Monday, November 21, 2016

Final Configuration for UM2 Laser Cutting Upgrade

I have been distracted by some other tasks but I have finally finished the configuration of my laser upgrade for my Ultimaker 2+ 3D Printer.  I don't really have a compelling requirement for a laser cutter though I am going to try do some of my own PCB's to save time over the shipment of tests from China.  I am also, as always, looking forward to playing with the laser!

My "user" requirements for installing the upgrade were two fold:  1st, the kit has to go onto my printer and come off of it quickly and easily as the primary use of the Ultimaker 2 is still as a printer! 2nd, I wanted to be able to use as much of the print area of the Ultimaker 2 as possible for laser cutting.  The rest of this post shows the final result.  There is detail that I am not covering here in previous posts on this topic.

This is the completed upgrade.  The laser that I am using is from J Tech Photonics purchased from RoboSavvy.  The specific laser that I bought was the, you guessed it, most powerful one available, the 3.8w Laser with the 2.5amp driver.  It is important to recognise that a 3.8w diode laser is not going to be competing with more powerful dedicated laser cutters!  But still, way powerful enough for what I need (err, want).  The door is also from J Tech Photonics with some printed hardware that I added.  Looking closely you may question why I mounted it the way that I did.  Measure twice and cut once was not how I did the door.

Here is the laser mounted on the extruder assembly of my printer using the mount that I designed and that is available on Thingiverse.  It slips underneath three of the bolts that tie the extruder together and is both sturdy and easy to get on and off.  At the top of the picture you can see the connections for the fan and for the laser.

The driver for the laser is to the rear of this picture.  It is connected to the following (all but one to the rear):
  1. Power supply
  2. Laser
  3. Laser Cooling Fan
  4. Printer Fan Power (via a voltage divider)
  5. Remote reset button
  6. End-stop Switch on Door for Safety Interlock
I have my printers standing on legs that I designed that provide some room under the printer for a tray and also give a little vibration protection as they are cushioned with a flexifill shock absorber.  In the foreground is the remote reset button for the driver as well as a switch that controls how the fan is connection.  Forward means the fan will work normally and backward means the fan power is being redirected to the driver as input to its PWM sensing logic.

The presence of the safety glass door is detected by an end stop switch that prevents the laser from operating when it is open.  Triggering this end stop with the laser running means that the driver needs to be reset...which is why the reset button is conveniently located where it is now.

I am leaving the glass on the build platform with sheets of MDF on top of the glass.  The little black prints keep the wood platform in place.


Finally, I wanted a way to be able to activate the laser without having the door installed.  I went with this approach as I really did not want a switch that could be forgotten.  I see this as being a little bit easier to remember.


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2 comments:

  1. Hi, sounds very interesting to me! But I wonder how you do create the G-Code für cutting/engraving. What software do you use?

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    1. There is software out there that will drive this but I hacked something in Python to meet my immediate need. It is not something that I can share though!

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