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    Member eh3378's Avatar
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    Default Looking for feedback on a build idea

    Been throwing around the idea of building a cnc mill, the end goal is to hopefully be able to mill most materials (although i believe in this first iteration rigidity will be an issue)

    I have compiled a list of components I believe I can cobble together, the feedback I'm looking for is if anything will absolutely not work together, if I am missing a component, and any huge safety issues.

    Drivers:
    https://www.geckodrive.com/g201x-dig...tep-drive.html
    x3 = 327
    heatsink = 74

    Axis Motors:
    https://www.automationtechnologiesin...34h2160-62-8a/
    X3 = 359.85
    16 awg wire

    Controllers:

    pmdx gecko mobo:
    PMDX.COM - Products for CNC and motion control applications
    x1 = 55
    pmdx 126 mobo
    PMDX.COM - Products for CNC and motion control applications
    x1 = 174

    spindle controller:
    PMDX.COM - Products for CNC and motion control applications
    x1 = 57

    smoothstepper:
    https://warp9td.com/index.php/products
    x1: = 180

    Driver power supply:
    https://www.ebay.com/itm/72v-16-5a-1...-/132199640758
    x1 = 305

    chassis c-beam machine:
    https://openbuildspartstore.com/open...-beam-machine/
    x1: 589.99

    spindle:
    https://littlemachineshop.com/produc...ory=-269978449
    x1 = 390

    vhd: hitachi nes1-015sb
    https://www.wolfautomation.com/ac-dr...-single-phase/
    x1 = 201

    total: $2713-ish

    Right now the problem I view is rigidity when working harder materials, I just do not have faith in the c-beams to hold up to the torques that the spindle and the nema 34's can apply to a workpiece. Also I do not have a vice selected right now that will be more of an addon.

    I am hoping to use this as a platform to upgrade itself although I am now questioning whether I should instead build a plasma cutter to be able to cut a heavy frame for a future mill.

    Thoughts, concerns, ideas?

    Similar Threads:


  2. #2
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    Quote Originally Posted by eh3378 View Post
    Been throwing around the idea of building a cnc mill, the end goal is to hopefully be able to mill most materials (although i believe in this first iteration rigidity will be an issue)

    I have compiled a list of components I believe I can cobble together, the feedback I'm looking for is if anything will absolutely not work together, if I am missing a component, and any huge safety issues.

    Drivers:
    https://www.geckodrive.com/g201x-dig...tep-drive.html
    x3 = 327
    heatsink = 74

    Axis Motors:
    https://www.automationtechnologiesin...34h2160-62-8a/
    X3 = 359.85
    16 awg wire

    Controllers:

    pmdx gecko mobo:
    PMDX.COM - Products for CNC and motion control applications
    x1 = 55
    pmdx 126 mobo
    PMDX.COM - Products for CNC and motion control applications
    x1 = 174

    spindle controller:
    PMDX.COM - Products for CNC and motion control applications
    x1 = 57

    smoothstepper:
    https://warp9td.com/index.php/products
    x1: = 180

    Driver power supply:
    https://www.ebay.com/itm/72v-16-5a-1...-/132199640758
    x1 = 305

    chassis c-beam machine:
    https://openbuildspartstore.com/open...-beam-machine/
    x1: 589.99

    spindle:
    https://littlemachineshop.com/produc...ory=-269978449
    x1 = 390

    vhd: hitachi nes1-015sb
    https://www.wolfautomation.com/ac-dr...-single-phase/
    x1 = 201

    total: $2713-ish

    Right now the problem I view is rigidity when working harder materials, I just do not have faith in the c-beams to hold up to the torques that the spindle and the nema 34's can apply to a workpiece. Also I do not have a vice selected right now that will be more of an addon.

    I am hoping to use this as a platform to upgrade itself although I am now questioning whether I should instead build a plasma cutter to be able to cut a heavy frame for a future mill.

    Thoughts, concerns, ideas?
    I'm not the most experienced on here, but my 2c, all your components will massively outperform that c beam frame. It's definitely going to be your limiting factor from lack of of rigidity. It all depends what you plan on doing. If you wanted to work on a wide range of materials, I would say a taig or sherline would far outperform that c beam in terms of rigidity, but obviously a much smaller workspace. I would imagine the the c beam could handle very slow work in aluminum with small tools, but more than that it's just gonna flex too much. Precision is also gonna be limited.

    I built my own machine from the ground up for about what you paid, but I had access to basic tools like a table saw, router, drill press. My machine uses some pretty beefy extrusions, mostly 50mm x 100mm, but it gets most of its rigidity from heavy reinforcement with 1/2" thick aluminum gussets that connect everything together, as well as solid aluminum plates on the front and rear of the gantry, and plates under every linear rail. I bought mic6 tooling plate for all the aluminum parts which can he cut on a table saw pretty easily. I rough cut the parts slightly oversize and made mdf templates for bringing the parts to final size with a carbide flush trim in a router. All drilling done in drill press, also using the mdf templates. I probably only held about a 5 or 10 thou tolerance on these parts, but I designed the machine in a way that it didn't rely on accuracy of the parts, only flatness was important which was already taken care of by using mic6. Holes were drilled slightly oversized for fasteners to pass through to allow adjustability of everything. bought a full set of 20mm linear rails and 1605 ballscrews on ebay for 500 bucks. Basically clones of hiwin but they have performed fantastic for hundreds of hours now. Precision is excellent, about 3 tenths backlash at the most. If I'm paying attention to tool runout, I can hold half a thou tolerance on aluminum parts. Since i knew i would be working in mostly aluminum, i went with the Chinese 24k rpm 2.2kw spindle (6k to 24k range). Not great for steel since sfm is too high at 6k, but I still do some occasional milling in steel with small cutters to keep sfm down. In aluminum it it's great, I run at 14k rpm with a 1/4 3 flute using mist coolant and can remove material at a very respectable rate. If speed is less important that working in a wide range of materials, something like the spindle you selected is better, although check out glock cncs new bt30 spindle, many advantages over r8. Eventually I'm gonna switch to that with a dmm servo driving it.
    So basically, if you have access to some basic tools, consider building your own frame, as it will massively outperform that c beam. If you want something more ready to go, I would still consider something different like a taig if you want to work in mostly metal.
    Also you can make some changes to your component list to sabe a lot of money. Your steppers and drivers are overkill. Get some 300 to 400oz nema 23's, and a gecko g540. Its an all in one unit with 4 stepper drivers and Bob built in, simply a db25 cord between smoothstepper a g540, that's all. G540 is like 280 bucks or so. Also has that extra driver if you do dual drive x on a Gantry machine which i would recommend. I didn't look at your power supply, but 300 bucks is alot, should be no more than 100 for what you need. Oh, and get the Ethernet smoothstepper, not the usb. Ethernet is so much more stable when it comes to pc controlled machines.

    Last edited by QuinnSjoblom; 10-18-2019 at 12:02 PM.


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    Community Moderator ger21's Avatar
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    Default Re: Looking for feedback on a build idea

    I'm not the most experienced on here, but my 2c, all your components will massively outperform that c beam frame. It's definitely going to be your limiting factor from lack of of rigidity.
    +1

    I wouldn't spend more than $500 for electronics on that C Beam machine. It's a lightweight hobby machine.

    Gerry

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    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Default Re: Looking for feedback on a build idea

    As other have said, the CBeam machine is truly the weak link here. I have a small one and it has a fair amount of deflection. You can get decent results if you run with a shallow DOC but that makes for really long run times for moderately complex operations. The forum at openbuilds is full of discussions about this and schemes to stiffen the various frames but you are better off starting with something you don't have to patch in the first place.

    Or, if you are willing to accept the limitations of a CBeam machine, you can put much lower cost components on it.



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    Default Re: Looking for feedback on a build idea

    Hi EH - A mill is a totally different thing to a hobby router. I think you need to look at small bench top mills and convert one to CNC. Peter



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    Default Re: Looking for feedback on a build idea

    I think you need to look at small bench top mills and convert one to CNC. Peter
    Yeah... perhaps something like a Sieg X3 or Grizzley G0704. I'd avoid the round column "mill-drills", though - the round column means that when you adjust the Z you lose the X & Y position.



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    Default Re: Looking for feedback on a build idea

    Quote Originally Posted by QuinnSjoblom View Post
    I'm not the most experienced on here, but my 2c, all your components will massively outperform that c beam frame. It's definitely going to be your limiting factor from lack of of rigidity. It all depends what you plan on doing. If you wanted to work on a wide range of materials, I would say a taig or sherline would far outperform that c beam in terms of rigidity, but obviously a much smaller workspace. I would imagine the the c beam could handle very slow work in aluminum with small tools, but more than that it's just gonna flex too much. Precision is also gonna be limited.

    I built my own machine from the ground up for about what you paid, but I had access to basic tools like a table saw, router, drill press. My machine uses some pretty beefy extrusions, mostly 50mm x 100mm, but it gets most of its rigidity from heavy reinforcement with 1/2" thick aluminum gussets that connect everything together, as well as solid aluminum plates on the front and rear of the gantry, and plates under every linear rail. I bought mic6 tooling plate for all the aluminum parts which can he cut on a table saw pretty easily. I rough cut the parts slightly oversize and made mdf templates for bringing the parts to final size with a carbide flush trim in a router. All drilling done in drill press, also using the mdf templates. I probably only held about a 5 or 10 thou tolerance on these parts, but I designed the machine in a way that it didn't rely on accuracy of the parts, only flatness was important which was already taken care of by using mic6. Holes were drilled slightly oversized for fasteners to pass through to allow adjustability of everything. bought a full set of 20mm linear rails and 1605 ballscrews on ebay for 500 bucks. Basically clones of hiwin but they have performed fantastic for hundreds of hours now. Precision is excellent, about 3 tenths backlash at the most. If I'm paying attention to tool runout, I can hold half a thou tolerance on aluminum parts. Since i knew i would be working in mostly aluminum, i went with the Chinese 24k rpm 2.2kw spindle (6k to 24k range). Not great for steel since sfm is too high at 6k, but I still do some occasional milling in steel with small cutters to keep sfm down. In aluminum it it's great, I run at 14k rpm with a 1/4 3 flute using mist coolant and can remove material at a very respectable rate. If speed is less important that working in a wide range of materials, something like the spindle you selected is better, although check out glock cncs new bt30 spindle, many advantages over r8. Eventually I'm gonna switch to that with a dmm servo driving it.
    So basically, if you have access to some basic tools, consider building your own frame, as it will massively outperform that c beam. If you want something more ready to go, I would still consider something different like a taig if you want to work in mostly metal.
    Also you can make some changes to your component list to sabe a lot of money. Your steppers and drivers are overkill. Get some 300 to 400oz nema 23's, and a gecko g540. Its an all in one unit with 4 stepper drivers and Bob built in, simply a db25 cord between smoothstepper a g540, that's all. G540 is like 280 bucks or so. Also has that extra driver if you do dual drive x on a Gantry machine which i would recommend. I didn't look at your power supply, but 300 bucks is alot, should be no more than 100 for what you need. Oh, and get the Ethernet smoothstepper, not the usb. Ethernet is so much more stable when it comes to pc controlled machines.
    Thank you for the suggestions, at first I thought building a frame would be more than I wanted to do but the more I research and hear it doesnt seem as daunting. Also great call on the gecko g540, the electronics I had selected were just overkill but i was having difficulty finding an alternative. Will the nema 23's scale into a larger future build?



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    Default Re: Looking for feedback on a build idea

    Like others on this thread, I don't believe that aluminum extrusion-based frame will do what you're expecting. If you really want to be able to mill metals, you're looking for an entirely different basic machine that's a lot more rigid. Take a look at various mills that actually were designed to cut steel, and you'll notice they're considerably different in their construction. Small ones can be made from welded steel, but ones with a part envelope like you're looking for tend to be made from cast iron. Unless you've got access to a foundry, it's a lot more cost and time-effective to find an older mill and retrofit it than to make your own mill from scratch.

    One thing I noticed about your list was that the spindle you indicated has its motor controls included - what's the VFD for? I should also point out that for the money you're anticipating having to spend, you can buy a Taig mill complete with CNC system; all you'd need to provide would be a computer. That would be able to make the motor mounts and other smallish machined parts you'd need for a future machine, as well as handle other projects you might have, that fit its envelope.

    Andrew Werby
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    Quote Originally Posted by eh3378 View Post
    Thank you for the suggestions, at first I thought building a frame would be more than I wanted to do but the more I research and hear it doesnt seem as daunting. Also great call on the gecko g540, the electronics I had selected were just overkill but i was having difficulty finding an alternative. Will the nema 23's scale into a larger future build?
    Yes, nema 23s will drive a decent sized machine. For example, the biggest tormach is driven by nema23, although those might be higher torque than the 300 to 400oz I mentioned. Someone correct me if I'm wrong, but going with higher torque steppers usually has a lower rpm limit, so rapids will top out lower if you go overkill on torque. The tormach machines use box ways and leadscrews, so they need the torque, but the rapids aren't so great. With my machine that uses 300oz steppers, linear bearings, and 5mm pitch ballscrews, i can get 10m/m rapids (400in/m) and ive never lost steps, not once. I'm also using Ethernet smoothstepper and g540. Really solid setup. Also I'm not sure what your experience is with cnc, but if you're just learning you WILL crash. With my setup I can do pretty aggressive cutting in aluminum, 3 cubic inches per minute with out ever losing steps, and the the power of stepper/ballscrew combination will stall out in a crash before damaging my machine. If o had crazy torque steppers, a crash could do some serious damage. Although that's just my machine which I consider to be pretty rigid. A c beam frame might just twist itself apart in a crash even with only 300oz.



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    Default Re: Looking for feedback on a build idea

    The spindle i was looking at (is basically a replacement head unit for that mini mill) comes with a variable speed PWM (? something like that) which allows you to change the speed by turning a dial, the VFD (variable frequency drive) im hoping would allow me to remove the existing speed control and replace it with one that can accept signal inputs from the controller.

    although now that you've pointed me at taig.... jesus how did i not find that company when i was researching....



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    Quote Originally Posted by eh3378 View Post
    The spindle i was looking at (is basically a replacement head unit for that mini mill) comes with a variable speed PWM (? something like that) which allows you to change the speed by turning a dial, the VFD (variable frequency drive) im hoping would allow me to remove the existing speed control and replace it with one that can accept signal inputs from the controller.

    although now that you've pointed me at taig.... jesus how did i not find that company when i was researching....
    Also check out glock cnc. They sell upgrades for taig and I believe are also a dealer for taig and will sell an upgraded machine instead of replacing stuff later. They have a bt30 spindle headstock that is about to be released. It's designed to work on sherline and also taig with an adapter. Bt30 is pretty much the ultimate spindle setup for a medium to small mill in terms of rigidity, repeatability, runout, and ability for atc. Combine that with a servo to drive it and you have an extremely capable setup. Servo driven spindle is nice for a lot of reasons. A lot of power in a small package, very wide range of useable rpm (torque all the way down to zero), spindle indexing for tool changer, rigid tapping, etc. Next upgrade for my home built machine is gonna be that bt30 headstock and dmm servo to drive it.



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    Default Re: Looking for feedback on a build idea

    One concept that I found fascinating is fox3d's granite mill, which is steel capable, pretty much just using hand tools. YouTube series video 1:


    He uses a granite surface plate as the base and bed (for his machine, a 24" x 36" x 4"), which is a mass-produced precision flat (to e.g. +/-0.0002") rigid surface. Granite countertop material for sides and the gantry.

    Cutting oil or flood coolant won't bother it a bit.

    Bosch PDB-40 benchtop drill press (head height adjusts on the column, 240V though) to slide on it, with a diamond cup wheel to grind the sides flat and parallel to the bed.

    Also bloody heavy, at 400# for the bed alone. Might want a size or two down. Pick one up locally if possible; $$$ for shipping.

    The less-accurate version would use only countertop material, which is not as flat or precise but is available as surplus, remainders and scrap.

    I think of it as brute-force elegance: use a mass-produced, low cost flat, rigid precision object as the basis for the machine.



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