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  1. #1
    Hi All,

    Here's the first ramblings and outpourings of my mind as I embark on my first CNC router build.

    Obviously I have already fallen into the trap of having purchased much of the gear before finalising the design. Here's what I have so far:

    4 qty Hiwin 20mm Linear Rails and Carriages @1000mm (X & Y Axes)
    2 qty Hiwin 20mm Linear Rails and Carriages @400mm (Z Axis)
    2 qty 2010 Ball Screws @ 1000mm (Y Axis)
    1 qty 2005 Ball Screw @ 1000mm (X Axis)
    1 qty 2010 Ball Screw @ 400mm (Z Axis) - May look to replace this with a smaller, lighter screw??
    2 qty 40 x 160 Alu Profile @ 1000mm
    2 qty 80 x 80 Alu Profile @ 1000mm
    4 qty 40 x 80 Alu Profile @ 1000mm
    4 qty NEMA 23 motors
    4 qty TB6560 Drivers
    24V 250W PSU
    4 qty Flex Couplers
    6 qty Proximity Sensors
    Misc Fasteners and fixings etc.

    Engage sarcasm mode: I'm having so much fun learning Fusion 360 :Disengage sarcasm mode. Here's my part finished design:

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    As you can see from my partial design I have opted to use tall profiles for the Y axis sides of the frame in order to reduce the height of the gantry support plates as much as possible. My thinking is that it will keep the CoG of the router as close as possible to the same height as the Y axis linear guides. On the X axis I have opted for 2 qty 80 x 80 profiles in the hope that it provides way more rigidity than I need. X Axis guides are mounted top and bottom of the gantry to minimise the router's extension from the gantry.

    My current design considerations:

    Direct or belt driven X and Y axes? I am currently leaning towards belt driven.
    Reduce the Z Axis ball screw size to reduce overall Z axis assembly weight and provide a finer pitch, perhaps a 1204 or 1604 screw?
    Use universal connectors or use L brackets to join the 40x80 of the bed to the 40x160?
    Are my stepper going to have enough grunt if I use a 1:1 belt drive? They are 270oz rated, perhaps a 2:1 ratio?
    Whether to make my own aluminium plates or have them made for me? I think I am plenty capable of making them but I have no mill or CNC machine so it'll all be hand work (I have woodworking tools such as mitre saw, jigsaw, router table, drill press etc.) so I question whther I can make them to the tolerances required for a really strudy machine.

    I have given very little thought to the Z axis at this point but I am treating it as a 'module' that I'll bolt on towards the end of the project.

    I think that's it for now. As I have more thoughts and ideas I'll vent them here.

    Cheers,
    Paul.

  2. #2
    4 qty TB6560 Drivers
    24V 250W PSU
    These will stunt the machine, if you can go with AM882 (not easy to find now) or https://www.ebay.co.uk/itm/2DM860H-2...-/401403682399 with a 68V power supply
    ..Clive
    The more you know, The better you know, How little you know

  3. #3
    Agree the 24V psu and TB6560 drivers give very low performance and possibly lost steps under load.

    You can hand make the large end L plates using a template and router with a carbide fluted end mill. Accuracy is not critical as the outline is mainly cosmetic and the holes can be drilled oversized. If you are fussy they can be the first things you remake with the machine.

    Belt drive is often neater as the stepper can be tucked away. At 2010 you would usually 1:1 drive for wood and 2:1 ( step down) for aluminium.

    Z axis should be sketched soon as the ballscrew location, ballnut, and stepper location at the end of the gantry all need to fit together. You also need to add the spindle plus a cutting bit to check the gantry is at the right height to give the range of movement you need on the Z axis plus clearance to machine over a vice.

    1605 is often fine for Z but if you have bought the other size then use that.

    Draw as much as you can before cutting anything because the details can catch you out !
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  4. #4
    Quote Originally Posted by Clive S View Post
    These will stunt the machine, if you can go with AM882 (not easy to find now) or https://www.ebay.co.uk/itm/2DM860H-2...-/401403682399 with a 68V power supply
    Thanks for that, I'll take a look at those drivers and an uprated PSU. I bought the motors and drivers as a kit and just assumed that they would all work well together. At the time I bought them I did have a smaller machine in mind but you know how it goes! As per your signature; as I get deeper into this I'm starting to realise just how little I know

  5. #5
    I bought the motors and drivers as a kit and just assumed that they would all work well
    Yes kits never work well, they just seem to put things together that don't match.

    Have a look through Joe's thread https://www.youtube.com/watch?v=pZo2...S3i705fuSogBXT and see his build log on here.

    He also has a very good vid on a power supply build.
    ..Clive
    The more you know, The better you know, How little you know

  6. #6
    Quote Originally Posted by routercnc View Post
    Agree the 24V psu and TB6560 drivers give very low performance and possibly lost steps under load.

    You can hand make the large end L plates using a template and router with a carbide fluted end mill. Accuracy is not critical as the outline is mainly cosmetic and the holes can be drilled oversized. If you are fussy they can be the first things you remake with the machine.

    Belt drive is often neater as the stepper can be tucked away. At 2010 you would usually 1:1 drive for wood and 2:1 ( step down) for aluminium.

    Z axis should be sketched soon as the ballscrew location, ballnut, and stepper location at the end of the gantry all need to fit together. You also need to add the spindle plus a cutting bit to check the gantry is at the right height to give the range of movement you need on the Z axis plus clearance to machine over a vice.

    1605 is often fine for Z but if you have bought the other size then use that.

    Draw as much as you can before cutting anything because the details can catch you out !
    Some good points there, many thanks.

    I think I am leaning towards cutting my own plates and, like you said, if I'm not entirely happy with them I'll machine replacements when I'm up and running. I normally tear through wood based projects because I am so comfortable and familiar with the material and I know how what tolerances I have to play with. Clearly working with metals is going to be a whole different ball game and I'm going to be working much more slowly, methodically and precisely (hopefully!). I'll also need to avoid errors as the raw material cost is so much higher than most woods - being a Yorkshireman I'm going to be sqeezing every last penny

    I like the idea that the motors are tucked into the footprint of the frame as there's less chance of them getting knocked. I'm operating in a fairly confined space (my garage) so anything that saves space is a bonus.

    Is it possible to have two sets of pulleys and belts and swap them over for specific materials? I imagine that I'll be cutting wood 95% of the time so could I run a set of 1:1 and then swap it out for a 2:1 when cutting acrylic and aluminium? Would I just need to change the parameters in my software to account for it?

    Looks like I'll be on the Fusion 360 for a few days! I have only had a few hours experience of it so far and after many years of using Sketchup I am finding the learning curve pretty steep.

    Thanks again for all the advice.

  7. #7
    Quote Originally Posted by Clive S View Post
    Yes kits never work well, they just seem to put things together that don't match.

    Have a look through Joe's thread https://www.youtube.com/watch?v=pZo2...S3i705fuSogBXT and see his build log on here.

    He also has a very good vid on a power supply build.
    I sat down last night and started watching Joe's YouTube videos, wow! Some brilliant info there, I learned a lot and got some great ideas about how to proceed with my own project. Thanks for that link, I thought I had watched every meaningful CNC video on YouTube, how I missed Joe's series I don't know.

  8. #8
    Quote Originally Posted by Clive S View Post
    These will stunt the machine, if you can go with AM882 (not easy to find now) or https://www.ebay.co.uk/itm/2DM860H-2...-/401403682399 with a 68V power supply
    Just been looking into AM882 drivers. They offer three variations - AM882, AM882H, DMA882S. According to the details the AM882H has "fun" but the AM882 has "no fun" and it seems both are being replaced by the DMA882S. Whichever version I choose I am looking at about 200 for four drives. I can get four 2DM860 drives for about 150.

    Is it worth spending the extra 50 or so for the AM882s over the 2DM860s? If I go for the AM882s, is it better to get the tried and tested AM882 or AM882H, OR do I get the latest DMA882S?

    AM882 Drives:
    2DM860 Drives:
    Last edited by CaptainBarnacles; 1 Week Ago at 11:39 AM.

  9. #9
    Quote Originally Posted by CaptainBarnacles View Post
    Just been looking into AM882 drivers. They offer three variations - AM882, AM882H, DMA882S. According to the details the AM882H has "fun" but the AM882 has "no fun" and it seems both are being replaced by the DMA882S. Whichever version I choose I am looking at about 200 for four drives. I can get four 2DM860 drives for about 150.

    Is it worth spending the extra 50 or so for the AM882s over the 2DM860s? If I go for the AM882s, is it better to get the tried and tested AM882 or AM882H, OR do I get the latest DMA882S?

    AM882 Drives:
    2DM860 Drives:
    The drive I linked to is the H version and shows : Supply voltage 30VAC (DC40V) ~ 80VAC (DC110V) this means you could just put a toroidal transformer connected to it because the drives can accept AC as well as DC

    Your link shows 48-75VDC, power supply, which is a bit low for a 68V power supply.

    I have used the 2DM860H several time and not had any problems
    ..Clive
    The more you know, The better you know, How little you know

  10. #10
    Quote Originally Posted by Clive S View Post
    The drive I linked to is the H version and shows : Supply voltage 30VAC (DC40V) ~ 80VAC (DC110V) this means you could just put a toroidal transformer connected to it because the drives can accept AC as well as DC

    Your link shows 48-75VDC, power supply, which is a bit low for a 68V power supply.

    I have used the 2DM860H several time and not had any problems
    Aaaahhh, I see. Thanks Clive, I'll get the 2DM860H drives that you linked to.

    Cheers,
    Paul.

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