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  1. #1
    hesstool's Avatar
    hesstool is offline Stainless
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    Default Can someone simplify, or explain Chip Thinning?

    I've been seeing a lot reference to Chip Thinning in a number of posts here and was wondering if someone could explain the good/bad/ugly of it? I have a vague idea, but I guess I'm still thinking 'old school'.

  2. #2
    SDConcepts is online now Stainless
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    chip thinning is the concept of maintaining the chip load on an end mill. sort of like maintaining sfm on a lathe. with a lathe to maintain sfm you increase your rpm as your diameter gets smaller. this ultimately takes a bigger bite of the material than if you were to use a slower rpm and the same feed.

    chip thinning is a process by which your trying to maintain the amount of material your taking off with an endmill. every tool has and edge, some are sharp and some are round. ideally you want to use more than the edge prep of the tool to remove material otherwise it will dull faster. you can do this two ways. 1 you can take a bigger bite of material or 2 you can move the end mill faster (thereby taking a bigger bite and increasing your chip load.) chip thinning is the second option.

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    Glacern's Avatar
    Glacern is offline Aluminum
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    Chip thinning = chips are thinner than the feed rate of cutter. E.g. the feed rate = 0.010 IPT, chip thickness = 0.006".

    Axial chip thinning occurs when the lead angle of the cutter is less than 90 degrees. It's like slicing a carrot diagonally... your slices are thinner and larger in area, but the number of slices stays the same.

    Radial chip thinning occurs when the WOC is less than the radius of the cutter. Observing from a top view perspective, imagine feeding an endmill at full WOC in a slotting operation. The chips are crescent shaped, thick in the center, thin at the sides. Then imagine taking a very light WOC in a profile finishing operation with the same endmill. The chips look like the thin sides of the crescent.

    Chip thinning occurs in drilling as well... the sharper the drill point, the thinner the chips.

    -Sol
    Glacern Machine Tools

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    Polaraligned is offline Hot Rolled
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  5. #5
    Greg White is offline Titanium
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    and to add to the cornfusion,climb cut verses conventional,where as it is in reverse,eh?
    I wish I could type fast enough to try and explain.....
    Gw

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    Arthur.Marks is offline Stainless
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    Quote Originally Posted by Glacern View Post
    chip thinning occurs when the WOC... -Sol
    Glacern Machine Tools
    Perhaps a newbie question here. WOC?

    Nothing matches
    WOC - What does WOC stand for? Acronyms and abbreviations by the Free Online Dictionary.

    May I assume this is a standard acronym for "Width of Chip"?

  7. #7
    Rstewart is offline Hot Rolled
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    Default

    That means Width of Cut, or Step-over.

  8. #8
    BobWarfield is offline Hot Rolled
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    Quote Originally Posted by Greg White View Post
    and to add to the cornfusion,climb cut verses conventional,where as it is in reverse,eh?
    I wish I could type fast enough to try and explain.....
    Gw
    Climb vs Conventional is a fascinating discussion too. Submitted for your approval (as Rod Serling used to say) is the curious case of when its better not to climb:

    Home

    Those are the Shearhog guys, so they know their stuff. Fascinating how climb milling will get you into negative rake territory on deep cuts, which is not necessarily how your cutter likes to cut.

    These sorts of things are what got me started building G-Wizard, which will calculate all that crazy stuff and build it into your Feeds and Speeds. It even tells you when to climb mill, LOL.

    Cheers,

    BW

  9. #9
    Hdpg is offline Stainless
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    Quote Originally Posted by BobWarfield View Post
    ....Fascinating how climb milling will get you into negative rake territory on deep cuts, which is not necessarily how your cutter likes to cut....Cheers,

    BW
    I never thought about that but it does make sense and maybe explains why a machine makes a lot more tool noise when cutting above 1/2 diameter engagement.

    But I do quibble with the "3/4 diameter or more"; when a tool is fully engaged the cutting edge entry is the same as conventional milling and the tool rake is performing normally.

    And I have to thank you for the information about thread strength further down the page. Many years ago when I was designing some gyro compass mounts for icebreakers I did some testing on 1/4"-20 pull-out strength on 6061 and came up with around 3500 lbs so it is nice to know I was not out to lunch. But what I find even nicer to see is the comparison between cut and formed threads in aluminum; essentially no difference. I have been looking for this comparison for a long time.

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