Home Forum The Makers Workshop CNC talk CNC mill and router shopping

This topic contains 7 replies, has 1 voice, and was last updated by  Paul Kelly 5 years, 10 months ago.

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  • #580

    Brad Webster
    Member

    I am looking to buy a new or used CNC mill and CNC router for small business use on a limited budget. I would appreciate your thoughts and experiences in the matter. I am looking for fully built machines rather than diy kits. The CNC mill would need to have a decent work envelope (say x400 y400 z100) with a proper spindle and linear bearings. It would have to be able to mill aluminium and acrylic. 3 axis would be fine but a rotary 4 axis would be better.
    For the CNC router I would prefer one that takes a standard sheet size 1200 x 2400 but if I can find a good bargain I am happy to compromise. It would be great to find a machine that does both milling and routing. It would also be better if they ran on single phase power. My budget is only about $5000 for both machines so if you guys know anyone looking to sell second hand equipment that would be great.

    #582

    Paul Kelly
    Participant

    A good CNC router will do Al with reasonable precision (say +-50um), but you’re not going to get a 1325 (that’s 1300x2500mm) router for $5K. Ours uses rack and pinion drive, gets about +-80-100um in Al and cost $15K by the time it was making swarf. You can get a lighter 1325 machine for about $3K less.
    $5K would get you a quarter sheet router.
    For an off the shelf mill, forget about linear bearings for $5K. Go for something like a Tormach or an RF45 with a conversion kit. Anything bigger and you’ll have to go to servo’s and that’ll blow your budget..

    Bottom line, if you want both a mill and router new and turn key then you’re up for >>$15K

    You could build a small router and do a CNC conversion on something like an RF45 mill for $5K though (maybe).

    I have both an NC mill and router (mill was a conversion, router was an import) and have built about a dozen or so NC machines, happy for you to take a look at our gear and discuss your options.
    PK

    #587

    Brad Webster
    Member

    Thanks for the info Paul. The Tormach CNC mills look pretty good. I was also looking at the Sieg kx1s/kx3s and Syil x4/x5 CNC mills which are at around the $8-9K mark but seem to have some mixed reviews. Another option would be to buy a Sieg x2 mill and a CNC conversion kit for about $1500. How difficult is it to do the CNC conversion for someone with pretty limited electronics knowledge.
    Brad

    #588

    Paul Kelly
    Participant

    Brad Webster, post: 442, member: 276 wrote: I was also looking at the Sieg kx1s/kx3s and Syil x4/x5 CNC mills which are at around the $8-9K mark but seem to have some mixed reviews.

    Not sure about the Kx1S, but all the rest are rubbish. They all seem to use the same open section column as the original X3. About 80% of that large spine you see going up the back of the machine is sheet metal work. Underneath is an open backed casting (think “a length of roof gutter standing on it’s end”). The problem is that this configuration suffers from very poor torsional stiffness and the head tends to vibrate around the column… I say this with some authority because I own an X3 and pig-headedly stuck with it until I got it working..

    See: http://web.archive.org/web/20120320071905/http://www.cncathome.com/X3.html

    Another option would be to buy a Sieg x2 mill and a CNC conversion kit for about $1500

    Yep, the X2 is a ripper little machine. Bit smaller than you specced up front though..

    How difficult is it to do the CNC conversion for someone with pretty limited electronics knowledge.

    About a carton.
    PK

    #591

    Brad Webster
    Member

    Thanks for the warning about the cheaper CNC mills and the X3. I managed to pick up a second hand x2 with a belt drive conversion from gumtree. Works pretty well. Very quiet and no vibration issues that I can see. Now I just need to do a bit of research on the CNC conversion kit.
    Brad

    #592

    Paul Kelly
    Participant

    Got a picture? I ask because a group I was in did a batch of belt drive conversions for X2’s and there’s a small chance it could be one of them…
    On the topic of NC kits. If you listen to no other piece of advice, then listen to this bit:

    “EVERYONE ends up using ball screws!”

    Ignore any kit that promises ball screw like performance, or claims to use revolutionary new anti backlash nut technology.
    PK

    #608

    Brad Webster
    Member

    This is the Sieg X2 mill I picked up the other day. It’s about 7 years old and has the LMS belt drive conversion. So far the only reliable CNC conversion kit I have found is from CNC fusion http://www.cncfusion.com/minimill1.html
    The 3 axis kit #2 with ball screws is about $580 US but a lot more hardware would be needed before it was up and running.
    Brad

    #609

    Paul Kelly
    Participant

    The kit looks quite well made. As a guide to pricing, you’d pay about$300 for the set ofbare ballscrews and maybe another $30-$50 for the bearings if you did a real DIY job..
    I generally reckon a CNC retrofit on a small machine (ie NEMA23 steppers) comes in at around $300-$400 per axis..

    Now, do yourself a favour and go buy a G540 http://www.homanndesigns.com/store/index.php?main_page=product_info&cPath=24&products_id=80&zenid=dkn7d6hrbaa3m6mfl9e49lpam1
    You get 4 axii of drive made by the best guy in the business and all you have to do is connect power… By contrast, here’s a 3 axis control box I made for someone a while back:


    You get most of that, all wrapped up in a tidy box like this:

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