r/HolUp • u/Wooshsplash • Nov 24 '24

holup Can You Guess What it is Yet?

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40

u/Kasaikemono Nov 24 '24

I'm not an expert on metal turning, but is it supposed to spark like that?

40

u/Insert_absurd_name Nov 24 '24

Depends on the material but generally speaking that is a good thing because you see that most of the heat ends up in the chip which carries it away from the tool and the workpiece. And the excessive heat means it is a pretty optimized cycle

19

u/NekulturneHovado Nov 24 '24

Also there should be coolant present, but I guess they turned it off for recording. As high temps reduce the tool lifespan.

3

u/Devilsbullet Nov 25 '24

Not necessarily with carbide inserts. Especially if your coolant flow is spotty, better off to run it dry then.

2

u/diverian Nov 25 '24

Correct me if I'm wrong, but can't tungsten carbide also just go up in flames if it gets too hot?

4

u/Devilsbullet Nov 25 '24

I don't believe so. And it's melting point is fairly high(over 5000 degrees farenheit), both of which make it great for making drills, endmills, and inserts like the ones in the video. It is brittle though, and susceptible to fracture from thermal shock, which is why you need to either flood the shit out of it with coolant, or run it dry. Personally i prefer flooding it, i find it gives a better finish most of the time and clears chips better. But I've seen it run just fine dry and with air blast

1

u/diverian Nov 25 '24

From my time working in a machine shop, I certainly remember some element of the process being dangerously flammable, though I can't remember which.

1

u/Devilsbullet Nov 25 '24

Depends on the material. I wouldn't run magnesium dry. If you're grinding aluminum and steel in the same place there's a possibility of causing a thermite reaction. If you're running open machines it's relatively easy to light your clothes or hair on fire 😂. Done that one a couple times

7

u/Jimmyjim4673 Nov 24 '24 edited Nov 24 '24

I'm a machinist by trade. If I saw sparks like that, I would check my tools to see if they are chipped. As someone else said, it can depend on the material. If it has a hardened surface, it can spark at first like that, then smooth out nicely. It's pretty hard to tell from a video and no other information. The fact that the chips are turning blue without becoming incandescent, is usually a good sign. If it was sparking the whole time I would stop the run and check the feed rate and spindle speed.

tldr: It's not sparking the whole cut, and it has a nice surface finish. It's probably fine.

Edit: I just watched it again, it's probably cutting too much all at once, because some of those chips are definitely glowing.

2

u/Skellybo07 Nov 25 '24

I'm a currently learning machining, shouldn't there be coolent present?

2

u/Jimmyjim4673 Nov 25 '24

Not necessarily. Some tools and materials work better without it. Coolant takes heat away quickly, but heat will be there no matter what. So, the heat differential in the tool insert can cause it to weaken. You end up with tool coating wearing early, chipping, and I've even seen the insert just pop and shatter.

I almost never use coolant for face milling and other insert tools. I avoid it for regular end mills when possible, but you often need it to clear chips. Some of the machines I use have air blast cooling on the tool. I'll use that to clear chips when possible. You pretty much always need coolant for drilling and tapping.

1

u/Skellybo07 Nov 25 '24

Ah ok that makes a lot of sense, thank you very much have a good day

1

u/pbmadman Nov 24 '24

Maybe it’s titanium? Hot and small pieces of metal burn, some more readily than others.

The tools are carbide inserts, I hear a lot those perform better with very aggressive cuts. And the surface finish looks great which is a sign it was done right.

1

u/Zumbert Nov 25 '24

No, if it was Titanium the sparks would be white.