Saturday, January 30, 2010

And so it begins...

I originally wanted to build a nice desktop 3 axis CNC machine for milling circuit boards but after following the RepRap project and seeing a MakerBot in action I knew I just had to build a 3D printer. The trick was to build it with enough rigidity for accurate CNC machining in order to get the best of both worlds. I also wanted to use as many off the shelf parts as possible to reduce the amount of custom machining/fabrication.

The build area measures 150mm x 150mm x 75mm but since it is a modular design I will be able to increase the travel of any one axis without completely rebuilding the machine.

I quickly made a list of requirements:

3D printing
accurate CNC machining
swappable toolheads
modular construction
heated build platform
small footprint
low cost

When I'm finished building it I'll post an entire build tutorial on Instructables.


So here's the parts I've gathered so far-


 
These two 80/20 Aluminum extrusions will form the main chassis components- they're quite heavy.


















 
 

The electronics (stepper driver boards, motherboard, end stops, extruder controller) all come together as a package from the nice folks at Makerbot, as does the power supply. Eager helper not included....

















 
For motors I'm using some surplus NEMA23 stepper motors. These will drive the linear slides using timing belts and pulleys.

 
The linear slides are manufactured by Igus- they're very high quality and can handle high loads.
 
 


The machining spindle will consist of a Foredom handpiece driven by a DC motor. Motor control is provided by an old R/C speed control that will get a PWM input from an Arduino microcontroller. Electrical power comes from a salvaged PC power supply. Eventually I'll make a better quality spindle using an ER11 collet system and a more powerful brushless DC motor.

The extruder toolhead will be built using some parts from Makerbot combined with my own design nozzle assembly.

 

Control for the heated build platform will be done using a PID controller w/thermocouple. The build platform will also double as a surface mount soldering hotplate.

I still need to get the drive belts, some bearings for the belt tensioners and the aluminum for the build platform.

Stay tuned....