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Thread: How much chip load can an end mill handle?

  1. #13

    Default parameters

    hp load an end mill can take is based on how long it is. In general a shorter end mill can take a much higher load, 1/2 length can take 2x2x2 or 8 times more.
    ....... also if flutes get clogged or chips stick to flutes you can overload these estimates by 10 - 100 times

    parameters at 100% max load based on Machinabilty rating of 4.0 cubic inches per hp per minute...... assuming I have not made an error in calculations

    5/8 diam, 3 flute, carbide end mill
    SFPM 2025
    Coolant used but minimal (not flood)
    Stickout from collet 2.0
    DOC 1.500
    WOC 0.138
    chip thickness with thinning 0.0041
    Feed 210 ipm
    RPM 14,000
    Hp 10.85
    Load on end of End Mill 478 lbs
    MRR 43.4 cubic inches per minute

    Stickout from collet 2.5
    DOC 1.500
    WOC 0.088
    Feed 168 ipm
    chip thickness 0.0029
    Hp 5.56
    Load on end of End Mill 245 lbs
    MRR 22.2 cubic inches per minute

  2. #14


    Thanks all. I got an email back from SGS. Took them one day to respond. Nice. They basically said the same thing Geoff said. After reducing to 4000 and increasing the stepover to .04 I was able to cut 2 min from the cycle while staying at 100% load. My poor machine, it's always at 100%. I don't think its seen anything lower than 50% in 2 years. Take that Haas haters.

    BobWarfield, What is this program your talking about? It sounds cool as hell. Same with DMF_TomB. What program are you using that gives all this useful info? Why isn't this data given in my expensive cam software?

    I wish you all could see the volume of material I'm removing with this little machine. It's truly breathtaking to watch a volumill toolpath hog out a 3x5x9 piece of billet. It's like it doubled the horsepower of the mill. I've even given up on the chip auger and started using a snow shovel to empty the chips.

    Again thanks for all the input. Happy cutting!

  3. #15


    Constant engagement angle toolpaths are the next best thing to magic, LOL.

    The software I refer to is G-Wizard, a feeds and speeds (and many other things) calculator I wrote for machinists:

    GWizard: A CNC Machinist's Calculator for Feeds and Speeds

    What's really needed is some way to cross optimize all these factors so we find the point of maximum MRR within the limits of what the tool can put out and within the limits of the power your machine can deliver. G-Wizard will optimize for max feeds and speeds within a tool deflection limit, but I'll have to think about how to do this sort of optimization.



    Try G-Wizard Machinist's Calculator for free:

  4. #16
    Gold Member
    Join Date
    Jul 2005


    Quote Originally Posted by double a-ron View Post
    .....My poor machine, it's always at 100%. I don't think its seen anything lower than 50% in 2 years....
    Don't worry they can take it.

    Because we do production work it was worth my while to refine programs to get the maximum productivity out of the machines so our machines often run between 100 and 120%.

    An open mind is a long as all the common sense has not leaked out.

  5. #17

    Default free Excel file for calculating Speed Feed DOC

    latest free Excel file for calculating speed, feed, depth of cut. it can be opened with the free Open Office Calc program. it will figure DOC, horsepower, force on the end of the end mill
    ..... experimental it needs data like
    1) diameter of end mill
    2) length it is sticking out
    3) SFPM you want to run at
    4) MR or machinabilty rating of metal being cut with a chart of common metal alloys. MR is how many cubic inches per hp per minute you get machining a particular alloy.
    has areas to help calculate what load setting you need to enter to get a particular DOC, or hp load, or force on end mill in pounds. has rows for side milling too, high DOC low WOC. and has row for ball end mill with rpm based on width of cut which is less with shallow depths with a ball end mill
    .... it is experimental

    Attached Files Attached Files

  6. #18
    Gold Member
    Join Date
    May 2004
    United States


    @TomB - Thanks. Maybe something like this is what these guys need.

    I would like to suggest that you just put all the fill-in-the-blanks with an answer box on the first sheet and then bury all the data in the follow up sheets. Be sure to lock cells and protect sheets as needed so that data or formulas are not accidentally changed.

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