[gravy]

Can anyone give me the formula for determining effective chip load for a small radial cut?

You know, like to determine how much you can increase the feed if your cut is light.

[merl]

if this helps you, you can determin chip load by dividing your feed by your spindle speed...
IPM=20.
spindle speed= 3500
20/3500=.0057 (per rev) now divide this answer by the number of flutes on the end mill you will be using (2,4,5....)
.0057/4=.0014 (per flute)
how much you can increase your feed rate also depends on the rigidity of your tool and setup.
Remember, the only time your tooling isn't wearing is when it's cutting air.
Liter, faster cuts aren't more efficient but, sometimes that is the best the machine will do.

[cam1]

Hi
Consider this if you halve the depth of cut, and double the feedrate (adjust the spindle RPM accordingly) you will remove the same volume/unit time. It's easier on the machine, less cutter deflection, and it makes the boss think that things are happening faster....

cheers

[merl]

cam 1, this is true however my point is that you are still wearing out your tooling at the same rate but, now you havn't finished your cut either.
We spent several years doing compairisons, keeping track of all the key data factors, and the end resault shows that each machine is different with each material type, as you would expect.
We currently have three Mazak maching centers that differ only in size of work envelope we also have five Toshieba CNC bars that differ in size and spindle power but, are otherwise the same configuration.
Some of our repeat jobs can be run on either type of machine but the programs are different (not because of the different controles) even though they are all very ridgid and powerfull machines.
We used to think that you could save time on a job by running it faster and taking a smaller cut but, then you tend to go through more finishing end mills and usually have to take an extra finishing pass with a new tool because the end of the tool is worn and leaves an unexceptable step on the part.
even with carbide tooling and high accuracy tool holders, you can not avoid tool wear.
The question is how many cubic inches of material was removed befor the tool no longer produces exceptable work?
Don't think your boss is fooled by extra noise and faster moving machine, at the end of the day he (and you) get paid by the number of good parts that get shipped to the customer.

[cam1]

Hi merl: I agree with your points, with the exception of the last point (which was not meant to be taken too seriously). Not all Bosses are savvy to machining. In general, most people think that people are working harder when the machine tools are moving faster. The same applies when you are driving in a truck @55 vs driving in a race car at 55. Which one feels like it's going faster?

cheers