Trigon inserts are pretty common in turning but not so much in milling. Why? I find them pretty lucrative, having six cutting edges, strong geometry and some manufacturers even offer ramping ability. The insert I'm currenly evaluating has maximum Ap of 7 millimeters, which is enough for roughing. Sure, everyone's favorite APKT inserts have more Ap and better ramping capability, but far worse cost per edge. What drawbacks are there?
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Trigon milling inserts
- Thread starter 316head
- Start date
- Replies 16
- Views 2,642
Bobw
Diamond
- Joined
- Feb 8, 2005
- Location
- Hatch, NM Chile capital of the WORLD
Geometry. Think how they would have to sit in a milling cutter to be able to actually cut.
and have enough relief. Both on the bottom and on the sides.
The geometry would be absolutely horrible and massively negative. There aren't a lot of
double sided milling inserts, and I'm guessing that is the reason why, and the ones that
do exist are pretty fancy things, not simple like a turning insert.
Personally I'm not a fan of WNMGs. I have some, and the theory behind them is good,
an extra corner with the strength of a CNMG. Cool. But they cost more, and aren't available
in as many different grades as a CNMG. And they don't have as much stability in the pocket.
CNMG's are just so common, I bet your grandmother
even has a box of them in her nightstand.
and have enough relief. Both on the bottom and on the sides.
The geometry would be absolutely horrible and massively negative. There aren't a lot of
double sided milling inserts, and I'm guessing that is the reason why, and the ones that
do exist are pretty fancy things, not simple like a turning insert.
Personally I'm not a fan of WNMGs. I have some, and the theory behind them is good,
an extra corner with the strength of a CNMG. Cool. But they cost more, and aren't available
in as many different grades as a CNMG. And they don't have as much stability in the pocket.
CNMG's are just so common, I bet your grandmother
even has a box of them in her nightstand.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
The design is stronger than a triangle insert, and works as a "feed mill" insert with the right body. And, as mentioned, six edges, perhaps twelve if you have a LH body too.
Hello.
Here's the contender I intent to replace Sandvik R390 with. Nothing wrong with R390 except that cost per edge is too high (operators consume them like candies). It is a bit thicker than R390-17 and preliminary machining test results were good.
Let's see how it turns out in the end.
Here's the contender I intent to replace Sandvik R390 with. Nothing wrong with R390 except that cost per edge is too high (operators consume them like candies). It is a bit thicker than R390-17 and preliminary machining test results were good.
Let's see how it turns out in the end.
ChipSplitter
Titanium
- Joined
- May 23, 2019
- Location
- Maybe
Honestly, I would go with this one if you want 6 edges. https://www.iscar.com/eCatalog/item.aspx?cat=3106662&fnum=3781&mapp=ML&app=59&GFSTYP=M&isoD=1
What is your application? R390 will last a long time if you have the right circumstances, if you don't they don't last for shit.
And of course the programmed speeds and feeds need to be correct as well (obviously)
R390 is a great insert, no doubt. It is practically used everywhere in this country. We use it for shouldering, facing and helical interpolation. For HI it has it place, but for shouldering and facing a 6-edge insert is simply much more economical. Operators are too afraid of destroying a cutter body so they change the inserts prematurely, especially when running multiple jobs of different materials at the same time. Also all the old programs have horrible cutting values, so the insert don't last "for shit" (I have a lot of work to do updating them, so why not experiment with something else at the same time?)
EDIT: for facing mostly 8-edge (wiper) / 16-edge (non-wiper) inserts are actually used.
Care to elaborate why? That is a much smaller insert (IC=6.2 vs 11.5), sure there is a larger version but I recall it has a much higher cost per edge than the trigon one.
Nah.
What you want is the SECO Square Six.
Square 6 - 6-Cutting-edge Double-sided Inserts | Secotools.com
I tell you what, if you guys need to do some hoggin with a facemill,the Sandvik Coromill 745 is a frickin monster.
14 cutting edges. The inserts will cost you your first born though.
We have one from a "test" that we did, and I fell in love with it right away.
14 cutting edges. The inserts will cost you your first born though.
We have one from a "test" that we did, and I fell in love with it right away.
How much are the inserts?
Best all around FM I ever used was the double octo. 16 edges and inserts to be had between 21 and 23 bucks a pop...really not a bad price for all those edges. Also you could not kill the inserts, things held up so long in so much different material (so long as you were using the right ones).
They list at around $40 each depending on size. But for 14 cutting edges... that's not really all that bad if you think about it.
CoroMill 745
ChipSplitter
Titanium
- Joined
- May 23, 2019
- Location
- Maybe
It has a max AP of 8mm vs. 7mm for your trigon. If you don't need a square shoulder, don't get one!
Get a Coromill 745 like MtnDew said or an Iscar Helido like this: https://www.iscar.com/eCatalog/item.aspx?cat=3107287&fnum=3854&mapp=ML&app=61&GFSTYP=M&isoD=1
Bill D
Diamond
- Joined
- Apr 1, 2004
- Location
- Modesto, CA USA
I like the theory of the circular insert. It has an infinaite number of corners. Rotate it 1/2 degree and expose a new sharp corner, in theory.
Bill D
Bill D
eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
In theory it's great. In practice, not so much unless the machine it's being used on is very rigid. Chatter city otherwise.
gregormarwick
Diamond
- Joined
- Feb 7, 2007
- Location
- Aberdeen, UK
There are endless choices for a shoulder mill system that is more economical than R390. If you want to stick to sandvik, R490 has twice as many edges and performs very similarly for basic shouldering.
All of the 6+ edge alternatives are a compromise in performance, but the cost/performance usually works out in their favour.
I use Tungaloy DoForce-Tri for general shouldering. Double sided triangle insert with high positive helical edge, true 90, nice cutting action and chip formation, and more DOC than trigon of the same size.
I keep the 490 for when I need high quality walls, and I keep the 390 for when I need high performance slotting - nothing can touch the 390 for that.
All of the 6+ edge alternatives are a compromise in performance, but the cost/performance usually works out in their favour.
I use Tungaloy DoForce-Tri for general shouldering. Double sided triangle insert with high positive helical edge, true 90, nice cutting action and chip formation, and more DOC than trigon of the same size.
I keep the 490 for when I need high quality walls, and I keep the 390 for when I need high performance slotting - nothing can touch the 390 for that.
snapatap
Aluminum
- Joined
- Apr 24, 2013
- Location
- south australia
Sumitomo make a double sided trigon shoulder mill, but you cant ramp with them. worked well for some stuff until the head of one of the screws sheared off mid cut, and destroyed the cutter and job, haven't used it since.
