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IndustryArena Forum > MetalWorking Machines > Benchtop Machines > PM25 CNC Conversion, cause of chatter?
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  1. #1

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    PM25 CNC Conversion, cause of chatter?

    I have a Precision Mathews PM25-MV milling machine I converted to CNC. It's been working for a few months now. I'm having a problem with chatter when machining on larger cuts.

    Video of said chatter, it's the worst when it gets to left side of this hole in the video: https://www.youtube.com/watch?v=exJE...ature=youtu.be

    In this cut I was running a 1/2" 4 flute end mill from Kodiak, 2500 RPM, 6in/min feed, .3" DOC, 0.044" WOC with flood coolant. Machining 1018 Steel 1 inch thick. It chatters a lot worse on one side vs the other when milling this hole.

    Any idea what is going on with this? Things to check?

  2. #2
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    Re: PM25 CNC Conversion, cause of chatter?

    You are machining out past the edge of the vise. Yes, it vibrates up and down even though it is 1" plate. For a part this wide you should use wide jaws, two vises, or clamp to the table.

  3. #3
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    Re: PM25 CNC Conversion, cause of chatter?

    Quote Originally Posted by patrick31 View Post
    I have a Precision Mathews PM25-MV milling machine I converted to CNC. It's been working for a few months now. I'm having a problem with chatter when machining on larger cuts.

    Video of said chatter, it's the worst when it gets to left side of this hole in the video:

    In this cut I was running a 1/2" 4 flute end mill from Kodiak, 2500 RPM, 6in/min feed, .3" DOC, 0.044" WOC with flood coolant. Machining 1018 Steel 1 inch thick. It chatters a lot worse on one side vs the other when milling this hole.

    Any idea what is going on with this? Things to check?
    Looks to me like you're using conventional milling, yes? (anti clockwise)
    Try climb milling instead and see if that helps (clockwise)

    With manual milling I find conventional makes it harder to move the table (goes against the cutter)
    When trying climb the table goes with the cutter and it moves very easy.
    Will be the same feeling on the CNC you just can't feel it for yourself.
    I climb everything with CNC conversions.
    Worth a shot.

  4. #4

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    Re: PM25 CNC Conversion, cause of chatter?

    Quote Originally Posted by dazp1976 View Post
    Looks to me like you're using conventional milling, yes? (anti clockwise)
    Try climb milling instead and see if that helps (clockwise)

    With manual milling I find conventional makes it harder to move the table (goes against the cutter)
    When trying climb the table goes with the cutter and it moves very easy.
    Will be the same feeling on the CNC you just can't feel it for yourself.
    I climb everything with CNC conversions.
    Worth a shot.
    I was climb milling on this cut. I tried conventional milling once, and the chatter completely went away, but the recutting was terrible and it dulled and then broke the small cutter after about 20-25 minutes of machining.

  5. #5

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    Re: PM25 CNC Conversion, cause of chatter?

    Quote Originally Posted by cool_one View Post
    You are machining out past the edge of the vise. Yes, it vibrates up and down even though it is 1" plate. For a part this wide you should use wide jaws, two vises, or clamp to the table.
    Thanks. Quick question, if I were to reclamp the part with the vice shown, but machine only inside the vice, would that fix it or help? It's not too hard to move and reclamp/touchoff if that will help. I need to look into wide jaws you mention, or just clamp to the table is probably a good option.

  6. #6
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    Re: PM25 CNC Conversion, cause of chatter?

    Quote Originally Posted by patrick31 View Post
    I was climb milling on this cut. I tried conventional milling once, and the chatter completely went away, but the recutting was terrible and it dulled and then broke the small cutter after about 20-25 minutes of machining.
    Yep. Ignore my comment. Been a long day.
    Might just be too much for the machine ie it's not rigid/heavy enough to cope that well.
    Maybe try shallower cuts and see how that goes.

  7. #7
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    Re: PM25 CNC Conversion, cause of chatter?

    Yeah, I think reclamping would work. It looks like shars has wide jaws for 6" vises up to 18 inches wide. For 4" vise, though looks like they only have 5" jaws. You could makes some as well.

  8. #8

    Re: PM25 CNC Conversion, cause of chatter?

    Hi Dear do you need tool charge for this machine I have good option https://shoptoolusa.com/product/20-p...-tool-changer/
    and other parts and machines

  9. #9
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    more flutes!

    Try a 5 flute tool. Even number flutes can sometimes produce that vibration because their snd shape is basically square. Going up to a 5 flute makes a rounder end picture and will always have a tooth engages so the vibration should reduce. Also with a machine that powerful, you may get some benefit from the added core strength of the higher flute count tools.

    oh also -
    I ran KODIAK tools for years and then my local guy pointed me towards titan. packaging and the tools inside look identical to the kodiaks, but the price was a few dollars less each which doesn't hurt. if you want to check them out its www.titancuttingtools.com

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