A36 Steel. New Mill 1st Cuts. Hss? Carbide?

[countryguy]

OK, so the new Mill is cutting plant foam really nice...time to Graduate and I'm getting cold feet.

The Mill: 2HP SuperMax YMC 30 taper.
The Part: A 6+ inch mold pattern the son needs for an Axe project. .125 total depth on two pockets. (2 passes for .125 ) Then a 'merge' or taper edge all the way around the larger pocket. (images below).

I was told that A36 was equiv to 1020 but that's not what I'm reading online?? Some say closer to 1030?? Here is my short list of Q's:

1) I bought HSS cutters for this and now wonder if I should break out the Carbides? I do not want to waste 2 or 3 endmills only to find out I need the Carbides.
2) With HSS end mills do you usually cut w/ Mist or air on part. I do not have the flood up yet.
3) Using GWizard HSS 5/8 end mill = IPt .003 , RPM 978 and Feed IPM of 15.57
4) Using GWizard: Carbide/Coated . IPT .0027 RPM 2892 Feed IPM of 40.87 (seems really fast!)

Just don't know the materials all that well yet! Appreciate any comment or suggestions. This is just some test stuff we wanted to do.

 

[JimDawson]

A36 machines OK, it's a little gummy. I would probably start with a cobalt rougher and reduce the feed to about 5 IPM and the RPM to about 600. Then run a finishing pass with a 4 flute at about the same feed and speed. I use a mist system on both HSS and Carbide. The only time I use just air is on tool steels. I generally run a bit slower than optimum speeds, no point in beating up the tooling and machine if you don't have to. I'm normally not in that big of a hurry.

The GWizard assumes a full blown production environment with optimized tooling and coolant.

 

[markknx]

Can't help on the feed as I do that by feel. I agree with Jim but would add Cut lots A36 (get for free from work) HSS will cut it fine and hold up good. Save the carbide for good steel. keep the chips out of the way because as mentioned by Jim A36 is gummy if you start re cutting them (Like in a pocket) they will gall the cutter and give a poor finish.

 

[countryguy]

Ok, Horse stalls are all plowed out for Spring.... My afternoon is now setting up for .625 @ IPT .002 (in range), an RPM of 575 on Coolant Air Mister and some crossed fingers. I know I need to just get in there! Thanks everyone!
JJ

A36 machines OK, it's a little gummy. I would probably start with a cobalt rougher and reduce the feed to about 5 IPM and the RPM to about 600. Then run a finishing pass with a 4 flute at about the same feed and speed. I use a mist system on both HSS and Carbide. The only time I use just air is on tool steels. I generally run a bit slower than optimum speeds, no point in beating up the tooling and machine if you don't have to. I'm normally not in that big of a hurry.

The GWizard assumes a full blown production environment with optimized tooling and coolant.

 

[countryguy]

Dear Diary, ohh horse pucks. Did not get to run my 1st CNC job yesterday. Came so close. but realized I did NOT:
- Put in a 0,0 mark where I could place the endmill to insure my part is cut where I want it.
- Did not have my 5/8 hold down kit and t-nuts. (Came UPS 4pm.. the gods do love me!).
- The cut setup I had for the "chamfer" was all wrong. Had to redo the entire program. (Manual milling sounds better all the time).
- The Boss called me to the barn . (wife I adore ;-) Noithing went right yesterday!

- Today, I have the plate sitting on the mill, Program all cleaned up, Ran a test 3" above the steel and just watched it go round & round to make
sure my bolt-down/hold-downs would be clear. And yep.... I think we're about ready to green light this after a refreshing cup O'joe.

My point is that I often see folks comment that they could have milled 3 of what-ever manually -vs- CNC and all the work ya do on the front end. ;-) But I think I like it? Looking to do more manually for sure in the coming months.

Being a rookie here w/ you guy's is very comforting! Thanks for ALL THE HELP to get us this far. To Jim D. I think the kid and I would be lost w/o ya!

Time to put this to bed.
CGout.

 

[Wreck™Wreck]

OK, so the new Mill is cutting plant foam really nice...time to Graduate and I'm getting cold feet.

3) Using GWizard HSS 5/8 end mill = IPt .003 , RPM 978 and Feed IPM of 15.57
4) Using GWizard: Carbide/Coated . IPT .0027 RPM 2892 Feed IPM of 40.87 (seems really fast!)

Just don't know the materials all that well yet! Appreciate any comment or suggestions. This is just some test stuff we wanted to do.

View attachment 99081 View attachment 99082

Is this a knee mill? If so the S&F's are a bit aggressive I imagine (-:
Without a good amount of high pressure flood coolant I wouldn't even try that, you will be recutting the chips over and over again in the pocket.

 

[countryguy]

Could you share some insight on DOC and WOC values and SFm's you'd suggest? The Carbide's are way too fast.... I agree. Jim's suggested feed of 5 and rpm 500-600ish. But I've been wondering how much to bite on the width and depth. I now have .06 depth and width's stacked up to reach my target depth of .125 I mean all this to get and 1/8th into the metal is a 3hr. CNC run w/ these feeds and speeds. sound about right?

 

[JimDawson]

I think you would be safe with a 0.4 stepover, and a 0.120 DOC, leaving 0.005 for a finish pass if you want, or just go for the full depth if the finish is not critical. Your machine is about the same size as mine so I'm pretty sure it will take a lot more than that.

Here is a picture of a 0.500 rougher plowing through 7/8 inch A36 @ 0.5 IPM at about 600 RPM



And the same rougher plowing through 1/2 1018 @ 3IPM This started as one solid plate, I did it in 2 passes, one roughing pass at full depth, and a 0.015 finish pass with a 2 flute. I should have used a 4 flute for the finish pass, but I didn't have a sharp one.

 

[countryguy]

Jim, When I grow up I hope to be as good as you I need a rougher! Going on Amazon tonight. Which brand do you like? HSS coated or plain? TIA!

Those are numbers I would expect as it's why I bought the 30taper and a 3000Lb Mill.
Jeff.

 

[JimDawson]

I'm not good, just lucky sometimes. I also never professed to be a machinist, I'm just a problem solver who happens to need to use machine tools sometimes.

I normally buy Interstate from Enco. Hertel is a higher end cutter, Enco sells both, but I haven't noticed a real difference in quality. There are fine roughers, course roughers, finishing roughers (now that's an oxymoron), uncoated roughers, coated roughers, coated in TiN, TiCN, Tialn, Bright

It really depends on the material and the job. Enco has pretty good explanation of the different roughers and their uses. I normally buy 2 to 5 at a time depending on how low my stock is, this is true for any cutters I buy. It really sucks to be in the middle of a job and break or wear out a cutter and not have a replacement to finish.