316 STAINLESS

[Thee Dragracer1951]

I'm drilling 316 stainless for a 5/16-18 roll form tap. The drill is going .625 deep. I'm running cobalt, 55sfm at .0055 per rev. I had been pecking just because that's what was working for a 3/4 spade drill in the same stuff but this ain't gettin it. I'm doing MAYBE 10 holes and the shoulders are going away. I have tried not pecking and that wasn't much better.

I'm open to suggestions here...

Really...

No Kidding, I am...

[jeff]

You are close to what I would run it at

45 SF .004 ipt peck about .150-.250

 

It's fun stuff!

[garyg]

We do a lot of 316 and use HSS run 35 SFM. I'd keep the peck and feedrate but use a lower SFM.

[Guest]

Make sure you check your coolant concentration. If it breaks down or gets to thin you'll burn tools prematurely

[Thee Dragracer1951]

I'll slow it down.

John , Hangsterfers CF500s at about 8%. I keep up on it.

 

I have a 3/4 spade drill that I called the tech guys at the mfg. They hit the numbers square on the head. I was using those numbers. Their inserts are cobalt but are coated

 

I also have some pockets I'm doing. .5 dia, veri helix Pro Max EM with .03 rad on the corners. I'm going to try .2 doc. 200 sfm and .004 per tooth. I think 75% on the stepover.

We'll see.

You can experct more questions.

Jebuz I don't like this stuff.....

[Guest]

sounds like heat build up (corners going away) as well as sfm is a little hotter than i have run with any success in this stuff.

it takes a lot of patients, esp. if you are tapping it. this material will work harden and cause all kinds of night mares.

slow and steady is my 2 cents.

 

doug

[Thee Dragracer1951]

I REALLY need some advice about speeds and feeds. I can't get an endmill to last more than a couple inches.

I was going 200 sfm. .004 per tooth. .1 deep. Slowed down to 150 sfm and .003 per. I'm throwing $65 in cutters every couple minuites at this part and getting nowhere.

HELP!!!!!

The setup is on a sub plate (10" dia 1" plate) and is pretty rigid. Box ways, 40 taper. Held in a ER32 collet. less then 5 tenths runout. Hangsterfers CF500s @ 8%

[?Mark]

Jim,

200+ sfm and .0018 ipt should cut for hours in this material. Looks like you pushed a little hard on ipt.

What brand of endmills are u using?

[Thee Dragracer1951]

Thanks Mark

I am using ProMax .5 four flute variable helix, I also have some other variable helix four flute I got on line. They work fine in 303 and 304 I also cut. I have also tried data flutes and hertels and wisper cuts. Thing is, I run these a lot. Every stinkin part is different. I have gotten LOTS of material removal from one set of material and then it all turns to crap on the next run/ If I could see what the inconsistancy was, I could deal with it.

The last time I ran these, I used 200sfm, .004 per tooth, .1 deep and 30% radial. Ran fine. Tried the same numbers yesterday and not a chance....

In fact, I had been ramping into the material nad not I have a 3/4" entry hole.

I'll give your number a shot

Thanks

[jeff]

Hanita Varimill!!!!!!!!

These things eat Stainless up!

You can run a 1/2 varimill all day in this stuff.

[Allan]

quote:

---

I have gotten LOTS of material removal from one set of material and then it all turns to crap on the next run/ If I could see what the inconsistancy was, I could deal with it.

---

The inconsistancy is diffrent "Heat" or "Lot" numbers. There is a 316L spec for that type of stainless usually found in bar stock that is "free machining" and would not give you the trouble you currently have. Perhaps annealing is an option?

[Thee Dragracer1951]

This is, by the certs, 316L fully annealed and pickled

 

Gives me da bluz...

[Guest]

fully anealed, i would be looking for some nice golden chips to find the sweat spot. feeding too hard it will tear feeding too slow it will work harden.

[Fig sign]

Hanita Varimill!!!!!!!!

These things eat Stainless up!

You can run a 1/2 varimill all day in this stuff.

 

~~~~~~~~~~~

+1000

This is my first choice in stainless in anything from 3 to 5 axes

Never ends .

Low vibration .

High feed.

Love them

[?Mark]

+1000 on Varimill.

I don't use anything else. (their speeds and feeds book is f^%#d up though...)

 

quote:

---

There is a 316L spec for that type of stainless usually found in bar stock that is "free machining"

---

This is what Allan is talking about: Project 70+ Type 316L SS.

hth

[Thee Dragracer1951]

This tuff is definitely NOT Carpenters Project 70.

I have trashed seven, count em SEVEN varimills this morning. 200sfm, .003 per and .1 doc. 25% stepover. I have an entry hole and that's dandy.

[?Mark]

So the material is either ht'ed or I'm almost ready to assume your er32 collet is not holding up...

[Fig sign]

We milling today 316 after heat treatment With Varimill 12 mm

V=45M/MIN AND FZ=0.045 MM/MIN downstep 6 mm sidestep 1/3 -1/2 diameter WORKS GREAT and I

would use greater feed if it was more rigid setup

[jeff]

quote:

---

I have trashed seven, count em SEVEN varimills this morning. 200sfm, .003 per and .1 doc. 25% stepover. I have an entry hole and that's dandy.

---

I would stop, and send the material out for analyzing. You say that you have certs, but who's to say those are right?

 

Do you have any other 316SS that you could cut on to compare?

[Thee Dragracer1951]

I may have. I'll have to go look through the material area.

I slowed the drills down to 30sfm and it went a bit better. I got through one part for the pockets. I'm about to start the next .

[YoDoug®]

I have had good luck with SGS Z carb endmills in 316. Their feeds and speeds from their website usually work great. I would run about 2200rpm, 22ipm, .1 deep, and 40-60% step over.

[Bruce Caulley]

Sounds like someone switched your 316 for duplex 2205.

 

Bruce

[Thee Dragracer1951]

I do not know Bruce

Don't know what Duplex 2205 is.

 

Doug, I don't know, that's 288 sfm. the feed may work, but I think that's too much spindle. But on the other hand....what I'm doin ain't workin.

The thing that bothers me is I'll find something that works. Next time I run them, same tools, machine , holders etc, I just bust stuff.

I'm going to call teh tech guys at hertel in the morning and see what they have to say.

[Allan]

Duplex 2205:

 

2205 is the most widely used duplex (ferritic/austenitic) stainless steel grade. It finds applications due to both excellent corrosion resistance and high strength.

 

The standard S31803 composition has over the years been refined by many steel suppliers, and the resulting restricted composition range was endorsed as UNS S32205 in 1996. S32205 gives better guaranteed corrosion resistance, but much of the S31803 currently produced also complies with S32205.

 

2205 is not generally suitable for use at temperatures above 300°C as it suffers from precipitation of brittle micro-constituents, nor below -50°C because of its ductile-to-brittle-transition.

Key Properties

 

These properties are specified for flat rolled product (plate, sheet and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.

[Thee Dragracer1951]

Well...another four endmills and I have one pocket half roughed

288sfm ain't it