509,955 active members
4,262 visitors online
Register for free
Login
Results 1 to 10 of 10
  1. #1
    Registered
    Join Date
    Feb 2007
    Posts
    16

    My First Wooden Cut

    Hello,

    I am very new to the world of CNC, I have been drawing for a few weeks now and been cutting some polystyrene foam with my router for a few days which has been working quite well.

    Yesturday I drew up a profile which is to be cut out of wood (MDF). The attached picture shows the result of that. I have also attached my .cad and my gcode file in the hope that someone could tell me why it has turned out this way.

    The wall in between the big holes is 10mm on the drawing but only about 2mm on the actual wood. Also the edges are all fury, I did use an old blade which may be quite blunt, is this the cause for that?

    Sorry for such a long post. If you have made it this far, Thank you. I appreciate any help you could give a begginner.
    Attached Thumbnails Attached Thumbnails DSC00329.jpg  
    Attached Files Attached Files

  2. #2
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    34611
    Did you use an 8mm bit? If so, you need to offset the lines in the drawing by the tools radius, as the center of the tool travels down the lines. Try a new sharp bit to get rid of the roughness. And use carbide, not HSS.
    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)

  3. #3
    Registered
    Join Date
    Jul 2005
    Posts
    668
    Use new tools to get the best cuts. Cut fast in MDF or slow the spindle down if your machine isn't up to it. Your tool is "chewing" the MDF instead of cutting it.
    Steve
    DO SOMETHING, EVEN IF IT'S WRONG!

  4. #4
    Registered
    Join Date
    Mar 2007
    Posts
    17
    Looks like you need to do a few things. Try using a straight cut bit ( one that is sharp ) or a down shear bit. It also looks like you may be getting a little burning which could mean 2 things, either you are feeding to slow for the RPM you are turning or your bit is just that dull. Also I think that if you use G41 or G42 to activate tool radius value it will make your holes the size you are aiming for. G41 and G42 should offset the tool center line by the radius of the tool.

    Hope this helps.

    Andrew

  5. #5
    Registered
    Join Date
    Feb 2007
    Posts
    16
    Thanks for all the help guys I think I am getting there now. In my drawing I have offset by the radius of my tool and used those lines as my toolpath. I have not yet run this on the machine as the simulation shows different to what my cut should actually be. Do I have to set the compensation in the tool setup dialog? or is there anything else I am supposed to do to get the right results.

    Thankyou for all your help,

    Dan.

  6. #6
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    34611
    I'd stay away from using compensation until you have the basics down. In what way is the simulation different?
    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)

  7. #7
    Registered
    Join Date
    Sep 2007
    Posts
    16
    When cutting MDF you need to run you inside edges clockwise inside and your outside edges counterclockwise outside using a down spiral cutter.

    Hope that helps

    CVV

  8. #8
    Registered
    Join Date
    Jun 2007
    Posts
    12
    I would say use a down cut spiral bit, but MDF has no grain orientation. You don't have to observe feed direction for internal/external cutting.
    Jack Briggs
    Briggs Guitars

  9. #9
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    34611
    Quote Originally Posted by jabguit View Post
    I would say use a down cut spiral bit, but MDF has no grain orientation. You don't have to observe feed direction for internal/external cutting.
    From my experience, you'll get a slightly better cut using conventional cutting MDF.
    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)

  10. #10
    Registered
    Join Date
    Sep 2007
    Posts
    16
    MDF will still frays and by using a down cutter and observing directions you will have a cleaner cut. Since he is pocketing he can use the down cutter for a clean look. He can also get a Mortising compression bit to assure a clean cut on both sides and use it to pocket.

    CVV

Similar Threads

  1. Wooden Gears?
    By spalm in forum Autodesk
    Replies: 14
    Last Post: 08-23-2012, 01:31 PM
  2. making wooden props
    By Paraprop in forum DIY CNC Router Table Machines
    Replies: 25
    Last Post: 04-14-2009, 01:28 AM
  3. my cnc wooden table.
    By steve knight in forum CNC Wood Router Project Log
    Replies: 4
    Last Post: 04-10-2007, 04:48 AM
  4. Epple Wooden CNC
    By keyne in forum DIY CNC Router Table Machines
    Replies: 7
    Last Post: 04-04-2006, 07:49 PM
  5. VCarved Wooden Sign
    By Tony Mac in forum Vectric
    Replies: 3
    Last Post: 11-25-2005, 01:30 AM

Posting Permissions

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