# CNC - Where to start?



## wildbill001 (Feb 28, 2008)

I bring this up because if I decide to go down this twisty-turny maze it would be to cut out/ make large-scale parts. BUT, and its a big but, I don't know enough about this to even know if this is something that would be worthwhile. It's just cool.

My only exposure to cnc so far has been some youtube and instructables videos. I'm thinking one of the Dremel-tool based CNC router/engraver might be useful. So, can anyone recommend websites, books, etc that would be a CNC for Dummies? I know I can build the frame, support-structure, or whatever its called out of MDF and Baltic Birch. That would be the easy part. The part I'm running around in circles about is the other stuff. I've got questions about stepper motors(bi-polar, unipolar or ???), CAD and CAM software along with driver compatibilities, O.S. to use, power-supplies, etc, etc. 


Help and "old" and easily confused modeler out.









Thanks

Bill


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## toddalin (Jan 4, 2008)

Sears Craftsman makes a 3-axis one operated by PC for under $2,000. I've been watching to find a used one but no luck so far.


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## John J (Dec 29, 2007)

What type of CNC we talking about? 

Are we talking Plasma Cutter? 

Mill or Lathe? 

I am interested in this subject I must bought a pair of Acme Screws for my Plasma Cutter Project. I have all the Steel and Two computers and soon Acme Screws. 

I bought a book on Servo magazine's Web Page about building my own CNC Plasma/ router cutter. 

I looked at Plasma Cam and got thier DVD. It is impressive but the price is around 10K 

So far all I got sunk into my CNC Plasma cutter is 85 bucks for the Acme Screws. So everything esle has been free. 

Tha Hard part is going to be the Plasma Cutter It's self


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## denray (Jan 5, 2008)

You must have a controller. The controller is what tells the motors to move. in the different directions and up and down. The computer tells the controller what to do, the controller and the program work together. There are many programs available, some are very expesive and some are affordable. We use two different programs, our Laser machines use Engrave-Lab by Cadlink and our two plasma cutters and our router uses Supercam, everything is drawn in CAD changed to a dxf format and imported into the program, and the program feeds the controller that drives the motors that moves the item that is doing the cutting. The programs that we use cost 500.00 each and they all have dongal keys to match the controllers, to prevent pirating the programs.
Dennis


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## SteveC (Jan 2, 2008)

Bill

It sounds like you want to go the DIY (Do It Yourself) route, here's a link to one fairly good site there are many others out there just use 'CNC do it yourself' as a Google search value, good luck in you quest.









*http://www.cncinformation.com/CNC_DIY/CNC_DIY.html*

*The CNC Wood Router Basics*


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## Dwight Ennis (Jan 2, 2008)

Sherline has some good info on CNC[/b][/b] and especially a very good tutorial on learning g-code (see links at bottom of linked page). That's how I learned.


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## wildbill001 (Feb 28, 2008)

DIY is exactly what I'm talking about. Here is the link I stumbled over that has gotten me interested.


http://www.instructables.com/id/Easy-to-Build-Desk-Top-3-Axis-CNC-Milling-Machine/

(Sorry, don't know how to make this "active". Guess you can just cut-n-paste)

This guy gives some good information but just enough to get me curious. Looks like something like this would be great for scribing panels, cutting windows, etc. Searching the web has done nothing yet but give me information overload and provide me with more terms to search for. I'm hoping someone out there can point me to a website(s) that is for the COMPLETE NEWBIE.


Bill


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## John J (Dec 29, 2007)

One of my ideas for the CNC router is to cut buildings out of Plexiglass with a router. Alsot cut them using the plasma cutter on metal


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## Allegheny (Jan 2, 2008)

Bill,

CNC is indeed an overwhelming area with many variables and choices. I think one of the first things you need to decide is what exact materials you want to work - power and rigidity requirements for machining steel are much higher than for working wood or even aluminum.


There are numerous CNC related chat boards on line that deal with virtually all aspects of the design, construction and use of these critters. There are also several YahooGroups that deal with CNC routers, plasma cutters, milling machines, lathes, etc. I personally own a ShopBot, a CNC router designed and built for processing sheet goods such as plywood or MDF. It does a fair job of cutting out parts, for say a kitchen cabinet. It can maintain accuracy to 0.005", which is fantastic for a cabinet. I could probably machine soft aluminum or brass on it as well, but the machine is not rigid enough to allow for high speed machining of these harder materials. Where I can cut up a sheet of plywood into six panels - all predrilled with shelf pin holes and with dadoed edges in about 12-15 minutes, cutting even a small gear blank out of T60-61 aluminum might take 6-12 hours because of the need for very small incremental cuts.


If you are interested in a CNC router for wood and plastics, there is only one website you will ever need: http://www.mechmate.com/forums/index.php The list moderator also owns a ShopBot and continuously tweaked it until he had designed an entirely new machine. The site is enormous and has threads on every aspect of the design and construction of a CNC router down to the choice stepper motors, break out boards, computers, software, and even the bolts to hold the thing together. The plans are freely downloadable (you have to register - it's free) and make resizing easy - while the common size built is for normal sheets of plywood, there have been mini ones built as well as a 15 x FOOT monster for processing SIP panels used in the construction of commercial buildings. Plan on spending several days or weeks going through even a portion of the site.


CNC Zone http://www.cnczone.com/forums/index.php?s=170a42cb7f4add6f25515572908b17cc is another massive site that deals with all sorts of CNC related issues. It is not nearly as focused as the MechMate site, so you will need to hone your search skills when using it.

If you are interested in machining metal, you can basically forget about building your own machine. The rigidity and tolerance requirements make home construction virtually impossible unless you have access to a machine shop. That's not to say that a home built CNC is not possible - you just have to start with a non-CNC mill and convert it. There are many highly detailed threads on CNC Zone that deal with this. However, I would recommend finding the first eight issues of Digital Machinist magazine where-in a very detailed, well illustrated, step-by-step conversion is documented on a Bridgeport style milling machine.


Cheers,

Brian


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## Les (Feb 11, 2008)

Bill,

About all I can directly address in your post is, I'm familiar with 'old and easily confused'.










I want to ask a question: do you intend to make parts and sell them?

Thinking CNC is 'cool' is cool by me, but I've seen the real thing up close and personal, and they tend to be horrendously expensive by hobby standards.

If you don't know much about machining, are you thinking that a CNC machine will eliminate the need for that knowledge? I think _if_ you are, that is a mistake. You still have to know how to get what you want, plus a lot of programming, etc.

CNC is an attractive concept. It's even vital, allowing production of items not possible by manual means. But for non-commercial uses, I remain doubtful it's worthwhile.

Having said that, if the subject fascinates you, go for it!

Les


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## wildbill001 (Feb 28, 2008)

I'm thinking that I will be "machining" wood and possibly acrylic. Maybe some thin brass at some point. I know enough to know that milling meta(steel, alum, etc.)l would require a real mill and lots of $$$.

I'm a long-time woodworker and have even done some production woodworking many years ago to suppliment income for a growing family. As for making parts to sell, well, that's not in the cards for now. IF that comes to be in the future,fine. I'm just looking into this for my own purposes at this point. I've also got 30+ years of experience in computers and programming.


As I said in an earlier post, I think this is really fascinating and, up until now, thought it was WAY out of my reach money-wise. It may still be but I like to build things. Especially things that will help me build other things. This little CNC mill just looks like a lot of fun to put together.

Thanks for all the links so far. Googling CNC brings up millions of hits. It's nice to narrow the field down to a few. Kinda how I found this board.


Bill


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## SE18 (Feb 21, 2008)

You don’t need to spend $$$ on a CNC. You could make your own like Bob j. has done on routerforums.com (see last photo). You can even "mill" aluminum on a router. 

(1st 2 photos show a jig he made and some toy train wheels he turned out. He made the jig and the wheels in just a matter of minutes and is able to use his router as a lathe as well.


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## Jack - Freshwater Models (Feb 17, 2008)

Hi Bill,


Building and operating a CNC router is a major undertaking with quite the learning curve. Best join some of the CNC groups on Yahoo and CNC Zone[/b]. Plan to spend some big $ if you actually want to be able to make some quality stuff.
I retrofitted a mini-mill a little over a year ago and just built a router. I'm a machinist so it may have been a bit easier for me than for a non-machinist.

Stick with XP SP3 for an OS. I would suggest going with Mach3 for controller software. You will also need some cad/cam ($$$$) software if you want to do anything other than very simple parts. I use Rhino/Rhinocam.

I would strongly suggest going with a plug and play pre wired controller for a beginner which will get you up and running fast and save a lot of frustration. I started with a Xylotex unit. Bipolar motors seem to be more the standard. If you can afford it go with linear ball bearings for guiding the moving parts and ball screws/nuts for driving the motion. I have purchased motion controls from both eBay and McMaster Carr.

Here is a pic of the router. The controller box is being moved and I have to finish the mount for the router.


Jack


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## Russell Miller (Jan 3, 2008)

We have 3 LASERS and one large CNC C. R. Onsrud Router here at TAP Plastics. The LASERS are much better for producing small parts like we use in our model building. When you use a router, you will always be left with a radius on any inside cutouts. A LASER will give you tight 90 degree inside corners. The detail is also much higher with LASERS because the actual cut width is much narrower. Also, with a LASER, you do not have the problem of the part moving that is caused by the rotation of the router bit. We use our router to cut materials that the LASER cannot cut, such as HDPE or very thick acrylic.
Russ


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## Jack - Freshwater Models (Feb 17, 2008)

Russ, 

You are correct that lasers are great! I'd like to own a laser but the cost is a bit much unless you have high production requirements. I usually farm out the laser work if it has to or should be done on a laser. I can farm out a lot of laser work for the cost of a laser. 

I chose a router and a mill because to me they are much more versitile. I plan on adding a cnc lathe shortly. I can do a wider variety of work with a router. For me the big plus is that I can use the router to cut complex 3D parts in addition to the 2.5D parts from sheet. I was able to build a cnc router for less than $2000 using quality components. It could have been cheaper if I had used wood instead of aluminum. By building my own router I was able to taylor the machine to suit my needs and having built it I can do repairs. 

The radius on 2.5D parts can be easily delt with by running a small endmill at high speeds and a couple of licks of a jewelers file can remove the slight radius. 

Jack


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