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  1. #1
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    Nov 2018
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    YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Hi Everyone,

    I am currently designing a 5 axis vertical mill for aluminum and wood working.The main frame will be a weldment of steel I-beams and rectangular tubing. My total budget is $5K and I plan on making it fully enclosed with sliding doors.

    I am in the middle of sourcing components but already bought the following:

    • 3X 1200oz-in NEMA 34 Stepper motors/ 7 amp stepper drivers
    • 20mm Linear rails and 16mm Ball Screws (1500mm, 1000mm, and 400mm)
    • NVEM 6 Axis Mach 3 controller and handheld MPG
    • 2.2KW Spindle with ER20 collet
    • 3X Steel I-Beams 4'' Deep 8ft Long

    See attached pictures. I also uploaded a 3D PDF.

    I would appreciate any input from the more experienced folks here!

  2. #2
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    You need to do a lot more research.
    Maybe it would be suitable to mill foam...

  3. #3
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Yes, not nearly rigid enough.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

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

  4. #4
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    With this u can mill aluminium , but wery slow , and precision , i don't think there will be one , maibe only to make decorative aluminium components .
    But for foam i think this will work ok , but u need more z travel , u can make nice thinks in foam with this machine .

  5. #5
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Thanks for the input. Are the any maximum deflection values I should design for?

    Somebody here mention 20,000 lbs/in for milling aluminum. Does that sound accurate?

    https://www.cnczone.com/forums/diy-c...71435-cnc.html

  6. #6
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    When you stuck the spindle out on that long unsupported arm, you lost the ability to mill soft wood, let alone aluminum. That would have to be about 100 times heavier before it would work. Take a look at the designs of milling machines that actually cut aluminum in the real world. There's a reason none of them look at all like your design. It might make a decent 3D printer, though, if you substitute an extruder for the spindle and provide a heated bed.
    Andrew Werby
    Website

  7. #7
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    When you stuck the spindle out on that long unsupported arm
    I missed that. Yeah, you won't be cutting anything with that.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

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

  8. #8
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by awerby View Post
    When you stuck the spindle out on that long unsupported arm, you lost the ability to mill soft wood, let alone aluminum. That would have to be about 100 times heavier before it would work. Take a look at the designs of milling machines that actually cut aluminum in the real world. There's a reason none of them look at all like your design. It might make a decent 3D printer, though, if you substitute an extruder for the spindle and provide a heated bed.
    Yes I was going to fix that =). I found a paper saying tangential cutting forces on aluminum are about 50lbs.

    https://www.researchgate.net/publica..._Manufacturing

    If I design around that, does permissible deflection of 0.0002'' sound like it would work?

  9. #9
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    Jun 2016
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Your current design is flimsy, even for wood and wastes a lot of space and material.
    And to top it off you mix a gantry style mill bottom with a vertical machining center column in a CNC where the operator does not need to be able to get to the parts as he does in a manual machine.

    If you do wood, you usually fixe the board/block and drive everything around it, as space is premium and small/medium motors are cheap and less strong structures that are fast to drive can handle this.
    This means you get the standard CNC router design that everyone builds.

    If you do metals the system needs to get beefier and it might pay off to move the part around on x and have the spindle fixed on a gantry that only moves in y/z.
    Or keep the part fixed and still move everything around like on the wood routers, but then the drivers get bigger and the whole thing needs to be made as sturdy as (usually the bed then moves down, past the y-rails, see very large machining centers, where one can walk in).
    Again economic decisions, as moving lot's of mass around fast goes into large motors and drivers which are expensive.

    You mix the worst of both and achieve even less, by doing exactly the opposite of what would be logical for your use case.
    And to top it off you take away rigidity by building a spindle arm, which is common on manually operated vertical milling centers, so that the operator can access as much of the volume as possible, while he was driving the milling head from a central motor/drive (historical reasons for how those things evolved with belt drives and what the hell do I know).

    Scrap this and start new. Really, just scrap it.
    That you didn't tell what kind of stuff you want to be able to do and what it should be capable of tells us a lot. That's not how one designs a machine.

    TL;DR: You don't understand the basics of designing something like this yet.

    First question: how large objects do you want to be able to work on.
    Second question: what material
    Third: how accurate and fast shall the outcome be
    Fourth: how much do you want to spend

    That's how you start.
    Then you go and look at what others did for similar specs as yours and analyze what they did.
    Then improve on it (if possible) and call it a day.

  10. #10
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Okay Negative Nancy please keep it constructive.

    I do not have a garage so I'm designing subassemblies that can be broken down and fit through a 36" door.

    For the size - everything will be shifted over for a separate electronics bay. Also standard size for i-beams is 8ft so I minimize fabrication time.

  11. #11
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Calling someone who's made some very cogent points a negative nancy just makes you look deluded, I'm afraid.
    The frst thing to take note of in any milling machine design is stiffness/rigidity - this is largely achieved through adding mass, as well as through clever stress analysis. Putting a spindle on the end of a scrawny arm is at best going to achieve a load of chatter, and at worst will eat toolbits and spindle bearings like nobody's business.
    Take a look at this eBay listing here, for example - the main difference between your design and this one is that everything's big and chunky, even for such a small work envelope. Most people here would consider the design on this to be a bit weedy as well, because it's cheap aluminium plates bolted together, and lacks mass as a result. I'd buy one quite happily, but wouldn't expect it to do much other than foams and softwoods - anything harder would tax it somewhat if I intended to run it at any appreciable speed.

    Your design at the very least needs extra bracing on the table, as well as having the spindle brought back in to where the Z axis is - you simply can't have it hanging out there if you want to machine anything hard at all - your chatter and tool deflection will be insane if you leave it like that.

    Stop spending money for the moment, and spend more time researching current 5-axis designs. They're a pretty mature technology, so most of the design decisions made nowadays are well-established for good reason.

  12. #12
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    Quote Originally Posted by aortiz21 View Post
    Thanks for the input. Are the any maximum deflection values I should design for?

    Somebody here mention 20,000 lbs/in for milling aluminum. Does that sound accurate?

    https://www.cnczone.com/forums/diy-c...71435-cnc.html
    Yes I was going to fix that =). I found a paper saying tangential cutting forces on aluminum are about 50lbs.

    https://www.researchgate.net/publica..._Manufacturing

    If I design around that, does permissible deflection of 0.0002'' sound like it would work?
    I believe I made it clear that I am increasing the stiffness of the frame and gantru which is why I asked the two questions above.

    However, it looks like most people would rather criticize than provide helpful answers. Not sure who they're trying to impress.

  13. #13
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    To start with you do not have a 'gantry'.
    A gantry is a beam that is supported on both ends, for stiffness with a traveler along that beam.

    As for cutting forces and related discussions:
    https://www.cnczone.com/forums/mechanical-calculations-engineering-design/100340-cutting-force-milling.html
    (the pdfs linked are available via https://web.archive.org/)
    https://www.mmsonline.com/articles/a...s-and-formulas
    https://www.cnczone.com/forums/gener...s-milling.html
    Be aware that this all is static and doesn't take into account dynamic forces that are results of oscillations and your YAAS will produce a lot of those, due to it's design.

    As for being a negative nancy.. well, you seem to use a very nice CAD package there, what is it?
    Does it have FEM?
    How about you put a 50N (~5kg) force at the tip of that spindle, pulling in the direction of the x axis and look what deflections you get?
    The anchor/non moving part would be the table your part is mounted on for that analysis.
    If your CAD tool doesn't have that but can export a STEP model I'd happily do that for you in my tool.

  14. #14
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by aortiz21 View Post
    I believe I made it clear that I am increasing the stiffness of the frame and gantru which is why I asked the two questions above.

    However, it looks like most people would rather criticize than provide helpful answers. Not sure who they're trying to impress.
    Critique is helpful. We're not telling you to give up and go away, we're saying that there are clear design considerations that you're either ignoring deliberately or are unaware of - saying "I am increasing the stiffness of the frame and gantry" without specifying how just leaves the whole thng open to misinterpretation - if you want valid design input, you need to offer more information than you have thus far.

    For starters, you don't have a gantry - that's an overarching frame that's supported at both ends. You've got a cantilevered spindle instead, which is a much weaker system of attachment when it comes to dealing with the kind of dynamic loading that a mill or router has to deal with. Ordinarily, this is resolved by having as short a cantilever as is possible, which is why the spindle is never normally mounted away from the z axis like that.

    Frame stiffness is also only part of the issue - how are you looking at vibration damping? Again, adding weigt is a great way of eliminating it as a problem, but the kind of airspace design you have at the moment has very few avenues available to it to be able to resolve that.

    When I said to stop spending money right now, I didn't say to quit, I said to continue researching the project - I'd really like to see you succeed, but I genuinely do not believe that you're going to get very far ith this current design, because it's just not going to be stiff enough to have any degree of consistency or repeatability in the cuts that it makes. This is too close to a 3d printer design, and the requirements are very, very different. 3D printers don't have any kind of serious load attached to the printing head - they're depositing material in what's effectiely a zero-resistance environment (unless something's gone very wrong), whereas a mill or router has got a continuous dynamic load applied to it, because it's being forced against material that it's expected to cut away.

    The pdf article you cited pertains specifically to toolbit deflection, and assumes a certain degree of rigidity in the CNC machine frame that yours won't have, due to having that massive arm hanging off of it. If the spindle were brought right back in to the Z axis, then it might be more relevant. As for the thread link, 20klbs probably isn't a bad figure to aim for, but you really do need to run an FEA test on your current design based on that. I absolutely guarantee that the spindle arm will need a thorough redesign.

  15. #15
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    However, it looks like most people would rather criticize than provide helpful answers
    No, they are trying to be helpful. You just aren't listening.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

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

  16. #16
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by JoanTheSpark View Post
    To start with you do not have a 'gantry'.
    A gantry is a beam that is supported on both ends, for stiffness with a traveler along that beam.

    As for cutting forces and related discussions:
    https://www.cnczone.com/forums/mechanical-calculations-engineering-design/100340-cutting-force-milling.html
    (the pdfs linked are available via https://web.archive.org/)
    https://www.mmsonline.com/articles/a...s-and-formulas
    https://www.cnczone.com/forums/gener...s-milling.html
    Be aware that this all is static and doesn't take into account dynamic forces that are results of oscillations and your YAAS will produce a lot of those, due to it's design.

    As for being a negative nancy.. well, you seem to use a very nice CAD package there, what is it?
    Does it have FEM?
    How about you put a 50N (~5kg) force at the tip of that spindle, pulling in the direction of the x axis and look what deflections you get?
    The anchor/non moving part would be the table your part is mounted on for that analysis.
    If your CAD tool doesn't have that but can export a STEP model I'd happily do that for you in my tool.
    Thanks for the links! I'll go through them tonight. I'm using Solidworks rendered with KeyShot. It does have FEM, so I'll do some analysis with the setup you described.

    Critique is helpful. We're not telling you to give up and go away, we're saying that there are clear design considerations that you're either ignoring deliberately or are unaware of - saying "I am increasing the stiffness of the frame and gantry" without specifying how just leaves the whole thng open to misinterpretation - if you want valid design input, you need to offer more information than you have thus far.

    For starters, you don't have a gantry - that's an overarching frame that's supported at both ends. You've got a cantilevered spindle instead, which is a much weaker system of attachment when it comes to dealing with the kind of dynamic loading that a mill or router has to deal with. Ordinarily, this is resolved by having as short a cantilever as is possible, which is why the spindle is never normally mounted away from the z axis like that.

    Frame stiffness is also only part of the issue - how are you looking at vibration damping? Again, adding weigt is a great way of eliminating it as a problem, but the kind of airspace design you have at the moment has very few avenues available to it to be able to resolve that.

    When I said to stop spending money right now, I didn't say to quit, I said to continue researching the project - I'd really like to see you succeed, but I genuinely do not believe that you're going to get very far ith this current design, because it's just not going to be stiff enough to have any degree of consistency or repeatability in the cuts that it makes. This is too close to a 3d printer design, and the requirements are very, very different. 3D printers don't have any kind of serious load attached to the printing head - they're depositing material in what's effectiely a zero-resistance environment (unless something's gone very wrong), whereas a mill or router has got a continuous dynamic load applied to it, because it's being forced against material that it's expected to cut away.

    The pdf article you cited pertains specifically to toolbit deflection, and assumes a certain degree of rigidity in the CNC machine frame that yours won't have, due to having that massive arm hanging off of it. If the spindle were brought right back in to the Z axis, then it might be more relevant. As for the thread link, 20klbs probably isn't a bad figure to aim for, but you really do need to run an FEA test on your current design based on that. I absolutely guarantee that the spindle arm will need a thorough redesign.
    I appreciate the input! I'm going to modify the spindle arm based on FEA to remove the cantilever arm. I'm also going to brace the frame with more rectangular tubing or trusses. For vibration - I'm exploring drilling holes in the tubing and filling with concrete post welding to add mass. It seems some members here had some luck with non expanding grout or epoxy granite.

  17. #17
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by aortiz21 View Post
    I appreciate the input! I'm going to modify the spindle arm based on FEA to remove the cantilever arm. I'm also going to brace the frame with more rectangular tubing or trusses. For vibration - I'm exploring drilling holes in the tubing and filling with concrete post welding to add mass. It seems some members here had some luck with non expanding grout or epoxy granite.
    Increased cross-bracing and mass will definitely help. Epoxy granite is a pretty popular awy of going about adding mass to a hollow structure, so that's a good call.

    Peronally, my next step would be to make everything more compact, to be honest - you've got a lot of travel into empty space in the current design that won't necessarily be of much benefit. It might be worth looking a bit more closely into what exactly you're intending to make with this: is it going to be processing sheets or blocks of material? If it's sheets or flatter material, then a gantry-style system with a lot of travel in X or Y would be easiest, with the A/B rotations happening on the head instead of the workpiece. If it's a block that you're looking at working on, then you can cut the amount of X/Y travel right down, and eliminate all the distance that'llbe amplifying vibrations and instability. That's when a trunnion and turntable will make the most sense.

    There's a certain amount of crossover that can happen between these design ideas, but there really does need to be a bias that you've chosen, because it's far easier to design for one thing that can accomodate another, than to design specifically for both, if that makes any sense.

    IIRC, you've already gone and bought some long lengths of steel, right? If that's the case, then I'd really be looking to go down the router table route, with the A/B articulations on the head. As many people have proven it's more than possible to machine metals on a router, provided it's stiff and heavy enough.

  18. #18
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by aortiz21 View Post
    Yes I was going to fix that =). I found a paper saying tangential cutting forces on aluminum are about 50lbs.

    https://www.researchgate.net/publica..._Manufacturing

    If I design around that, does permissible deflection of 0.0002'' sound like it would work?
    I think that 50 lbs is for a very light cut. Says 1.27mm deep, 6.35mm slot @ 381 mm/min (1/16" x 1/4" x 15 ipm.) That's about a 0.1 HP cut. The smallest common high speed spindles (800W) have 10x that power. Actually, that load sounds pretty high for that cut (break strength of a 1/4" endmill is only somewhere around 300 lbs.) May be that they were cutting well outside the ideal parameters for their cutter. 20,000 LBS/in would be a minimum for an 800W spindle probably. Would still have a lot of chatter I think though.

    There were a couple recommendations against having a long cantilever from the Z axis. I disagree with this, as most non-quill mills and VMC's have this cantilever. It's just that on a mill it's usually a large casting and it would need to be 1000x as stiff as what's in your model.

  19. #19
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by skrubol View Post
    There were a couple recommendations against having a long cantilever from the Z axis. I disagree with this, as most non-quill mills and VMC's have this cantilever. It's just that on a mill it's usually a large casting and it would need to be 1000x as stiff as what's in your model.
    This s entirely true - however, as you say, since the casting is massive by comparison, it's got significantly less 'lever' in the cantilever.

  20. #20
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    Re: YAAS! DIY 5 AXIS VERTICAL MILL - OPEN SOURCE

    Quote Originally Posted by GerryG View Post
    Increased cross-bracing and mass will definitely help. Epoxy granite is a pretty popular awy of going about adding mass to a hollow structure, so that's a good call.

    Peronally, my next step would be to make everything more compact, to be honest - you've got a lot of travel into empty space in the current design that won't necessarily be of much benefit. It might be worth looking a bit more closely into what exactly you're intending to make with this: is it going to be processing sheets or blocks of material? If it's sheets or flatter material, then a gantry-style system with a lot of travel in X or Y would be easiest, with the A/B rotations happening on the head instead of the workpiece. If it's a block that you're looking at working on, then you can cut the amount of X/Y travel right down, and eliminate all the distance that'llbe amplifying vibrations and instability. That's when a trunnion and turntable will make the most sense.

    There's a certain amount of crossover that can happen between these design ideas, but there really does need to be a bias that you've chosen, because it's far easier to design for one thing that can accomodate another, than to design specifically for both, if that makes any sense.

    IIRC, you've already gone and bought some long lengths of steel, right? If that's the case, then I'd really be looking to go down the router table route, with the A/B articulations on the head. As many people have proven it's more than possible to machine metals on a router, provided it's stiff and heavy enough.
    Thanks for the advice! I'm mostly going to mill blocks of material so I cut down the X to 1000mm and Y to 750mm. I've redesigned the frame and FEA is showing a stiffness of 330,000 lbs/in (0.0001'' deflection at 33 lbs). I'm on Christmas break so I'm planning on refining it a lot more this week.

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