CNC Machine Boasts Big Bed, Impressive Power From Off-the-Shelf Parts

A lot of homebrew CNC machines end up being glorified plotters with a router attached that are good for little more than milling soft materials like wood and plastic. So if you have a burning need to mill harder materials like aluminum and mild steel quickly and quietly, set your sights higher and build a large bed CNC machine with off-the-shelf components.

With a budget of 2000 €, [SörenS7] was not as constrained as a lot of the lower end CNC builds we’ve seen, which almost always rely on 3D-printed parts or even materials sourced from the trash can. And while we certainly applaud every CNC build, this one shows that affordable and easily sourced mechatronics can result in a bolt-up build of considerable capability. [SörenS7]’s BOM for this machine is 100% catalog shopping, from the aluminum extrusion bed and gantry to the linear bearings and recirculating-ball lead screws. The working area is a generous 900 x 400 x 120mm, the steppers are beefy NEMA23s, and the spindle is a 3-kW VFD unit for plenty of power. The video below shows the machine’s impressive performance dry cutting aluminum.

All told, [SörenS7] came in 500 € under budget, which is a tempting price point for a machine this big and capable.

30 thoughts on “CNC Machine Boasts Big Bed, Impressive Power From Off-the-Shelf Parts

  1. First, I love this build, really impressive for a home job. But one thing worries me, he has a TON of hardware on the gantry in front of the bearings, does that worry anyone else? Personally, I would have tried to balance it a little more to take some pressure off those bearings, but I really don’t know, so maybe someone could fill me in and share a little knowledge on the subject?

    1. I work on commercial CNC cutting equipment, mostly routers. They normally do have a lot of stuff on the carriage. The base on the risers of the commercial equipment is much wider to give a more stable platform. Counter balancing the carriage is not the solution. Adding mass has drawbacks.

    2. There is no really easy way to do that, which is why most professional cnc machines have the spindle fixed in x and y (movable in z) and the work holding bed moves in x and y. It makes for a much studier Z axis given the weight of bigger spindles.

      that being said, it looks like he is using 30mm extrusions for his construction, and they dont look like the thicker extrusions. Maybe he could go with 40 mm extrusions or step it up to a heavier profile?

      It also looks as if extrusions are cheaper in europe than they are in north america

      1. If you skip Bosch Rexroth and use some alternative (MiniTec or Lipro) you can make a same thing for 20/30%. And at the end it is not the profiles that cost you but all the joints and hinges are the thing that racks up the bill.

  2. How many hours did it take to design, source, build, assemble, setup, calibrate and troubleshoot? That should be included in the price or at least be acknowledged.

      1. I guess HaD seems to largely ignore or gloss over the time involved in a project instead focusing on the cost being as low as “free” if using found or scavenged parts. That feels somewhat misleading at best.

          1. For finite beings time always counts. In this case time needed allows one to fit their “hobbies” in between others things that aren’t hobbies, and gives a rough estimate to reaching one’s goal.

        1. I don’t get the people say “but your time isn’t free”. Of course if you don’t enjoy doing something then you have other things you could be doing with your time that are more valuable to you. You might choose for example to pay someone to clean your house because you can afford it and you can use the time to do something you want to do instead.

          However if you enjoy building things then not only is your time free, you are actually doing something you enjoy and learning things along the way making them valuable to you. Sites like Hack a Day are not saying look you can make this thing for less than a commercial machine, so you are bing ripped off if you buy a machine. They are saying look you can have fun building a machine of your own and the cost of parts is reasonable enough that the you won’t feel like you may as well gone out and purchased a commercial machine as it would have been cheaper.

          1. I like making things as well, I just try to personally be a bit more accurate about evaluating the scale and scope of a project before undertaking it and while it removes a bit of the glamor of a project or doesn’t make for quite as good of a headline about how cheap something is, it is important to also be realistic about what it will take to achieve a successful project.

            It also helps improve the overall experience to have a good understanding of what might be involved assuming you have the set of skills and equipment necessary to undertake said project so you can at least have a baseline of what to expect (and also how much extra time you might have to put into something in the event you need to fail / learn things along the way).

            I like making things very much but I also like being able to accurately evaluate what is necessary to be able to do so and I feel like that is commonly missed or intentionally glossed over and it would help me and help others to better understand what that is.

  3. I’m not an expert in CNC builds, but the thought of material chips/dust/(maybe coolant) and those uncovered ball-circulation spindles/rail bearings makes me cringe. Am I wrong?

    1. Its not ideal, but for hobby use in soft materials you aren’t really wearing out the parts.

      If you are cutting something hard and abrasive like cast-iron (which turns into a disgusting powder that gets everywhere) there will be problems, but linear rail and ballscrews are very hard and come with wipers. Aluminium and plastic isn’t going to be an issue (although some types of wood can be abrasive).

      Covers aren’t really an option because they are obscenely expensive and must be custom ordered to fit.

      1. I guess my concern was less with abrasion and more about it pilling up and jamming the drive in mid cut, but with wipers (and perhaps a little compressed air) you could keep it pretty clean.

        (“……obscenely expensive and must be custom ordered to fit.” That sounds like a hackaday-worthy project…)

      2. Bellows fail too. I haven’t seen anyone make one yet, but I suspect someone will eventually. At least then you could repair or replace it yourself. Especially if cutting dry, you should be able to use some heavyweight canvas tarps and cut, sew, even thermally weld them together. There’s just no shortcut to all that work, however, with all the ID-OD sewing/welding required.

        This issue is also why you often see the linear motion on the sides or even hanging upside down from the bottom, in a U channel (open to the bottom), to reduce the chance of buildup on the rails and screws. The engineering challenge goes up with that setup, however.

    2. They can be exposed, the linear slides do have wipers, though there should be caps put in the screw holes to make them sealed and keep the crap out. The screws are a different story, they should be protected in some way, there are wipers before but small chips usually get by them. he really should come up with some sort of way cover for them.

  4. Nice build especially for the price. Agree time should be mentioned but if its well documented it will take the next person a fraction of the time to build. Which might make it an attractive option for others to copy and improve on.

  5. Hello guys,
    this is my machine.

    With lots of comments you are right.
    – Of course 2 slides for x axis would be better… maybe for future update. For the moment this is enough.
    Each linear slide is specified to handle 105Nm in this direction for 100km. Having approx. 11kg in 0,15m distance should be no problem.
    (2 rails for Z would also be better.. it is already prepared that I just need to buy the rail and slide for modification.)
    – I used 30mm profiles, B type.
    – protecting the ball-circulation spindles is also in my mind. I am currently searching for kind of telescope pipe or hose.

    -Regarding time: Screwing everything together was not the big thing. Selecting components especially with the requirement of fitting directly together was much more time consuming. This was also the reason of selecting 30mm profiles. They fit directly to the flange type 15mm linear bearings.

    Now, with access to CNC machined parts, I would select other components, but without any machining tools except of drilling machine, this components are a very good choice.

    -It is true, this machine is not made to mill steel, but it worked with very small milling depth.

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