New Machine Build Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw


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Thread: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

  1. #1
    Member kinghong1970's Avatar
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    Default Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Howdy folks of CNCZone!

    It's been a while since I've last posted here!
    Well, it seems i've been bit by the bug again and probably spending too much time on the internet.

    I've watched a lot of videos of folks building amazing machines and one that has caught my attention was RoboCNC seen in link below:
    https://www.youtube.com/playlist?lis...yCkJLcRBChdojC

    he details his build and have provided access to drawings for detail analysis.

    roughly based off his ideas, this is what i have so far.
    Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw-cncr-01-assembly-v4-jpg

    Lime Green: 80x160 aluminum extrusion
    Yellow: 1" aluminum plate
    Pink: 1/2" aluminum plate
    D.Blue: Linear Rails & Ball Screws
    Red: TBD

    Travel
    Approx 900mm (35.43") X Axis (Gantry)
    Approx 1500mm (59.05") Y Axis
    Approx 218mm (8.58") Z Axis - not including spoil board etc...
    ... and yes, i'll probably shoot myself and have tons of double face-palm moments by going metric...

    Machine Size & Frame
    as you can see, the drawing/design is nowhere near finished. perhaps there are some points where it is overkill, perhaps it is prone to deflection and such. inputs would be greatly appreciated.
    i am considering building torsion box top with some frame below out of wood...
    1) i can have more "efficient" storage below the cnc.
    2) i can eventually enclose the build

    concerns being will it be rigid enough out of wood?
    i have no way of building out of metal at the moment.

    Ball Screws
    2010 Ball Screws on the X & Y
    Still researching on Z axis... seems 2005 on Z should suffice

    Linear Rails
    either Hiwin or BLH 20mm Ball Screws
    probably opt for flanged mount on the Y axis, narrow mount on the X & Z axis

    Electronics
    i like the idea of MASSO G3 touch... i'm kinda leaning towards that at the moment.
    currently using Mach3... damn biggest complaint is that the damned screen is fugly and i'm constantly worried about windows running pc near my #1 dust producing machine in the shop.
    but again, i blame myself... i wish MASSO had a neater and cooler GUI like Datron... (lol... see what i mean about too much time on the web?) perhaps they will enable custom screen designs?

    Motor Drivers is still pending... see below in Motors section.

    Motor
    this is something i've been looking into recently and while i was quite interested in the whole servo thing... i am not quite sold on the "need" for servo on a machine this size.
    i should be able to build a rigid and accurate machine with Nema34 steppers, and if i am tempted to explore into something new, perhaps trying out a hybrid closed loop stepper may be of interest.

    i am open to suggestions... i'm not looking for crazy speed and i hardly run anything at 200ipm with my current machine.

    in the meantime, i have contacted ClearPath for some information and they have been great to deal with so far.

    Please, correct me if i'm wrong, but achieving accuracy, precision & repeatability (if those are the correct terms) first and foremost is a better "foundation" or structure of the machine?
    there is some ease and convenience (at a hefty cost) of using extrusions but to limited weekend warrior DIY'ers, it's a cost i have to pay imo... hence the main frame of the machine will be based off the metric extrusions.

    so in terms of motor, yes, i was awed by the rapid, silent movements of high torque from servos... but i'm not getting any younger and my ninja skills are dull. i don't think i'll be comfortable seeing something that'll zoom by before i can even think to react... and my machine is <900mm X travel, <1500mm Y Travel... how fast do i need it to blink?

    silent... wow... when i heard my 1/4" compression bit go through 3/4" plywood... first thought... i should have not spent money on silent watercooled spindle... damn cutting noise is loud enough to cover all.

    so, current setup is an oldie, CNCRP 2448 and since my incomplete build log, i've added a HY 2.2kW watercooled spindle and VFD and it's running fine for the cost.
    plan is to tune up my current machine as best as i could... and use it to make the custom risers and plates.

    i can use some help and ideas on motor recommendations for this.
    review and comments on component choices or just recommendation on components.

    looking to work with aluminum, wood, and plastics.
    i'll be happy with 250ipm to 300ipm travel...

    i'd be happier with detail accuracy than time.

    sorry for long read.

    Any/All comments, criticisms, & suggestions welcomed!
    just be kind... i'm a novice at best and suffer from clicking the mouse to quickly when it comes to shopping...


    thanks in advance!
    Al

    Similar Threads:
    Attached Thumbnails Attached Thumbnails Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw-cncr-01-top-jpg   Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw-cncr-01-iso-back-jpg   Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw-cncr-01-side-jpg   Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw-cncr-01-front-jpg  

    [SIZE="1"]my first..."[B][COLOR="Red"]Big Ape[/COLOR][/B]" CNCRP 2448 [URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/151447-big_apes_crp-2448_build.html"]Build Log[/URL][/SIZE]


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    Member peteeng's Avatar
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    Default Re: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Hi Al - Plywood CNC's are very doable. Here's a link to a German company that does it commercially. N34 motors are overkill. N23 or N24 will do your job easily and save $$$ on electronics and power supplies etc. I wouldn't go hybrid servos I would go the extra mile and go servos if that's within reach. The hybrids don't offer enough for the cost delta to a std stepper IMO. Better to use the $$$ somewhere else on the machine. Just coat the plywood with good resin to seal out moisture and you may never build that aluminium machine....

    https://www.cnc-holzfraese.de/

    Attached Files Attached Files


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    Quote Originally Posted by peteeng View Post
    Hi Al - Plywood CNC's are very doable. Here's a link to a German company that does it commercially. N34 motors are overkill. N23 or N24 will do your job easily and save $$$ on electronics and power supplies etc. I wouldn't go hybrid servos I would go the extra mile and go servos if that's within reach. The hybrids don't offer enough for the cost delta to a std stepper IMO. Better to use the $$$ somewhere else on the machine. Just coat the plywood with good resin to seal out moisture and you may never build that aluminium machine....

    https://www.cnc-holzfraese.de/
    Peteeng
    Thank you for your reply.
    That German company is very interesting!

    I used to do things with epoxy resin a while back and loved working with it.
    It is definitely interesting for sure!

    Sadly, as I’ve aged a wee bit, seems I’ve grown to be sensitive to epoxy and usually have to be in full hazmat suit. Lol?

    Your write up was very well put and have found it quite informative

    At the moment, I’m leaning more towards aluminum plates and extrusions...

    Oh and when going to N23 motors, do I need to use some form of timing belt and pulley or direct drive to ball screw should suffice?

    Thanks again.

    Al

    [SIZE="1"]my first..."[B][COLOR="Red"]Big Ape[/COLOR][/B]" CNCRP 2448 [URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/151447-big_apes_crp-2448_build.html"]Build Log[/URL][/SIZE]


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    Default Re: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Hi Al - I use alot of polyurethane adhesives these days they are very good. Motor coupling depends on what you want. Force or speed. A 10mm pitch screw with a 4Nm direct motor will put out 4x2xpix0.9/0.010/9,81 = 230kg of force initially. This reduces to zero at about 1000rpm. So if you want speed you can gear it up if you want more then 100kgf at 500rpm then gear it down... Sp speed is important if there are lots of rapids and lots of finishing like in moulds. If its grunt work profiling then you need force.... What do you want to do most? Peter



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    Default Re: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Peter,

    let me get a clearer/better understanding of steppers so i can ask more intelligent questions.

    but shooting off the hip, best of both worlds... wouldn't N34 offer both ability for speed and grunt? of course at a cost...
    i'd love to have the option.

    Al

    [SIZE="1"]my first..."[B][COLOR="Red"]Big Ape[/COLOR][/B]" CNCRP 2448 [URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/151447-big_apes_crp-2448_build.html"]Build Log[/URL][/SIZE]


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    Default Re: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Hi KH - N34 have quite a bit more rotational inertia then smaller motors so they are harder to accelerate. N34 are "fatter" then smaller motors this means their inductance is greater as well. Inductance is the resistance created by the back EMF created as the motor turns. High inductance means the motor won't spin fast at some rpm the motor is developing nearly the same back emf as the driving voltage so it slows down . The forum is littered with discussion on inertia and inductance. The usual solution to this is to use as high a voltage as possible 60V or more. Using high voltage high current systems jumps up your costs. You need to define what you want to do with the machine and then you can calculate the motor size required. Peter



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    Default Re: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Peter,

    thank you for your patience in explaining to this noob. i really appreciate it!
    i'm going from a plug and play kinda system to this and it is definitely a learning process.

    ok, let me see if i understand this correctly...

    taking this stepper for reference:
    StepperOnliine Nema 23HP45-4204S @ $35.67 ea
    P Series Nema 23 Bipolar 3Nm (425oz.in) 4.2A 57x57x114mm 4 Wires Stepper Motor CNC

    https://www.omc-stepperonline.com/ne...motor-cnc.html
    Electrical Specification
    Manufacturer Part Number: 23HP45-4204S
    Number Of Phase: 2
    Step Angle: 1.8 deg
    Holding Torque: 3.0 Nm(425oz.in)
    Rated Current/phase: 4.2 A
    Phase Resistance: 0.9 ohms± 10%
    Inductance: 3.8 mH ± 20%(1KHz)
    Physical Specification
    Frame Size: 57 x 57 mm
    Body Length: 113 mm
    Shaft Diameter: ?10 mm
    Shaft Length: 24 mm
    D-CUT Shaft Length: 20 mm
    Number of Leads: 4
    Lead Length: 400 mm
    Weight: 1.8 kg

    with the below torque curve according to their website.
    Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw-23hp45-4204s-torque-curve-jpg

    so before moving on to the advanced course...

    directly connected to a 2010 ball screw, one revolution of ball screw moves 10mm
    hence a motor running at 300rpm will move 3000mm roughly yielding 118 IPM? (3000 / 25.4)
    and looking at the torque curve, i'm looking at somewhere between 200-250 N.cm torque?

    so for a guy who slept through physics, am i understanding correctly?

    also, do i need to concern myself with
    Phase
    Step Angle
    still reading on Inductance at the moment.

    but lazy man in me wants to say, go Nema 34 and get the additional PSU...
    still way cheaper than what i've budgeted for initially...

    [SIZE="1"]my first..."[B][COLOR="Red"]Big Ape[/COLOR][/B]" CNCRP 2448 [URL="http://www.cnczone.com/forums/cnc_wood_router_project_log/151447-big_apes_crp-2448_build.html"]Build Log[/URL][/SIZE]


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    Default Re: Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

    Hi KH - Yes the lazyman in us does these things sometimes. So keep reading, the inertia of the ballscrews and motor can be significant if you want to move fast. Just try to be aware of things like if one motor looks the same as the other pick the one with the lower inductance. Yes your torque estimate is correct. Phase is how the motor is connected and thats just follow the wiring diagram. Step angle of a std motor is 1.8deg ie 200 steps per rev. You can get 400 step per rev motors as well not as common. Keep at it... Peter

    In regard to questions like which one performs better you have to define what you want to do with the machine. You will hit limits like ballscrew whirling, ballscrew buckling, inertial speed caps and these may or may not be within a simple stepper setup capacity.. You can just do something and get what you get or you can specify what you want then check that the system will deliver...So you need a feed force requirement (timber. foam or aluminium cutting etc say 20kgf to 250kgf)) , a feed speed range (500-3000mm/min?) and a max rapid speed ( 10-25m/min?). Maybe an acceleration (0-0.5g) as this will become important... keep informing yourself... Peter

    Last edited by peteeng; 03-05-2021 at 11:06 PM.


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Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw

Design Input on CNC Router 900mm X 1500mm with 20mm Linear Rail and Ball Screw