A quick demo of steel's internal stress as it pertains to machining.
I'll show you something cool over here at the milling machine. This is Cold Rolled Steel 836 I Believe there might be another designation very mild steel, but it's been cold rolled. You can see dimensionally, it's quite. On Target We're gonna machine a lot of this in order to well make a coat hanger, but show the internal stresses of it.
It's going to bend like a dog's hind. Lake Got the dick of ice if in your clipboard Warrior type. you know, an engineered or such. Don't let them filthy-handed Tradesman fool you ain't nothing too.
Machining Turner Up to 11. hit the big green button. That's all there is to it. Spit redundant.
you'll notice I put in the two pieces. But the beautiful thing about CNC is if you don't tell the confuser, you can trick it into taking two pieces and making them into one. Which way is this gonna Bend Is it gonna hog or is it gonna bow? If I was a more disingenuous fella I'd ask you to put the answer in the doobly-doo but everybody knows that's so now that we've removed all that material, is it going to bend up or is it going to? The thing is, you can picture it. It's rolling through.
It's getting squeezed by the rollers Into this shape. Every action has an equal and opposite reaction. So if something's squeezing on it, that means that it's pushing out on those rollers. Okay, this flat stock is pushing out on the rollers.
What are squeezing them? And we go ahead. and Lop off the half of this, what do you think is going to happen? That's right, it's going to bow down this way. which means the center is going to blow up. Make a sense witnessed.
all the power of residual stress. We could stress relieve this that is before Machining We would heat it up and let it cool real slow like but you can see over not but 24 inches. We're out by half an inch in the belly. That's an incredible amount of stress just in that material.
In this case, it's not that critical because all we need to do is just bend it back straight but you can see as you're Machining If you're Machining asymmetrically more on one side than the other, more on one thickness than tether, you are always going to get some amount of deflection due to residual stress. So thanks for watching. Keep your dick in a place.
A standard note on pretty much every drawing at my second enginerding job nearly 50 year ago: Stress relieve before machining.
😂 how can I send picks
Cold roll is usually 1018, slightly nicer than A36.
Had a professor in engineering school who loved telling us about "beneficial compressive residual stresses". Most of the time I've only encountered the "UN-beneficial" types…. like this.
The opposite of hog is sag.
OMG the fake knob is GENIUS!
I guessed the other way, so, turn it over, eh?
Good advice.
This issue is mitigated quite easily. Just feed it some devil's lettuce before you start, to get rid of the stress. Bob's yer auntie.
This video was stressful…
The giver 11 😍
This is why we rough the cavitys on molds before anything else gets done. Then we let them sit for a day before squaring them up. Then they get finished.
Hog n das boot
my tip: drill a hole between 2 hubs to release the stress
I'll take your word for it, you're the one with the high falutin' metal munching robot!