Carbide Inserts - Face Mill Cutter

Franko,
I've confused you with the use of variable Helix, my bad :( the end mills linked too are variable flute although there are variable helix end mills.
Not to be confused with a variable helix, a variable flute in the 3 fl example would have the flutes not indexed at exactly 120º but at varying degrees of index. This breaks up the harmonics/vibrations, offers a smoother cut and allows a more aggressive feed, if I may coin a phrase from Martha Stewart, "it's a good thing" :D


Ken
 
It's like shooting fish in a barrel, Ken. I'm easily confused. :) Thanks for the clarification.
 
Gentlemen: There is a very easy way to predict HP when machining Aluminum or any other material for that matter. For example 6061T6, pretty common stuff and usually printed on the material. The Metal Removal Rate (MRR) predicts HP. This term refers to Cubic Inches of metal removed Per Minute, per HP. How do we calculate MRR? Just like we do any other cubic measurement. Length x Width x Height. 1 Inch Width of Cut x .100 Depth of Cut x 10 Inches per Minute feed will net 1 cubic inch per minute of metal removal. General standards indicate that 1 HP will remove 4 cubic inches of aluminum per minute. Steel, including plain carbon, stainless 300 or 400 series, alloy steels and tool steels will require between .85 and .95 HP per cubic inch. We use these calculations almost every day when we are specifying tooling for our customers. We also use this method to see if there is room for process improvement when optimizing cutting tool applications. No matter how you slice it and dice it, one HP will only remove only so much material per minute weather you are milling, drilling, or turning. A Bridgeport cannot spin a tool too fast for aluminum, even if the tool were 8" in diameter. Even if we could reach the melting temp. of aluminum, it just can't hurt the carbide all that much in our little machines. Common production speeds are 2,000 to 6,000 SFM and 10,000 SFM with Poly-Crystalline Diamond (PCD). (Except when Silicon content exceeds 8%)

Franko: The tool on E-bay you are looking at is using AMPT1604PDER inserts. They may do OK in several materials, but, the "P" in the third position indicates that the tool is probably not GROUND and is more than likely molded to size at +/-.0015. And the "E" near the end indicates that the insert is honed. (If that position was an "F" in place of the "E" it would indicate a sharp edge with no hone)
As suggested earlier, look for triangular inserts. They are common with a radius for turning but also with a facet for fine finishes when milling. And almost every insert maker makes 3/8 IC triangles. Look for TPG321, TPG322, ("G" indicates that the insert is ground and will probably be sharp, particularly if it is designated for non-ferrous materials. Or search for any of the 3/8 IC TPKN style inserts typically used for milling. Pay attention to the coating.... Best choices for Aluminum are TiCN and even better is TiB2 Titanium Di-Boride. Aluminum does not adhere easily to TiB2. Both coatings are bright silver. I almost always use Tap-Magic of Aluminum. Use your old toothbrush and brush on a drop or two and you will be delighted with the results. Pick up some Mag Wheel Polish at the local Auto parts store and you will put a great shine on all your aluminum projects.

Good Luck!
Gary
 
Thanks Gary. Very informative.

I did not order the face mill on eBay, but ordered the one pictured in an above post that is supplied with TPC32 inserts. The inserts I ordered are TPC-321. I think the third number designates the radius of the points. The other inserts I use on my lathe tools have what I think is called a chip breaker (a flute behind the cutting edge).

I ordered a fairly complete (up to .75) set of TiN coated end mills when I bought the mill. They are all still as sharp as I remember when they were new. I think I chipped one when I dropped it. They are all 4-flute end mills. They've always gummed a little at the cutting edge, but I have always run them way too slow. Drill bits have also clogged. Cutting that last part, at higher speed, I had no gumming on the bit.

I keep a small 2-0z. squeeze bottle with a nipple spigot of cutting fluid by the lathe and mill. It says cutting fluid on the label. It looks and feels like thin machine oil. I just drip a drop down the flutes of end mills, drills and taps, and put a drop on the tip of my lathe bits. I saw a guy on uTube use a small can and acid brush to apply cutting fluid. I think I prefer the drip bottle since I don't have to have an open can of something that can spill.

I watched a long uTube video of a guy making a pair of mill stops. It looked like he really knew what he was doing. He had a big spritzer that he sprayed on the parts while cutting. I have no idea what it was, but I'd guess it is like Slugger Cutting Fluid I mix in water to use on my horizontal band saw.
 
G Morsh,
While I genuinely respect what you seem so knowledgeable on, personally, there's nothing that requires me to learn all that nor do I have any interest or present need. Bottom line I guess is, I chose to remain ignorant in that incredibly confusing area (it's all real easy once you know) and simply purchased HSMAdvisor and it happily calculates all that for you and warns when a cut is beyond a power curve for a particular machine, if I've still a question I call my tool suppliers :D

Ken
 
Thank you for sharing that Gary.
 
G MORSCH said:
As suggested earlier, look for triangular inserts. They are common with a radius for turning but also with a facet for fine finishes when milling. And almost every insert maker makes 3/8 IC triangles. Look for TPG321, TPG322, ("G" indicates that the insert is ground and will probably be sharp, particularly if it is designated for non-ferrous materials. Or search for any of the 3/8 IC TPKN style inserts typically used for milling. Pay attention to the coating.... Best choices for Aluminum are TiCN and even better is TiB2 Titanium Di-Boride. Aluminum does not adhere easily to TiB2. Both coatings are bright silver. I almost always use Tap-Magic of Aluminum. Use your old toothbrush and brush on a drop or two and you will be delighted with the results. Pick up some Mag Wheel Polish at the local Auto parts store and you will put a great shine on all your aluminum projects.
Click to expand...

Gary, I have several tools with brazed carbide. It seems like some of them don't perform very well or feel very sharp. If I wanted to touch them up, what grit diamond wheel should I use? I don't have a tool grinder. I do have a fixture that will hold the bits and allow me to rotate them to angles with a veneer scale. I also have a couple cupped wheels, and I plan to make an arbor to adapt them to one of my bench grinders, which should also work with the diamond wheel (or wheels).
 
I finally got around to using my new facing mill.

I'm making some parts out of Delrin. The flats of the 3/4" material had some planer chatter marks and the sawed edges had very minor circular blade marks. Of course, I want them to be perfect to impress my client.

I gang-clamped them in the mill vise to shave the four sides to exact matching dimensions, trimming them flush with the facing mill, removing the saw marks. Then I set them flat and milled off the chatter marks.

I am impressed! It is the prettiest surface I've ever made on my mill. This may be my new favorite tool bit.
 
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