Z Axis Design - Researching Prior to Build


Page 1 of 2 12 LastLast
Results 1 to 20 of 25

Thread: Z Axis Design - Researching Prior to Build

  1. #1
    Member
    Join Date
    Sep 2015
    Posts
    43
    Downloads
    0
    Uploads
    0

    Default Z Axis Design - Researching Prior to Build

    In the next few weeks here I hope to start building my CNC router, and I'm currently in the research and ordering phase. Where I'm currently stuck is the Z-axis. I'll post a photo of what I have drawn up so far (if I can get a sketchup pic to load), but basically I'm stealing ideas from all over cnczone (and I'll give credit once I start my actual build thread). It will be a large steel framed machine, and hopefully will have 3 Z-axis on it, or at least have room for 3 down the road (as long as it's in the budget I'll do 3 right out of the gate).

    X and Y will be on 25mm linear rails - I'm stuck on the Z. I have been looking at ball screws, but many sites don't list the sizes of their end blocks, bearings, etc. which makes it harder to design on paper. Furthermore, I'm scared of the Z-axis - the other ones seem much easier to build to me.

    Does anyone know of a commercially available Z-axis that won't break the bank? Ebay everything seems to be the round rail, and mostly unsupported variety. If I can find a good one, in the $150 to $200 range, I would order 1 to 3 of them. If not, I'll have to take a stab at building them, which means just ordering components, then measuring them, then drawing what I want, then building or paying a machinist to build the components, and then slapping it all together, and that's not the most efficient route, and if I mess it up it will be even worse... Any suggestions? Thanks,

    Dameronw

    Similar Threads:
    Attached Thumbnails Attached Thumbnails Z Axis Design - Researching Prior to Build-cnc-mockup-pic-1-jpg  


  2. #2
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    If I can find a good one, in the $150 to $200 range
    The linear bearings alone will cost that much.
    It's really pretty simple.
    Two aluminum plates, 20mm rails, and a 1605 or 1610 ballscrew.
    20mm rails should give you enough clearance for the ballscrew.

    Something like this, but with 2 bearings per rail.


    Keep in mind that 3 Z axes will be very wide, and you'll need a long, extended gantry if you want all 3 spindles to be able to reach the table.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


  3. #3
    Member awerby's Avatar
    Join Date
    Apr 2004
    Posts
    5728
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    You might look at some linear actuators to use for your Z axes, which have the rails and ball screws built in and set up orthogonally in an aluminum extrusion. They usually come with a motor as well, although these may be hard to drive with generic controllers. But even if you have to strip off the motors and mount new ones, you'll often come out ahead versus buying all the components separately. Here's one currently on Ebay (just as an example, not that I'm endorsing this particular brand or seller): IAI Robo Cylinder ISD-S-16-60-400-CR Ball Screw Actuator 400mm Travel 60W Servo | eBay

    [FONT=Verdana]Andrew Werby[/FONT]
    [URL="http://www.computersculpture.com/"]Website[/URL]


  4. #4
    Member
    Join Date
    May 2011
    Location
    Canada
    Posts
    790
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Quote Originally Posted by dameronw View Post
    Iand hopefully will have 3 Z-axis on it, or at least have room for 3 down the road (as long as it's in the budget I'll do 3 right out of the gate).
    Am I reading this right? 3 Z axis on the same plate (all driven together horizontally with independent Z) so you don't have to do tool changes? I have to think there is a better option out there for you, keep an eye out for an ATC spindle? If it's for three independently moving spindles to make stuff faster, I have to think your money is better spent of servos, etc, to give you some nice acceleration and speed for one spindle.

    But perhaps you have a specific purpose in mind for this, and I'm not an expert on the subject of multiple spindles, so I will stop talking about it now.

    Quote Originally Posted by dameronw View Post
    X and Y will be on 25mm linear rails - I'm stuck on the Z. I have been looking at ball screws, but many sites don't list the sizes of their end blocks, bearings, etc. which makes it harder to design on paper. Furthermore, I'm scared of the Z-axis - the other ones seem much easier to build to me.
    You can get CAD files here:

    SYK-?????????? SONYUNG Industry Co.,Ltd-Ballscrew Support Unit,Nut Bracket,Motor Bracket
    SYK-??????????

    Those won't work with sketchup (unless you can import .igs or .step, which I don't think you can) but you could always look at the 2d files and draw them, or find a different program to use.

    As far as I know, double checking is a good idea, all manufacturers of fk15 end supports, for example, follow the same dimensions. Just be sure to add the spacers at the fixed end, and probably best not to order your ballscrews until you have your bearings and mounts in your hands.

    I just got a bunch of FK15's and BF15's and SYK MBA 15F's (Fits nema 34). That size works well for 25mm ballscrews. 15mm is the inner bearing diameter, which has to be less than the ballscrew.

    I say 5mm pitch is good. Nema 23's are good if you have 3 Z's and Z's that aren't too heavy. I don't know what mount that corresponds to, you'd have to look it up. There's no need for a belt drive. Direct drive is OK. Belt drives can give more clearance because you can move the motor to a different position. You need spacers otherwise. 25mm ballscrew is overkill for a light Z ballscrew. By light I mean 50lbs or less. 18mm leadscrew would work. Of course, I have no idea how much travel you need, the weight of your spindle, etc. etc.

    Quote Originally Posted by dameronw View Post
    Does anyone know of a commercially available Z-axis that won't break the bank? Ebay everything seems to be the round rail, and mostly unsupported variety. If I can find a good one, in the $150 to $200 range, I would order 1 to 3 of them. If not, I'll have to take a stab at building them, which means just ordering components, then measuring them, then drawing what I want, then building or paying a machinist to build the components, and then slapping it all together, and that's not the most efficient route, and if I mess it up it will be even worse... Any suggestions? Thanks,
    $150 - $200. You won't buy anything good for that. Forget about paying a machinist to do anything!

    You could search "Linear Stage" on EBay and see if three exact good but used ones come up. People usually want too much on EBay but occasionally you can get a deal. Sometimes sellers have more than 1 available if you click on an item. I have to warn you that most linear stages make really poor Z axis. If you get something I'd say, you need two square rails on it, and 4 bearing blocks. Less important is if it has a leadscrew or a ballscrew. You might get lucky.



  5. #5
    Member
    Join Date
    May 2011
    Location
    Canada
    Posts
    790
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Quote Originally Posted by awerby View Post
    You might look at some linear actuators to use for your Z axes, which have the rails and ball screws built in and set up orthogonally in an aluminum extrusion.
    LOL! It took me a while to actually hit the "Submit Reply" button, so I didn't see that you had suggested this first.



  6. #6
    Member
    Join Date
    Mar 2014
    Posts
    735
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    I've gotten 3 linear actuators from this Ebay seller to use as a Z axis:

    http://stores.ebay.com/XYZ-Axis-CNC/...sub=2987891015

    He's got a wide selection and several listing's with multiple identical units. Here's a tip; make him an offer. I got my 3 at steep discounts over his listed price.



  7. #7
    Member
    Join Date
    Sep 2015
    Posts
    43
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Thanks for the info and advice. I'll definitely search ebay for actuators, and check out that store 1jumper10. He has some options it seems, if I can get him down in price some... I know I'm on the cheap side, but we'll see what I can work out.

    From my research it seems as if a dual or triple Z machine is a quite a bit cheaper option than an ATC, although not necessarily as good. I've read through a few build threads on people who have done it (one is here: http://www.cnczone.com/forums/diy-cn...96192-cnc.html ). I like the idea partly because of cost, but also because I like the idea of having backup spindles ready to go if one dies (definitely a possibility with the Chinese ebay models). Also, for most of what I do, I could use one halfway decent spindle for most cuts, but the side ones could be smaller or a drill attachment - currently I have speaker cabinets to do with tons of little holes with a small chamfer on each, in MDF, and even a trim router could handle it. It's the bit change which is killing me. Also lots and lots of tiny holes for pre-drilled screw locations.

    I'm drawing it up in sketchup partly just to force myself to learn it. I can draw somewhat well in a couple of other CAD programs, but I have a lot of people bringing me sketchup files that I wish I could work with better, so I need to jump on that train.

    Here is a sketchup image of what I have so far:

    The above uses these 20mm rails: automation products from Automation Overstock: BLH20Rxxxx, BLH20mm size linear rail, BLH 20mm Linear Guideways With smaller rails I might be able to reduce the footprint a bit, or with a slimmer commercially available design. We'll see.

    Also, here's a couple of not great images of a Shop Sabre dual Z:



    If anyone has any other advice or ideas, then let me know. If I have to I'll take the plunge and try to use my current router to make the Z plates in aluminum, or try to see how accurate I am in steel with a drill press... I'm less worried about that part then I am about getting the correct stand off to make my ballscrew nut and mounts get into exactly the same plane as my linear rails/blocks. Thanks again,

    Dameronw



  8. #8
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    I'm using 15mm rails for my dual Z axis, to try to keep it as compact as possible. I've got them 6" apart, center to center. That's using round 80mm spindles. If I went with square spindles, I could get them closer, but I'd need to put the screws on the outside. That wouldn't help with 3, though.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


  9. #9
    Member
    Join Date
    May 2011
    Location
    Canada
    Posts
    790
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Quote Originally Posted by dameronw View Post
    currently I have speaker cabinets to do with tons of little holes with a small chamfer on each, in MDF, and even a trim router could handle it. It's the bit change which is killing me. Also lots and lots of tiny holes for pre-drilled screw locations.
    I was thinking that for the expense of three spindles and z assemblies it would be better to spend the money on one better system, but I see now that multi spindle machines can have their advantages, and that you have a specific use in mind, and the system you are designing could be the best thing for what you want to do.

    Quote Originally Posted by dameronw View Post
    I'm drawing it up in sketchup partly just to force myself to learn it. I can draw somewhat well in a couple of other CAD programs, but I have a lot of people bringing me sketchup files that I wish I could work with better, so I need to jump on that train.
    That is the exact reason I chose to use sketchup for my drawings. The big drawback I found is that I haven't been able to find CAD files from part manufacturers that are compatible with sketchup, or file conversions that actually worked.

    Bearing blocks, linear rails, mounts, even fasteners, etc., most reputable manufacturers post CAD files of their products that you can download, but not in a format you can use with sketchup, so you have to redraw them. The bearing blocks I have drawn up won't be the same sizes you need, so I can't help you there.

    Quote Originally Posted by dameronw View Post
    If anyone has any other advice or ideas, then let me know. If I have to I'll take the plunge and try to use my current router to make the Z plates in aluminum
    Dameronw
    If you can find 3 good used linear stages at a decent price, then that is probably the most inexpensive way.

    I think if you have a current router, using that to make your parts out of aluminum is the best idea if you're going to make the whole thing yourself. You can use it to surface your parts also.



  10. #10
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    I was thinking that for the expense of three spindles and z assemblies it would be better to spend the money on one better system,
    You can add a complete z axis assembly, including chinese spindle, for under $500/axis.
    An ATC spindle with tool holders would start at about $3000. And if you only need to use 2-3 tools, multiple spindles would be faster.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


  11. #11
    Member
    Join Date
    Sep 2015
    Posts
    43
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Can anyone identify the ball screw 'nut' from the photos in this link: LINEAR STAGE ACTUATOR TABLE 9" TRAVEL 0.25" SCREW PITCH LOW PROFILE

    I tried searching the hiwin site, as well as ebay and others and haven't found it. It seems nice and narrow, which would be great for my application. All the ones I have found are the big blocky kind such as these: MGD steel ball screw nut bracket, HD aluminum ball screw nut bracket

    I spent a couple hours drawing tonight, and now I want to redo it, but I think I'm getting closer, and it's wide, but not horredously wide. If I can figure out what those narrow nuts are, I might be able to slim it even more.



  12. #12
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Can anyone identify the ball screw 'nut'
    Yeah, it's not a ballscrew.
    It even says in the listing, that it's a Kerk acme screw, and it's an anti backlash acme nut.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


  13. #13
    Member
    Join Date
    May 2011
    Location
    Canada
    Posts
    790
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Quote Originally Posted by dameronw View Post
    Can anyone identify the ball screw 'nut' from the photos in this link: LINEAR STAGE ACTUATOR TABLE 9" TRAVEL 0.25" SCREW PITCH LOW PROFILE
    It's a Kerk Acme Lead Screw, not a ball screw. No ball bearings in there, but a lead screw should work fine. I wouldn't go with that particular linear stage as it only has two linear bearings, but I'm sure you knew that and you're just looking at the lead screw nut from that add.

    KERK® LEAD SCREWS

    Looks like if you register on the site you can download 2D/3D CAD models



  14. #14
    Member
    Join Date
    Sep 2015
    Posts
    43
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    I searched Kerk as well, but didn't find it... could just be me though. Happens all the time around the house, to the wifes annoyance. I'll search for anti-backlash acme nut now. Thanks once again ger21 - BTW, and opinion on the pros v cons of ballscrew versus acme?



  15. #15
    Member
    Join Date
    Apr 2009
    Location
    USA
    Posts
    5516
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Quote Originally Posted by dameronw View Post
    I searched Kerk as well, but didn't find it... could just be me though. Happens all the time around the house, to the wifes annoyance. I'll search for anti-backlash acme nut now. Thanks once again ger21 - BTW, and opinion on the pros v cons of ballscrew versus acme?
    Check CNC Router Parts... they have a compact AB nut, but you'll have to use a 1/2"-10, 5 start screw as that is the pitch of the AB nut they sell. I don't think for the Z axis, especially considering the flat stock you're cutting, that you need a ballscrew on the Z. The ACME screw is more worry-free when it comes to dust and contamination, and it has just enough friction to prevent the screw from backdriving and dropping your spindles to the table when the power is off.



  16. #16
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Acme. Cheap and easy, but not as efficient as ballscrews. Acme screws can be 40-80% efficient, where a ballscrew is 95% efficient. Ballscrews can also handle higher loads.

    I'm using acme on my dual Z axes, with plastic nuts modified to be anti backlash.
    https://www.roton.com/family/hi-lead...-nuts-7060986/

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


  17. #17
    Member
    Join Date
    Sep 2015
    Posts
    43
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    I've been getting further with this design, as well as getting better in Sketchup, although sometimes it is an incredibly frustrating program.

    Here are a couple of pictures of the Z axis thus far:



    My question is, what is the ideal bearing to place between the flex coupler, and the top plate? I have it drawn to try to achieve a nice snug fit for something like this. But, my knowledge of bearings and the best way to assemble things like this is virtually nil. I've been looking at other builds, threads, pictures, etc. but haven't quite figured out what is the best, but also fairly easy, approach.

    I don't want to use the CNC routerparts bearing blocks and thrust bearings because of their width, and because the standoff from the mounting plate isn't ideal for what I want, and I'm not sure what conglomeration of parts I should use to achieve my axial/thrust bearing/flex coupling arrangement. Also, depending on how all my tolerances play out, I may eliminate the flex coupling, and put a gear there instead, with a belt going back to the motor to make more clearance for the spindle. Either way, I need to figure out the bearing arrangement. Any advice you experts gives cuts hours off of my research, so thanks in advance,,,

    Dameronw



  18. #18
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    My question is, what is the ideal bearing to place between the flex coupler, and the top plate?
    The fixed version of these:

    1 Set Fixed Side+Floated Side Ballscrew End Supports Bearing Block FF12/FK12 | eBay

    This would be the easiest, because you just bolt it on.

    The proper bearings are a pair of angular contact bearings, which handle thrust loads better than standard bearings.

    Keep in mind that the screw needs to be machined, so that the bearings/bearing assembly is holding the screw in place.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


  19. #19
    Member
    Join Date
    Sep 2015
    Posts
    43
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Thanks Ger21.

    So with these kind of bearings, the bottom bearing takes the weight/downward forces, and the upper bearing stops the upward forces? Which is why the ends of the screw need to be machined, correct? I know it would be a not as slick approach, but could you just use a stop collar on the screw to act as the machined shoulder? Or would this be super hoaky? Not that buying a screw with machined ends is that big of a deal - just sort of wondering, and also, it would allow me forgiveness if I don't build it quite accurately enough, as you can just clamp the collars on whereever you want.

    My other issue is that I only have 32.3mm to play with, between the Y-carriage plate, and the Z Plate. This may not be too big of a deal on the upper end, depending on where the spindle wants to travel, but on the lower end it causes issues. The above linked bearings I believe are 40mm or 42mm (not sure which is which, or if they're square - not the best dimensions given). Either way it doesn't easily fit. I'm hoping that I can machine out a spot for a bearing, which locates it perfectly or near perfeclty, and if it's just a round bearing, I'm able to keep everything lower profile - either that or I need to space out my Z-plate. Does that make any sense?

    Dameronw



  20. #20
    Member ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    35538
    Downloads
    1
    Uploads
    0

    Default Re: Z Axis Design - Researching Prior to Build

    Basically, yes. The housing captures the two bearings The shoulder on the screw pushes up against the bottom bearing. A nut threads onto the screw to hold the screw onto the two bearings.

    You did ask for what was "ideal".

    You could use a flange bearing on the top and bottom of your plate, and shaft collars to hold them and the screw in place.

    Gerry

    UCCNC 2017 Screenset
    [URL]http://www.thecncwoodworker.com/2017.html[/URL]

    Mach3 2010 Screenset
    [URL]http://www.thecncwoodworker.com/2010.html[/URL]

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

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


Page 1 of 2 12 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Z Axis Design - Researching Prior to Build

Z Axis Design - Researching Prior to Build