Newbie Fixed Gantry CNC Mill for cutting Aluminium and softer materials - Page 2


Page 2 of 2 FirstFirst 12
Results 13 to 16 of 16

Thread: Fixed Gantry CNC Mill for cutting Aluminium and softer materials

  1. #13
    Registered
    Join Date
    Dec 2017
    Location
    Germany
    Posts
    6
    Downloads
    0
    Uploads
    0

    Default Re: Fixed Gantry CNC Mill for cutting Aluminium and softer materials

    So I did some simulations (I have Fusion360) and for a 100Kg down force in the middle of the bed (in the first configuration, with the carriages at the edge of the bed) I get only a 5 micron deflection. This would be one and a half times my weight pushing down on a drill bit right in the middle. I would say, no reasons to worry at all.
    Same 100kg force pushing the bit upwards into the spindle will result in a 0.05mm maximum deflection (here were the ballscrews not yet attached, so it might be less at the end).
    I know, in real life we have much more play and the real deflection might be 50% more, but I am still happy with this result. I don't see any reasons to spend more for the wider tubes at the bottom.
    I will go ahead and order the steel tubes cut to size. And a drill press as well.. .
    Fixed Gantry CNC Mill for cutting Aluminium and softer materials-simulation-jpg

    Attached Thumbnails Attached Thumbnails Fixed Gantry CNC Mill for cutting Aluminium and softer materials-simulation-jpg  
    Last edited by unromeo21; 11-23-2018 at 08:58 AM.


  2. #14
    Registered
    Join Date
    Sep 2016
    Posts
    66
    Downloads
    0
    Uploads
    0

    Default Re: Fixed Gantry CNC Mill for cutting Aluminium and softer materials

    I would think that if the rail position was enough alone to make or break your bed deflection spec that your bed just wasn't thick enough full stop. But my thinking was more that no matter how thick and stiff your bed is, putting the rails not on the edge should let it respond better to vibration, rather than letting the entire middle of the bed ring. Could all just be made up.

    With those numbers on the gantry you're just over 100k lb/in stiffness, which should be good for this type of machine. That's the guideline I used designing my current build and that's worked out really well.



  3. #15
    Gold Member
    Join Date
    Jan 2005
    Location
    USA
    Posts
    8611
    Downloads
    0
    Uploads
    0

    Default Re: Fixed Gantry CNC Mill for cutting Aluminium and softer materials

    Quote Originally Posted by unromeo21 View Post
    So I did some simulations (I have Fusion360) and for a 100Kg down force in the middle of the bed (in the first configuration, with the carriages at the edge of the bed) I get only a 5 micron deflection. This would be one and a half times my weight pushing down on a drill bit right in the middle. I would say, no reasons to worry at all.
    Same 100kg force pushing the bit upwards into the spindle will result in a 0.05mm maximum deflection (here were the ballscrews not yet attached, so it might be less at the end).
    I know, in real life we have much more play and the real deflection might be 50% more, but I am still happy with this result. I don't see any reasons to spend more for the wider tubes at the bottom.
    I will go ahead and order the steel tubes cut to size. And a drill press as well.
    That was a worth while check 100Kg is more than your machine will ever see, for example if you could or used a 12mm drill in your machine, most likely never will this would require 72 Kgs of thrust force to cut aluminum,

    You could add some aluminum bar stock like 16 x 38 under the table this would help to change the resonance in the aluminum plate

    Allow to fill your steel tubes with sand or a epoxy sand mix when you have completed the build

    Mactec54


  4. #16
    Registered arizonavideo's Avatar
    Join Date
    May 2008
    Location
    USA
    Posts
    1126
    Downloads
    0
    Uploads
    0

    Default Re: Fixed Gantry CNC Mill for cutting Aluminium and softer materials

    Nice simple design.

    The one thing you might find is the steel likes to ring. You might think of some kind of fill for some of the tubes. Even the cans of expanding foam will reduce ringing a lot.

    Make sure you leave a way to tram the mill.

    youtube videos of the G0704 under the name arizonavideo99


Page 2 of 2 FirstFirst 12

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

Fixed Gantry CNC Mill for cutting Aluminium and softer materials

Fixed Gantry CNC Mill for cutting Aluminium and softer materials