Need Help!- Surface Finish

[dlange]

This video

http://www.datrondynamics.com/High_Speed_End_Mills.htm

Half way down the page is a short video showing an amazing finish.
If I can get anywhere near that I'll be happy!

I've been trying to figure out my speeds and feeds but no where I can find a sure SFM. One site says 400, another says never over 350.. I don't know what to do or how to calculate how many RPMS I need and how many inches per minute I need to put into the settings.

I'm using HSS 6mm single flute end mill. I could also use a 2 flute similar size, but last time I trying a 2 flute I went too slow .15 IPM and snaped the bit like a twig going 15k RPM

Please help!

Thank you forum!

-D

[Cmailco]

400 SFM is fine for HSS in most aluminum alloys and I'd suspect that breakage was due to excessive run-out and/or too heavy a cut. If you have run-out issues, achieving a "good" surface finish will be difficult no matter the end mill used.

I watched the video and I don't know the type of machine you're using but it looked as though Datron was using a machining center, with a MQL setup for 'coolant'.

What machine are you working with?

You will want to keep axial depths high and radial depths low to stay productive, but it is all dependent on your approach to toolpathing, If you cannot generate low engagement angle toolpaths, your axial and radial depths are totally dependent on the amount of hp available at the tool.

A 2-flute 6mm will probably run fine at .002 inch/tooth as a starting parameter in 6061-T6.

[dlange]

I feel so over my head, I don't know axial depth or radial depth.. The aluminum is only 1/8 an inch thick so I've just been doing once pass.

I don't understand the concept of run out.. is that like lag in the machine?
.002 in/tooth this is where I'm lost. What the machine wants is RPM and inches per minute. I've only played in between .15 and .30 I'm scared to go any faster or slower..
I only got .15 when I'm on lower RPMs like 13K cutting PVC.

I'm sure I'm making many mistakes I'm so new!!
I'm on a 4 axis Peak power 12Kw 16.1HP
I would give the name of the machine, but I don't see it anywhere on this forum and I think its against company policy lol :-)

[dlange]

We have converted our machine to English, and so all values are entered in english

The formula for the feed rate reads as follows
mm/100*g
Labeled as tool operating speed

I am assuming this is feed rate for inches per minute

I usually try and go with higher RPMs 15K and above and run about .20 to .25 feed.

Any slower or faster things don't sound pretty! lol
PLEASE ADVISE

[dlange]

mm/100*g

by taking all values in metric, doing the formula and converting final answer to inches..
The most rational soluation I have come up with is the lenth of the tool mm
90.17/100
*g for G I'm using the Diameter in mm
90.17/100*6 = 5.1402
converted to in = .212
.21 sounds great, right where I want to be, but what RPM?

I'll be here all day.. 5 days a week. Could use a lot of advice!

[Cmailco]

Originally Posted by dlange I feel so over my head, I don't know axial depth or radial depth.. The aluminum is only 1/8 an inch thick so I've just been doing once pass. I don't understand the concept of run out.. is that like lag in the machine? .002 in/tooth this is where I'm lost. What the machine wants is RPM and inches per minute. I've only played in between .15 and .30 I'm scared to go any faster or slower.. I only got .15 when I'm on lower RPMs like 13K cutting PVC. I'm sure I'm making many mistakes I'm so new!! I'm on a 4 axis Peak power 12Kw 16.1HP I would give the name of the machine, but I don't see it anywhere on this forum and I think its against company policy lol :-)

This might explain runout a bit better than I could without going through the trouble of producing diagrams:
Radial and Angular TIR

Inch/tooth is used in calculating the feedrate via the formula: feedrate = rpm x inch/tooth x number of cutting teeth

In other words, a 15k rpm tool with 2 flutes cutting at .002 inch/tooth would need a programmed feedrate of: 15,000 x .002 x 2 = 60 inch/min

You should be using the tool company's recommendations (inch/tooth, mm/tooth) for that particular size cutter. They typically list this information in the technical data section of their catalogs.

Axial depth of cut is the the depth of cut as determined by the 'Z' axis. In other words, if you set tool zero at the top of a part and program a cut at Z-.100, you are taking an axial depth of .100.

Radial depth of cut is the amount of cutter actually engaged in the cut.

Radial is displayed in the left part of the image (a), axial in the right (b).

[dlange]

CmailCo
Thank you all of this information helps a lot.
I'm not sure in what format this machine is reading
The best finish for an 8mm end mill single flute was 15k rpm and .16 feed.
I'm guessing that is .16 of one inch. I couldn't imagine putting in 60.0 or even .6
I could sure try it!
I've been taking out .1 at Z which has been working great. I snapped the 2 flute when I was taking all .25 out at once. Which I will not repeat!
Thank to you I understand more about radial and axial.
My main issue here is trying to figure out the interface software of this machine. I have so much to learn.

Thank You!