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  1. #61
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    Quote Originally Posted by allloutmx View Post
    Most of this looks pretty good...but I dont think I can concur with you on the drilling..you wouldnt feed an .03 drill the same as you would say a .500 drill
    You are right. For the most part, it works well. If you keep the SFM constant as the diameter gets smaller, the chip load is reduced proportionally by keeping the feed/inch constant.

    Your .03 drill would need 13,000 RPM to get to 100SFM. If you had that much RPM, I think you could feed it at 7 IPM.

  2. #62
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    Quote Originally Posted by ewlsey View Post
    You are right. For the most part, it works well. If you keep the SFM constant as the diameter gets smaller, the chip load is reduced proportionally by keeping the feed/inch constant.

    Your .03 drill would need 13,000 RPM to get to 100SFM. If you had that much RPM, I think you could feed it at 7 IPM.

    For off the shelf endmills, I use manufacturers recommendations. Fo my regrinds, its from memory from previous runs. I find the calculators to be too light on the feed. On the subject of drills, a smaller drill should have a faster ipm eventhough the ipr is less. This is from "by the book" numbers.

  3. #63
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    Quote Originally Posted by jamesu229 View Post
    For off the shelf endmills, I use manufacturers recommendations. Fo my regrinds, its from memory from previous runs. I find the calculators to be too light on the feed. On the subject of drills, a smaller drill should have a faster ipm eventhough the ipr is less. This is from "by the book" numbers.
    Your EM's should come with their own book...titled...phenomenal

  4. #64
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    Hardened toolsteel 58-62 Rc
    6 flute endmills TiAln
    600SFM
    60-80 IPM
    .006-.01 Radial DOC
    1x-2xø Axial DOC
    Dry

  5. #65
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    Default simple excel feed and speed calculator with chip thinning

    attached is free simple Excel spreadsheet where either enter existing end mill cutting parameters or enter new ones. i use for checking existing running programs and the tools in the cnc machine and to calculate new sfpm and feed. i run CNC with Excel on a computer open anyway with Setup and Inspection checklist open as standard practice (along with program loading software, cad viewer, etc). the free openoffice software open excel files and is free. excel file needs to be copied or saved from zip file to be able to change it.
    .
    i added 3 columns for width of cut (if not the same as cutter width), chip thinning calculation, and adjusted feed for chip thinning
    so

    .75 end mill WOC .075 can have feed 38 ipm compared to 23 ipm because of chip thinning.
    .
    i used a standard chip thinning math formula found in cutting tool manufacturer catalog and put it in excel
    .
    i would enter sfpm and feed recommended by cutting tool manufacturer and adjust as needed. obviously a heavily loaded, long length sticking out of tool holder cutter will need a reduction in max recommended DOC , sfpm, feed
    .
    if a 40 hp machine has load meter near max, to me it does not matter much how it is cut as metal removal rate is based on hp limit, ability to hold part, and ability of part to take cutting force with out bending and vibration. my main concern is holding a flatness and straightness tolerance of less than 0.0005" per foot. putting a 10 ton part back on the CNC mill because inspections says it is 0.0006" off is a rework job i like to avoid. running a 5" dia finish face mill at 10 ipm taking 0.001" depth of cut is done purposely slow to avoid cutting waves in the surface from the servo motors fluctuating more than 0.0005" at higher feeds.
    ....... raw power or hp can remove metal fast. end milling or side milling decision is often because what needs to be removed and where it is located
    Attached Thumbnails Attached Thumbnails chipthinning.jpg  
    Attached Files Attached Files

  6. #66
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    For a free trial of The Machinist Black Book email [email protected],com and put trial in the subject.
    Speed and Feed calculator for over 3000 materials and handy references for the machinist and programmer.


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