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  1. #1
    Join Date
    Oct 2012
    Posts
    19

    steel 60x90 router table

    Hello everyone,

    After many month browsing this forum learning from your posts and threads, i decided to start my router build, it will be about 600mmx900mm .
    i learned from one posts here about the google sketchup program, after downloading & playing on it for 4-5 days i managed to create the router primary design using some models from model store, i attached the design here hope to see your comments on it and if need any modifications please tell me.
    i did small calculation for the gantry weight, and the total weight will be around 45 kg. about 100 lb.
    also i have to tell that i already ordered the mechanical components and it's arrived yesterday via DHL.
    the items as followed:

    X axe
    1-TBR 20 Length 1130mm x 2
    2-TBR 20 UU x 4
    3-Ballscrew SFU 2005-4 1150mm x 2
    4-EK,EF 15 x 2

    Y axe
    5-SBR 20 length 980mm x 2
    6-SBR 20 UU x 4
    7-Ballscrew SFU 2005-4 1000mm
    8-FK,FF 15 x 1

    Z axe
    9- SBR 16 length 300mm x 2
    10-SBR 16 UU x 4
    11-Ballscrew SFU 1605-4 250mm
    12-EK,EF 12 x 1

    Plus SRJ coupling for shaft
    for the electronics i'm still confused between G540 4 axis kit with 380 oz-in stepper & KL4030.

    any comments is highly appreciated

    Regards
    haz
    Attached Thumbnails Attached Thumbnails CNC Project 25-1.jpg   CNC Project 25-3.jpg   CNC Project 25-4.jpg   2012-11-30 15.38.25.jpg  


  2. #2
    Join Date
    Aug 2011
    Posts
    388
    Nice modeling -- good job learning sketchup so quickly! What materials do you want to machine?

    For the z-axis, a channel cross-section (or similar reinforcement) will be much stiffer than a flat plate. I'd also space the bearing blocks apart a bit more, though that does lose some z-travel.

    The gantry will be much stiffer with these changes:
    - Make the main cross-member a single large rectangular tube, rather than the 2 small square tubes shown. This will also help keep the y-rails in the same plane.
    - Use less z-clearance. If you need that much clearance, increase the vertical spacing between the y-rails (at least as much as the z-clearance).
    - Add lateral reinforcements to the side plates (prevents parallelogram flex). Also fill-in the cut-outs (even if they do look cool). A tall thin triangular cutout would be fine.
    - More separation between the X bearing blocks (especially when mounting them below the table). This prevents tipping flex during accel/decel.

    Ideally the cutter, the x-rails, and the x-leadscrews are all in the same horizontal plane. Try raising the leadscrews as high as possible.

    A 45 kg gantry is pretty heavy for the design you show -- are those steel plates or aluminum?

    The gussets in the lower frame will stiffen some, but not nearly as much as adding diagonal members to the faces. A "V" arrangement will give room for the lower gantry cross-member. Also minimize the unsupported leg length near the floor -- that will be the major source of flex after adding diagonals above it.

    How do you plan to make the joints in the frame and gantry?

    Definitely get the G540 over KL4030s -- more V and A, better electronics, easier wiring. The 381 oz-in 2.8 mH motors are a great match for it.

  3. #3
    Join Date
    Mar 2003
    Posts
    35538
    I'd try to rotate the X axis bearings to an upright position.
    Gerry

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

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

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

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

  4. #4
    Join Date
    Oct 2012
    Posts
    19
    Quote Originally Posted by ger21 View Post
    I'd try to rotate the X axis bearings to an upright position.
    Thanks Gerry, i were confused about that, and wanted to make it as you said in upright position after i knew that this round shaft linear and their blocks is not stiff as linear guiderails (hiwin & others).

    regards
    haz

  5. #5
    Join Date
    Oct 2012
    Posts
    19
    Quote Originally Posted by dmalicky View Post
    Nice modeling -- good job learning sketchup so quickly! What materials do you want to machine?

    For the z-axis, a channel cross-section (or similar reinforcement) will be much stiffer than a flat plate. I'd also space the bearing blocks apart a bit more, though that does lose some z-travel.

    The gantry will be much stiffer with these changes:
    - Make the main cross-member a single large rectangular tube, rather than the 2 small square tubes shown. This will also help keep the y-rails in the same plane.
    - Use less z-clearance. If you need that much clearance, increase the vertical spacing between the y-rails (at least as much as the z-clearance).
    - Add lateral reinforcements to the side plates (prevents parallelogram flex). Also fill-in the cut-outs (even if they do look cool). A tall thin triangular cutout would be fine.
    - More separation between the X bearing blocks (especially when mounting them below the table). This prevents tipping flex during accel/decel.

    Ideally the cutter, the x-rails, and the x-leadscrews are all in the same horizontal plane. Try raising the leadscrews as high as possible.

    A 45 kg gantry is pretty heavy for the design you show -- are those steel plates or aluminum?

    The gussets in the lower frame will stiffen some, but not nearly as much as adding diagonal members to the faces. A "V" arrangement will give room for the lower gantry cross-member. Also minimize the unsupported leg length near the floor -- that will be the major source of flex after adding diagonals above it.

    How do you plan to make the joints in the frame and gantry?

    Definitely get the G540 over KL4030s -- more V and A, better electronics, easier wiring. The 381 oz-in 2.8 mH motors are a great match for it.
    Thanks for your comment, it's mostly for wood and for composite panel cutting(4mm).
    for z-axis the distance between 2 blocks is 80mm and the travel distance is only 130mm and planing to make it from 10mm aluminium plate.
    for the gantry i thought to make it from one rectangular tube but it will add a more weight for it , maybe the double weight for 2 square tubes especially if i increased the vertical space between them as you said.
    the gantry side plate is 8mm steel & the square tube is steel 50x50mm with 2mm wall thickness. that's why the gantry is weight much. i wanted to use aluminium extrusion as 8020 but the problem that i can't get that here and need to order from abroad & it will cost lot for shipping. for the joints planing to weld it except for the gantry lower cross-member it will fix by screws.
    for the electronics i will take your advice and go for G540
    i will change somethings in the model later hope you give your opinion again.
    Thank you dmalicky & please excuse my weak english
    regards
    haz

  6. #6
    Join Date
    Apr 2009
    Posts
    5516
    I don't think you'd gain a significant advantage by turning the long axis rails up. The TBR blocks have a lot higher load rating than the SBR (as you probably know due to your choice of it for your gantry axis) so even at 70% load rating you still have a lot of headroom.

    Really though, 100lbs in the CNC world is not a lot of weight, especially considering it will be distributed among four linear bearing blocks.

    If there's one modification I'd make it would be to source a larger spindle; O don't think you'll be ultimately happy with the performance of the smallish spindle you have now, especially considering that you won't get the benefits of using the higher end linear components and screws...

  7. #7
    Join Date
    Mar 2003
    Posts
    35538
    The TBR blocks have a lot higher load rating than the SBR
    How do they have a higher load rating when the bearings themselves appear to be the same, and only the housing is different?

    You're still carrying all the weight on 1 row of bearings.
    http://www.cnczone.com/forums/781695-post6.html
    Gerry

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

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

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

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

  8. #8
    Join Date
    Oct 2012
    Posts
    19
    Quote Originally Posted by louieatienza View Post
    I don't think you'd gain a significant advantage by turning the long axis rails up. The TBR blocks have a lot higher load rating than the SBR (as you probably know due to your choice of it for your gantry axis) so even at 70% load rating you still have a lot of headroom.

    Really though, 100lbs in the CNC world is not a lot of weight, especially considering it will be distributed among four linear bearing blocks.

    If there's one modification I'd make it would be to source a larger spindle; O don't think you'll be ultimately happy with the performance of the smallish spindle you have now, especially considering that you won't get the benefits of using the higher end linear components and screws...
    Hi Louieatienza
    I'm really confused about fixing the rails on side or upright, it's right that the TBR is more stiff than SBR and weigh more and larger but the two have the same bearings which is the LM20UU-OP(as Gerry said), i attached some catalouges i have about it (not very clear).
    even that i preffer to fix it onside because it's much easier for me and less weight for the gantry.
    for the Spindle still not decide what i will use ,and the one in my model picture just to make it easier for me and downloaded from sketchup model store.

    :cheers:
    haz
    Attached Thumbnails Attached Thumbnails TBR 20.JPG   TBR.JPG   SBR.JPG  

  9. #9
    Join Date
    Jul 2009
    Posts
    690
    The real point to TBR blocks is that thanks to its design the adjustment pressure is even, which creates a more consistent contact between the blocks and the rail, while on the SBR it's at the center. SBR's (single and dual bearing blocks) can be drilled and tapped to add extra setscrews so the pressure is more evenly distributed, the difference in fit is quite noticeable. SBR rails can be mounted on their sides, no problem at all, just check two things:

    1) Sometimes the screws that mount the rail to the aluminum support are bad quality and come stripped, I usually replace them with new ones.

    2) Check the orientation of the internal LMXXUU bearings so that the side riding on top of the rail has two rows of balls supporting the gantry weight instead of just one (they are not symmetrical).
    http://www.build.cl

  10. #10
    Join Date
    Aug 2011
    Posts
    388
    Thanks for the dimensions on your z travel (I forgot the scale of 600 x 900). Your English is pretty good, actually.

    As Louie said, a 45 kg gantry is not excessive, but a more strategic design would give more stiffness for that weight. The most important place for stiffness is in the upper cross-member(s). Stiffness isn't as important for cutting wood, but is for composites.

    Right, for steel gantry tubes, it's hard to find thin walls in the larger sizes, so 2 smaller tubes is probably best if going with steel, and that makes it easy to get more separation between the y bearings. The stiffness of a square tube varies by the 4th power of its width (w^4), so even a small increase in size makes a big difference in stiffness. Can you get larger tubes than 50x50 in the 2mm wall thickness? In the US we can get (the equivalent of) 50x75, 50x100, 75x75, etc. If so, I'd make the top and sides out of tubing. Making everything from 50x100x2 (2 upper cross-member tubes, plus small plates for the x bearings) would weigh about the same as the current design, but would be many times stiffer.

    For an aluminum gantry, I'm guessing you can't get a large rectangular tube (~150x75x5)... that's an easy, straight, and ~lightweight way for a single cross-member.

    For overall configuration, you can save weight and gain stiffness by placing the x-rails a little above the table height, and moving the x-leadscrews outboard near the rails (deleting the lower gantry cross-member). ShopBot does something similar (with R&P on this one): Shopbot PRS Alpha 48x96x6 (Phoenix, AZ) - by RJones @ LumberJocks.com ~ woodworking community
    That table config also makes it straightforward to mount the bearing blocks vertically (stiffest), although the TBR blocks and rails should have reasonable stiffness for side mounting / side loading. The only disad is side access to the table, but a 600mm machine is easy to reach across.

    David

  11. #11
    Join Date
    Dec 2007
    Posts
    2134
    Quote Originally Posted by Walky View Post
    Check the orientation of the internal LMXXUU bearings so that the side riding on top of the rail has two rows of balls supporting the gantry weight instead of just one (they are not symmetrical).
    All the LMUU series ones I have in 16/20/25mm sizes are cut as you mentioned, so one side has more races than the other, they definately need to be oriented sideways in one way only.

    cheers,
    Ian
    It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!

  12. #12
    Join Date
    Oct 2012
    Posts
    19
    Quote Originally Posted by Walky View Post
    The real point to TBR blocks is that thanks to its design the adjustment pressure is even, which creates a more consistent contact between the blocks and the rail, while on the SBR it's at the center. SBR's (single and dual bearing blocks) can be drilled and tapped to add extra setscrews so the pressure is more evenly distributed, the difference in fit is quite noticeable. SBR rails can be mounted on their sides, no problem at all, just check two things:

    1) Sometimes the screws that mount the rail to the aluminum support are bad quality and come stripped, I usually replace them with new ones.

    2) Check the orientation of the internal LMXXUU bearings so that the side riding on top of the rail has two rows of balls supporting the gantry weight instead of just one (they are not symmetrical).
    Hi,

    1- i checked most of the screws it's all new and in good condition.
    2- good point for LMXXUU, thank you for the valuable information,even the vendor who sold me the bearings didn't mention anything about it , as he knew that i'm fixing it at their side.

    i attached one pic. for the bearing (from what i understand) is this right?
    Thanks again
    haz
    Attached Thumbnails Attached Thumbnails SAM_0592.jpg  

  13. #13
    Join Date
    Oct 2012
    Posts
    19
    Quote Originally Posted by dmalicky View Post
    Thanks for the dimensions on your z travel (I forgot the scale of 600 x 900). Your English is pretty good, actually.

    As Louie said, a 45 kg gantry is not excessive, but a more strategic design would give more stiffness for that weight. The most important place for stiffness is in the upper cross-member(s). Stiffness isn't as important for cutting wood, but is for composites.

    Right, for steel gantry tubes, it's hard to find thin walls in the larger sizes, so 2 smaller tubes is probably best if going with steel, and that makes it easy to get more separation between the y bearings. The stiffness of a square tube varies by the 4th power of its width (w^4), so even a small increase in size makes a big difference in stiffness. Can you get larger tubes than 50x50 in the 2mm wall thickness? In the US we can get (the equivalent of) 50x75, 50x100, 75x75, etc. If so, I'd make the top and sides out of tubing. Making everything from 50x100x2 (2 upper cross-member tubes, plus small plates for the x bearings) would weigh about the same as the current design, but would be many times stiffer.

    For an aluminum gantry, I'm guessing you can't get a large rectangular tube (~150x75x5)... that's an easy, straight, and ~lightweight way for a single cross-member.

    For overall configuration, you can save weight and gain stiffness by placing the x-rails a little above the table height, and moving the x-leadscrews outboard near the rails (deleting the lower gantry cross-member). ShopBot does something similar (with R&P on this one): Shopbot PRS Alpha 48x96x6 (Phoenix, AZ) - by RJones @ LumberJocks.com ~ woodworking community
    That table config also makes it straightforward to mount the bearing blocks vertically (stiffest), although the TBR blocks and rails should have reasonable stiffness for side mounting / side loading. The only disad is side access to the table, but a 600mm machine is easy to reach across.

    David
    Hi david,

    as for aluminium gantry, 100x75 is available here but the issue in wall thickness, i'm trying to find a tube in reasonable thickness , 4mm maybe 5mm.
    if not i'll go again for steel tubes.

    haz

  14. #14
    Join Date
    Jul 2009
    Posts
    690
    Quote Originally Posted by haz_kiev View Post
    Hi,

    1- i checked most of the screws it's all new and in good condition.
    2- good point for LMXXUU, thank you for the valuable information,even the vendor who sold me the bearings didn't mention anything about it , as he knew that i'm fixing it at their side.

    i attached one pic. for the bearing (from what i understand) is this right?
    Thanks again
    haz
    Yes, exactly. I don't think many sellers know about this as it will still work the other way around (in fact, it took me some time to realize this), but using them this way should make both the bearings and rails last longer.

    Of course, this assumes that the gantry weights down on both bearings. Some overhanging designs, depending on the weight distribution, would need the rear bearings to be facing upside down.
    http://www.build.cl

  15. #15
    Join Date
    Apr 2009
    Posts
    5516
    I might have had it backwards... Found this in my hard drive. The SBR blocks (at least according to these guys) have a higher load rating than the TBR blocks. I don't see a reason as to why in this document, though I do have another document somewhere I believe that has numbers suggesting exactly the opposite.

    Misumi sells heavy duty aluminum extrusion with 6mm wall thickness....
    Attached Files Attached Files

  16. #16
    Join Date
    Oct 2012
    Posts
    19
    Hi,
    today i finished assembling the Z axis, i used a 8mm aluminium plates i found in scrapyard at 1/6 the new ones price, i wanted to use 10mm plates but after i found these i could not resist the price
    still need to be painted.
    i'm wondering if i can this 8mm alu plates in the gantry side if i (paste) two plates togather 2 x 8mm each side?? is that possible??

    haz
    Attached Thumbnails Attached Thumbnails SAM_0593.JPG   SAM_0595.JPG   SAM_0596.JPG  

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