. .
  1. #1
    Any ideas ? I have an A4 gantry machine and when doing a fast travel in the + direction only, the Y axis makes a nasty high pitch juddery noise in two places on its' travel. I have almost had the whole machine apart and can't find any reason for it. The gantry seems aligned as far as I can tell using squares. The only thing I can think of is one of the linear bearings is causing the problem. If I put pressure on the gantry on the side that the noise is coming from it stops the noise.

    Help please.

    Rob

  2. #2
    edited yip see below, its likely what jazz has said having read his post,an oversight on my part ive had the same juddering on all axis but random instead of specific areas of the machine,as i did i can see why someone would think it was mechanical.
    Last edited by dazza; 11-07-2013 at 02:34 PM.

  3. #3
    My next job then, is to get the machine unbolted from the bench and slacken, jiggle, check and retighten the rail mountings. I'll probably take out the Y motor and check the feel of the Y slide on the rails.

    It is only a hobby machine with ACME screws and delrin, but the hobby seems to be getting it aligned and working smoothly.

    When I have got the machine off he bench I will take some pics.

  4. #4
    Quote Originally Posted by cropwell View Post
    My next job then, is to get the machine unbolted from the bench and slacken, jiggle, check and retighten the rail mountings. I'll probably take out the Y motor and check the feel of the Y slide on the rails.
    first just disconnect the ballnut mount from the back of the plate,that will free up your z without removeing motors or screw,then slide left to right,if somethings not aligned or theres bother with the bearings you'll feel it tighten as you go,.
    Last edited by dazza; 11-07-2013 at 02:38 PM.

  5. #5
    If there's nothing obviously mechanical causing this judder then it could possibly be resonance causing the motors to judder. This is a typical mind band resonance problem. Called mind band because it affects motors at mid to high rev ranges or frequency.

    To quickly see if this could be the cause then try changing the micro stepping on the drives and see if it changes or moves the point when it happens.
    If it's midband res then changing the MS can often eliminate the judder altogether, doesn't fix the problem just changes the frequency to a point it doesn't affect motors.
    Last edited by JAZZCNC; 11-07-2013 at 01:56 PM.

  6. #6
    Well chaps,

    Progress has been made ! I took off the machine bed and unscrewed the block with the lead nut in it. The Y axis moved easily and smoothly. BUT when I unscrewed the lead nut block it was 1.2 mm above the mounting on the gantry, so it was bowing the lead screw. I have shimmed the block and now it runs smoothly. I just need to finish reassembling and test it again.

    Hopefully, End of Story.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 12
    Last Post: 25-05-2013, 12:41 AM
  2. RFQ: Z axis and y axis carriage
    By D-man in forum Projects, Jobs & Requests
    Replies: 0
    Last Post: 08-04-2013, 10:06 AM
  3. NEW MEMBER: Goal - Enable 3-Axis CNC Bed Mill to Perform 5-Axis Milling
    By LoveLearn in forum New Member Introductions
    Replies: 2
    Last Post: 25-01-2012, 08:46 PM
  4. Y axis is making X axis stall...!!
    By fasteddy in forum Machine Discussion
    Replies: 83
    Last Post: 24-10-2011, 12:19 PM
  5. Precision metal processing (3 axis, 5 axis, 7 axis) OEM
    By 7AxisCNC in forum Manufacturer News
    Replies: 0
    Last Post: 17-05-2011, 02:04 PM

Bookmarks

Posting Permissions

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