<blockquote>Homemade modified CO2 Laser-Cutter K40 (40 Watt):
motivation for upgrading:
<li> bigger workspace </>
<li> air-assist</>
<li> opensource controller</>
<li> standalone device</>
<li> focus gauge</>
<li> Z-table</>

The project has finished now. Here are some details of my experiences:
<b>
workspace </b>
The workspace has been expanded from original dimensions (300 x 200 x 80) to 340 x 270 x 80 mm. Some "heavy" modifications were neccessary, i.e. removing some distance hoders on the Y-axis, removing the dust inlet, cutting the I-profile on the  rear side (see pictures), removing the ground plate distance holders, reposition both mirrors on the transport, changing the dual shaft coupling. Best practise for all this modifications: remove the whole transport for better working outside the main casing.
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0280.jpg" alt="" />
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0279-382x215.jpg" alt="" />
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0280_-382x215.jpg" alt="" />
Due to the bigger workspace, the endstop parts have to be repositioned. After some cutting experience, I no longer don't use the endstops now because the normal cutting workflow is: manually positioning the transport to the coordinates of the workpiece and start the job. With some pre/post gcodes you can first remember the actual (manual) position and return to this position afterwards. There was never a need of a homing process. The only thing you have to take care is not exceeding your workspace dimensions by your overall cutting rectangle. Anyway, here are some pictures of my endstops if someone want to mout them.
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0284-382x215.jpg" alt="" />
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0283-382x215.jpg" alt="" />
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0278-382x215.jpg" alt="" />

<b>air-assist</b>
The first attempt was to use a very cheap air pressure pump, typically used in some blood-pressure gauges. For operation this a electrical wiring was needed. <img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0275-382x215.jpg" alt="" />
<img src="http://johann.langhofer.net/wp-content/uploads/2016/11/DSC_0277-382x215.jpg" alt="" />




Controller: original Chinese-Japanese? m2NANO replaced by smoothieboard-X3
Workarea: expanded from (300 x 200 x 80) to (340 x 270 x 80 ) mm
Focusing added (double red-point laser with intersecting rays)
Air-assist added (pump from a blood-pressure gauge)
Software: Inkscape + LaserWeb3
Software update (much better): Inkscape + VisiCut </blockquote>
[supsystic-gallery id='6']

<blockquote>Homemade Laser-Cutter/engraver (6 Watt):
Controller: Arduino-Mega +Ramps 1.4
Workarea: DIN-A3
Laserdiode: Lasertack 445nm 6W 
Transport: Core-XY
Mechanical parts: BAUHAUS
Software: Inkscape + Universal GCode sender</blockquote>
[supsystic-gallery id='7']

<blockquote>Laser-Cutter pprojects done with GCC Spirit GLS (60 Watt)
Workarea: 960 x 610 x 180 mm</blockquote>
[supsystic-gallery id=4 position=center]