The goal of this Instructable is not to show a full step by step progression but rather to pass along my experiences with making my own CNC.
I'm a MFA candidate (art student) at Rutgers University - Mason Gross College of the Arts. I designed this machine for the sculpture department to primarily cut soft material (foam, wax, some plastic and wood). I tried to leave as much room as possible for modification to suit the departments changing needs i.e. repurposing into a CNC plasma-cutter.
The design of my machine is loosely based around the Solsylva.com - Large Dual Leadscrew Table plans. I choose these plans a jumping off point - extracting what I needed and adding to the design to fit my needs. Linear motion control, next to the drive train, is often the most expensive system on a CNC device and the Solsylva plans present a simple yet elegant solution to cutting the cost of linear movement buy using roller skate bearings, angle iron, and EMT conduit.
There were a few concepts behind the design of this machine. The first was the use of scrap or existing materials - in essence recycling as much material as possible. The second idea was that any materials I needed to purchase I would try to obtained locally (Local Hardware Stores, Home Depot/Lowes, etc.) - the Solsylva plans are also based around this concept.
College art departments tend to generate a lot of usable scrap/waste. After a student projects are finished, they usually end up back in the scrap bin, metal recycling, or the dumpster. My goal for this project was to use as much of this "waste" material as possible and design the machine around these materials. The dimensions for parts were often times dictated by the size of the scraps available. The finish of this machine was inevitably dictated buy the materials I chose to use. I personally appreciate the scrappy junk-bot aesthetic - but then again I did build it ;)
This is project is a labor of love and a work-in-progress so there are a few things still unfinished - please excuse some of the inconsistencies in the photos as they've been taken at different time throughout the project.
Enough with the college talk and on to the good stuff -
The Machine Specs:
Materials: Recycled Steel and Aluminum.
Total Travel (x,y,z): 60" x 60" x 5"
Motors: 425 oz.in. dual shaft stepper Nema23 mounting.
Router/Spindle: Porter Cable 690 router (1/2" - 1/8" collets) or 1/4" trim router.
Motor Drivers/Electronics: Xylotex XS-3525/8S-3
Software: Mach3 (controller), various CAD/CAM software for object creation, tool paths, and g-code.
The table is geared, crank driven with quad lift screws and 1000lb capacity - and it's movable too. It's way overkill, but makes Z hight adjustment a dream. In the future this could become the Z axis if more movement is needed.
Step 1: The Z axis (up and down).
Step 2: X and Y axis come together - the frame takes shape.
Step 3: The Y axis drivetrain.
I really like the dual lead screw design - it has given us a lot of flexibility to have a movable table underneath the machine. Single lead screws designs usually have the screw running down the middle of the machine with a fixed cutting surface above. This limits the depth of the Z axis to the fixed table height.
Step 4: The driver board and box - cooling overkill.
With the execption of the xylotex driver board and power supply, everything in this assembly was fabricated or from a recycled source.