Back to the basics!

[Tazzer]

After getting our shop put back together after some major renovation this summer. I started a new project but for the love of me I am having a hard time getting my feed rates and depth of cuts calculated. To that my teacher doesn't know what is wrong with my speed and feeds. I think my major concern is the depth of cuts which is where I hope someone can explain on how they determine the DOC.

I am cutting into 6061 Aluminum with a 1/4" 4 Flute HSS end mill. I will be using a Haas Mini Mill with a Max spindle speed of 6000.

I have been through all my books and all my calculations come out the same but I am more concerned about my DOC. I have been doing a 0.0625 DOC at 12 IPM with at 6000 RPM.

Can someone point out what I might be doing wrong and what calculations that you would use in situation. I know I must have something wrong so any help will be great.

[jonbanquer]

Originally posted by Tazzer After getting our shop put back together after some major renovation this summer. I started a new project but for the love of me I am having a hard time getting my feed rates and depth of cuts calculated. To that my teacher doesn't know what is wrong with my speed and feeds. I think my major concern is the depth of cuts which is where I hope someone can explain on how they determine the DOC. I am cutting into 6061 Aluminum with a 1/4" 4 Flute HSS end mill. I will be using a Haas Mini Mill with a Max spindle speed of 6000. I have been through all my books and all my calculations come out the same but I am more concerned about my DOC. I have been doing a 0.0625 DOC at 12 IPM with at 6000 RPM. Can someone point out what I might be doing wrong and what calculations that you would use in situation. I know I must have something wrong so any help will be great.

Change to a 2 flute endmill or 3 flute high helix endmill. Try at least .125 depth of cut and at least 20 IPM.

jon

[Rekd]

Or if you want to go the other direction, I generally go .025 DOC, 6,000 RPM, 75 IPM with a 4 flute. That'll give you around .0031 chip load, which when only going .025 deep, you can safely run. You could prolly go up to 100 IPM (at .004ish chip load), but work your way up to it.

Lighter load on the machine, tool and is generally a faster cycle time. BTW, I'm running VF-3's.

'Rekd

[wms]

Tazz,


I would agree with REKD. I would go to light depths and fast speeds and feeds.

I have a Mini mill also and anything above 80 ipm you will start to "stutter step", if your code is all short lines and small arcs.

At you present setting of >1/4 4fl > 6000 rpm> 12 ipm, your chip load is only .0005.

If you go 4200 rpm > 60 ipm , your chip load will be .0036. Which is much better.

3000 rpm > 50 ipm would be chip load of .0042

[hardmill]

Originally posted by Tazzer I am cutting into 6061 Aluminum with a 1/4" 4 Flute HSS end mill. I will be using a Haas Mini Mill with a Max spindle speed of 6000.

4 flute I would ditch w/ alum. Not enough clearance.

Is that you max spindle speed?

PEACE

[Jcadwell]

Going even more basic than that, could someone explain the relationship between number of flutes, depth of cut, chip load, etc, or reccomend a book or online reference for learning more about this. Thanks.

[Tazzer]

Thanks fuys for everything. It answered my question.

First I should have explained what I am doing. I am machining a crankcase for this miniature V-Twin engine that I am building. Anyway the crankcase is 2.25" deep and I want to machine the outside profile in one pass without having to go halfway down then flipping it over and doing the other half. With that being said I cannot find a 1/4 2 or 3 flute that has a long enough shank to do this. Plus I had 4 of these 4 flutes that had a long enough to do this.

Now I am programming this in Mastercam, and how I have it set up when I do the contour I am using 3 different 1/4 endmills with different lengths.

2 Flute .75"
4 Flute 1.5"
4 Flute 2.5"

Hopefully that explains why I am using 4 flute with aluminum.

Anyway thanks again and Rekd what type of formulas do you use to get your DOC. I know how to get the Speed and Feed rates but as I said the DOC normally gets me a little confused. Plus my teachers never really explained the whole process in depth as I wish they would.


Oooo right now we only have one Mini-Mill as we are waiting for Haas to deliver our new machines (two VF-3, VF-1, Mini, and Toolroom) And the mini only has a max spindle spped speed of 6000.

Thanks
Chris

[steele]

If you want to get the job done and are not concerned about high production I'd run a 2 flute extended reach HSS end mill @ 6000 rpm, a .025" depth of cut and feed about 10 ipm. Make absolutely sure you're not recutting any chips.
Jim
www.picopascal.com