Light Duty CNC Router
 

The following describes the construction of a homemade CNC router based on drawer slides

NOTE: the following is for information purposes only.  Remember, you get what you pay for.  And, unlike many web sites on home CNC, I'm asking for no money for the "knowledge" contained here.  I will bear no responsibility for any loss or injury resulting from the somewhat crazy ideas below.  Use at your own risk.



  full picture
  Light duty mini-cnc router

The following describes a light duty mini-cnc router that I have recently constructed.  Although I do have a smaller mill CNC mini-mill, the need to machine larger sheet parts drove me to design this machine.  The machine is based around cheap drawer slides mounted on malimine covered particle boards.  As can be seen by it's light weight construction, this cnc machine is only intended for light duty machining, such as PCB milling & drilling, cutting modelling parts from balsa wood and plastics.  The machining volume of the machine is x=24", y=8" and z=5".  Most of the parts can be purchased from local hardware stores.  Lead screws, gear racks and stepper motors can be purchased from surplus dealers and gear & belt suppliers.

spindle

Above is a close up of the spindle head.  A light duty Makita laminate trimer is used as the spindle.  To the right is a 12V blower motor picked up at a local surplus store.  The blower is used to remove dust and to keep the tool cool when machining plastics.  A white LED light was added to help "see" when you are finding the zero.

y-axis

Here is a close-up of the y-axis lead screw.  The zero-backlash nut can be seen at the back of the picture.  The drawer slides have very little slack in the "side-ways" direction.  However, in the "verticle" direction, there is almost 1/16" movement.  This can be compensated by pre-loading the slides by using a pair of clamp spreaders before the assembly is fixed to the table.

y-axis

Here is a close-up view of the y-axis stepper motor and coupling mounts.  The teflon zero-backlash nut can be clearly seen in the centre of the picture.

z-axis

Above is the rear view of the Z-axis.  Springs are used to lighten the load on the z-axis stepper motor as the lead screws are not self locking.  Again, the two drawer slides were pre-loaded with clamps before the assembly was fixed to the front panel.  The X-axis drawer slide can also be seen. They are mounted 90 deg. from each other, again to prevent any slack.  These inner portion of these slides had to be cut to allow for a full 24" of motion on the X-axis.

x-axis

Viewing from the bottom side, the x-axis rack & pinion is shown.  The 24" rack is 32-pitch.  Luckly, the stepper motors came with the pinion gear.

controller

The three stepper motors are driven in unipolar fashion with Allegro UNC5804b driver chips.  Also visible are switches for both the laminate trimer and the blower motor.  An amp meter connected to the spindle motor allows for monitoring of the current draw.  5V and 12V for the whole machine is supplied from a surplus computer power supply.


created April 17th, 2004 by V.Chan.