[super95awd]

I have a job in front of me that is to be cut out of 4140PH and has a decent amount of material removed. I was planning on just machining it from 2.5"x5" flat bar. Quantity is 50 of this part and 50 of another that is 4"x5"x5" and looks similar. Would you guys go at this with a 3/4"-ish solid carbide or switch over to a bigger indexable cutter of some sort to do the majority of the roughing? I have a 2011 VF-2 with a gearbox.

Interested to see what you guys have to say! Thanks!

[Sthibeault]

I would rough with a feed mill (indexable inserts). A 1" or so tungalloy feed mill will easily run 100-200 ipm at 0.030" doc in your material. You will be amazed at the performance if you have never used one of these.

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[Geof]

Indexable using TiAlN coated inserts, NO coolant, very strong air blast and you can probably push it up to 400fpm. And, if you are not using them already, find out about the peel-milling options in your CAM program.

[Delw]

Recently changed to a 3/4" sandvik indexable , was able to run 3 times faster. I ran with flood coolant and my inserts lasted 1.5 parts longer.

Reason being I think was because I had to drill tap and had to use coolant on those. and that was shocking the carbide.

if you run carbide make sure you get a rad. corner carbide endmill and good quality, 3/4" with run around 105 and 1/2" will run about 54 bucks.

my 3/4 indexable was a 2 flute as thats all the local place had. three flute is much better and a 4 if you can find one.
I had 5/8 to 1 1/4 ones at the shop but no 3/4 size.

[dertsap]

a decent sanvik insert can be run at 1100-1200 sfm on 4140
do a google search for the sanvik cutter module , it'll help in choosing the best insert grade as well as provide optimal speeds and feeds for their particular grades
I agree with Delw in regard to coolant , 7 times out of 10 I'll find an big improvement on tool life when coolant is used , no matter what the coating is .
one thing to keep in mind is that many of the hard grades do not like interrupted cuts , cermets are wicked when engaged , but throw a bunch of holes into the equation , then they'll chip

[super95awd]

Thanks for all the input so far!

Since indexable seems like the way to go, what cutter body would you recommend? There are so many options it's ridiculous.

Merry Christmas everybody!

[holbieone]

that's a big shift fork !

try 1/2 3 flute Data flute

[6061-t6]

I run iscar for all of my indexable tooling with the exception of my ni9e tools, i am EXTREMELY happy with iscar

[dertsap]

what cutter body would you recommend?

sanvik 390

[Donkey Hotey]

And, if you are not using them already, find out about the peel-milling options in your CAM program.

Geof, you left yourself logged in again.

(I take a year off from this place and now Geof is advocating CAM programs? What is the world coming to? Hi Geof! :cheers

I do not have any direct experience with this method but, their booth at Westec always blows my mind: Greenleaf ceramic cutters. I assume from your post that you have the 10K spindle? If not, forget it. You need the RPM to get the SFM up to where it needs to be for this to work.

It's the same methodology mentioned above by others: peel milling, something like only 5-10% engagement, 1-2 diameters deep, max RPM, 1" diameter (to get the SFM up), constant engagement cutter paths and totally dry.

Using this method, you literally WANT to see sparks coming off the part. This looks like the demo they run at Westec--all day long, cutting like this:

Graveyard Motorsports - Greenleaf Ceramic Cutters - YouTube

This is more of similar:
Hard Milling with Ceramics - YouTube

I haven't personally used this combination but, I've seen it running at the shows and seen the results. If I had 100 of those to make, that's what I would try.

[super95awd]

That's interesting, I hadn't even considered ceramic since the material should only be about 32-35Rc. I do have a 10k spindle.

I took a look at the Sandvik 390 as well as the Iscar bodies. I don't think I could really go wrong with either of them. Should I be looking at something bigger than 1" since I don't have any size restrictions on the cutter?

I normally wouldn't be asking all these questions, but I don't want this to take 10 years to make 100 parts! The only thing I've dealt with lots of material removal in is aluminum.

Thanks a bunch guys!

[dertsap]

Should I be looking at something bigger than 1" since I don't have any size restrictions on the cutter?

Both small and large have their own advantages which makes it worth having both .
cutter diameter is basically restricted to how much material you want to have left on the part for finishing . So in speaking the obvious , a small cutter will get into the radius's much closer than a large cutter .
A larger cutter usually has more inserts which increases the material removal per rev , but usually you'll take larger cuts with a large cutter (even more metal removal) which will produce a lot of force on the part , so you don't want to go too large or holding the part will become an issue .
If it fits the tool budget for the job then I'd highly recommend getting a large insert cutter to remove the bulk , then a smaller insert cutter to leave a minimal amount of material for the finish end mill to remove . I'm sure you wouldn't regret it .

[MarineMachinist]

Geof, you left yourself logged in again.

(I take a year off from this place and now Geof is advocating CAM programs? What is the world coming to? Hi Geof! :cheers

I do not have any direct experience with this method but, their booth at Westec always blows my mind: Greenleaf ceramic cutters. I assume from your post that you have the 10K spindle? If not, forget it. You need the RPM to get the SFM up to where it needs to be for this to work.

It's the same methodology mentioned above by others: peel milling, something like only 5-10% engagement, 1-2 diameters deep, max RPM, 1" diameter (to get the SFM up), constant engagement cutter paths and totally dry.

Using this method, you literally WANT to see sparks coming off the part. This looks like the demo they run at Westec--all day long, cutting like this:

Graveyard Motorsports - Greenleaf Ceramic Cutters - YouTube

This is more of similar:
Hard Milling with Ceramics - YouTube

I haven't personally used this combination but, I've seen it running at the shows and seen the results. If I had 100 of those to make, that's what I would try.

Impressive, I hadn't thought about ceramic for hardened steel before, not sure if I missed it, but how hard is "hard" in RC. I'd assume 60+?