584,814 active members*
5,420 visitors online*
Register for free
Login
IndustryArena Forum > WoodWorking Machines > DIY CNC Router Table Machines > How can I increase the feed rate of my machine?
Results 1 to 14 of 14
  1. #1
    Join Date
    Oct 2008
    Posts
    85

    How can I increase the feed rate of my machine?

    I have a diy (mdf with steel reinforcement) router machine for wood routing. The cutting area is 20" x 40". I'm running Mach 3, with 425 oz/in nema 23 steppers, C-10 bob, 1/2-10 Acme lead screws, and a 24v power supply. My machine runs smoothly at 35 ipm. When I try to increase this in motor tuning the motors "whine" and the gantry stops moving or "slips". There is not a lot of friction in the machine as it moves quite freely when I hook up my 14v cordless drill to the leadscrews. Does anybody have any ideas as to some good starting settings for velocity and accel? I would like to get this to 80-100 ipm. I was told that a Smoothstepper might accomplish this by changing the connection from parallel port to usb. Is this correct? Any other ideas? How do some of these machines with smaller steppers possibly run at 200-300 ipm and more?

    Thanks, Jeff

  2. #2
    Join Date
    Feb 2007
    Posts
    4553

    Post

    Jeff,

    What stepper driver are you using?

    Need more info.

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  3. #3
    Join Date
    Mar 2003
    Posts
    35538
    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
    Join Date
    Jan 2007
    Posts
    355
    Hi Jeff,

    You didn't mention what stepper driver you're using. If the driver can handle more voltage, go for it. More voltage = more power to the stepper.

    You can also replace the 1/2-10 acme rod with a 1/2-10 2 start acme rod. This will give you twice the linear speed at the same rpm.

  5. #5
    Join Date
    Oct 2008
    Posts
    85
    My drivers are Keling 4030's. How do the 2 start acme screws change the speed at the same rpm? Will they also increase the load on the motors? I've seen them but don't understand them.
    Thanks, Jeff

  6. #6
    Join Date
    Feb 2007
    Posts
    4553
    Dampers will help a lot if this is what you are experiencing.

    [ame="http://www.youtube.com/watch?v=8Am69_F93yA&feature=channel_page"]YouTube - 65 ipm[/ame]


    After adding dampers you might consider raising the power supply voltage to 36-40 volts, that will increase rpm about 30 percent.

    Changing the screws to 2 start would double your feed rates.

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  7. #7
    Join Date
    Feb 2007
    Posts
    4553

    Post Screw Start Diagram

    Screw Start Diagram:
    Attached Thumbnails Attached Thumbnails Screw Starts.JPG  
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  8. #8
    Join Date
    Feb 2007
    Posts
    4553

    Post

    The number of starts on most threads is one (single start). However, a number of thread series including Roton's Hi - lead(r), Torqspline(r) Lead Screw, and Ball Screw series screw threads may have from 2 to 20 starts or more. Multiple starts are used to increase the lead (linear advancement per revolution). In most cases, increasing the number of starts is preferable to increasing the pitch because larger pitches reduce the minor diameter. A small minor diameter decreases the screw stiffness and makes it more difficult to tap nuts because of the likelihood of the tap breaking during tapping. Also, for the same lead, increasing the number of starts actually increases the thread contact area when compared to a thread with the same lead but using fewer starts and a coarser pitch. Close examination of the thread will reveal the number of starts (Figure 49). Simply place a pencil or marker pen in the thread groove and rotate the thread one revolution. If the end of the pencil mark is in the adjacent thread groove, the screw has a single start. If there is one thread between the beginning and the end of the mark, it is a two start thread, two grooves, a three start thread and so on. Another way to discover the thread starts is to examine a transverse section of the screw. As illustrated in Figure 49, if the end view is an offset circle, the screw is single start. A two start thread will have roughly a football shape, a three start thread will have a tri-oval shape and a four start thread will be noticeably four cornered. Usually, five starts and up can simply be counted in the transverse section.
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  9. #9
    Join Date
    Oct 2008
    Posts
    85
    Thanks Jalesi,

    That is an excellent description of the screws. So with 2 starts, will the same nuts work? They will just move across twice the distance per revolution, correct?

    Thanks, Jeff


    About the dampener, That video could be from my machine, That's exactly what it does. What can I use as a dampener and how do I determine the weight? The one in the vid looks a bit dangerous to me. I think I prefer the disk type.

    Thanks again, Jeff

  10. #10
    Join Date
    Oct 2008
    Posts
    1147
    Woa, I've seen the word Dampers thrown around before but it is the first time I've seen one in action. It looks like something I would be interested in putting on my machine once it is done.

    Is the point of them to help the steppers to not loose steps by giving it a little torque support? If you have any additional infor and their prs and cons I'd really like to read about them.


    Quote Originally Posted by jalessi View Post
    Dampers will help a lot if this is what you are experiencing.

    YouTube - 65 ipm


    After adding dampers you might consider raising the power supply voltage to 36-40 volts, that will increase rpm about 30 percent.

    Changing the screws to 2 start would double your feed rates.

    Jeff...

  11. #11
    Join Date
    Feb 2007
    Posts
    4553

    Post

    FandZ,

    The damper helps to suppress resonance, see the attached documents for more info.

    http://www.ferrotec.com/products/fer...nertiaDampers/

    Jeff...
    Attached Files Attached Files
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  12. #12
    Join Date
    Oct 2008
    Posts
    1147
    Quote Originally Posted by jalessi View Post
    FandZ,

    The damper helps to suppress resonance, see the attached documents for more info.

    http://www.ferrotec.com/products/fer...nertiaDampers/

    Jeff...
    Thanks for the link. I guess I'll see how my machine does once it is up and running. I'm just glad I'll be ready for the problem if it pops up.

  13. #13
    Join Date
    Feb 2004
    Posts
    1086
    Unfortunately, you need a multi-start nut (with the same number of starts and pitch as your screw) if you switch to a multi-start screw -- you cannot use the original nut. It will not physically fit.

    That being said, I highly recommend multi-start screws. My machine went from ~110 IPM to 300 when I went from single start ACME to 5 start ACME. There are two big advantage of multi-start screws for stepper applications. 1 is the increased linear speed at the same RPM, as stepper motors produce more torque at lower RPMS. 2 is the increased efficiency of higher lead screws. This is just an inherent reduction in frictional losses due to the higher contact angle of the threads.

    Hope that helps,

    Ahren
    www.cncrouterparts.com

  14. #14
    Join Date
    Oct 2008
    Posts
    85
    Thanks, Ill check into the multi starts.
    Jeff

Similar Threads

  1. c axis feed rate on a turn /mill machine
    By bike in forum G-Code Programing
    Replies: 5
    Last Post: 09-30-2008, 12:57 AM
  2. Feed rate for 5/8-18 tap
    By Eagle View in forum MetalWork Discussion
    Replies: 2
    Last Post: 09-24-2008, 03:25 PM
  3. Feed rate Ovverride also Increases rapid rate.
    By Korellibopper in forum Machines running Mach Software
    Replies: 1
    Last Post: 01-31-2008, 12:37 AM
  4. Feed Rate and Spindle Rate for this cut?
    By DroopyPawn in forum MetalWork Discussion
    Replies: 20
    Last Post: 11-22-2007, 06:12 AM
  5. How can I up my feed rate ?
    By ynneb in forum DIY CNC Router Table Machines
    Replies: 7
    Last Post: 07-13-2004, 03:40 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
  •