Make Your Own DIY CNC

Step 2: Bill of Materials

Attached is a breakdown of the components and the cost of the machine. The hardware and aluminium were purchased in batches from local home improvement stores as a matter of convenience as the design progressed and those prices are shown. With a complete bill of materials these could be sourced from dedicated metal and fastener suppliers at a significant discount. All prices are in Canadian dollars; these items will be much cheaper off of the same shelves for my neighbours down in the US. Even though Canada is a metric country, all stock sizes of lumber, metals and hardware are imperial with a hefty mark-up on metric components if they are even available. Because of this all components are imperial sizes other than the plywood (I'd never seen metric plywood in a home improvement store before, which is probably why it was half the price of imperial stock of similar thickness).

The overall cost of the machine was above what I was expecting when I started my first machine but these costs have been spread out over the four years I have been working on the project. A comparison to entry level commercial products on the market shows that the DIY route is still a cheaper way to go. While these machines may have better performance than a home built wood framed design, there is no replacing the satisfaction of making a machine yourself. I am also unsure how flexible these are for running different driver software and overall flexibility on how you can use the machines.

ShopBot Desktop $4995 + Taxes + S&H + spindle
Laguana Swift $4900 + Taxes + S&H
Rockler CNC Shark Pro Plus $3800 + Taxes + S&H + spindle
General International i-Carver $2100 + Taxes

Lumenlab's M3 kit looks like a nice product but at $999+ S&H + software + driver the overall price will be over $1500 to get it up and running. 

A note on designs titled CNC for less than $XXX dollars (usually under $200). There will always be a trade off between performance and price. Machines with very little forces on the tool can be made very cheaply (for drawing, cutting foam and 3d printing) but when cutting harder materials things have to be beefed up.  These aren't bad machines but be clear with what you're building so you're not disappointed when the thing folds in half when it comes to cutting plywood. These prices also skip over several key parts, only including the major components in the price. Its amazing to see how quickly some 1/4" and 3/8" bolts add up and they certainly don't include software (or count trial versions as a permanent solution) and driver boards. Without these your $150 CNC is just an overkill paperweight.

BOM Summary:
Plywood & Metals:                $158.25
Hardware:                              $107.77
Drive Line Components      $261.46
Electronics                             $442.04
Software                                 $522.26
Miscellaneous                         $11.19     
Grand Total                          $1502.96

Comments

[lperkins]

An arduino microcontroller with stepper motor drivers programmed as a p-code interpreter will substitute for most of the electronics for considerably cheaper, and, depending on what you're hoping to make with the machine, there are several open-source programs (notably inkscape and blender) that will generate 2d and 3d models which are convertible into p-code for it to run. That would slice about a thousand dollars off of your cost.

[billgeo]

Do you have any stepper motor controlling libraries for the Arduino in mind??? Thank you

[lperkins]

I use the easydriver stepper motor drivers, they're about $10 apiece if you shop around.

grbl is a good, professional quality p-code interpreter suite that will run on an arduino. http://dank.bengler.no/-/page/show/5470_grbl?ref=mst It also happens to be open source.

Inkscape has a plugin (http://www.slackersdelight.com/instructables/laserengraver.zip) that will turn a drawing into 2d code to move your head and turn your tool on and off. It would work best with some kind of drawing or engraving head.

Blender supposedly has programs/plugins to generate code from a 3d mesh, but I don't remember what they were off the top of my head. Some of the other CNC instructibles around here have instructions for using them. Lots of them work best on Linux. Given the cost savings available on both hardware and software available by using it though, it's definitely worth taking the time to learn it.

[nick2334]

Definitely something I'll have to look into.