can someone recommend a good site that has instruction on figuring out the correct feeds and speeds for milling allum and stainless. For the past 3 or 4 years I have been doing in blindly but I know I can get so much more out of my machine in terms of efficiency and surface finish. I have downloaded a lot of charts that have sfm, ipr, rpm etc and a bunch of formulas with no real explanation. I am a self taught relatively new(4 or 5 years) machinist (I use that term lightly in regards to myself) and have a hard time deciphering the formulas and what is important in them.

thanks

Mark

basic and free - http://www.niagaracutter.com/techinfo/index.html

in-depth but not free - http://mrainey.freeservers.com/MEPro.html

thanks a lot

mark

o.k

could someone please explain this to me

when entering info into the calcuator programs you enter in sfm ipr dia of cutter # of flutes you get an rpm and ipm number. As you change the ipm or rpm the sfm changes. If allum is 600 to 900 sfm and the calculations tell me that it would be 300 sfm instead of say 600 to get the desired chipload (.003) is that ok. or do you have to stay between 600 and 900 sfm.

sorry, I hope thats not all too confusing

Mark

Mark,

Changing IPM shouldn't affect SFM.

Try downloading the demo version of the program I referred to previously. Youl'll be able to easily see how changing one value effects other values. Reading the Help file should clarify the whys once and for all.

It won't time out and you don't have to ever buy it if you don't want to. Just play with it.


Mike

thanks a lot mike

I will have a look now

mark

Mark,

Send me your email address - I have something better than the demo, which is maybe a little too crippled to be of best use to you.

rainey47 at bellsouth.net

thanks a lot, I was about to send you a pm

Mark

Here is what I made/use. It's very basic. The reason there are 2 colomns for feed and speed is one is the actual calculated, and the other is another calc. based on the fact that the first calc came up with an RPM over 2500 which is my max spindle speed. The second column is the speed based on the 2500 rpm max.

On the right are two charts for common SFPM and Chip loads.

Eric

Here is what I made/use. It's very basic. The reason there are 2 colomns for feed and speed is one is the actual calculated, and the other is another calc. based on the fact that the first calc came up with an RPM over 2500 which is my max spindle speed. The second column is the speed based on the 2500 rpm max.

On the right are two charts for common SFPM and Chip loads.

Eric

thanks a lot

thats a great spreadsheet

mark

I was told when cutting Aluminum, to run as many SFM as you can...
(within reason)... Is this true.. ?

Eddie Weeks

1000 - 1400 with carbide

I think that the general rule of thumb should be use what works best for the application. With aluminum and high end CNC qualified endmills, the spindle speed will generally become the limiting factor. For high production, run it till it breaks and back off. If you don't do it the guy on the next shift will.

When you find a feed and speed that works well. Note your chip load per flute. Width and depth of cut. Cubic inch remove rate. As well as your feed per tooth.

SFPM = RPM x tool dia / 3.82
(3.82 = 12/pi)
IPT = IPM / RPM / number of flutes
CIPM = IPM x width of cut x depth of cut
chip load = IPT x sqr(width of cut / tool dia)

You want to keep your chip load constant.
IPM = number of flutes x chip load x sqr(tool dia / width of cut) x RPM

Once you know a chip load that works for given material and tool. Find the "index" value. index value = chip load / tool dia.

Then for any size tool a new chip load for that size tool can be estimated.
Chip load = index x tool dia.
IPM = number of flutes x chip load x sqr(tool dia / width of cut) x RPM