Facing with a mill

[verbotenwhisky]

Don't get drawn into flycutting...
They are hard on your spindle bearings, especially if it is a hobby size.
They can be very dangerous, especially when the tool extends past the cutter body it becomes invisible.
A flycutter is a face mill with one insert left in, but far less balanced.
Modern tool manufacturers can make inserts and pockets that are extremely accurate to one another for superb finishes.
For the best tool life and finish, get a button insert face mill, look for a close pitch for higher mmr & smoother cutting.

Fly cutters are good tools when used properly, for light cuts to finish a surface they work fine and a small mill can support a much larger fly cutter than they can a multi-cutter face mill. In the world of danger there are many tools which a dangerous in a mill, pretty much any end mill, woodruff key cutters, slitting saws, gear cutters, etc... the real secret is keep your darned fingers out of it. You loaded the tool, understand what it does and stay clear of it while it works. Its like the warning label on a fan belt, "do not install while engine it running", huhh.... really, if we cannot figure that out then we likely need to find a different hobby...

 

[Archer60x]

So i did pick up this Haas shell mill and these inserts i want to use on Aluminum. I never appreciated how exact and precision machining is until i got the PM728 and these tools in my hands. I cant wait to keep learning how to chase precision.

Now how the heck to i figure out what RPM to run it? I am on a PM728VT just hand feeding (no power feed yet).

I have seen formulas like
Aluminum = 150 Surface Feet/Minute

so i take (150 x 4) / Diameter of Tool = RPM of tool
example:
150 x 4 / .5 = 1200 RPM

how do i calculate the RPM for these carbide cutters? It is very confusing on the Haas Speeds and Feeds chart. I know carbide needs to go "faster".

HSPP, 2-1/2" Ø Shell Mill, 3/4" Pilot Bore x 45° Lead Angle, 5 Flute, Positive/Positive Geometry

HSPP, 2-1/2" Diameter Shell Mill, 3/4" Pilot Bore x 45° Lead Angle, 5 Inserts (Square), Positive/Positive Geometry

www.haascnc.com

HSPP, Carbide Shell Mill Insert, Square Positive Positive, Grade HN25 - Pack of 10

HSPP, Carbide Shell Mill Insert, Square Positive Positive, Grade HN25 - Pack of 10

www.haascnc.com

 

[MrWhoopee]

So i did pick up this Haas shell mill and these inserts i want to use on Aluminum. I never appreciated how exact and precision machining is until i got the PM728 and these tools in my hands. I cant wait to keep learning how to chase precision.

Now how the heck to i figure out what RPM to run it? I am on a PM728VT just hand feeding (no power feed yet).

I have seen formulas like
Aluminum = 150 Surface Feet/Minute

so i take (150 x 4) / Diameter of Tool = RPM of tool
example:
150 x 4 / .5 = 1200 RPM

how do i calculate the RPM for these carbide cutters? It is very confusing on the Haas Speeds and Feeds chart. I know carbide needs to go "faster".

In school, Harry taught us to run carbide at 2x-10x faster than HSS. That leaves it pretty wide open. Just crank it up, it's only aluminum. Use some WD-40 or kerosene as cutting fluid.

 

[mksj]

In aluminum I run my 2-2.5" at 3500-4000 RPM, my 4" at 3000-3200 RPM at around 10-12 IPM and sure I could push them harder. On steel I run about 1/3rd those RPM's and also depends on the if surfacing, shouldering and DOC. On your size mill for aluminum I would probably run around 2500 RPM, in steel 800-1500 RPM (depends on the material and cutting parameters) given less rigidity and Hp with your mill. A small amount of lubrication and some air to clear the chips can also help significantly in surface finish. A x-axis power feed short be on the short list to get, so that the cutting are even. Also make sure to lock you head and quill, tramming is also very important to prevent ridging if multiple passes on wider material.

 

[Archer60x]

Thanks for the ball park numbers. It will give me a starting point so i can start, listen and see how things go when i try it out.

Having Quinn's youtube channel to help me understand the mill is so valuable! It helps me get ready for the depth of cut's i should expect and keeps my expectations in check with the size and quality of machine i bought.

Power feed is on it's way!