Z Axis Plunging during cut


Results 1 to 5 of 5

Thread: Z Axis Plunging during cut

  1. #1
    Registered
    Join Date
    Oct 2017
    Location
    United States
    Posts
    3
    Downloads
    0
    Uploads
    0

    Default Z Axis Plunging during cut

    I have a CNCRP 5x10 with CNCRP spindle. I am having problems running larger bits. I set Z zero to the machine bed. Once it starts under load, it's almost like it pulls the spindle down further and further. I am running the Amana 46199-K (1/2" D, 2"CH) compression bit. I never have this problem when I am running 1/4" bits. It's really frustrating, especially since it just went through my spoil board and took out two my threaded inserts!!! Any thoughts?

    Similar Threads:


  2. #2
    Registered
    Join Date
    Oct 2017
    Location
    United States
    Posts
    3
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Plunging during cut

    I actually figured it out. To my surprise, the torque of the cutting is putting so much down force on the bit that it is actually pulling it out of the collet. I am not really sure how to remedy that, as my collet is a relatively new ER20 1/2". Any suggestions??? I suppose the easiest thing is to just take smaller bites.



  3. #3
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Location
    Shelby Township
    Posts
    33256
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Plunging during cut

    Tighten the nut more.
    With a 1/2" compression bit, I can cut 1" deep at 800ipm with no issues. (With a 15HP spindle).

    If the bit is coming out of the collet, it's just not tight enough. It's that simple.

    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
    Member
    Join Date
    Nov 2013
    Posts
    278
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Plunging during cut

    Hi,
    good quality collets are required also.

    You might be tempted to think 'how can one collet be good when another seemingly identical one is not?'

    The angle of the taper is critical. The clamping force of the nut forces the collet deeper into the taper and the collet closes on the shank of the
    tool. If there is the slightest difference between the angle of the internal taper and the taper of the collet then the transmission of the clamping
    force (nut tension) to clamping force on the tool is much reduced.

    I have a set of Jones & Shipman collets for my ER25 and I use Rego-Fix collets in my ER16 high speed spindle. They work well. I have used cheap Chinese
    ER32 collets but had the same problems as you.....the tool pulling out....even with the nut clamped to 200 ft.lb....as tight as I could get it.

    Next issue is the shank of the tool. It should be spotlessly clean and oil free. I use a methylated spirits soaked rag to wipe the shank before I fit the tool.
    If the shank of the tool has a Weldon flat then it will almost certainly pull out.

    Craig



  5. #5
    *Registered User* RoverJ1530's Avatar
    Join Date
    Jan 2019
    Posts
    5
    Downloads
    0
    Uploads
    0

    Default Re: Z Axis Plunging during cut

    Quote Originally Posted by ger21 View Post
    Tighten the nut more.
    With a 1/2" compression bit, I can cut 1" deep at 800ipm with no issues. (With a 15HP spindle).

    If the bit is coming out of the collet, it's just not tight enough. It's that simple.
    Is it a 2 flute or 3 flute compression bit? RPM's? I'm cutting 37 & 55 mm thick birch with a 3 flute, 1/2" compression in 3 and 4 passes respectively. 315ipm I'm going too slow, arn't i?



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 Plunging during cut

Z Axis Plunging during cut