Quality, economical CNC

Discussion in 'Workshop Tips and Secrets / Tools' started by narfi, Nov 21, 2019.

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  1. Nov 21, 2019 #1

    narfi

    narfi

    narfi

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    Boss said buy one.....
    What is a good quality, economical CNC setup?

    30"x30" minimum bed

    Cuts .050 or thicker aluminum (I don't think should be an issue with most)
    Plywood
    Two color layered plastics for placards (Im not sure what that plastic stock is called)

    Addition of a laser module later would be a plus.

    Not sure if realistic but cutting vinyl for decals/masks would be a bonus.

    Software for ease of use and cost???
     
  2. Nov 21, 2019 #2

    FritzW

    FritzW

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    I got mine from CNC Router Parts They were a good company to deal with and the machine is VERY beefy. After 7 years and thousands of hours it's still running great.

    You can mount anything you want to the Z axis (laser, drag knife for vinyl, etc.)

    Software:
    For ease of use, the CAM addon for your CAD software is probably the easiest.
    IMHO the best bang for the buck in CAM software is standalone CamBam

    Mach3 seems to be the standard machine control software. Mach4 is out but from everything I've read Mach3 is still the way to go.

    Lots of google, youtube and forum support for all of the above.
     
  3. Nov 22, 2019 #3

    narfi

    narfi

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    We won't be putting those kinds of hours on it...... Not much more than hobby levels really.
    For lower use how would something like this, https://bulkman3d.com/product/wbf/ compare to those you linked?

    So the Process is,

    Cad(outputs file) -> Cam (outputs gcode) -> Controller Software on a Computer or computing device -> Serial cable -> Controller board for the motors

    I have solidworks through my EAA membership, but can't figure out if it includes solidworks cam plugin or not....

    Controller software Mach3 or whatever..... needs to be installed on a desktop(not laptop) dedicated to the setup? and the desktop must have a dedicated graphics card(not integrated)?



    List of what is needed,

    Router table/kit
    Ridged table to mount it all to
    Controller computer with controller software
    Cad Software
    Cam Software

    Wasteboard
    clamps (depending on the system?)
    bits
    etc....
     
  4. Nov 22, 2019 #4

    FritzW

    FritzW

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  5. Nov 22, 2019 #5

    narfi

    narfi

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    Wow thanks for your advise. This is looking really doable. (Still lots to learn though)

    Maybe(probably) I am reading the mach3 requirements page wrong?


    The one I was looking at has the option for 2.2kw water cooled 110v spindle. Is the PWM separate than that, or covered in that?

     
  6. Nov 22, 2019 #6

    ScaleBirdsScott

    ScaleBirdsScott

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    That workbee kit, if that size of envelope looks good, and it actually truly comes with everything, all the motors, all the drivers, all the cables, all the everything... it seems ridiculously low priced for what you get. I can assure you all of it is the cheapest possible stuff out there, but some of that stuff looks still fairly decent. And that can still work; the prices on all of this stuff seems to just be dropping all over the place as more people get into it I guess. It seems 4-5 years ago the floor was around $3k for a build. And the kits actually come with everything now!? Jealous.

    I have not heard of this company BulkMan 3D. Definitely look into it from 3rd parties. Based off the looks and name tho it looks to be a cheaper version of a machine from OpenBuilds https://openbuildspartstore.com/openbuilds-workbee-1510-60-x-40/

    Now whether that's an approved version, or is the same version, or a simple knock-off or what, I am not sure. I'm gonna guess OpenBuilds sells kits but their whole thing is open source maybe so, probably fine. But do your due-diligence, see if they're legit. Don't support someone making unauthorized clones if you can help it.

    But assuming the BulkMan guys are legit and the machine is real, I'd just go for the maxed out version they offer: 1500mm with the high-torque steppers, 2.2kw spindle, get the screw drive I think, and Bob's your auntie.

    I've tried the OpenBuilds C-beam, and I have big a chunk of it installed on my router now as a way to stiffen my gantry and help prevent my Z-axis twisting my gantry while trying to drill thru sheet. And it did a trick. That stuff seems way more sturdy than the rails my machine originally uses. If I needed to build a cheap aluminum-rail router table tomorrow that's the stuff I would use hands down.

    For context I'm currently running a 48x96" machine using basically the same polycarbonate wheels on extrusion rails, and it works. It's not gonna cut steel (I've done it, but certainly I shouldn't have). It's not gonna cut terribly fast. But it's gonna work, and still outpace doing it the old ways. I've had my homebrew aluminum machine running for something like 4+ years now, and it's had a few glitches and hiccups from time to time, chased down bug bears, basically disabled my limit switches and just kept them for homing, probably blown a spindle bearing but been too lazy to swap it, etc. I've done a few upgrades over the years and replaced the v-wheels twice, and a few things are starting to wear a little, but I run this thing hard and it works. The WorkBee machine would be smaller and thus stiffer, so I can't see any reason it can't do what you need if you truly just want something that can get it done, and don't mind the bit of fiddling and patience required.

    If you plan on doing any actual sort of serious production work or making money off the unit, it's a harder question. You then start looking into other factors. I can say that before I start making any actual kitplanes I need a much more heavy duty machine than the one using aluminum rails and so-on. Probably an Avid CNC kit like Fritz posted, though there's a few alternatives I'm looking into (There's a kid down the highway about 20 minutes who runs a small job shop with a brand new Laguna Smart Shop SUV, which can do 1000 inches per minute with a 12hp spindle and full automatic tool changing, compared to an Avid which runs 500ipm with a 2hp spindle and no tool changing - Maybe I just pay him.)

    In any case, for $1500 or less, go for the WorkBee if it looks good. If you catch the bug and do a lot of work on it and decide its time to upgrade there's tons of heavier options out there, and you've still got a fully functional small machine to tinker with and the investment was minimal.
     
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  7. Nov 22, 2019 #7

    FritzW

    FritzW

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    The requirements they're asking for are very basic. I think just about any computer made in the last 5 years is going to be more than enough. Even my humble little $300 Lenovo email checker that I use for the HBA is showing 1,064MB of "Total Available Graphics Memory".

    >>>I hope I remember all of this correctly, it's been a while<<<

    If your breakout board (controller board) requires a parallel cable (and a PC with a parallel port) then it relies on the PC clock to handle all the timing, hence the need for a parallel connection. For some reason (old) laptops don't support the timing requirements (maybe it was the lack of a parallel interface?).

    Modern USB (serial) breakout boards handle all of the timing on the board and don't care how it comes in.


    Things like plywood wing ribs, sheet metal gussets, oil filler covers for a VW, tube profiles, etc. are 2.5D and don't require much graphics power. (Post #7 on this thread is a good example of a 2.5D part that looks like a 3D part).

    Things like carving fancy grape vines on your kitchen cabinets is 3D and takes more graphics power. ...but even 512MB isn't much.

    >>>

    The kit your looking at has lots of options, maybe talk to them about what kind of breakout boards they have. Or just buy the basic frame and get everything else on ebay. That's how I built mine, I saved a bunch of money but the learning curve was pretty steep.
     
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  8. Nov 22, 2019 #8

    addicted2climbing

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    I have come very close to buying a workbee many times and the only thing stopping me is I need a larger machine. I designed one years ago using Surplus Hiwin Linear rails but never got around to building it. Mostly because I did not have the room. Now things have changed, I am recently self employed and building out a hangar full of machines. Just found a tormach for a song. Hangar only has single phase so the hobby sized tormach was my only option in this price range. Anyhow, for your application, buy the best machine you can afford and the largest you think you will need. These things have a way of finding uses and trust me in saying you will run it more than expected and likely on projects and materials larger than you think you need now. Maybe see whats the larges machine you can fit in your workspace and go from there.

    Also Fritz is an invaluable resource on this forum for things such as this. Also he has been there done that usually for most of the questions that come up. Since he already posted a reply, you can pretty much take his advice as gospel and its a good foundation to build on in your search.
     
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  9. Nov 22, 2019 #9

    stanislavz

    stanislavz

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    my two cents is on shapeoko cnc router in plastic rollers router world, due to biggest and closed profile used in rails. 80x40x5 mm. Much better than T slotted open profiles.

    But if go heavy duty way - you need normal hardened rails mounted on cast iron.

    Anything between is just a waste of money.
     
  10. Nov 22, 2019 #10

    narfi

    narfi

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    There are multiple sites selling WorkBee kits, from what I can figure out it is an open source kit designed by openbuilds but anyone can use their plans to build their own setup or build kits to sell. Similar to the way anyone can manufacture and sell the open source Arduino boards if they want. The bulkman homepage says "open source kits, machines and parts".

    For a 1500x1500 bed, which is better, belts or screws?
    I have an email into them asking about their control board and what requirements for the connecting computer running mach3 are.
     
  11. Nov 22, 2019 #11

    ScaleBirdsScott

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    I like rack and pinion drive for anything big, and I think I'd do screws over belts just because I know a screw won't stretch in the same way. That said I'm picturing they're just using regular threaded rod or something not any sort of fancy thread, so I don't know the longevity of such things.

    And to be fair to belt, I've seen belt drive units cut all sorts of stuff. It's all about respecting the limits.
     
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  12. Nov 22, 2019 #12

    FritzW

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    Looking at the website you linked, for the size of machine your looking at, ACME lead screws are only $40 more than belts. I'd definitely go with lead screws.
     
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  13. Nov 24, 2019 #13

    addicted2climbing

    addicted2climbing

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    Leadscrews are almost always better than belts. Where they fall short is when the screws become so long they begin to sag in the unsupported area. When they sag if you try and do a rapid move you can get leadscrew whip where the centrifugal force increases the sag and it can permanently bend the screw. In cases like this belts and racks do better with a bit if a hit to accuracy and repeatability. But for our applications the hit is not all that noticeable. For my day job I use to make capitol equipment machined with NPM linear motors and they would work great for routers but they are pricy and need to be energized when holding position since you cant just shut them off and have them not move.
    http://www.nipponpulse.com/
     
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  14. Nov 24, 2019 #14

    rv7charlie

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    I know less than nothing about cnc, but your single phase issue (as long as it's 220V) really isn't any more, as long as you have adequate *current*. Solid state 3rd leg makers are amazingly inexpensive these days. I convinced our power company to bring 3 phase to my house when I moved it to the airport, thinking it would allow me to buy heavy duty surplus machine tools on the cheap, but seeing current prices on 3 phase inverters, I could have avoided a lot of hassle with the power company (and expense). As long as you're not trying to run an entire shop at once, you should be able to get that 3rd leg for a couple hundred to 5 hundred dollars. Look at the ones here that *don't* have 'motors' in the pics.
    https://www.grainger.com/search?searchBar=true&searchQuery=3+phase+converter

    Many cheaper ones if you're willing to 'go Asian', or ebay:
    https://www.ebay.com/sch/i.html?_fr...C2.A0.H2.TRS0&_nkw=3+phase+converter&_sacat=0

    Charlie
     
  15. Nov 24, 2019 #15

    FritzW

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    Fortunately there's no need for three phase.

    You only need 220v if your spindle (router) requires it for the VFD and it only requires single phase 220. It only takes a few minutes to wire up your own 220 single phase outlet.
     
  16. Nov 24, 2019 #16

    rv7charlie

    rv7charlie

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    No doubt that's correct for your specific application; I was responding to his much more general point about big shop equipment (especially stuff you can pick up surplus for less than scrap value) that often does require 3phase power.
     
  17. Nov 24, 2019 #17

    Turd Ferguson

    Turd Ferguson

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    Variable Frequency Drive or VFD is the way to go for converting single phase to 3 phase easily up to 10 hp for electric motors. Plus you get instant reversing, variable speed, instant braking, all for gratis.
     
  18. Nov 24, 2019 #18

    ScaleBirdsScott

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    Yeah single phase isn't a limitation with a good phase converter, but you still need a service with hella juice (amps) if you're running a mill larger than a Tormach, and most hangers aren't setup for that.

    I'm looking at a Haas TM series mill, which along with their Mini Mill series is the next step up from a residential-use-ready Tormach and that will need a good 40+ amp service for single phase. Three phase service requires far fewer amps but then these machines are light duty for a shop running three phase. Someone going into more full production would be looking at a mill with a 20, 30, maybe even 60hp motor, and so-on; so they'd be needing serious cables, especially if running off of a phase converter which needs more amps than 3-phase. I can't imagine many hangers are so wired unless you've got direct access to the panels, and it's a serious panel.

    I've got a lathe with maybe a 3hp motor three-phase motor for $1,000 on Craigslist. Spent $200 for a Teco VFD and it runs like a champ on a basic 220v Single-phase setup. All I did was add a e-stop switch in the line near the machine to fully cut power if needed.

    And yes for larger CNC units I'm afraid the VFD approach doesn't work, simply due to how the control boxes are wired up in the first place.

    But, for sure, with a home router running a straightforward 1-3hp spindle, I can't imagine not using a VFD to control it, and so you only need a decent single phase 220v input.
     
    Last edited: Nov 24, 2019
  19. Nov 24, 2019 #19

    addicted2climbing

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    Hello all.
    Sorry if my mention of buying a Tormach due to my hangar having only single phase power sent this thread a bit off topic. I considered a TM1 but it was larger than I had room for and its amp draw was at the max of my power. Also I kind of need to keep things less obvious that im doing other things in the hangar due to some ridiculous airport rules.

    if you do decide on leadscrews over belts another machine to consider is called “lead machine” its a but cheaper than the workbee if I remember and also worth looking into.
     
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  20. Nov 24, 2019 #20

    ScaleBirdsScott

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    I think for the lengths of the workbee, the screw drive should be fine. My recollection was its when people have machines that are getting up to the 40+ inch lengths when the screw whip would start to get to be a real concern. Once up to that size you have a good case for using rack and pinion.
     

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