History

Last year I sold my seldom used metal lathe and used the money to buy a Chinese CNC6040 on ebay. This is the first major project that I undertook, and I have learned a TON about the process of bringing a project from idea to finished item by way of CNC router. I am writing this partly in retrospect (Phase 1) and partly real-time (Phase 2) to hopefully help others in their quest to learn how to use a hobbiest level CNC router.

Present

If you are new to your CNC router coming from a start in 3d printing, you are probably like me with the first question being, where's the "slicer"???

You now need to come to grips with the fact that no one else's gcode will work on your machine. If you are going into this thinking you will just download other people's gcode and run it, similar to what you can get away with in 3d printing, STOP NOW. CNC routers are a level of complexity deeper than 3d printing. Seriously though, when you get a CNC router and are going the way of free software, there's not a one-stop software solution. You will need to LEARN GCODE. Really, it's not that hard and there are plenty of tutorials on the internet so I will forego any gcode training on this site unless I had a eureka moment that I want to tell you about. Lastly, you need to figure out a lot of stuff on your own. If you don't know how to do something, and you aren't getting good suggestions from the internet, just figure out your own way. It's part of the learning experience.

How to Get Started in CNC Routing

I firmly believe that the fastest way to learn is to do it yourself. In the first phase, I am going to do some of the the hard work, but encourage you to take on as much as possible. I'll lay out the process I went through step by step and publish the files to go with it. This project focuses on the easiest type of routing, which only involves cutting out a shape. The same principles could apply to a laser cutter, water jet, or plazma cutter, except that I'll focus on material removal with a router bit.

The Task

I am presenting the steps to cut out pieces that can be assembled into a Rocking Horse suitable for a toddler (1-3 yrs). The plans come from www.woodworkingdownunder.com and I used the"Rosie" plans found here, as my daughter was 16 months old when I started this.

The Software

www.Onshape.com is a free online modeling software. If you want to use my model or drawing files, you can register for an account and then use the link from the links section on this page to find my project in the public documents. Feel free to fork it.

For writing/editing gcode, I use windows notepad for quick edits, but prefer Notepad++ with the "G-Code (most CNC machines)" syntax language add on. (search the page for that text and use the link for the XML).

For converting drawings to gcode, first export the drawing from ONSHAPE as a PDF, then open in Inkscape, then export to DXF, then utilize dxf2gcode to write your base file. Knowing how to read the output and modify it will be key to fully taking control of your machine.

For Machine control I use Mach3 that came with my SeeMeCNC H1 3d printer. It appears to be an old version, but it came with the stepper driver controller. I keep looking at Linux CNC as an upgrade path. In general, everything I present will have application in whatever control software you use, as I will focus on the standard Gcodes, and program specific functions like setting up your machine to talk to the control software will not be covered here. The bottom line is, if your machine accepts gcode, this project should apply to you, but you will have to understand the limitations of your machine.

The Hardware

I purchased a 1.5KW CNC 6040 from the electronics bay, but they are widely available in the range of $1200 for the 3 axis models in multiple places on the internet. If you are just starting out, don't bother with the 4th axis, because you can use that money to buy the other stuff you will need - bits, collets, screws, wood.... and I highly recommend the 6040 over the 4030 because if you want to do anything of size, the 4030 runs out of space REALLY quick. The numbers stand for the approximate usable space in cm, and the beds are larger than that. I consider that my machine has a usable space of 590mm x 380mm

You will need to get router bits. Personally I love to use 1/4" HHS router bits at the moment. I have had very good success with the 2 flute straight bits in cutting both pine and MDF. I just picked up a pack of 1/4" 2-flute spiral cutters as well. Make sure your bits have a cutting edge on the tip that goes all the way to the center of the bit, otherwise you can't plunge. You can find these any place that sells routers, or on the internet.

A note on spiral vs straight flutes: Straight flute cutters are VERY stiff compared to spiral. I can cut more than a full diameter deep with no deflection on a straight flute cutter in MDF, but the spiral must be kept to about half a diameter.

You will need collets specific to your machine to hold your bits. Something to note here is that there is a wide range of price for collets that is directly proportional to their manufacturing accuracy. I got a really cheap set and they say that they are accurate to .015" (.38mm) Which is pretty crappy for metal, but just fine for wood. This number tells you how close the center of the bit will be compared to the shaft center of the spindle. Worst case scenario, if my tool center is .015" from my spindle shaft center and I bore a hole, the hole will be .030" (.76mm) larger than the tool diameter. So my .25" drill will make a .28" hole. In practice, it's much closer than this, but I haven't tried to measure.

You will need a sacrificial work surface. I have had really good results with 3/4" MDF and bought a whole sheet at a big box store and had them cut it into pieces that exactly fit my machine. I got 8 scarfboards out of one full sheet of MDF. The MDF is attached to the t-slots in the machine's surface using wing nuts turned up-side down. I'll have to post pictures of this later.

Do yourself a favor and pick your basic material to work with. I chose 1x12 x 4ft "common board" from a big box store because it is nice pine wood and is easy to work with as well as being lower on the cost scale for wood. Stay away from MDF as your main material because it doesn't cut well and the high glue content can wear your bits (so I have read).

Clamps came with my router, but since I added a scarf board, the clamps are now useless. The deep scarfboard, however, gives the advantage that I can put a hold-down anywhere using a few scraps of wood and a wood screw.

Dust collection is a must. Get a cheap shop vacuum. Empty it often, or build a dust collection system with 5 gal buckets. Plans are available on the interwebs. Just pick one, don't worry too much about how they perform. They all suck. (ha ha ha) Anything will help keep your shopvac's filter cleaner.

The Computer

There is lots of information on line about what to get, but you will need a DESKTOP (not a laptop) with a parallel port. The specs are not really important, as long as you can plug a usb drive in and there is enough storage for the control software you choose. Dust off that computer sitting in your closet that you always wanted to turn into a retro gaming system but never found the time for... Now it has a purpose and your significant other won't keep bugging you to get rid of it.

Every machine has a slightly different setup, so you will need to follow the instructions of the controler hardware you purchase or that comes with your machine.

The Instructions

Please refer to my Phase 1 and Phase 2 posts for the time being. Very soon I will write a more complete step-by-step in a printable format in the documents for both Phase 1 and Phase 2.