What face mill do u use???

[Highpower]

Ken, how much horsepower do they have pushing those 5 inserts? I know it's all dependent upon the material, depth of cut and chip load etc., but just as a general 'rule of thumb' lets say - what's it take to run a cutter like that? What if it was a 3" cutter instead?

As a hobbyist, how do I know when to say 'when', in regards to the diameter of the tool and the number of inserts?   

[PixMan]

It's been about a year and a half since I saw it running, but if I recall it was a 20HP Matsuura vertical machining center. And the Walter F4041 has only 4 inserts on a 2" cutter, the outgoing Seco had five. At the same spindle speed and feed rate in inches per minute, that means that the Walter cutter was at a 20% higher feed per tooth. They couldn't go bigger in diameter because of the restrictions on the part geometry. Neither cutter was pulling even 30% load with fresh inserts, but that's still about 5.5HP.

I found a great load calculator on the Walter website "downloads" section, and have it on my phone, tablet and home PC.

You ask a good question Willie. The home shop machinist may have everything from a Harbor Freight 1/2HP drill/mill to a war period Cincinnati Universal to a full blown mutli axis CNC, and many points in between. I think the key indicator as to what diameter and type of cutter one can use, along with cutting parameters, would be the spindle adaptation.

A Morse taper spindle probably shouldn't use carbide insert tooling at all. An R8 spindle with 2HP (what I have) can run up to a 2-1/2" lead angle face mill or a 2" shoulder mill, but I push mine harder than I probably should and have 3" face mill and up to 2-1/2" shoulder mill. An NMTB30 would be in that same class, an NMTB40 might be able to step up a little bit. The key isn't HP, it's torque that matters. Chip load per tooth matters. You don't want such a light feed rate that you are rubbing inserts to death, so better to be in the torque range of your spindle and get some load rather than go high speed and have no power.

On my machine in a typical 1018 steel, I can face with my 2-1/2" 4-insert 45º lead cutter up to about a .075" (2.0mm) depth of cut at 1.5" width of cut and feed at 20 inches per minute. The machine is protesting, but doing it. If I go to the F4041 shoulder mill, I'm more limited on material removal rate so with that one I'll use it's deeper shoulder milling capacity and run up to .400" (10mm) deep but engage it by only .050" (1.2mm) width. Or, go the other way around, My cutters were selected with the mindset of getting at least a 10HP CNC mill in a couple of years.

Try to think of getting more cutter by virtue of lowering the cutting force in high positive cutting geometry. A cutter using those TPG inserts has very little axial shear angle and ZERO radial That's why they hammer on the spindle, especially when using a cermet insert which will have a heavier edge hone than a ground carbide TPG. Forces are greater, cuts use more HP. Get modern cutters with positive geometry, high shear and rake angles, and you can get higher material removal rates per HP. A 1HP Bridgeport (like I had until last year) can easily run a 1-1/2" or 2" cutter with 3 or 4 inserts and the right style of cutter & inserts.

[mike-sid]

(03-08-2015, 09:52 PM)PixMan Wrote:  Get modern cutters with positive geometry, high shear and rake angles, and you can get higher material removal rates per HP. A 1HP Bridgeport (like I had until last year) can easily run a 1-1/2" or 2" cutter with 3 or 4 inserts and the right style of cutter & inserts.

 My Frankenmill with a 1.5 HP high speed Bridgeport J head runs my 2" V555 face mill with out a problem.  My problem with any milling operation would be the limited rigidity of my base.  The J head can bite off more than my base can chew.  Ken's advice is like gold to me. Ken has not steered me wrong yet......except the time he tried to get me to buy a Triumph.  

[PixMan]

Hey now, I did NOT try to get you to buy a Triumph! I tried to get you to simply take a ride on one, and still would today.

THEN you would rush out and buy one.

Scared, aren't you?

That V555 cutter is exactly what I mean about low force cutter geometry. It's got both axial shear angle and radial rake. And it's very similar in performance to my F4080's, except that it gets better finishes at a given feed rate than mine, but I got eight corners per insert. And PLENTY of 'em!

[Highpower]

(03-08-2015, 09:52 PM)PixMan Wrote: A 1HP Bridgeport (like I had until last year) can easily run a 1-1/2" or 2" cutter with 3 or 4 inserts and the right style of cutter & inserts.

But you can not run the full width of the cutter - is that right? Where as with a 10HP machine you can?  

I'm just wondering what kind of gain I would achieve (if any) by investing in a face/shoulder milling cutter vs. using a fly cutter in my small mill.

[PixMan]

Whether or not you can run the full width of any cutter depends up the material, depth of cut, feed per tooth, rigidity of the setup, and geometry of the tool.

Consider that a 2" face mill with three or four inserts could still outperform a single point flycutter with the light depth of cut that a flycutter can do simply because there's four times as many edges. As long as you have enough power to keep from getting built-up edge on the inserts it could be worth a look. What machine do you have?

[Highpower]

Ken, my mill is a 8x36 (3/4 size Bridgeport clone) with a 1-1/2 HP motor. Bear in mind though, those are Chinese horses, so they are smaller than 'normal' horses....   

[DaveH]

Hi Willie,

First and foremost I use mine just for facing. It’s 25 mm diameter and I run it with two inserts out of the four, I think it would run with 3 inserts but then the cutting is asymmetrical.

Now Ed, also has a four insert face cutter and he did find it troublesome with all  four inserts, with one insert it was OK. Also bear in mind Ed’s mill had a lead screw nut problem which probably made it worst.

The main reason I bought mine was at the time I was running a small engineering shop  often I needed something to just square off the ‘edges’ like that 16mm thick material. Using an end mill (HSS) was really wasteful just using the end part – yes I use to sharpen them (off hand) a few times. That mill scale can soon blunt HSS end mills, I can’t zap it off in one cut my milling machine just wasn’t capable of doing it. So for me the carbide insert milling cutter was a good investment. 

I agree with what Ken has said, I know it sounds like we don’t agree but we do agree on most things regarding insert cutters and the odd minor point we don’t agree we still agree (to disagree) that’s all.  

If I ask a question – what will you use to face a 16mm or 25mm thick piece of steel?  Single point fly cutter – hardly suitable for that type of job. Use the end of an end mill then one has lot of end mills that are blunt just on the end.

You asked what would you gain over a fly cutter, you will have a face cutter and with the correct inserts and proper use will last you forever (not really but a long time). A very versatile facing cutter that is nearly indestructible and never needs sharpening.

However you must choose the correct inserts – this is 99% of using a cutter with inserts I cannot stress this enough the right insert for your machine. Ken can tell you which insert to go for. (I think the same as Ed’s)


If it was me I would go for a 40mm dia. with four inserts – some materials may cut better with just two inserts and it will work with one. We are talking only facing if you want to use it milling a shoulder then you are on your own.
 

DaveH

[EdK]

Dave,

My mill is a shoulder mill not a face mill. I probably mistakenly called it a face mill at one time.

Ed

[DaveH]

Ed,
So you weren't using it for facing?
 
DaveH