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Tooling suggestion for hardmilling?

ashort

ashort

Aluminum
Joined
Sep 8, 2009
Location
A.P.M.M.
We have started getting into making our own replacement die blocks. I'm looking for tooling advice from anybody with some experience at it. Material is usually either hardened D2 or DCMX. What is good to use to hardmill the form shape? Solid Carbide or Indexable? I currently have been using an ISCAR HCM ball cutter (12mm), but I tend to go through a lot of inserts.
 
Give us an idea of the machines and tooling systems you're currently using, and what size cutters are used most. You mention a 12mm insert ball cutter, if that's the "go-to" tool it may not be the most efficient cutter for the bulk of material removal. Perhaps a toroidal cutter will have a longer life and cost less, letting you save ball cuts for needed details.
 
I have had 0 success using inserted tooling for hardmilling. (not saying there isnt something available that I am unaware of).A tool rep I spoke with explained it to me by saying interrupted cuts are the worse thing you can do while machining hard steel....and an inserted tool is a series of interrupted cuts on each revolution of the tool. A good tool to start learning with would be a 6 flute YG 5070 w/corner radius (I use a 3/8" w/.03" CR for a general tool). YG is more budget friendly. I prefer Fraisa, Mitsubishi or OSG. I do quite a bit of hardmilling of D2, A8 and 4140 up to about 65Rc
Think large axial depth, small radial depth and higher feed rate. RPM's will be lower than you might expect. When done correctly with the correct tool you will not be seeing a bunch of glowing chips.
Good luck.....speeds/feeds DOC and plenty of air will make or break it.
 
Toolsteel makes a good point, use air not coolant! If you don't have air blow on your machine it is worth rigging something up. One job we ran an air hose over the enclosure, fastened to the side of the head, used a mighty mag to mount a valve and short length of loc-line. Worked great.

McMaster-Carr

McMaster-Carr
 
My machine is a Haas VF5-SS. As far as tooling systems, we mostly use 1/2" and 3/4" endmills, but we have a small random assortment of indexable cutters. Most of the tooling we have purchased was for our SNK 50taper gantry mill, that we used for die crashes and modifications. Most of the indexable tooling we have is on the large size. I bought a 25mm Mits feed mill, 12mm index endmill, 8mm ball, and the 12mm ball to try to save on using the solid carbide.

I also have a lot to figure out as far as programming the toolpaths. In the past, the jobs allowed me to get away with a one cycle type finishing operation. I think this block I'm cutting now could have used a larger tool to finish 90% of it and went back with a smaller tool to get the corners, but I used the 12mm tool to do it all. I am not familiar with a toroidal cutter, I will look one up.
 
I am using an air line, that is run into the machine and air blasts. Since Haas couldn't get the Trough spindle air blast system to work on my machine.
 
I would suggest getting in touch with someone from Seco Tools. I used to work for Seco, and they have a very solid line of tools for hard milling. Their MH1000 grade is ideal for milling hardened steels if you need to rough with indexable tools. Their "High-Feed 2" & "High-Feed 4" high-feed tools are very mild-cutting by design, and I believe both are available with the MH1000 grade inserts.

On the solid carbide endmill front, they have a big range or product in both the Niagara Cutter, and Seco-Jabro lineups. I believe that the Jabro line (Netherlands) was born from hard-milling.

Equally important, they have some very experienced people available for technical support, who specialize in hard milling. Several people that I can think of who are a very valuable resource for any shop wanting to get serious about hard milling.
 
We do loads of S-7 forge tools for the lifting industry (Hooks, Shackles, Hammer-Locs) and I was a Dapra fanatic until Ingersoll came out with the ISO Plus and Powerfeed 13. The inserts are massive and can take a lot of abuse. Running in a VF-5/50 60 HP about 50-70% load with 2"-3" diameters.

Hi-Feed Face Mill
 
FOr solid carbide Jashley mentions Seco of course :D Jabro is a great line. I sell US Union Tools Hardmax to my mold and die clients cutting over 40 HRC materials and they are excellent. One of my clients runs Garr VRX for general purpose and he says the US Union will run 10x longer than what the Garr runs in hard material. It costs twice as much making it worth it in tough applications. Here is a link to their site many people are unfamiliar with them Products : Metal Cutting Tools : Carbide End Mills

The Hardmax is for over 40 HRC. Their UT coat is for materials under 40 HRC or anything with S/S or nickel content. They also have carbide cutting end mills, diamond coated tools for Graphite.

Also good options are NS Tool, Mitsubishi/Hitachi (super expensive though) and Jabro/\.

The US Union like the NS, Hitachi & Jabro are ground to .0001" tolerances which makes the price jump but also have excellent grinds and top of the line coating options which make them worth it in tough applications.

For indexable mold and die work
DiJet is a great brand for mold and die work. They have indexable ball nose mills down to 6mm/1/4". They have geometries both in ball and bull nose for hardened material. DiJet, Ingersoll & Mitsubishi are the real players in the mold & die world for the Big 3 and their suppliers in my neck of the woods.

Here's a link to their site DIJET USA | Plymouth, Michigan | 800-743-4538

PM me if you need a source.
 
I didn't think to look at DIJET, because none of our local suppliers carry them. I have some DIJET facemills that came with the gantry mill and they are very tough.
 
We use a mix of solid tools and Hitachi inserted tools to cut 46-48 Rc Prem H13 with great results. However, some tough die steels at this Rc reduce tool life a lot and also other die steels above 50 Rc, in the 55-60 range. We produce mostly medium size aluminum and magnesium die cast molds (5K-20K pounds) so most of our molds are in the 46-48 Rc range, not 55-60 such as some steels used for plastic injection. It's always changing over time...Ingersol worked for us for a while then, Mitsubishi, then Iscar, then Hitachi; it never ends.

One thing to keep in mind when you are testing a new inserted cutter against an existing one you use is to make sure your existing cutter is new or close to new condition. If not then everything you try out will look better compared to your old, inserted cutters. This also goes for reconditioned cutter bodies too; I recommend not using them in a comparison test because reconditioned cutters seem to rarely perform as good as brand new IMO.
 
I've had great results with Helical brand cutters in 17-4 H900 and Ti6Al4V. 5 hour life dynamic milling with a 1/2" 7-flute at recommended parameters. I've occasionally used them on harder materials with good results too; Cobalt Chrome, full-hard S-7, didn't make enough parts to wear out a tool.
 
D2 is kinda crappy, yes.
CPM15V or CPMM4 makes D2 look easy, and S7 like cutting butter.

When you get into materials with higher concentrations of carbides and vanadium, stuff gets interesting.

Thats where the CBN tools come in. But recut a chip, hit an interrupt.... yer done.

The Mitsubishi stuff is pretty good, I like the specialty OSG, and De Boer does some nice specials.

In my opinion, dont bother with inserted tools in the real hard stuff. Small ball mills, and small bull mills is where its at.

Have to find the balance between machine\tool\workpiece rigidity, and the smaller the tool, the better the results.

Also, use MQL on an air blow.
 
We had a job cutting Haynes 282. I brought in all the tool reps to do a test with the customer. After a week of testing with ball endmills CID Performance tooling based in Saco Maine beat them all. We measured tool wear after a pre determined time in cut. On top of that we sent them back and had them reground and they were back to their original condition with minimal loss as we were only using the ball. Tested against Saco,Niagara,Kennametal and Guhring.
 
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