[zaebis]

Folks,

I am interested to know what type of cutting tool would need more power / more rigidity while executing the same cut under the same conditions.

In particular if I take R8 shanked 3/4" indexable endmill with 3 APKT branded uncoated insert vs 3/4" colleted solid carbide 3 flute (uncoated, non rougher) assuming both inserts and endmill are designed for aluminum. Which of the two would require more from the machine and why?

What characteristics should I look for in an endmill in order to get the most possible material removal while utilizing the least power/rigidity. Assuming aluminum and BP style 2hp machine.

p.s. I am not talking about technique of cut, only about the tool itself. I understand that technique of cut also plays a role.

Thx

[txcncman]

Without math data to back it up, I am betting the inserted tool will take less HP and have better chip control. Inserted tools (once both cuts have been optimized) are probably less efficient do to the fact of limited cut depth compared to solid tools, so your time in cut increases and total power used increases also. Looking at the big picture, inserted tools will give the least cost per volume of material, even adding in extra time in cut.

[louieatienza]

If I am not mistaken, insert tooling requires more HP. And although you have a limited doc, you could (provided that the tool is necked or relieved) cut a deeper hole or pocket since it's more ridgid than a standard endmill.

[DMF_TomB]

Folks,

I am interested to know what type of cutting tool would need more power / more rigidity while executing the same cut under the same conditions.

In particular if I take R8 shanked 3/4" indexable endmill with 3 APKT branded uncoated insert vs 3/4" colleted solid carbide 3 flute (uncoated, non rougher) assuming both inserts and endmill are designed for aluminum. Which of the two would require more from the machine and why?

Assuming aluminum and BP style 2hp machine.
Thx

inserts are not all the same but APKT are pretty efficent
you ask what needs more power or what can take more power?
solid carbide cutter (carbide shank) can take more hp (stiffer and stronger) as long as machine does not vibrate too much. a short length cutter can take more than a long one.
........it has been my experience that using over 1 hp on a bridgeport which also is usually limited to 4200 rpm too, will vibrate and chatter and destroy the end mill cutting edges far sooner than cutter shank will break.
3/4" dia end mill on aluminum can usually require 0.22 - 55 hp at maximum. cutter length and how much sticking out of collet has a huge effect
...... in general a bridgeport can only take 1/2" dia cutter or less. of course you can use a larger diameter cutter but your depth of cut is severely limited to what the machine can take, not the end mill shank

[Anders6612]

It also depends on the machine, if it is an old machine, maybe it dont have good
enough torque on lower rpm. In general, a solid carbide tool should not have to high surface speed.
But the sharper the tool is, the less power it needs to run it. Using insert for medium or fine cut is
also an option for underpower machines, since they are sharper.

[fizzissist]

You have to compare apples to apples. I don't fault the question, but you need to understand that the correct answer is complex.... solid tools and insert tools are two different animals. ( assuming you're talking milling cutters here...)

Let's assume a high spindle speed/high hp, rigid machine...

A solid tool will generally have positive rake, which will take less horsepower, and the edges will be sharp, also lowering hp requirements. Inserts are generally negative rake, and your DOC often needs to be limited to just under the screw, or beyond it..... since hp varies with DOC.... that's a wild card.

The depth of cut or length of engagement on a solid tool is generally much greater unless you go to a multiple insert, with inserts stationed along the axis... an expensive tool... So you've got a cost factor.

... And so on.... Bottom line, for a 1" dia 3fl mill running 3/16" DOC and a .003 chip load.... a solid carbide will very probably pull less power than the equivalent insert mill. Solid wins in the horsepower category.

When it comes to tool life, total chip removal rates, insert costs, and total tool amortization, ... and money... the insert wins. Keep in mind, you chip a tip on a solid, the whole thing is junk. Chip an edge on a WNMG, you're out 3 bucks.

Maybe some of the guys here have run a solid mill at hp capacity.... but I've never seen it. It's always the guys with insert tools pushing the meter to 120%.

[fizzissist]

I should clarify.... I was thinking steels, not aluminum....
To your application, with a BP, you can run either solid or inserts.... it's going to depend on the job. IF the machine is rigid enough.... Older machines have more backlash, and carbide don't get along well with backlash. Backlash wins.

You've got limited hp to start with, and lack the hp, rpm, and rigidity to really push the insert tool to its full capacity.
Inserts for alum are sharp, so I'm gonna say that the hp requirements aren't going to be all that different in practical terms. It boils down to $$$.

To be honest, for my manual BPs, endmills are almost always HSS, carbide for facing (2.5"dia, 5 insert...'cause you can approach the SFM the inserts like). You can use carbide for regular milling, and I do on occasion... but you just can't maintain proper toolpath control or take full advantage of carbide and get the expected life out of it. For the CNC, however, I seldom use HSS for milling, especially alum.