RPM Formula???

[Hardmill]

quote:

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Well with a Marge Simpson hair do

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Keep my momma outta this

 

Good morning wheelie, err Mayday

Hows the rest of the chopper bunch doing??

 

 

PEACE

[Charlie Pierson]

It is my understanding that SFM is related upon how much heat the tool can take before degeneration. Feedrate (amt. cut/tooth) is related to how much force the tool can take before degeneration.

 

in general:

Harder Part Materials -> lower SFM & (vice-versa)

Harder Tool Materials -> higher SFM & (vice-versa)

Higher transverse rupture strength in tool material -> higher feed (ipt)

 

modifications to general rules can depend upon tool coatings , chip evacuation, effective rake of the tool etc.

ex: TiAln likes to be run hot, in order to generate the aluminum oxide barrier which actually increases the efficiency of the coating, and w/ heavier feeds ( blow the chip out of the way fast so the heat generated stays in the chip).

 

btw: the 3.82 figure is derived from 12/pi which is (to 4 places) 3.8197 , a difference of way less than 1%, so use whatever is easier to remember.

[mayday]

Howdy Hardmill. meh backup QB blew the day off today, so Im solo today, prolly get a lot more done (NOT)

EDIT

after reading Charlies post,meh head hurts

[Hardmill]

quote:

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meh backup QB blew the day off today, so Im solo today, prolly get a lot more done (NOT)

EDIT

after reading Charlies post,meh head hurts

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Whys your head hurt?? Did your co-worker keep the other half brain you guys share??

:slam: J/K, no really J/k LOL LOL

 

PEACE

[Charlie Pierson]

my apologies for MayDay's head,

 

speaking of feeds & speeds , has anyone tried Iscar's 'FINISHRED' endmills ??

They are designed for materials like Inconel but I tried a 1/4 incher in 410 stainless and wound up w/ a feed increase of 3x , tool life increase of 5x while running it dry. Saved company 3 grand over a 200 pc lot.

End mill is 3 time the cost of conventional carbide endmill but the results more than justified the cost.

[Threept82]

quote:

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(blow the chip out of the way fast so the heat generated stays in the chip)

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Scare away the material.

 

How every thing in Athol? I golf out that way sometimes.

[Threept82]

everything

[Hardmill]

3.82 use your edit button, top right corner.

Or you just bump'n the count???

 

 

PEACE

[ktd]

We use:

 

Rpm = 4 x Cutting speed(SFM) / Dia.

 

Feed = # of teeth x chip load per tooth x Rpm

[Threept82]

quote:

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We use:

 

Rpm = 4 x Cutting speed(SFM) / Dia.

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From: otterville

[Hardmill]

LOL

 

 

PEACE

[Charlie Pierson]

THREEPT82,

things still slow but gradually improving

 

gone @ 11

 

cp

[Storkman]

And if you want to make it more complicated you could add in the radial chip factor. There are so many other varibles that can be added in. For example, A 1" ball end mill cutting .01" deep only has a true major diameter engaged in the work of .199". So if your spinning it at 1" speeds, it's way to slow. I have some Iscar spread sheets that figure this stuff for you if anyone would like them.

[Code_Breaker]

quote:

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btw: the 3.82 figure is derived from 12/pi which is (to 4 places) 3.8197 ,

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Hey, Charlie . . . check out the post about nine before yours . . . mmmmm dajevu

[ChuckM]

+1 to Storkman on RCTF...

 

That's a lengthy calculation when you're wanting instant answers. Buy yourself a Casio graphing calculator (~$30), write a program and forget about the math. Only need to do it once that way.

 

Does dumb you down a little bit though. lol

 

-Chuck

[Code_Breaker]

Alright . . . already . . .

 

(Note: not shouting, just that formulas look better in caps)

IPM = RPM * CHIP_LOAD * #_OF_ FLUTES

RPM = 3.82 * SFM/EFFECTIVE_DIA (ED)

RPM = IPM/(CHIP_LOAD * #_OF_FLUTES)

SFM = ED * RPM/3.82

CHIP_LOAD = IPM/(RPM * #_OF_FLUTES)

 

EFFECTIVE_DIA = CUTTER_DIA * .06

 

FLAT AREA:

STEPOVER = SQRRT(CUSP_HT * 8 * CUTTER_RADIUS)

 

ANGULAR AREA:

STEPOVER = (SQRRT(CUSP_HT * 8 * CUTTER_RADIUS) * (COS A)

 

+++++++++++ OR ++++++++++++++++

 

You can use the tool manufacture's recommendations for speed-feed-stepover-stepdown-etc.

[Storkman]

quote:

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Alright . . . already . . .

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methink all the math getting to code breaker.

 

 

 

No more formulas, PLEASE!, it's Friday for petes sake.

[JazzBass]

Use the MEConsultant.

[Code_Breaker]

Friday

Friday

Friday

Friday

Friday

Friday

[Tom Szelag]

The senior machinist where I work just pulls numbers outta the air. And it works great. Then again he's be doin it for 40 years.

 

I use 3.82 and then round it down a bit to stay on the safe side. Carrying it to more decimal places isn't really going to make much difference.

[pip]

Storkman

what format are the spreadsheets I.E. excel.

Could you put them on the FTP site please.

[Storkman]

Pip,

They are Excel spreadsheets. I put them in the unspecified uploads folder. They are called Iscar sheets.zip. There is also one for determining surface finish with ball end mills.