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  1. #1
    Hi guys,

    After finishing my G540 powered Aluminium gantry design, and having a few teething problems, I feel I am making progress - but was wondering what realistic figures ppl are using for their rapids. or for clearing / roughing cuts.

    My X axis ( single 380 Oz nema 23 stepper with 10mm pitch) I got up to 18,000 mm/min at 1000 mms accel - so I set the rapid at 12,500 and base acceleration at 1,500mm/sec^2

    My Z axis - same but 5mm pitch - 3,000mm/min acceleration 1,500 mm/sec^2

    My Y axis ( which carries the gantry ( around 70 kgs ) 2 x nema 23, 10mm pitch ) - uses 6,000mm/min with 1,500 mm/sec

    Cutting wise, ( wood ) I have been using 2.2KW spindle at 50% speed ( 12,000 rpm) or 18,000 RPM, and around 3,000 mm/min 4-5mm depth of cut.

    Any other guys out there with 2KW systems, or using Nema 23, could you comment on your rapids, and also you cut depth/speeds?

    Here is a short clip of a Fusion360 spiral plunge, cutting at 3,000, with the above rapids towards the end.

  2. #2
    Neale's Avatar
    Lives in Plymouth, United Kingdom. Last Activity: 4 Hours Ago Has been a member for 4-5 years. Has a total post count of 964. Received thanks 162 times, giving thanks to others 5 times.
    My machine has a welded steel gantry that weighs, at a guess, somewhere around 60-70kg all-up. I drive that with 2 Nema 23 3Nm steppers, driving through 1-1 belt to 2005 ballscrews. I am currently running at 5000mm/min rapids. Haven't yet tried faster but that was the design target anyway - approaching critical speed for that length ballscrew and also corner speed for steppers. I could probably go faster with 2010 but at the time I starting collecting the hardware these weren't so easily available. Machine is still very new so haven't explored cutting capacities yet. To be honest, at the moment that seems fast enough for rapids on my size machine (cutting area 1500x750) but I get the impression that faster could be useful for cutting wood. Given that my old router could only manage 900mm/min, 5000 seems like lightning! Can't remember what acceleration is set to.

  3. #3
    Not that easy to compare with others unless using similair components.?
    For instance your using Analog drives which don't compare to Digital drives. Then your using less than 50v and most like Neil who have paid attention will be using 60v+ with digital drives.
    Then we throw into the mix external Motion control which makes huge difference in performance over parallel port or low spec cards. Together all these things can make night and day difference in performance for machine using same motors/weight setup.

    With your setup I wouldn't expect much above 8000mm/min and still be reliable.

  4. #4
    5000mm/s is perfectly ok for normal work.

    First of all use your spindle to the max RPM and better download HSM adviser so you figure better what speeds and feeds combinations will give you better Material Removal Rate, which is what matters, not how fast your machine moves.
    project 1 , 2, Dust Shoe ...

  5. #5
    Ok - but the RPM the calculators are asking for are actually more like 6000 rpm, if I'm cutting at say 3000 mm/min. If I wanted to use the router at 100% ( 24,000 rpm ), then it would ask me to go faster than my rapid speeds - 12,000 mm/min

  6. #6
    Quote Originally Posted by dachopper View Post
    Ok - but the RPM the calculators are asking for are actually more like 6000 rpm, if I'm cutting at say 3000 mm/min. If I wanted to use the router at 100% ( 24,000 rpm ), then it would ask me to go faster than my rapid speeds - 12,000 mm/min
    enter carbide tool, if you enter HSS that could happen. And you can limit the rapid speed programming your machine. DId you down load HSMAdviser trial?

    here bellow 3 simulations 12mm indexing 1 flute bit / this is absolutely tremendous cutter/ , 6mm and 3mm .

    these are real speeds for wood, as i use them without problem. just adjusted to your machine. On mine i cut ~16000 mm/min on some occasions at 3000mms2, but my point is that such speeds are not everyday needed. only special bits go at that speed.


    Click image for larger version. 

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    project 1 , 2, Dust Shoe ...

  7. #7
    Yes, cutting speeds maybe not needed to be that high, but my work pieces are huge, so having a quick rapid can reduce machining time for things like parallel climbing finishes, by hours, also, the finishing cuts where only 1/2 MIL of say wood is removed, I don't need to be doing 3000 mm/min, I should be going faster?

  8. #8
    I'm running a uc400 Ethernet motion controller, no parallel or USB,ports. At 400hz. What type of motion controllers would be a lot faster

  9. #9
    Quote Originally Posted by dachopper View Post
    I'm running a uc400 Ethernet motion controller, no parallel or USB,ports. At 400hz. What type of motion controllers would be a lot faster
    I suggest you re read your other post http://www.mycncuk.com/threads/10592...-problem/page4

    And sell your drives. Have you had a response from the manufactures yet?
    ..Clive
    The more you know, The better you know, How little you know

  10. #10
    Quote Originally Posted by dachopper View Post
    I'm running a uc400 Ethernet motion controller, no parallel or USB,ports. At 400hz. What type of motion controllers would be a lot faster
    The G540 is limited to 200kHz so you should not run the UC400 at 400kHz, you are risking missing steps if you do that, even if it looks as it works, it may not work that well all the time.

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