Set up for some hard core gadget cosmos? If you thought your dremel tool was handy before, in today's How-To nosotros'll offset  building our own CNC machine. Aside from the geek factor, information technology can exist handy for making things like PC boards without chemicals or possibly some little styrofoam voodoo heads of all your enemies, uh friends.

Gentlemen, get-go your soldering irons.

Computer controlled mills have been around for a long time. If you simply want to buy oneone, Sherline makes mills that are ready to get (pictured is their CNC set model -- just add your own motors and controller). But then again, if you wanted to buy one, you probably wouldn't exist reading this, at present would you? A CNC machine is a lot like a precision drill printing with a table that moves in two directions -- seeing a commercial unit of measurement like the one above should help you visualize the end goal. We'll be making ours from scrounged, recycled, and adapted parts; today we'll be going over the bones parts we'll need to build our own.

[Update: If you lot're not quite certain what a CNC motorcar is, check out the Wikipedia article, mkay.]

Parts Hunting
For Part ane of the How-To, nosotros'll go over all the major components of the project and get started with the controller.
The major components of the DIY CNC machine:

  • Stepper motors
  • drive positioning screw
  • iii Centrality stepper motor controller
  • Linear slides

The nigh important component to determine the structure of your milling auto is the motor. Motors can be purchased from surplus houses, but the cheapest place to become them is from old dot matrix printers. Apple Imagewriters are 1 of our favorite sources. They incorporate multiple stepper motors, and the chief is pretty beefy. As a bonus, just about every dot matrix printer has a hardened steel rod that can be useful for our nefarious goals.

A stepper motor is an odd fauna. Nearly motors spin when ability is applied, stepper motors contain multiple coils. If the coils are energized in the proper social club, the motor will rotate a small corporeality (a step). Nosotros'll have full advantage of the nature of stepper motors with this project. To simplify your life later on, you'll desire to find stepper motors with more four wires. Four wire motors are commonly Bipolar motors. They produce more than torque, but finish upward complicating the control circuit. The preferred type of motor for the frugal hobbiest is Unipolar. These usually take v or 6 wires, and they're pretty like shooting fish in a barrel to work with.

Well-nigh stepper motors are labeled. The major points of involvement include the voltage, resistance and the number of degrees per step.  Knowing the number of degrees per footstep is vital for configuring the software to properly control the machine afterward. For a 3 axis auto, at the very least you'll desire the X and Y axis to both have identical motors. It's not the stop of the earth if they don't match, merely it's more of a pain later on.

The drive spiral is the next slice of our project. Commercial units use linear brawl screws or linear gears. The commercial parts aren't cheap, but yous can go away with some i/4-inch threaded rod from the hardware store. Instead of anti-backlash nuts, we'll utilise these handy 1-inch long 1/4-inch nuts. But nearly every hardware store has them, and they produce very little play. Try out the hardware at the shop because defects in the nut or rod volition produce drag that's easily noticeable by spinning the nut on the rod.

To couple the rod to the motor shaft, we'll use vinyl tubing with a pair of collars. The tubing is 1/four-inch inner bore and prevents bounden past allowing some play between the rod and the motor. You can get suitable collars from a model plane shop (The hardware store had some, just they were overpriced). Alternatively, you lot can make your ain similar we did from nylon bushings and hex screws.

Finally, we'll need some linear slides. One piece of cake out is to purchase a used or surplus XY table that's congenital just for this purpose. Custom designs tin can be congenital using brawl bearings. To a higher place is the linear rail that ShopBot uses. They machine the edge of a piece of steel and utilise this cool angled roller bearing.

Nosotros built this linear slide from a 1/2-inch steel rod and multiple bearing surfaces. It works, simply nosotros don't recommend edifice it if you value your sanity.

Once uou've bought or salvaged a set of motors, y'all'll need a controller. The controller provides the interface to the calculator, drives the motors and can provide some simple feedback to the computer. The stepper controller has to be powerful enough to bulldoze the motors you've selected. We sifted through lots of stepper controller designs looking for one that presented the all-time value.

In the end nosotros found this design for a relatively simple parallel port interface that originally appeared in a 1994 issue of Nuts and Volts. Today, the expensive UCN5804B is but bachelor every bit a surplus detail, but now the entire controller can be built for about $22-$30 in parts. (If you use a heavier motor like the ones from the Imagewriter, yous might need to add some carve up power transistors.)

The parts listing at the link is a scrap outdated, here'southward our updated shopping list.

  • 3 - UCN5804B - alltronics.com
  • 12 - 1N49355 Diodes - Part 625-1N4935 from Mouser.com
  • 2 - .01uF Capacitors - Part 581-SR155C103KAT from Mouser.com
  • 1 - 10uF Capacitor - Part 140-HTRL25V10-TB from Mouser.com
  • 3 - 4.7k Resistor Network 652-4608X-101-4.7K from Mouser.com (Has an extra resistor, just works fine)
  • 1 - D-Sub 25 pivot Male person - Mouser, RadioShack, etc.
  • 1 - Butt power connector - Whatever works for your power supply. (We used a spare 12V ability brick)
  • Stranded Cat-5 is sufficient for wiring
  • Terminals and male headers are optional, see the page for the circuit.
  • Rut sinks for the 5804Bs are needed. We used some aluminum channel.
  • Copper clad PC board (Nosotros stock upwardly on ebay every so frequently)
  • Etching solution - Ferric Chloride, etc.

We made our ain board using the template from the web page. We used similar techniques to the 1 in role iv of our iPod Superdock How-To. We reversed the pdf image using Gimp, and printed it onto a laserprinter transparency. This method doesn't create as prissy of a trace equally the paper, but it'southward speedier.  Clean the board, and continue the newspaper backing betwixt the plastic and the fe. Once the toner is ironed, just cool it with water and pare.

We etched the board using Ferric Chloride from RadioShack in a disposable Zip-Lock container. It needs to be warm and agitated to piece of work well. The acid and hydrogen peroxide solution etches fashion faster.

We drilled the board with our drill press and tungsten carbide bits from Drill Bit City. We had to refer to the placement schematic several times to make certain we drilled everything right. Getting the pins holes aligned for the 5804s is a claiming!

If you want to practise a toner transfer of the placement mask, do it before drilling the holes. Otherwise the surface is too uneven to allow a good transfer. If y'all screw it up similar we did, you can cheat. Just print the mask onto a transparency and burn holes for the components with a soldering iron. Information technology works surprisingly well.

Next time we'll start building the bodily machine and bear witness you how to build some elementary and effective slide systems. For at present, hither's a teaser of what's coming! Good luck!