indexable milling cutters

I haven't used any indexable milling cutters yet, and have some questions.

First, are indexable end mills that take triangular inserts really end mills in the sense that an ordinary end mill is an end mill? That is, do they mill on the end, or just the side? If not, then aren't they

*really* small diameter 90 degree angle face milling cutters?

Second, does any company sell 45 degree indexable dovetail cutters?

Thanks.

Reply to
himog
Loading thread data ...

They're not center cutting, you can't plunge with them. If you have too, you can angle down as you traverse. Many, not all, ground endmills are center cutting

Sandik. Hold on to your shorts when you see the price.

Karl

Reply to
Karl Townsend

I bought a small one in the process of acquiring standard tooling for a new minimill, but am a bit vague about the correct use of it. Conventional fluted mill seem to fit most of what I'd be doing, and flycutter is for finishing a surface. So what is the indexible carbide cutter best used for ?

Rex B

Reply to
Rex B

...

This is one of those things you'll have to just try on your machine. On my machine, I use insert endmills for almost all jobs that can use a large endmill. If you have finish problems, most likely chatter marks, then you won't be able to use it for finish cuts. If your machine can handle the cutter, you can remove metal far faster.

Karl

Reply to
Karl Townsend
[ ... ]

Bulk metal removal, and abrasive metal removal.

Cast iron raw castings come with a "skin" which is quite hard and abrasive. Until you are below that skin, carbide insert tooling wins.

Anodized aluminum has a surface related to sapphire, and is also quite hard and abrasive.

Either of them can eat HSS cutters alive -- though there is more thickness on the cast iron skin, so it will wear faster.

Use a HSS tool for removing a constant thickness of the "skin" of either, and after the job is done (or half-done, depending on the amount of material to remove) an examination of the HSS cutter will show a significant wear "groove" at the height of the hardened skin.

Cast iron, itself, is somewhat abrasive, even without the skin, as are some aluminum alloys. So -- if you are cutting a lot of these materials, the carbide insert tooling should do most of the job, followed by a switch to a sharp HSS for the final finish pass -- if you need a better finish than the carbide inserts are giving you.

Note that insert tooling can be end-cutting or side cutting, depending on the orientation of the inserts. Square inserts can even be both at once.

As others have mentioned, insert tooling can be run faster, and thus remove more material per unit time, with a sufficiently rigid machine.

And the benefits of replacing or turning the inserts on an insert milling cutter and continuing without having to re-establish your zero (as you would with a replaced HSS tool) is a big benefit with CNC operations, because you don't have to define a new tool offset to get your cuts to be at the right height after such a change. (This is assuming that the insert cutter is held in an appropriate end mill holder, not in an R8 collet, which will lose the Z-axis projection setting when you remove the tool to change the inserts (though you *can* change the inserts with the tool in place, although that is rather awkward.

BTW In reference to another recent thread, the inserts in my insert tooling (both a two-insert and a three-insert one) are neutral rake -- neither negative or positive. This would make them a good choice with brass and other copper alloys.

I hope that this helps, DoN.

Reply to
DoN. Nichols

That isn't a problem if you use the proper grade of carbide, which many don't understand. Steel grades (C5-C6, etc.) behave exactly as you described, and you're sure it's because the material is abrasive. Truth is, it's not, but the formulation of carbide isn't proper for the conditions at hand. . By using a C2 grade for both cast iron or aluminum, what appears to be abrasion quickly comes to an end. Being from the "old school" of carbide, I know to use Carboloy 883 on stainless, cast/ductile iron, and aluminum.

I've yet to find a situation where HSS would perform better than carbide when machining iron. Please keep in mind I'm a strong supporting fan of HSS----but it, too, has limitations.

Harold

Reply to
Harold and Susan Vordos

Thanks -- this is useful information. Though I was really talking about the abrasion on HSS tooling, where the hard skin on cast iron or the sapphire layer on anodized aluminum would wear a groove in the areas which were exposed regularly to the hard skin.

I know that you are.

Indeed so. I keep it on hand, and use it for some purposes, and carbide for others.

Enjoy, DoN.

Reply to
DoN. Nichols

That brings to mind an experience we had many years ago, when I was employed at Sperry Utah. The shop had a few Gorton Mastermils (I-22), all of which were step drive. The brake system was nothing more than a portion of the bottom of the driven pulley on which a caliper clamped down, inside and outside. The pulley, being aluminum, was hard anodized, and held up extremely well, but like any brake system, it needed a rebuild occasionally. In order to remove the old, worn surface, the area used as a brake was machined, so it could be re-anodized. The brake pads wore the surface a small distance away from the edges, so in order to get the cut started, you had to penetrate the old hard anodizing, which, in that particular zone, was still 100% intact. HSS wouldn't touch it. Any attempt yielded a tool tip well ground away, with virtually no affect on the anodizing. Bear in mind, this is hard anodizing, which can be applied considerably deeper than is the ornamental type of anodizing. The proper grade of carbide (883) worked perfectly, although you still had to penetrate the anodizing to get the cut started. The surface created by anodizing is, indeed, similar to a sapphire!

Harold

Reply to
Harold and Susan Vordos

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.