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OpenBuilds LEAD CNC

Discussion in 'CNC Mills/Routers' started by MaryD, Nov 20, 2018.

  1. wojak

    wojak New
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    Exactly the same as me. I rented small workshop but it is too small.
    I will be trying to mount Lead CNC on the wall, or under plasma so while not being used it will take less space. However I designed all stuff to be 82 cm tall, so it can be more modular...
    Basically I am trying to use free vertical space bottom up.

    Something like this:
     
  2. Rob Mitchell

    Rob Mitchell Well-Known
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    Has anyone experimented with extending the Z axis c-beam? What were your observations? Conclusions?
     
  3. Batcrave

    Batcrave Journeyman
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    I don't think there's much to be gained by just extending the Z-axis beam, unless you have an unusually long spindle (significantly longer than the standard beam, which I haven't seen) and want to mount it at top & bottom. Regardless of C-beam length, your actual Z travel is still limited by the space between the gantry (probably the lower wheels on the gantry plate, since that's where the endplate on your beam will hit first) and the spoilboard and/or workpiece.

    The only time I could see it becoming useful is if, instead of a workpiece mounted on a spoilboard mounted on top of the frame, you were to set your entire machine on top of the workpiece (presumably working between or removing some of the bed supports to avoid crashes), at which point you'd want to be able to plunge much deeper than usual. I seem to remember someone mentioning they wanted to do exactly that (as a means of gaining Z travel without the rigidity loss of a higher gantry), but I don't recall whether it was with a Lead or some other build.

    Otherwise, you're also looking at raising the gantry height, which, in addition to making the gantry less rigid would also give the tool more leverage against it - sort of a one-two punch against it. If you primarily work with soft materials, though, it could be worth the tradeoffs.

    I'd really like another inch or so of Z on my machine, but even now (and especially if I eventually rebuild with a 3/4 or full-length gantry) I'm worried more about maintaining/increasing rigidity.


    -Bats
    ( my spam folder says there are pills I could give my Lead for maintaining and increasing rigidity... but then it would probably start speaking Russian and watching my while I sleep )
     
  4. Rob Mitchell

    Rob Mitchell Well-Known
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    This is what I was considering. Lever/cantilever effect could be more pronounced against the y-axis wheels.
     
  5. Batcrave

    Batcrave Journeyman
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    Going the Workbee route and doubling up the wheels supporting the gantry seems like it might help compensate for that. Unfortunately I've never been able to get a clear idea of just how much of a difference it makes (has anyone done any experimenting with this?), and it looks likely to require custom plates, making it a little harder to try out on a whim.

    Of course, it also wouldn't do anything to prevent that leverage from flexing/twisting the gantry C-beam, but I don't know which factor is likely to be more pronounced. At least the leverage against the Y wheels is likely to be consistent across the axis, while the twist is likely to get worse in the middle of the beam.


    -Bats
    ( give me a long enough lever and a fulcrum on which to place it, and I shall make a royal hash of your cutting accuracy )
     
  6. ljvb

    ljvb Well-Known
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    So my unit arrives tomorrow. I don't have space for it yet.. **** FedEx and quick shipping.. is the OB lead kit with the v4 and 23 motors..

    Question.. I currently only have my Porter Cable and Hitachi, the Hitachi is only 2 1/4 up, weighs around 10 pounds. Is it going to be too heavy. The PC weighs in at almost 15 pounds, so I figure I'll go with the Hitachi rather than the Pc. Or should I just suck it up and purchase a mill of Amazon or eBay...
     
  7. Batcrave

    Batcrave Journeyman
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    Tell me about it... First mine got delayed & wasn't showing up soon enough... then it got here and I didn't have anywhere to go with it yet.

    23 motors? Wow... that must be at least a 12-axis machine! :jawdrop: How come they don't list that beauty on the web site?

    I doubt trying a 10lb spindle (or even the larger one) is going to damage the machine, so, sure, if it's not too much of an additional hassle to get it mounted, give it a shot. The problem is that the accuracy will tend to suffer. The flexing of the gantry C-beam may result in an inaccurate/uneven depth of cut from one side to the other (becoming worse in the center), and it may twist, causing less-than-straight sides on some cuts. You may also need to set your acceleration and/or rapids a bit lower to keep the motors from stalling. These aren't likely to be drastic differences, so depending on the types of work you're using the machine for and the types of materials you're cutting, you may not notice, or may decide it's not enough of a problem to worry about. If you're trying to do high-precision work, on the other hand - whether that means rocket surgery or fine inlays and joinery - you may find it's unacceptable, at which point it's time to start looking at trim routers or Chinese spindles.

    If you do decide to give it a go, it'll definitely be the heaviest spindle I've seen anyone mention using on a Lead, so I hope you'll keep us updated. I'm especially curious because I've got an already unusually heavy spindle on a shortened gantry, and it'd be nice to have a better idea what to expect if I try moving to a longer one.


    -Bats
    ( that clock didn't say 3am a minute ago, did it? )
     
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  8. ljvb

    ljvb Well-Known
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    Heh..., yes, the clock did say 3am :) my kid is sick and he through up all over his bed in the middle of the night, so I was up.

    I went short hand with my comment.. although.. I guess I could be building a robot :) with routers for hands..
     
  9. Batcrave

    Batcrave Journeyman
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    Ugh... my condolences. On the brighter side, at least you had a decent excuse :p

    That sounds absolutely terrifying.

    I want one.

    -Bats
    ( maybe even two )
     
  10. ljvb

    ljvb Well-Known
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    Who does not want a Robot.. just make sure you are on good terms during the uprising..
     
  11. ljvb

    ljvb Well-Known
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    Back on topic, when I was asking whether it would damage the unit, I was less concerned about flex in the frame. Based on what what I have been seeing in the Blackbox thread, the V4 with the Nema23 steppers is under powered. Dropping a router that weighs 3 times as much as the dewalt on it might cause some serious issues.

    I just got the package, and pulled out the mount. The hitachi is about 1/8 of an inch too large, the PC is way too large.. so I guess I will go pickup the DW611 later today.. when I buy 20 2x8x8's to build a table for it. Been needing an outfeed table anyways. I could build a temp mount out of wood to mill a larger AL mount.. or maybe I'll just get a spindle from Amazon, it would get here long before I am ready to assemble the CNC (I have a bathroom to finish tiling this weekend too... the to do list is ridiculously long, and this is a toy for me to play with).

    Also, holy crap is that box heavy.. OB knows how to pack a box.. and bubble wrap.. so much bubble wrap... my 6 year old is already asking me for it to pop it.. I said no.. so now I have a pouty sick 6 year old..
     
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  12. GrayUK

    GrayUK Openbuilds Team Elder
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    Let her pop it!!! :thumbsup::thumbsup::thumbsup:
    She can run around on it and make a great noise :D
    Or are you saving it for yourself? :rolleyes:
     
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  13. ljvb

    ljvb Well-Known
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    Him.. and maybe I am.. lol

    And it would drive my wife insane...
     
  14. Batcrave

    Batcrave Journeyman
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    "Cause serious issues" might be overstating it, but you're right - the stock leadscrew with a standard (non-high-torque) stepper on the Z might have trouble just holding up something that heavy, and would be even more likely to have trouble moving it quickly (never mind changing direction) without losing steps. I forgot that I'd used a high torque stepper for my Z axis as a precaution, so I don't really have a good sense for what the standard ones will and won't tolerate.

    Mine showed up when I was in the middle of (and already running desperately behind on) Christmas prep... I made the excuse that "well, maybe I can use it to make a few of the gifts I've had trouble shopping for" - only to get it built and realize it was going to be a lot more work to get either of the spindles I had running with it.

    Veritable seas of bubble wrap! I was worried I might drown in it.

    But I'm with Gray - bubble wrap is made for 6 year olds to pop. Especially since Openbuilds is considerate enough to use lots of the sort with the big bubbles that make a really satisfying "POP!", instead of just the wimpy little bubble mailer sort that make more of a weak wheezing fart.


    -Bats
    ( fondly reliving memories of being six years old and stomping - heels first - from one bubble to another )
     
  15. sn4k3

    sn4k3 New
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    Is BlackBox a good replacement for the v4 board and good match for LEAD CNC or the v4 still have some advantages?
     
  16. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Its been designed to properly run all our bundles yes. If you are still shopping, go BlackBox. If you have an Xpro already, try it first.
     
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  17. sn4k3

    sn4k3 New
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    Thank you, i plan to buy it since it have more options for control tool and water, the only thing is missing is wifi, maybe a addon with AUX header is possible...
    I'm planing buy a 1.5KW 80mm spindle with mount adapter for the LEAD, there are air and water colling versions, i contact seller about weight, he say's they both weight the same (Water and air spindle), arround 4KG+/-. There is also the 68mm version 1.2KW that weights 3KG.
    Do i really have any advantage going the water colling variant or for 1.5KW the air does the job just fine and water is irelevant?
    Will i benefit from a 1.5KW spindle compared to 1.2KW on LEAD? 1KG diference seens will make the diference over time with axis, also i will go for high torque motors.

    Also does any one know a European openbuilds distribuitor that sells the LEAD and/or blackbox?
    Regards
     
  18. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    In theory yes.

    In practise, Wifi is unstable. USB is awesome
     
  19. Rob Mitchell

    Rob Mitchell Well-Known
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    Anyone ready to post videos of the BB in action?
     
  20. Batcrave

    Batcrave Journeyman
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    I figure I've posted my ramblings on spindle weight enough times in this thread that everyone's probably memorized them (feel free to skim back and/or stalk my post history), so I'll just say "lemme know how it goes", since I'm still really curious to know how the larger spindles work out on a full-width gantry.

    Both will do the job they're designed to under the conditions they're designed for, but it's definitely not irrelevant.
    • If you're only running at high speeds, they'll both keep your spindle from overheating, but the fans on air cooled designs become less effective the slower the spindle turns - I've usually seen 6-7000rpm quoted as the range below which you're at risk of cooking your spindle. If you're only going to be using small tools on wood, that probably doesn't matter, but when you get into larger tools and/or harder materials like aluminum, it's nice to have the option to go slower (it's also nice never to have to worry about it).
    • Air-cooled spindles, like routers, blow downward and send chips/sawdust flying everywhere. This can be a good thing, as it helps to keep chips from building up around the tool... but it doesn't help much (especially with deep slotting cuts, which is where chip buildup is most dire). It can also act as a bellows if the packed in chips at the bottom of a deep slot start burning (not that I'd ever be so careless as to let and endmill buried in chips heat up like that - at least not twice). A well-designed dust shoe can help control the mess and control chip buildup, although it also tends to kill your ability to see what the tool is doing.
    • Water-cooled spindles are really, really quiet - although the air-cooled models are still reportedly a fair bit quieter than routers. They obviously still make plenty of noise once they're actually cutting something, but I've been surprised by just how little noise mine makes while it's running.
    • Water-cooled spindles require a cooling loop. In the simplest setup, that'll be a 5 gallon bucket with cheap submersible pump at the bottom, and a hole in the lid for the pump's power cord & two tubes. If that takes up too much space, you can go shopping for PC watercooling components and put together a tiny little loop with a small reservoir and a radiator with fans on it.
    (I think I may have posted most of that several times before, too. oops.)

    Personally I love my water cooled spindle and wouldn't dream of going to air, but different people have different priorities.

    I've never seen a 1.2kW or 68mm version of the standard Chinese spindles, so there's a chance you're looking at an entirely different design, in which case I can't really comment - the standard options are 800W, 1.5kW, and 2.2kW in either 65mm or 80mm packages (I've only seen the 2.2kW in 80mm). That said, I've commented before that I suspect there's little to no advantage in power between an 800W and a 1.2kW spindle on a lightweight machine like the Lead (or anything else in this class) - even the 800W is likely to be bottlenecked by machine rigidity. That doesn't mean there's no reason to go for the larger option, though, since the 800W models are usually equipped with an ER11 collet chuck (which can only take collets up to 7mm or .3125") while it's possible to find the larger models with an ER16 (10mm/.4375") or even, at least on 2.2kW models, ER20 (which is the smallest ER collet that can hold a 1/2" shank router bit, although it'll go as large as 13mm/.5625").

    I don't think time really factors into it - sagging or deformation over time isn't the issue people usually focus on when they talk about heavy spindles. The main problem that comes up with spindle weight (and this goes for any spindle/router/dremel, really - it's all a matter of degree) is that it causes the gantry to flex and/or twist - the longer the gantry and the heavier the spindle, the more pronounced the effect. Because it gets worse as you move toward the center of the gantry, this means you end up with (among other things) an uneven depth of cut as you move along the X axis and ridges between passes. Twist (which isn't limited to the gantry rail itself twisting, and is exacerbated by how far out from the rail the weight it mounted) can cause vertical cuts to be less or greater than 90° and cause (slightly different) ridges between passes. Again, this is entirely a matter of degree, and what point it becomes intolerable (or even becomes detectable) depends entirely on what sort of work you're doing and/or the sensitivity of the tools you're using to measure it.

    Don't make a snap decision on this one without a bit of research, or you my handicap yourself. It's easy to assume "it's only a couple bucks more, so I'll go for the high torque motors just in case", but price isn't the only tradeoff here - unfortunately the parts store doesn't do anything to clarify this (to be fair, most similar sites aren't any better), doesn't provide torque curves, and currently don't even seem to have a datasheet on the standard model (which I hope is just a bug), making the differences especially difficult to quantify. The short version is that higher torque steppers tend to be more power hungry (meaning they may not work, or may underperform with a power supply & drivers that were sufficient for the standard models - I don't know how much of an issue this is on the xPro or Blackbox), and to operate at lower speeds than their lower-torque brethren.

    I did use a high torque stepper on my Z axis to support my 1.5kW spindle (and Z speed really isn't a significant factor for CNC anyhow), but for X & Y I stuck with steppers pretty close to the stock ones. The speed of your X & Y rapids is a significant factor - even more so if you're impatient - but torque is less of one (again, bottlenecked by machine rigidity), and it doesn't take significantly more to slide around a 4kg spindle than a 1kg one. I do probably have to set my X & Y acceleration a little lower than usual to keep the motors from stalling, but I haven't seen any numbers from anyone else for comparison.


    -Bats
    ( one of these days people will learn not to mention spindles when I'm in earshot. typeshot. batshot.... hey! no shooting the bats! )
     
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  21. sn4k3

    sn4k3 New
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    Thank you for such reply. That’s a bunch of gold information.

    Then water cooled to me, since I plan to do some aluminum cut. I’m new to CNC but I work with 3D printers so I have some experience with the mechanical build part. There are any table showing feedrate, rpm, tool size and material recommendations for beginners?

    Another thing I notice is ER11 is lighter than ER16 (Same KWs, same diameter, same size) why? And Air versions are lighter than water version (I’m based on page specs which can of course be wrong and not 100% trustable) The lack of weight information on spindles kill me, and communication with china sellers are bad, I found a seller that ship within Europe and he have weight information on each spindle, still I don’t know how’s that accurate or correct - Water cooled spindle motor - Shop Cheap Water cooled spindle motor from China Water cooled spindle motor Suppliers at POWACE CNC on Aliexpress.com

    If 800W is at bottleneck already think I would go with it, that’s around 3KG to 4KG, since I plan to have a dust collector + water cooling in top it will adds more weight. 1.5KW ER16 is at 4.6KG water version.

    About tool visibility I saw a shoe made from transparent material, maybe acrylic? Don’t know about durability…

    For people looking for spindle mounts they can be find here: aliexpress.com/item/Funssor-63-5mm-65mm-69mm-71mm-diameter-Router-Spindle-Mount-for-shapeoko-X-carve-OX-CNCs/32825005607.html

    Great explanation on motors! As I can see v4: “Drive 4 motors with DRV8825 Stepper Drivers - 2.5A (peak) with 1.75A (RMS) with up to 1/32 microstepping” Well just looking at drivers they are weak and wide used with not power hunger 3D printers. NEMA High Troque MT-2315HS300AW-OB are 3A Rated, that’s already out of driver capability and we should never use the PEAK on drivers, each mean you are totally right. Blackbox can be the answer here: “4 x High Powered 3.2A Stepper Drivers (Max rating 4A)” So 3.2A RMS and 4A Peak will benefit the high torque motors. Otherwise v4 is a bit useless with them. Even the normal MT-2303HS280AW-OB are 2.8A rated which is out of the driver, but of course we never run them at max power beside who wan’t cook motor and drivers. Anyway 1.75A for normal NEMA are still low. The solution for high torque motors without blackbox is the drivers: dq542ma DQ542MA Stepper Motor Driver

    [​IMG]
     
    #351 sn4k3, Mar 9, 2019
    Last edited: Mar 9, 2019
  22. Batcrave

    Batcrave Journeyman
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    I've never seen a table that isn't either woefully inadequate and/or entirely inappropriate for lightweight machines. Usually I use some combination of math, calculators and guesswork, then start at about half the recommended speed and crank it up from there as the machine fails to explode and/or turn itself into a pretzel. This goes triple for hardwood, since every species - and really every piece - can behave very differently.

    The traditional math is simple :banghead: and looks something like this:
    Vc = (RPM * Pi * D) / 12
    RPM = (Vc * 12) / (Pi * D)
    Vf = RPM * z * fz
    f = z * fz​

    Where:
    Vc is Surface feet/min (in SFM)
    RPM is occasionally also called 'n'
    Vf is feed rate (in IPM)
    z is number of flutes or teeth
    K is the _effective_ number of flutes or teeth (which equals z except when it's less than z. got that? no? me either. that's why I ditched it for 'z' in the equations)
    f is feed per tool revolution (in/rev)
    fz is chipload or feed per tooth (in IPT)
    D is cutter diameter​

    Some of those figures are obvious or easily (or "easily" :banghead:) calculated from others, but chipload (fz) - which is essential for finding feed rate - is different for each tool and each material, and is a figure (or table) the tool manufacturer is supposed to give you. Of course, if you're a hobbyist and buy crappy cheap Chinese endmills off Amazon (or really great cheap Kyocera endmills with non-catalog model numbers from drillman1 on ebay - highly recommended!), you're pretty much left guessing or trying to extrapolate from other sources and past failures & snapped tools. Even if you actually like that mathy stuff, this is where feed & speed calculators come in handy, as they generally have a built in library of (approximate, but usually mostly safe) chipload values for a range of different tool and material types. Also, they involve less math.

    GWizard is the big name in feed & speed calculators, has a huge list of options & features (a few of which are incredibly useful), a miserable interface, an $80/year price tag, and a month free trial. It also has a weight-based derating option that'll dial back its estimates based on machine weight (although it may occasionally dial them back a little too much for machines as light as these). While the price is technically a subscription, it's not quite as bad as it sounds - each year you pay for gets you a free +1HP spindle rating for life - so if you quit paying after two years you can still keep using it free for calculations on up to 2HP spindles. That said, it's still not cheap enough to be an easy purchase for me, but it is amazingly useful, when I'm not swearing at bizarre decisions that pointlessly defy standard UI/UX conventions, lead to different results depending on what order you set options or fill in fields, or just plain make things awkward.

    HSMAdvisor is their big competitor. While it gets less press in the hobbyist scene (probably for the same reason that I haven't tried it - the lack of free trial), it seems to be fairly well regarded in the professional space. It's a fair bit cheaper than GWizard, if still not an impulse buy (a flat $65 for 1HP w/1yr unlimited power, or $97 for 3HP w/3yr unlimited - apparently goofy hybrid purchase/subscription licensing is the hip thing when you're an aspiring F&S calc).

    Also by HSMAdvisor is FSWizard - a lightweight (and free!) browser/mobile app calculator. It's seriously stripped down compared to the other two, but it's definitely handy when you're just looking for a ballpark figure (or a second opinion because you don't trust your math or your other calculator). It sometimes feels a little fiddly or like the recommendations are way off, but usually I end up finding that I forgot to set something properly and it starts behaving properly - the lesson here (with any method of calculating feeds & speeds) is that if something seems like it might be a bad idea, double check it with another method and then start slow. It also uses "Vc" and "fz" notation, which is the real reason I included all that mathy junk up top.

    I'd ask the seller for confirmation on that one, because I suspect either their weights are wrong or there's a lot more difference between the two than the collets. An ER16 collet nut is larger and heavier than an ER11 collet nut, but not by much. The only other possibility is that they actually use a thinner shaft on the ER11 models rather than just keeping the ER16's shaft and turning/boring/tapping the end differently for the smaller collet - that might make for at least a measurable weight difference, although it seems unlikely (it would at least require different bearings, probably a different motor - would the additional manufacturing headaches really be offset by the slight material savings?). The air & water variants do differ in weight slightly but that's not so surprising, and it seems to vary from one model/size to another which one is heavier.

    Yeah, I had a hell of a time finding any weight figures at all - or they'd quote the weight of the entire spindle+VFD+pump+box+styrofoam+customs bribe+whatever-else-was-lying-near-the-scale package. Or occasionally some sellers would include a weight table that didn't actually match up with the models they were offering - I ended up guessing largely based on the assorted tables I found kicking around online (including the OB forums). Of course, I still keep forgetting to pull out a scale when I have mine off its mounts, so I have no idea how accurate my guess was, either. 4kg seems about right, though.

    Wow... they've got a lot of designs I've never seen before - I guess shipping to the EU must be easier than to the US. That 1.2kW ER20 looked awesome, too... at least until I noticed that it's absolutely gigantic. 125x298mm? WHY??? (I'm also not sure what that third fitting down by the collet is for - "gas sealing"? a compressed air line to keep positive pressure inside, maybe?)

    The water cooling doesn't add much weight (even the water doesn't. there's not much in the coils at any given point in time - even less than there is in the tubes leading from the spindle to bucket reservoir) ... Well, unless you're planning a compact loop with your radiators and a reservoir/pump combo all strapped to the spindle. A dust shoe generally won't weigh much either. The vacuum hose is another matter, but that's a little more complicated since it's often trying to pull to the sides as much/more than pushing down. If you're happy with the range of tool sizes in an ER11, though, go for it - as much as I'm dying to know how a 4kg+ spindle handles on a 1m long gantry, it's not exactly an experiment I could recommend trying.

    Durability's not a big deal - acrylic's cheap, and you can always cut yourself a new one if it breaks. Even with a clear material, though, the cut edges, the brushes, the acrylic getting beat up by constant abuse by aluminum chips, and the big ol' vacuum hose in the middle of it all still combine to do a number on visibility. I'm not saying it's not worth the tradeoff - I just have trust issues and don't yet feel confident in letting my machine do its thing where I can't clearly see what kind of things it's doing. In the long run, it's almost certainly the way to go for woodworking (and definitely for MDF :where'sthe"I'mChoking"smiley?:). For aluminum, I'm looking at a (very) cheap air blast and/or misting rig.

    Interesting... and much nicer looking than the usual cast garbage they sell with the spindles. I was worried about how carefully the two mounts were aligned on that backplate, but it looks like the holes on one side of the plate are drilled oversize for eccentrics to adjust the whole whole unit as one. I wish I'd thought of that when I was trying to sort out the design on mine - I may still try it, if I ever have to re-mount the damned thing. You might want to ask for the hole diagram/measurements, though. I don't know about the Shapeoko or X-Carve, but I think the Ox puts their mounts on a 60mm Z-axis rail (with three slots) instead of the 80mm C-beam (four slots) the Lead uses. I also can't imagine those big socket cap screws not getting in the way (although countersinking/counterboring the holes & using OB-standard flat head screws could probably take care of that).


    This is getting into complicated territory and I think I've already exceeded my dissertations-per-post quota (it's also been a few years since I've dealt with enough of the math to trust myself with the details) and it looks like you've probably got it sorted, but there are a few things worth taking into consideration here. I'll try (try) to summarize:

    1) Stepper power requirement specs aren't exactly intuitive - actually, they're that thing that would be almost the exact opposite of intuitive except that that thing doesn't include phases, windings, or different wiring options - so unless you're buying motors/drivers/power supplies that are explicitly specified to work together, it's worth looking up the equations to understand exactly what's being specified on each part before filling up the shopping cart... I seem to remember voltage requirements in particular getting pretty abstract (I think the recommended power supply voltage is something like 32 times the square root of the motor inductance or 4-20 times the winding voltage).

    2) Don't sell the xPro short just because their main following is in 3D printers - it also seems to have been pretty much the default Openbuilds CNC control package for some time now, and I've seen impressively (ok, surprisingly) few complaints. That being said, yeah, I don't think I'd want to run the high torque steppers on an xPro either, and my poor neglected little v3 has still never been plugged into anything - go with the BlackBox.

    3) They really don't make the BlackBox specs easy to find, do they? I had to google (lowercase 'g') your quote to find the thread, then dig down a couple pages - if anyone from Openbuilds had the stamina to read this far, how about adding/linking those on the store page? It looks awesome, though (and the specs look pretty good, too!) - and definitely much better suited to handle the high torque steppers than the xPro. It is a new and immature product so there are inevitably some kinks yet to be worked out, but I've been thoroughly impressed with the way Openbuilds supports their products and don't see that being a problem. I'd probably be looking at grabbing one myself if I didn't already have my old Gecko G540 (rock solid... absolutely amazing... but uses a parallel port). The only thing that would give me pause is that it looks like the BB can only handle 24V compared to the Gecko's 50V cap... but the Gecko's more than half again the price. And parallel.

    4 is a little pedantic, but worth pointing out on the off chance that anyone's still reading) You'd never guess it from reading hobbyist 3D printing/CNC forums/blogs/shops, but "NEMA 23" doesn't actually specify anything about the motor's capabilities. Technically it's "NEMA frame size 23" (not to be confused with a NEMA 23 power connector, which is entirely different (and doesn't actually exist outside the NEMA standard)) and doesn't specify much beyond the mounting plate dimensions. A larger diameter motor can generally provide more torque than a smaller diameter, but, as is obvious from looking at Openbuilds "standard" vs high-torque NEMA 23 options, girth ain't everything - it's entirely possible to have a NEMA 17 stepper with higher torque than a low-torque NEMA 23 stepper (is such a thing commonly available or even practical? no idea). So a "normal NEMA" doesn't actually mean anything, and even a "standard NEMA 23" only makes sense in the context of somewhere (like Openbuilds) that only offers a "standard" and a "high torque" option. If you go to another supplier and pick a box marked "NEMA 23" off the shelf (even if it's also marked as 175oz and 2.8A), it could be round, have eight wires hanging out the back, and an inductance making it utterly unsuited to your application and/or controller/drivers.

    5) Even if the electronics support it on all four channels, due to the speed tradeoff I'd still only put a high torque stepper on the Z axis (especially since the Blackbox appears to be limited to 24V, meaning you can't just crank the voltage in an attempt to compensate - which probably wouldn't be a great idea anyhow).


    -Bats
    ( congratulations- you made it to the end! you get a cookie! of course, you'll have to share it with everyone else who got here... but let's be honest, who's really going to read all this? you can probably keep that cookie all to yourself. )
     
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  23. sn4k3

    sn4k3 New
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    Again fantastic content! This should sticky somewhere or you should write a paper…

    Sometimes the content is hard to be found on forums and advanced information like this are skip most of the times. People keep repeating same questions, some don’t search others can’t find them. There is a guy from 3D printing that also provide good and complete answers, he also replies on forum but when he has to write new content he copies and post an article in his website (personal notebook), when someone ask the same, he just point out the website to not repeat everything or lost time searching back the content he already posts. Also provide a good information source on the matter. You can see here as example: 3D Printing Projects — Bob's Project Notebook 0.0.1 documentation a good path to follow for people like you which are always helping people with detailed content.

    Well back to CNC matter:

    I think I can trust math, also try error is a good source of knowledge. About calculators I find them old-school and expensive for start or hobby use, also hate subscription model. Maybe you can create a better program based on your experience or maybe a community open source app which people can contribute and also accept donations :)

    About weights I had ask seller, but answer was short and not provide a list of weights for every combination I ask but I got this:

    “80mm 1.5KW Air and water ER11 the weigth around is 4.8kgs

    80mm 2.2KW Air and water ER20 the weigth around is 5.4kgs

    air cooled spindle motor ER16 weigth around is 5.4kgs and water cooled spindle motor ER11 aweigth round is 4.8kgs”

    So based on last paragraph ER16 = 5.4kg and ER11 = 4.8kgs. And that was for 80mm, don’t know other specs but that’s why I keep asking why such difference ER11 VS ER16, I have seen that on every store that have the weight specs…

    Also I ask if air version is lighter then water, he replied:

    “the weight is same”

    But well as I saw on other websites there are a difference so not the same, in best scenario is similar.

    I also doubt sellers take off a spindle and measure it just for reply us, they are relying on a table for sure. Otherwise, the square spindles trend to have weight write down on labels from factory, which is far better than trust china support guy, eg: aliexpress.com/item/New-arrive-1-5kw-air-cooled-spindle-motor-cnc-spindle-motor-220V-1-5KW-inverter-1set/32498495711.html (See main pictures before last.) I wish the same for round ones, why not laser write the weight :(

    Yes, there are many choices and combinations now. But that spindle looks like constant power, so no regulation ie. Speed up or down?

    They also have one dedicated to metal: aliexpress.com/store/product/EU-ship-Quality-2-2KW-Waterproof-Water-Cooled-Spindle-Motor-ER20-220V-4-bearings-Carved-Metal/512815_32881434813.html

    The good part of this store is the EU warehouse, free shipping no import duties to me :)

    Yes and there are many designs if you find, just search for “spindle mount ox” you will get many variants.

    I will ask for hole spacing to the seller.


    About voltages, won’t motors work with much lower voltage? The drivers will convert the input to something like 3V per phase and drive fixed current? As far I know step down much higher voltages to lower ones generate more heat and then waste power. But Trinamic drivers for example work much better with 24V then with 12V, 12V generate more heat and driver got overheated, so I guess it depend on the driver and on psu voltage and not motor itself? Because motor is driven by a driver and not the PSU directly. But amps take in account. 3V*3A * 2 = 18W that’s 1.5A @ 12V, but 0.75A @ 24V and 0.375A @ 48V more some mA from buck conversion efficiency, that’s why higher voltage benefit driver from overheating. And if driver have a very good efficiency then higher voltage = less amps for the same watts = less heat = more efficient system, but there’s of course a sweet point for the driver/voltage.

    The POWACE also haveCNC machines, and with EU stock is a huge benefit for me, as you have the experience can you tell me if the machine they sell is stronger/robust than the LEAD or the LEAD wins? They use smooth rods instead of vwheels. At least they know what they are doing on brains, they use 3 x high power drivers for the steppers and even a 32 bit board that not required but always welcome. Link: aliexpress.com/store/product/4Axis-2200W-8060Z-USB-Mach3-2-2kw-CNC-Router-Engraver-engraving-Drilling-and-milling-Mahcine-110/512815_32817911749.html
    Pricewise would end on same if I import LEAD, so that’s why I’m asking for best.

    Regards
     
    #353 sn4k3, Mar 10, 2019
    Last edited: Mar 10, 2019
  24. Batcrave

    Batcrave Journeyman
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    Sorry for the slow reply - someone forgot to send out my 'new reply' notification *glares at the poor overworked OB forum notification bot*
    Nah, "old-school" is doing all the math yourself - ideally with a slide rule. I don't like subscriptions much either, and I hate the whole "software as a service" direction that licenses have been heading in, but in our case they're really subscriptions in name only, since for a 1HP spindle (again, based on the lightweight machine structure, I find it hard to believe we can even take advantage of even that much spindle power) after the first year it effectively turns from "subscription" to "owned". Also, HSMAdvisor's "lite" calc, FSWizard is completely free anyhow.

    The big advantage to the calculators, though (aside from convenience), is that it's hard to do the math without that pesky little "Fz" number, which changes with each material, and each tool/manufacturer (who may or may not bother to publish the figures).

    Trial and error is definitely a valid alternative (hell, it was the only alternative when I had a setup that couldn't handle high enough feeds or low enough speeds to ever run with anything even vaguely resembling the right settings), but it tends to mean a lot more broken and/or cooked tools than when you can start off already in the right ballpark.

    Yeah.... No.

    Aside from not having much interest in going back to programming and even less in trying to herd cats organizing an open source project (never mind the difficulty of attracting said cats to contribute in the first place), the programming on something like that is the easy part - after all, it's just a handful of forms with some math in the background (organizing a decent UI is another matter, but that's something open source has never been much good with anyhow). The important parts are the math (simple for the basics - which FSWizard and a hundred less useful websites and mobile apps already offer - but getting more involved the more variables you account for), and the material/tool database, which requires a whoooole lotta empirical testing - which is something that's difficult to crowdsource with any sort of meaningful control over conditions. Otherwise you get a haphazard collection of settings that work efficiently sometimes, work inefficiently other times, and occasionally just destroy your tool, workpiece, or machine.

    I'd much rather enjoy my time making new things than being miserable while reinventing the wheel.

    That sounds like they're giving you the weight for a 2.2kW ER16 vs a 1.5kW ER11.

    If you're comparing the air vs water cooled versions of the same design, same size, same power, then they won't be identical, but, yeah, they will be pretty close to the same.

    Yup - almost certainly. Although if you're dealing with a manufacturer or other big seller, they're likely to at least have their own tables, which will probably be correct. If it's a random dropshipper on ebay, half of them seem to just steal their specs from other people selling sorta-vaguely-slightly-similar products, and may have no idea what their actual products are like.

    Otherwise, the square spindles trend to have weight write down on labels from factory, which is far better than trust china support guy, eg: aliexpress.com/item/New-arrive-1-5kw-air-cooled-spindle-motor-cnc-spindle-motor-220V-1-5KW-inverter-1set/32498495711.html (See main pictures before last.) I wish the same for round ones, why not laser write the weight :([/quote]
    Yeah, the square ones are definitely better labeled - a whole lot easier to mount, too. I just wish they offered a water cooled version.


    It's the same as the rest in that regard. Technically none of these spindles have any speed regulation by themselves - that's all handled entirely by the VFD.

    No, they have one that's advertised as "work for metal"(sic) - it doesn't look like it's actually any different. Any of these will work on aluminum, and while, yes, a 2.2kW spindle is probably much better for steel than, say, an 800W, that's immaterial when we're using machines that can't stand up to milling steel in the first place.

    That part's definitely good. It might also make things easier to return if there are problems - and being able to easily say "the runout is out of spec, gimme a new one" would be really nice.

    Unfortunately for me, even if those ox mounts fit the Lead (which I'm still skeptical of), trying "spindle mount ox 80mm" mostly just gives the usual cast garbage... although it did turn up this one, which is fascinating (but won't actually fit an Ox or a Lead)

    There's "working" and there's "doing useful work". Yes, you can generally run steppers (drivers, really) on much less voltage, but below a certain point you'll find that, while the motor will work, it won't actually be able to do what you want it to. In the case of the high torque steppers (which is what I think we were talking about?), you need more voltage to get the same speed as the lower torque models. Because the BlackBox is capped at 24V, this effectively means that high torque steppers are going to be slower. Obviously the same is true if you've got 35V drivers, or 50V - they just offer a bit more headroom (and after a certain point the rest of the machine limits how fast you'd want to run anyhow).


    Now that's something I couldn't tell you - a large part of what attracted me to Openbuilds is the modularity and easy of modification, so I didn't spend a lot of time looking into the Chinese 6040-style systems. Design-wise, ballscrews are great & largely eliminate backlash, and linear bearings on rods are probably more durable in the long-term than V-wheels (although the wheels are dirt cheap to replace if they do end up worn), but depending on diameter, length, and quality control, those rods could just as easily mean far more or far less rigidity than C-beams. Those systems are pretty common, though, so it shouldn't be too hard to dig up details from people who actually know what they're talking about.

    Actually the electronics are where I'd be most inclined to worry. Power & specs (which they seem to have an almost complete lack of anyhow, at least at that link), are only half of the picture - I've always seen far more complaints about Chinese CNC electronics than Chinese CNC hardware, and you can be assured of having exactly zero support when things don't work the way you want them to. Granted, a lot of people out there do get by using the assorted cheap Chinese drivers - some of them haven't even dealt with multiple failed boards - but I'm not sure I've ever seen someone claim that they liked dealing with them. Getting an all-in-one turnkey setup like this seems like it should solve a lot of the fiddly little problems like that, but it's only true if you can count on the guy who put it together to stand by it when things go wrong - and while I trust Openbuilds, Gecko and maybe even Spark Concepts to support their options (either when something breaks, or when I'm just plain not smart enough to figure it out on my own), I don't have a lot of faith in AliexpressCNCCheapHappyDeals15531 to do the same.

    More than that, my feeling has always been that if you're going to splurge on one piece of your CNC rig, splurge on your control/drive electronics. Compared to hardware, they're obscure & difficult to troubleshoot, they have lots of ways for things to go wrong, and even more ways for things to be designed wrong, and if you do narrow down a problem to a design or quality control problem, there's generally no way to fix it except to buy a new one and hope for the best. What's more, your electronics (and maybe your spindle) can carry over from one machine to another as you upgrade, so it's worth thinking long-term. The G540 was by far the most expensive component in my first system and is now doing a fantastic job running my Lead (aside from the parallel port headache), while the rest of the rest of the old machine is scrap.


    -Bats
    ( actually, the old machine was largely built from scrap in the first place, so being reduced to scrap may not be a significant change of station )
     
  25. wojak

    wojak New
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    So again me with heavily modified BFLCNC. IDK if it is still Lead CNC or something else, however I wanted to show it to you .
    From first run without calibration I got about (less then) 0.01mm error.
    I added cold rolled U profile to C-Beam to get it more riggid, also I created most of the plates in 5mm stainless steel.

    zl rf v5.png

     

    Attached Files:

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  26. Trooper11040

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    So far I love my lead but I felt the Z was lacking a bit. I was not a fan of the v-wheels or the low height of the axis. I ruined a few pieces because the Z was so low, I would hit clamps accidentally. I decided to upgrade the Z to a cnc4newbies 7” square linear bearing Z axis. So far it’s amazing. Fast up/down movement and extremely rigid. It works great on 3D carves
     

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  27. Batcrave

    Batcrave Journeyman
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    Whatever it is, it's impressive.

    Now for your next trick, you need to make sure your X & Y can cut squarely to each other to the same degree that they can hit an accurate distance. And if you want a real challenge, try to keep that .01mm tolerance in thickness.

    Sounds like you're laying the groundwork to support a real monster of a spindle, and/or some serious hogging cuts... I may have to try a few of your tricks, if I ever manage to finished this mill (don't say the words "spindle bearings" around me, or I might cry) and get back to playing with the Lead.

    Two questions, though:

    One, how did you fasten the U-profile to the C-beam? Screws & T-nuts? Drilling/tapping/bolting?

    And two, what are you using to cut & drill your steel plates? A mill? Plasma cutter & drill press? Dremel & hand drill (hacksaw & bow drill? rusty spoon & dull screwdriver?)? Your BFLead can't really handle 1/4" stainless, can it?


    -Bats
    ( great, I said "spindle bearings" and made myself cry )
     
  28. Batcrave

    Batcrave Journeyman
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    Even with my stupidly short X travel, it's the limited Z that makes my Lead feel most cramped, so I'm definitely interested in improvements. I've seen the cnc4newbies axes linked before, and I like the design (although it looks like they've had some nut problems), but I'm curious about the impact on rigidity - whether the rails/bearings make things better, the increased height makes them worse, or the two just sort of cancel out. Have you gotten any X/Y deflection measurements yet?


    -Bats
    ( considering the obsession with increased rigidity, it's amazing we aren't buried in 'male enhancement' spam. OB should sell their antispambot as a kit - including options for belts, leadscrews, and frickin' lasers )
     
  29. Trooper11040

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    So far I’ve not gone above a 2” height. Most of my carves are usually pretty low so I’ve done no measurements. I tried to move the top of the new Z and couldn’t move it by hand. Seemed pretty solid....
     
  30. wojak

    wojak New
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    Thank you :)

    All tests passed, I forgot to mention about squareness. Generally design of plates simplifies it, for Y carriage there are two plates that support c beam, then I squished it with clamps, also all holes are perfectly fit for screws, so I am getting mostly straight or perpendicular connections. I've used U profiles because when I tried to mill aluminium on lead CNC it was bending, currently it is really rigid, even when bit stucked and destroyed wasteboard, the machine did not even bend a little.

    Plates were cut on laser. Whole machine was rather experiment (however I am very happy with result), because I want to use similar design for long one - 3 m x 2 m.

    U profiles are connected on T nuts, however I squished them on whole length and then press into C beam.


    [​IMG]

    End design will utilize it, and those profiles will be welded or screwed to whole construction. I hope that way using Everman belt I will be able to get big but rigid machine.



    I am going to buy 2.2 or 1.5 spindle, rather 1.5.

    I will calibrate it next week and we will see if it will keep sizes. However first test in aluminium was also successful, like a hot knife in a butter.

    On attached file, there is a deep circle on current machine, and two circles from previous machine failed tests.

    Nice, now I will do the same :p
     

    Attached Files:

    #360 wojak, Mar 17, 2019
    Last edited: Mar 17, 2019
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