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DIY CNC


Poeloq

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Hi guys! Does anybody know a good DIY CNC project? I would like to build a CNC machine to create 19" Frontpanels (big ones*g*).

If not, i will have to start my own:)

Poeloq

PS: Sh**, this Midibox stuff is really addictive! I check the forum now at least 20 times a day:)

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  • 3 weeks later...

I am in the process of building a CNC-machine for pcb-milling, drilling and front panel engraving.

I have found an excellent free CNC-program at http://www.cncplayer.de./uk.htm

There are many different ways to build a CNC-machine, some of them more expensive than others.

Here is a site with less expensive designs http://www.luberth.com/cstep/

For very good (and more expensive) mechanical parts, check out the italian company http://www.ronchinimassimo.com/index.htm

Regards

/Daniel, Sweden

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Kellycam is the best when it comes to CNC software.  It will do the needed file conversions for drilling circuit boards and it makes a better than average G-Code interpreter/machine controller.

I have to suggest that anyone thinking of building a CNC consider buying a manual milling machine and convert it with stepper motor or servo motor drive.  You can make your own machine with normal tools, but the accuracy and repeatability will be hard to maintain.  A cheap machine that can be converted to CNC is the common Asian made mini-mill http://www.mini-lathe.com/Mini_mill/Main/mini-mill.htm

If you are only doing small pieces (work that can be moved in the vise to finish the job) and circuit boards this mill: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=47158 would be a great candidate to convert to CNC.

Also remember that most milling machines have a much smaller cutting capacity than their large cousins, so if you are working with metal you will need to do the job with a lot of small cuts that take a very small amount of material away with each pass, otherwise you will bog the machine down and your accuracy will suffer badly.

A high speed spindle is required for PCB work (16,000 rpm+) but you must use a much lower speed for metal work.  A decent Dremel tool will work for smaller runs of circuit boards, but will be almost useless with aluminum.  I would suggest than anyone interested in cutting metal with a CNC find a local school that teaches machining or a machine shop that will let you take a look at a job in progress, this will clue you in on the cut speeds, required side forces on your cutting tools, and other things that don't really come with book knowledge.

Also see http://www.sherline.com/ and http://www.taigtools.com/ for both manual and "CNC ready" mills.

Before you start on a DIY CNC keep in mind that to have decent accuracy without constant maintenance, a pre built mill will serve you well.  But if you are wanting a DIY project with a lot of metalwork and/or woodwork, that will take most weeks or months to complete, and a huge learning curve (unless you are a machinist!) build your own like I did.  8)

The electronics/controller part of the machine is the easy part, there are stepper controller chips (ULN5804 is the best) that are easy to implement for driving your motors.  Add some transistors and a large power supply and you can drive some extremely high torque motors.  Servo motors (higher accuracy) can be used in place of steppers to move things around, but the cost of the motors and control will be at least double the cost of steppers.

Remember that you don't need a machine with 19 inches of travel to cut a 19 inch panel, you can design the job as two separate jobs and move the workpiece+re-align to cut the second half.

All of these thoughts are my own observations, they come from real world experience and not from theory.

Have fun!

SmashTV

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