision(self.decimals)
 
         if machinist_setting == 0:
-            self.gendz_entry.set_range(0, 9999.9999)
+            self.endz_entry.set_range(0, 9999.9999)
         else:
-            self.gendz_entry.set_range(-9999.9999, 9999.9999)
+            self.endz_entry.set_range(-9999.9999, 9999.9999)
 
-        self.gendz_entry.setSingleStep(0.1)
+        self.endz_entry.setSingleStep(0.1)
 
-        self.grid3.addWidget(self.endzlabel, 9, 0)
-        self.grid3.addWidget(self.gendz_entry, 9, 1)
+        self.grid3.addWidget(self.endz_label, 9, 0)
+        self.grid3.addWidget(self.endz_entry, 9, 1)
 
         # Feedrate X-Y
         self.frlabel = QtWidgets.QLabel('%s:' % _('Feedrate X-Y'))
@@ -1804,16 +1804,16 @@ class GeometryObjectUI(ObjectUI):
               "It is useful only for Marlin,\n"
               "ignore for any other cases.")
         )
-        self.cncfeedrate_rapid_entry = FCDoubleSpinner(callback=self.confirmation_message)
-        self.cncfeedrate_rapid_entry.set_precision(self.decimals)
-        self.cncfeedrate_rapid_entry.set_range(0, 99999.9999)
-        self.cncfeedrate_rapid_entry.setSingleStep(0.1)
+        self.feedrate_rapid_entry = FCDoubleSpinner(callback=self.confirmation_message)
+        self.feedrate_rapid_entry.set_precision(self.decimals)
+        self.feedrate_rapid_entry.set_range(0, 99999.9999)
+        self.feedrate_rapid_entry.setSingleStep(0.1)
 
         self.grid3.addWidget(self.fr_rapidlabel, 12, 0)
-        self.grid3.addWidget(self.cncfeedrate_rapid_entry, 12, 1)
+        self.grid3.addWidget(self.feedrate_rapid_entry, 12, 1)
         # default values is to hide
         self.fr_rapidlabel.hide()
-        self.cncfeedrate_rapid_entry.hide()
+        self.feedrate_rapid_entry.hide()
 
         # Cut over 1st point in path
         self.extracut_cb = FCCheckBox('%s:' % _('Re-cut'))
diff --git a/flatcamGUI/PreferencesUI.py b/flatcamGUI/PreferencesUI.py
index 92e06f69..33c23ab3 100644
--- a/flatcamGUI/PreferencesUI.py
+++ b/flatcamGUI/PreferencesUI.py
@@ -3128,21 +3128,21 @@ class ExcellonOptPrefGroupUI(OptionsGroupUI):
         grid2.addWidget(self.toolchangez_entry, 3, 1)
 
         # End Move Z
-        endzlabel = QtWidgets.QLabel('%s:' % _('End move Z'))
-        endzlabel.setToolTip(
+        endz_label = QtWidgets.QLabel('%s:' % _('End move Z'))
+        endz_label.setToolTip(
             _("Height of the tool after\n"
               "the last move at the end of the job.")
         )
-        self.eendz_entry = FCDoubleSpinner()
-        self.eendz_entry.set_precision(self.decimals)
+        self.endz_entry = FCDoubleSpinner()
+        self.endz_entry.set_precision(self.decimals)
 
         if machinist_setting == 0:
-            self.eendz_entry.set_range(0.0000, 9999.9999)
+            self.endz_entry.set_range(0.0000, 9999.9999)
         else:
-            self.eendz_entry.set_range(-9999.9999, 9999.9999)
+            self.endz_entry.set_range(-9999.9999, 9999.9999)
 
-        grid2.addWidget(endzlabel, 4, 0)
-        grid2.addWidget(self.eendz_entry, 4, 1)
+        grid2.addWidget(endz_label, 4, 0)
+        grid2.addWidget(self.endz_entry, 4, 1)
 
         # Feedrate Z
         frlabel = QtWidgets.QLabel('%s:' % _('Feedrate Z'))
@@ -4055,24 +4055,24 @@ class GeometryOptPrefGroupUI(OptionsGroupUI):
         grid1.addWidget(self.toolchangez_entry, 5, 1)
 
         # End move Z
-        endzlabel = QtWidgets.QLabel('%s:' % _('End move Z'))
-        endzlabel.setToolTip(
+        endz_label = QtWidgets.QLabel('%s:' % _('End move Z'))
+        endz_label.setToolTip(
             _("Height of the tool after\n"
               "the last move at the end of the job.")
         )
-        self.gendz_entry = FCDoubleSpinner()
+        self.endz_entry = FCDoubleSpinner()
 
         if machinist_setting == 0:
-            self.gendz_entry.set_range(0.000, 9999.9999)
+            self.endz_entry.set_range(0.000, 9999.9999)
         else:
-            self.gendz_entry.set_range(-9999.9999, 9999.9999)
+            self.endz_entry.set_range(-9999.9999, 9999.9999)
 
-        self.gendz_entry.set_precision(self.decimals)
-        self.gendz_entry.setSingleStep(0.1)
-        self.gendz_entry.setWrapping(True)
+        self.endz_entry.set_precision(self.decimals)
+        self.endz_entry.setSingleStep(0.1)
+        self.endz_entry.setWrapping(True)
 
-        grid1.addWidget(endzlabel, 6, 0)
-        grid1.addWidget(self.gendz_entry, 6, 1)
+        grid1.addWidget(endz_label, 6, 0)
+        grid1.addWidget(self.endz_entry, 6, 1)
 
         # Feedrate X-Y
         frlabel = QtWidgets.QLabel('%s:' % _('Feedrate X-Y'))
@@ -4207,14 +4207,14 @@ class GeometryAdvOptPrefGroupUI(OptionsGroupUI):
               "It is useful only for Marlin,\n"
               "ignore for any other cases.")
         )
-        self.cncfeedrate_rapid_entry = FCDoubleSpinner()
-        self.cncfeedrate_rapid_entry.set_range(0, 99999.9999)
-        self.cncfeedrate_rapid_entry.set_precision(self.decimals)
-        self.cncfeedrate_rapid_entry.setSingleStep(0.1)
-        self.cncfeedrate_rapid_entry.setWrapping(True)
+        self.feedrate_rapid_entry = FCDoubleSpinner()
+        self.feedrate_rapid_entry.set_range(0, 99999.9999)
+        self.feedrate_rapid_entry.set_precision(self.decimals)
+        self.feedrate_rapid_entry.setSingleStep(0.1)
+        self.feedrate_rapid_entry.setWrapping(True)
 
         grid1.addWidget(fr_rapid_label, 4, 0)
-        grid1.addWidget(self.cncfeedrate_rapid_entry, 4, 1)
+        grid1.addWidget(self.feedrate_rapid_entry, 4, 1)
 
         # End move extra cut
         self.extracut_cb = FCCheckBox('%s' % _('Re-cut'))
diff --git a/preprocessors/Berta_CNC.py b/preprocessors/Berta_CNC.py
index 784f0cd0..6da9d5d6 100644
--- a/preprocessors/Berta_CNC.py
+++ b/preprocessors/Berta_CNC.py
@@ -22,7 +22,7 @@ class Berta_CNC(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = '(This preprocessor is used with a BERTA CNC router.)\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
@@ -80,7 +80,7 @@ class Berta_CNC(FlatCAMPostProc):
         gcode += 'G54\n'
         gcode += 'G0\n'
         gcode += '(Berta)\n'
-        gcode += 'G94\n'
+        gcode += 'G94'
 
         return gcode
 
diff --git a/preprocessors/grbl_laser.py b/preprocessors/GRBL_laser.py
similarity index 92%
rename from preprocessors/grbl_laser.py
rename to preprocessors/GRBL_laser.py
index a3f4da7d..6c7a7c34 100644
--- a/preprocessors/grbl_laser.py
+++ b/preprocessors/GRBL_laser.py
@@ -12,7 +12,7 @@ from FlatCAMPostProc import *
 # is compatible with almost any version of Grbl.
 
 
-class grbl_laser(FlatCAMPostProc):
+class GRBL_laser(FlatCAMPostProc):
 
     include_header = True
     coordinate_format = "%.*f"
@@ -20,7 +20,8 @@ class grbl_laser(FlatCAMPostProc):
 
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
-        gcode = ''
+        gcode = '(This preprocessor is used with a motion controller loaded with GRBL firmware. )\n'
+        gcode += '(It is for the case when it is used together with a LASER connected on the SPINDLE connector.)\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
@@ -55,7 +56,7 @@ class grbl_laser(FlatCAMPostProc):
         return ''
 
     def lift_code(self, p):
-        return 'M05 S0'
+        return 'M5'
 
     def down_code(self, p):
         sdir = {'CW': 'M03', 'CCW': 'M04'}[p.spindledir]
@@ -68,7 +69,7 @@ class grbl_laser(FlatCAMPostProc):
         return ''
 
     def up_to_zero_code(self, p):
-        return 'M05'
+        return 'M5'
 
     def position_code(self, p):
         return ('X' + self.coordinate_format + ' Y' + self.coordinate_format) % \
@@ -106,4 +107,4 @@ class grbl_laser(FlatCAMPostProc):
         return ''
 
     def spindle_stop_code(self, p):
-        return 'M05'
+        return 'M5'
diff --git a/preprocessors/ISEL_CNC.py b/preprocessors/ISEL_CNC.py
index 7753669c..c32b4272 100644
--- a/preprocessors/ISEL_CNC.py
+++ b/preprocessors/ISEL_CNC.py
@@ -17,7 +17,7 @@ class ISEL_CNC(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = '(This preprocessor is used with a ISEL CNC router.)\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
diff --git a/preprocessors/ISEL_ICP_CNC.py b/preprocessors/ISEL_ICP_CNC.py
index 5898437e..ca820d8f 100644
--- a/preprocessors/ISEL_ICP_CNC.py
+++ b/preprocessors/ISEL_ICP_CNC.py
@@ -15,7 +15,7 @@ class ISEL_ICP_CNC(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = '; This preprocessor is used with a ISEL ICP CNC router.\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
diff --git a/preprocessors/Marlin.py b/preprocessors/Marlin.py
index 65428e8f..128d1937 100644
--- a/preprocessors/Marlin.py
+++ b/preprocessors/Marlin.py
@@ -66,8 +66,7 @@ class Marlin(FlatCAMPostProc):
         gcode += ';Spindle Speed: ' + str(p['spindlespeed']) + ' RPM' + '\n' + '\n'
 
         gcode += ('G20' if p.units.upper() == 'IN' else 'G21') + "\n"
-        gcode += 'G90\n'
-        gcode += 'G94\n'
+        gcode += 'G90'
 
         return gcode
 
@@ -219,8 +218,11 @@ G0 Z{z_toolchange}
             return sdir
 
     def dwell_code(self, p):
+        gcode = 'G4 P' + str(p.dwelltime)
         if p.dwelltime:
-            return 'G4 P' + str(p.dwelltime)
+            return gcode
 
     def spindle_stop_code(self, p):
-        return 'M5'
+        gcode = 'M400\n'
+        gcode += 'M5'
+        return gcode
diff --git a/preprocessors/Marlin_laser_use_FAN_pin.py b/preprocessors/Marlin_laser_use_FAN_pin.py
new file mode 100644
index 00000000..36d958a4
--- /dev/null
+++ b/preprocessors/Marlin_laser_use_FAN_pin.py
@@ -0,0 +1,120 @@
+# ##########################################################
+# FlatCAM: 2D Post-processing for Manufacturing            #
+# Website:      http://flatcam.org                         #
+# File Author:  Marius Adrian Stanciu (c)                  #
+# Date:         8-Feb-2020                                 #
+# License:      MIT Licence                                #
+# ##########################################################
+
+from FlatCAMPostProc import *
+
+
+class Marlin_laser_use_FAN_pin(FlatCAMPostProc):
+
+    include_header = True
+    coordinate_format = "%.*f"
+    feedrate_format = '%.*f'
+    feedrate_rapid_format = feedrate_format
+
+    def start_code(self, p):
+        units = ' ' + str(p['units']).lower()
+        coords_xy = p['xy_toolchange']
+        gcode = ';This preprocessor is used with a motion controller loaded with MARLIN firmware.\n'
+        gcode += ';It is for the case when it is used together with a LASER connected on one of the FAN pins.\n\n'
+
+        xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
+        xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
+        ymin = '%.*f' % (p.coords_decimals, p['options']['ymin'])
+        ymax = '%.*f' % (p.coords_decimals, p['options']['ymax'])
+
+        gcode += ';Feedrate: ' + str(p['feedrate']) + units + '/min' + '\n'
+        gcode += ';Feedrate rapids: ' + str(p['feedrate_rapid']) + units + '/min' + '\n\n'
+
+        gcode += ';Z Focus: ' + str(p['z_move']) + units + '\n'
+
+        gcode += ';Steps per circle: ' + str(p['steps_per_circle']) + '\n'
+
+        if str(p['options']['type']) == 'Excellon' or str(p['options']['type']) == 'Excellon Geometry':
+            gcode += ';Preprocessor Excellon: ' + str(p['pp_excellon_name']) + '\n'
+        else:
+            gcode += ';Preprocessor Geometry: ' + str(p['pp_geometry_name']) + '\n' + '\n'
+
+        gcode += ';X range: ' + '{: >9s}'.format(xmin) + ' ... ' + '{: >9s}'.format(xmax) + ' ' + units + '\n'
+        gcode += ';Y range: ' + '{: >9s}'.format(ymin) + ' ... ' + '{: >9s}'.format(ymax) + ' ' + units + '\n\n'
+
+        gcode += ';Laser Power (Spindle Speed): ' + str(p['spindlespeed']) + '\n' + '\n'
+
+        gcode += ('G20' if p.units.upper() == 'IN' else 'G21') + "\n"
+        gcode += 'G90'
+
+        return gcode
+
+    def startz_code(self, p):
+        if p.startz is not None:
+            return 'G0 Z' + self.coordinate_format % (p.coords_decimals, p.z_move)
+        else:
+            return ''
+
+    def lift_code(self, p):
+        gcode = 'M400\n'
+        gcode += 'M107'
+        return gcode
+
+    def down_code(self, p):
+        if p.spindlespeed:
+            return '%s S%s' % ('M106', str(p.spindlespeed))
+        else:
+            return 'M106'
+
+    def toolchange_code(self, p):
+        return ''
+
+    def up_to_zero_code(self, p):
+        gcode = 'M400\n'
+        gcode += 'M107'
+        return gcode
+
+    def position_code(self, p):
+        return ('X' + self.coordinate_format + ' Y' + self.coordinate_format) % \
+               (p.coords_decimals, p.x, p.coords_decimals, p.y)
+
+    def rapid_code(self, p):
+        return ('G0 ' + self.position_code(p)).format(**p) + " " + self.feedrate_rapid_code(p)
+
+    def linear_code(self, p):
+        return ('G1 ' + self.position_code(p)).format(**p) + " " + self.inline_feedrate_code(p)
+
+    def end_code(self, p):
+        coords_xy = p['xy_toolchange']
+        gcode = ('G0 Z' + self.feedrate_format % (p.fr_decimals, p.z_end) + " " + self.feedrate_rapid_code(p) + "\n")
+
+        if coords_xy is not None:
+            gcode += 'G0 X{x} Y{y}'.format(x=coords_xy[0], y=coords_xy[1]) + " " + self.feedrate_rapid_code(p) + "\n"
+
+        return gcode
+
+    def feedrate_code(self, p):
+        return 'G1 F' + str(self.feedrate_format % (p.fr_decimals, p.feedrate))
+
+    def z_feedrate_code(self, p):
+        return 'G1 F' + str(self.feedrate_format % (p.fr_decimals, p.z_feedrate))
+
+    def inline_feedrate_code(self, p):
+        return 'F' + self.feedrate_format % (p.fr_decimals, p.feedrate)
+
+    def feedrate_rapid_code(self, p):
+        return 'F' + self.feedrate_rapid_format % (p.fr_decimals, p.feedrate_rapid)
+
+    def spindle_code(self, p):
+        if p.spindlespeed:
+            return '%s S%s' % ('M106 ', str(p.spindlespeed))
+        else:
+            return 'M106'
+
+    def dwell_code(self, p):
+        return ''
+
+    def spindle_stop_code(self, p):
+        gcode = 'M400\n'
+        gcode += 'M107'
+        return gcode
diff --git a/preprocessors/Marlin_laser.py b/preprocessors/Marlin_laser_use_Spindle_pin.py
similarity index 93%
rename from preprocessors/Marlin_laser.py
rename to preprocessors/Marlin_laser_use_Spindle_pin.py
index e67e9bb5..a1f7fb1e 100644
--- a/preprocessors/Marlin_laser.py
+++ b/preprocessors/Marlin_laser_use_Spindle_pin.py
@@ -9,7 +9,7 @@
 from FlatCAMPostProc import *
 
 
-class Marlin_laser(FlatCAMPostProc):
+class Marlin_laser_use_Spindle_pin(FlatCAMPostProc):
 
     include_header = True
     coordinate_format = "%.*f"
@@ -19,7 +19,8 @@ class Marlin_laser(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = ';This preprocessor is used with a motion controller loaded with MARLIN firmware.\n'
+        gcode += ';It is for the case when it is used together with a LASER connected on the SPINDLE connector.\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
@@ -44,8 +45,7 @@ class Marlin_laser(FlatCAMPostProc):
         gcode += ';Laser Power (Spindle Speed): ' + str(p['spindlespeed']) + '\n' + '\n'
 
         gcode += ('G20' if p.units.upper() == 'IN' else 'G21') + "\n"
-        gcode += 'G90\n'
-        gcode += 'G94'
+        gcode += 'G90'
 
         return gcode
 
@@ -57,7 +57,7 @@ class Marlin_laser(FlatCAMPostProc):
 
     def lift_code(self, p):
         gcode = 'M400\n'
-        gcode += 'M5 S0'
+        gcode += 'M5'
         return gcode
 
     def down_code(self, p):
diff --git a/preprocessors/Repetier.py b/preprocessors/Repetier.py
index c149513c..fa760dfd 100644
--- a/preprocessors/Repetier.py
+++ b/preprocessors/Repetier.py
@@ -19,7 +19,7 @@ class Repetier(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = ';This preprocessor is used with a motion controller loaded with REPETIER firmware.\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
diff --git a/preprocessors/Toolchange_Probe_MACH3.py b/preprocessors/Toolchange_Probe_MACH3.py
index 38371154..424848f8 100644
--- a/preprocessors/Toolchange_Probe_MACH3.py
+++ b/preprocessors/Toolchange_Probe_MACH3.py
@@ -18,7 +18,7 @@ class Toolchange_Probe_MACH3(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = '(This preprocessor is used with MACH3 with probing height.)\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
diff --git a/preprocessors/default.py b/preprocessors/default.py
index e57ed812..ce4bd85b 100644
--- a/preprocessors/default.py
+++ b/preprocessors/default.py
@@ -18,7 +18,8 @@ class default(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = '(This preprocessor is the default preprocessor used by FlatCAM.)\n'
+        gcode += '(It is made to work with MACH3 compatible motion controllers.)\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])
@@ -66,7 +67,7 @@ class default(FlatCAMPostProc):
 
         gcode += ('G20\n' if p.units.upper() == 'IN' else 'G21\n')
         gcode += 'G90\n'
-        gcode += 'G94\n'
+        gcode += 'G94'
 
         return gcode
 
diff --git a/preprocessors/grbl_11.py b/preprocessors/grbl_11.py
index 9a53c0ab..a8a03b88 100644
--- a/preprocessors/grbl_11.py
+++ b/preprocessors/grbl_11.py
@@ -18,7 +18,8 @@ class grbl_11(FlatCAMPostProc):
     def start_code(self, p):
         units = ' ' + str(p['units']).lower()
         coords_xy = p['xy_toolchange']
-        gcode = ''
+        gcode = '(This preprocessor is used with a motion controller loaded with GRBL firmware.)\n'
+        gcode += '(It is configured to be compatible with almost any version of GRBL firmware.)\n\n'
 
         xmin = '%.*f' % (p.coords_decimals, p['options']['xmin'])
         xmax = '%.*f' % (p.coords_decimals, p['options']['xmax'])