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DIY Woodworking CNC machine

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  • 02-12-2010 2:45pm
    #1
    JoeB-
    Registered Users Posts: 689 ✭✭✭


    Hi

    I'd like to build a woodworking CNC machine.

    I'd be thinking of a table size or working area of approx 1,500mm x 700mm working size, ... with three axis, and only very short travel of perhaps 120mm to 250mm on the up-down axis.


    Similar to this..
    http://buildyourcnc.com/blackToe2x4v40.aspx

    blackToe%204-0%201%20300.JPG
    (Image from http://buildyourcnc.com)

    I'd be hoping to do this for between 1,500 and 3,000 Euros.

    The guy above sells a complete kit for a working 8'x4' version of the machine above for 3,000 dollars or so, plus shipping and taxes. That's not bad,.. if he was in the UK I'd buy it.. I may still buy a smaller version from him,.. he also does a 325mm x 915mm version, with the same electronics, stepper motors but timing belts rather than steel chains. It's 1,400 dollars plus shipping and taxes, but it's a complete system, with high torque motors.. all you need is a PC, a router, and some skills to assemble it all. It looks very well made, on this link,
    http://buildyourcnc.com/DesktopCNCMachineKitblueChick.aspx

    blueChick%201%20300.JPG(Image from http://buildyourcnc.com)


    There are several aspects to a design like this...
    Linear motion of large axis.
    Linear motion of short up-down axis.

    Power to linear motion..
    Stepper motors etc.
    Driving boards, PC interface
    limit switches, emergency stop


    That guy uses approx 3.1 Nm stepper motors, to pull timing timing belts on the smaller version, and metal chains, with 6.35mm pitch, for the larger version. He uses a 12.7mm lead screw with anti backlash nut on the same stype of stepper motor for the up down motion. The X and Y motions are guided by using V groove ball bearings running against normal aluminium angle.


    What do people think... is it feasible to build something like this? (for less than 3,000). Is precision or tolerance of .5mm or so achievable with these materials and methods?

    A complete electonic system with powerful stepper motors is available as a kit from the Uk,... this is intended as a powerful CNC setup... total cost of electronics and motors approx £280 to £370 , from
    http://www.diycnc.co.uk/html/cnc_systems.html

    This would leave all the linear motion and tables etc still to be done... while the parts are availalbe from RS they can quite expensive. V groove bearings are 20 Euros each (or more) and linear motion rails are very expensive. And then there's loads of sprokets, chains, etc that are also expensive.

    I think it could be very hard to assemble all that into a working machine, so would people recommend that a keen amatuer should perhaps buy the small working version for 1,700 dollars or so.. and go from there?

    Can reasonable results be got by just using the V groove beaings against a metal angle of some sort?



    Comments, help, etc?

    Cheers so,
    Joe


Comments

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    #2
    enda1
    Registered Users Posts: 5,166 ✭✭✭enda1


    I'd say you'd need to keep your workshop conditions quite controlled to hope for close tolerances. Humidity or temperature changes would surely distort the geometry of the apparatus.

    Wonder on the stiffness of the plywood structure too.

    Depends what you're getting it for really. I guess hobby work?
    If it was for any professional work I'd be a bit wary.


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    #3
    JoeB-
    Registered Users Posts: 689 ✭✭✭JoeB-


    Well, I'd be interested in the machine as a hobby, but I also work as a cabinet maker and would hope that I could use it for work too...


    There are some ready made machines available...

    like these ones
    http://www.prototools.co.uk/Heiz_SSeries_CNC_page_1_c_521.html

    product_image.php?imageid=3279 (from ProtoTools above)

    The Prototools CNC is available in three sizes, up to 600 x 1000 x 110mm, for about 3,000 plus VAT... smaller versions available for less. German made, and quite high quality, with precision rods and l imit and reference switches on all axis, also emergency stops etc.




    There's also
    http://www.routoutcnc.com/z90router.html

    wp8ad878e0_05.jpg
    these have an Irish distributor.

    working size 900 x 480 for about 3,000 Euros plus VAT



    Finally there's great components available from
    http://www.slidesandballscrews.com
    Zapp Automation..
    so they're great for stepper motors, drivers etc
    (Zapp Automation are doing a sliding kit... 2 x 1,000mm 20mm precision rods, with four x rod bearing and pillow blocks, also four end supports for less than 100 Euro which is fantastic.. they also do a 1,100mm ball screw, 16mm, with a ball nut and lead screw ends for less than 100 Euro too... so that'd be a fantastic system for one axis.)
    (Zapp also do supported round rods.. so a 2,200mm 25mm thick rods, fully supported along it's length, and two rod bearings costs around 180 Euros, and you need two for a 1,900mm X axis, but you'd make great linear motion using those components.. no slack there I wouldn't imagine.



    There's great aluminium profiles, and a very full range of connectors etc from
    http://www.aluminium-profile.co.uk
    KJN Aluminium.
    This would allow the machine to be made quite solid, and easily repairable.




    So if building myself...
    I'd use 2 x 2,100mm 25mm supported round rods for the X axis. (cost 400 Euro)
    I'd use the 2 x 1,000mm 20mm rods, with 1,100mm ballscrew for the Y axis (cost approx 250 Euro)

    Z Axis.. not decided, probably a small ball screw. (cost 100 to 150)


    Motion of X axis... 6.35mm pitch chain, running on sprokets. (cost 100?)
    Motion of Y Axis, ball screw. (included above)
    Motion of Z axis.. ball screw. (cost 100)


    Motors..

    some choices available.
    complete kit from
    http://www.diycnc.co.uk/html/cnc_systems.html

    for £357 + 22 shipping, including 3.1Nm motors (Nema 23) (257 or so without motors)
    Zapp Automation do Nema 34 motors for about 40 to 60, torque increased from 3Nm to 4.5Nm or so.. (larger 8Nm for about 80 Euro per motor)
    I'd need to upgrade the 'complete system' from DIYCNC to use more powerful power supplies etc if I want to use larger motors.

    Total cost of better motors and controllers.. = approx 500 Euro
    Aluminum etc = 200 to 300.



    I'm undecided to buy a smaller machine for 2,000 to 3,000, which will be too small for me. ... or perhaps I could try to build a very large verison for 2,000 to 3,000... but this may never work at all! It's a hard decision.



    So, do people have any other companies that sell this type of stuff cheaply.. (I know about Misumi, and RS, Radionics.. would these be better than Zapp Automation above?, prices from Zapp seem much cheaper, especially for linear motion precision rods)..


    Cheers so


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    #4
    DublinDilbert
    Registered Users Posts: 5,366 ✭✭✭DublinDilbert


    Do Zapp automation do kits? Eg a single axis kit?


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    #5
    random.stranger
    Registered Users Posts: 442 ✭✭random.stranger


    Misumi & RS are great for getting your hands on stuff that is difficult to source elsewhere.

    I wouldn't be surprised if you were getting comparable quality for 1/2 to 1/3 of the cost that they are offering.

    Also, RS give you the manufacturer and manufacturer's part number for most parts listed, if you can find the manufacturer's website, find the Irish/UK distributor & get a quote to do a like with like comparison.

    Best of Luck.


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    #6
    aidanki
    Registered Users Posts: 1,262 ✭✭✭aidanki


    how big a cutter you intend to mount on this?

    what precision do you hope to achieve?

    what software you going to use to do your drawings and set it cutting


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    #7
    forex
    Registered Users Posts: 70 ✭✭forex


    Hi, have you being able to build a CNC router ?


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    #8
    forex
    Registered Users Posts: 70 ✭✭forex


    I found this web site: http://www.tron-cnc.de/english.html
    They claim to build CNC router with Working area: 980x480x90 for less than 1000 euro ...


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    #9
    yrpizd163
    Registered Users Posts: 1 ✭yrpizd163


    Next time you can try China CNC router Machine wich is high quality with competive price.


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