Instructor approves cutting steel at 2000sfm

[Scruffy887]

Sometimes people get stuck in their own "comfort zone". Key work is STUCK. Expand that zone and you will have a larger comfort zone.

 

[kustomizer]

For a long time the world was flat and everyone knew it

 

[Conrad Hoffman]

Every cutter company will be happy to tell you what speeds and feeds will give optimum results with their tools. I think RTFM applies here.

 

[EndlessWaltz]

This guy be trolling or WAS the instructor.

I mean in 2021 , what kid thinking they are right about this wouldn't film it and put it up on tik tok.

To let you know about how bad it is with instructors. For High School, at least in MN and WI you need an actual teaching degree as where if you teach college you can teach with X amount of job hours/years. A guy I respected didn't go into teaching because while trying to get a degree for teaching shop class he was be trained on clapped out bridgeports etc and couldn't get a proper education himself. Sad times we are in.

 

[Kitsyfluff]

As long as the chipload is correct and doesn't experience any shock, you can crank that surface footage as hard as your machine is capable. But only 4-5 horsepower? that's a bit low sounding for 2k SFM of a 3/4 tool to me. I would be doing that with a 15Hp spindle. And while I don't know the acceleration of your machine, it is a factor since you wouldn't actually get the performance you think you are out of the cut.

Regardless High speed steel isn't really meant for those speeds, that's what carbide is for...

 

[CarbideBob]

As long as the chipload is correct and doesn't experience any shock, you can crank that surface footage as hard as your machine is capable.

WHAT????
Bob

 

[Milland]

WHAT????
Bob

It works just like a friction bandsaw, Bob - you just run the tool in reverse.

[Or maybe this will be a new form of Additive Manufacturing!]

 

[gkoenig]

I mean in 2021 , what kid thinking they are right about this wouldn't film it and put it up on tik tok.

IDK - the same kind of people who would use HSS end mills?

Seriously, the program sounds like a fucking scam. HSS tooling? Instructor still stresses hand code? That kind of attitude is part of the reason America drained 60% of our manufacturing base to the god damn Chinese - these fat dumb fuckers wanted more hourly $$$, but didn't want to evolve beyond the old codger junk tools/techniques to increase productivity.

 

[Mechanola]

The high art of machining is about slow cuts. Many mechanics file too fast. HSS on steel, 130 sfm under coolant, not more

 

[sendithard]

Bro although your tone is harsh, that is how I see it

. I see it as lazy actually. The old timer can't get their hand around a simple square part setup in HSMworks/fusion360. He is in love with Saladworks so he thinks he is using solidcam when he is actually using camworks, which has zero online help. As a student, who doesn't love zero online help. I had to take my laptop to the machine today to get him from forcing me to do hand coding changes.

I learned more today than in the past month by overcoming cutter comp errors on the haas st-10 than running 2 hand coded programs onthe haas. Hand coding is fine, but has it's place.

 

[G00 Proto]

I love breaking shit, especially other peoples shit. One of the first questions I ask when someone calls me in to help with a production program. How hard do you like to push your machine. If they tell me push them as hard as they’ll take, I tell them we are going to break some stuff and then back off till we are breaking less stuff.

I’m more conservative on my own machines.

That high an RPM on a .75 HSS endmill on those conditions is just going to melt…. I bet I could get it to work with a fairly deep axial depth of cut and maybe .040” radial, maybe 150 IPM. There’s a sweet spot somewhere in there where all the heat goes out in the chip.

If you’re only going .040” deep, you’ll melt the corners off. Since it’s an old school shop, abrasive cutoff saw the end and resharpen.


Sent from my iPhone using Tapatalk

 

[mhajicek]

We have a basic small vertical mill with a bt-30 holder and 4-5 horsepower spindle that can run 10,000rpm and weights roughly 2500 lbs.

Ok, I think I see what's happening. The "school" has a Tormach, or similar entry level hobby machine, and when the cutter makes contact with the work it practically stalls, slowing the cutter down to a reasonable SFM. The instructor has learned by trial and error on this hobby grade machine, that no matter how fast he programs the cut, the machine can only go so fast; it doesn't have the horsepower to melt the cutter.

I punched some numbers into HSMAdvisor, here's what I got:

HSS 4 flute uncoated endmill, 0.750" diameter, 1.0" stickout, 0.400" deep full slotting in 1018.

Recommended: 448 RPM, 88 SFM, 3.89 IPM, 0.00217 IPT, 0.6 HP required, cutting force 233 pounds.

At the instructor's parameters:

10,000 RPM, 1963 SFM, 120 IPM, 0.00300 IPT, 19.2 HP required, cutting force 322.2 pounds.

Yup, there's no way that machine can push that hard.

 

[plastikdreams]

Bro although your tone is harsh, that is how I see it

. I see it as lazy actually. The old timer can't get their hand around a simple square part setup in HSMworks/fusion360. He is in love with Saladworks so he thinks he is using solidcam when he is actually using camworks, which has zero online help. As a student, who doesn't love zero online help. I had to take my laptop to the machine today to get him from forcing me to do hand coding changes.

I learned more today than in the past month by overcoming cutter comp errors on the haas st-10 than running 2 hand coded programs onthe haas. Hand coding is fine, but has it's place.

I'm sorry to say, modifying programs at the machine is the way it's done, unless you are completely reprogramming a feature, small tweaks are done at the control.

 

[plastikdreams]

The high art of machining is about slow cuts. Many mechanics file too fast. HSS on steel, 130 sfm under coolant, not more

You are about 50 years to late my man...the actual art of machining is getting it done as fast as possible while producing a good part and having acceptable tool wear. This varies from material to material, so another art is knowing how and what to do with the material presented.

 

[doug925]

here's what you do. Come up with a catch phrase for yourself. Something like "Get er done" and then scream it at the top of your lungs constantly.
Be sure to also scream words like, Awesome, bitchen, radical
Buy yourself a truck with $80K of gaudy accessories and get lots of stupid tatoos.
Now you're ready to host your own show

Hey, I resemble that remark!!!
Bitchen!
Now, I need to go to the corner store. Want a ride?

 

[Dalego]

You can get Vendor recommended feeds & speeds. The only thing that has a SFM of 1000 is plastic with a 3/4 carbide endmill. For 1018 you would be in the ballpark of 300-500 SFM. You are not wrong.

 

[moonlight machine]

Hey, I resemble that remark!!!
Bitchen!
Now, I need to go to the corner store. Want a ride?View attachment 342102

All that useless POS needs is 6" diameter chrome twice pipes through the bed standing behind the cab.

 

[broke]

It's only going to take about 2 seconds for the dust to settle. It's going to be noisy and things are going to go flying. I would recommend you stand back and cover your groin and throat

 

[Rick Finsta]

When I saw the thread title I was like "yeah sure, Sandvik Grade 4335 CCMT in mild steel all day long at that speed" and then I clicked and was like

 

[Zeuserdoo]

I'm sorry to say, modifying programs at the machine is the way it's done, unless you are completely reprogramming a feature, small tweaks are done at the control.

Not in this shop. Unless it a speed or feed change, "tweaks" are not allowed. Too many people who think they know what they are doing have caused too many crashes.