Desktop CNC Laser Cutter

     
                 
 

Introduction:
  I built this desktop cnc laser cutter just for fun. I wanted to play around with stepper motors since I have a lot lying around that was salvaged from numerous machines. I then stumbled upon www.pc-control.co.uk, got myself the stepper pack and started playing with the software included on the cd.  There is a very nice tutorial on how to use the included software, together with a few pointers on writing your own. After writing a few codes in Visual Studio 2010, I wanted to try it out on some of my other steppers, and it worked! Thus the idea of a 2 axis cnc machine...with a laser engraver/cutter attached to it.

   
                 
     
                 
 

Construction:
   The size of the machine was limited to what parts I had at my disposal, and that the stepperbee can only operate up to 500mA.  This is my first cnc so I had to keep it simple, and that it was not going to move heavy objects nor have a high torque in any direction. I used skate board bearings for the bearings, 2x 8mm silver steel rods from a scanner and 2x 8mm silver steel rods from printer cartridges (because I only had so many broken scanners). All the aluminium came from a scrap yard, and the steel square tubing from local steel store.

   
                 
     
                 
 

    The 2 stepper motors came from 2 scanners, and their drive belts together with their gears were used. Didn't feel the need in changing something that were already there, and working. I only had to fasten the drive belt a little as one can see from the photo above, on the bottom of the Y axis bed. The glass top is only there for cosmetic reasons, I though it would give a nice finishing touch to the metal and aluminium

   
                 
     
                 
       The next stage was to construct the x-axis, which you can see above. The same principles were used as had been used for the y-axis    
                   
       
                   
        It was now time for a laser test, (above). The picture doesn't do any justice to the whole blue effect that truly fills the room.    
                   
   
                   
   

Laser:
    Its a 445nm 1000mW blue laser diode, driven at 440mA to get power at around 300-400mW, and is from a dvd writer or blu-ray writer. A relay is used with one of the digital outputs from the stepperbee, which then switches on the laser and acts as the 3rd axis, so to speak. As you can see the laser cuts neatly through paper in the photos above. Great care is taken when operating the laser since it is very dangerous and even the slightest reflection off a shiny surface can cause blindness. This is why I always wear safety goggles specifically designed for 200-560nm wavelengths (445nm from the laser), and always use a book or something between the glass bed and the paper.

   
                   
   
           
                   
   

Software:
   Using the included DLL file and a tutorial on the functions at hand, I wrote a little VB program. At the time, the program could only instruct the steppers to do horizontal, vertical and 45degree lines. In order to write text with the laser I had to create my own font, figures 9 & 10, and also threw in a few simple drawings :-)
    In order to get the steppers to move in mm and not steps, a small test was done to see how long in mm a 1000 steps (for example) would be, and then derive a formula to use in the program.  After successfully getting the alphabet 100% correct, the first sentences were cut on a 'going away' card that was made from some kind of paper, for someone at the office the following day (photos above).

   
                   
   

Final Product:
   Just a few photos below with the latest modifications made to the machine. Both Y and X axis have got limit switches now. This enables the bed and laser to go to a home position.

   
                   
       
                   
       
                   
       
                   
       
                   
       
                   
       
                   
        The Stepper Bee which allows the motors and other devices to be controlled from a PC's USB port can be seen above sitting nice and snugly on the bottom right corner    
                   
                   
    Overall picture of the machine can be seen below    
                   
   
                   
    Philip B, Pretoria, South Africa    
                   
                   
                   
                   
    More info on Stepper Bee  and Stepper Pack    
                   
                   
 

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