Big Crash

[gcode]

Many years ago ....

I was running an engine lathe. It was set up so that my back was to an Okuma LC-30 CNC lathe. My face was to a wall.

The Okuma was running 4 in square steel bar

sawed about 10 inches long in special soft jaws.

The CNC operator crashed the Okuma, ejecting

this big chunk of steel out the open door of the machine. It went over my left sholder and blew a hole through both sides of the plaster board wall in front of me.

The Okuma was heavily damaged and I managed to convince my boss that he should put the engine lathe in a safer spot or find some other fool to run it

[awheeler]

This isn't a machine crash but a machinist crash. Some of you may have seen the picture before (or may be the same guy). I use it in my saftey lecture in my machine shop classes. A guy caught his class ring on the lathe chuck he was running and it literaly tore his finger off at the base including ripping the tendons out of his forearm. As for me I haven't had any machine destroying crashes, plenty of endmill shearing mistakes though, and no feeling left in my middle finger thanks to a 1" OD .025" thick slitting saw that I wasn't watching out for.

[TheePres]

I was new to CNC back when prgramming was done on teletype machines. Was drilling 1.25 diam hole thru cast iron parts. Programmer inserted Z-60.00 instead of Z-.600, funny thing is I watched that drill go right thru table without realizing anything was wrong, it cut beutifully. Next morning we discovered that our night crew used metal stamps to engrave "OIL HERE DAILY" around that hole.

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[Guy]

Hey no more FUNNY story...

 

Come on!

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Guillaume Côté

Hexco inc, Montreal Canada

Stainless steel specialist

[KMaynard]

My Partner here tried to do some hard tapping ..he neglected to check the spindle speed and attempted to tap at 5000 RPM on a milltronics ..needless to say the spindle was moving way to fast to stop at the desired depth ...

[Fred from Université de Sherbrooke]

A scary one...

A guy was working on a old Matsuura milling center. He wanted to unlock the spindle so... thinking he was in MDI mode, he write something like M20 and while holding the spindle with his hand he pressed cycle start. DOOOO!!! He was in memory mode and the program in memory was calling a tool change. His index finger got 1 inch shorter. I still make nightmares on this one...

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***FRED***

[Toby]

OK here's a couple of treats:

1) We had just purchased a brand new Kitamuura Mi3-X1. The first week on the floor, with next to no time on the machine, some rocket scientist did a full rapid Z axis crash! It was ugly. Since the machine was soo new the replacement spindles could only come direct from Japan which effectively rendered that mahine out of commission for about a month. The person at fault was let go.

2) At another place I worked a co-worker of mine was attempting vacuum chuck work with a piece of 12 x 12 alum. He unfortunately was pocketing from the outside in with a terribly thin floor. As the cutter worked it's way to the center the resulted form was a thick island which at some point started to lift off the fixture. The vacuum couldn't hold against the e-mill pressure and the 12 x 12 plate went flying. It blew thru the front door window, sailed past my buddy who, wasn't wearing safety glasses, and slammed into a tool box leaving a nice stupidity reminder.

3) The final for these machinist Darwin awards goes back to the late 80's when running hss hoggers was popular - at least where we worked. I happened to be running a problem job with a poor fixture design - not my design! we were hogging out a big window out of aluminum and the cutter grabbed the part, twirled it around the cutter and thru it so hard it blew the safety window out and literally mushroomed the steel around the window outwards. The part Then lay next to my trembling feet.

Hope everyone enjoys.

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Toby Baughman

Programming Supervisor

Saint Gobain Semicon Group Inc.

Vs8.1.1 LvL3 Mill + solids

[ChrisD]

Mazak VTC 41M May 1995 to JUNE 1995

R.I.P.

"G43 Z-19.000 H19 M08"

Those numbers, I will never forget!

[Guy]

nice one ChrisD

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Guillaume Côté

Hexco inc, Montreal Canada

Stainless steel specialist

[TomT]

Mazak VTC 20 B

someone changed the tool's lenght( fly cutter) without knowing what he had done!!!

I made and ran the program! on my birthday!!!

poor birthday!

[Guy]

thanks everyone

soon i'm willing to make a web site with crash's stories and picture

yo

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Guillaume Côté

Hexco inc, Montreal Canada

Stainless steel specialist

[Charles Davis]

Older Mazak lathe with horizontal indexing turret. New to machine and didn't realize insert drills required the spindle to run in reverse. Operator didn't pick it up either.

We both calmly watched as a 1.5" insert drill tried it's best to push it's way through the part. It glowed such a beautiful red-orange color before we dove for the big red button. Can you say "friction welding"?

Scrapped the part, but the tool was actually salvaged (not the inserts!).

[gmenzies]

 

it's amazing how many edge finders we go through , went we are training a new operator.

they often forget to set M3 S250 , instead it's usally 10,000 rpm.

the look of oops , never changes

[lovell110]

Instead of the oops look we call it the deer in the headlights look!

Warner & Swasey 2Sc (50 hp motor)

2" Dia HSS drill

G0 X0.0 Z.1

G1 Z-3.0 F222.00 M08

Operators question " Is it supposed to do that?"

[This message has been edited by lovell110 (edited 07-12-2001).]

[cadcam]

You just have to love that.(" Is it supposed to do that?")

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jay/ aka cadcam

Precision Programming

email: [email protected]

web: www.ppcadcam.com

[ronengineer]

Excellent stories, mine goes like this;

One day ,a long time ago, we were turning a prototype job on a Mori Seiki Tl-5 Lathe. This job was an unusual shape so a lot of time was spent making special wrap-around jaws which held the part a treat. The other unusual thing was that the datum for the programme chosen was the far left of the job (ie inside the jaws on the face which the part located). So the programme was all in Z+ .

Now all was going well untill a modification was required. Someone (OK it was me ) edited in a Z change and out of habit put in Z- !

We watched in horror as the tool turned along the part, past the point it should have stopped, straight into the chuck going at 2000 revs

We were still staring blankly ahead as the remains of the job, pieces of chuck, tool, turret and carefully created jaws were duly dispached into the bin by the swarf conveyor...

[ngkim]

whilst i was working as a night shift operator setting up inserts for cnc milling.one night a colleague set up as usual a mold insert for roughing,and calmly went to sleep.the next morning the cutter milled right thro the soft vise leaving a profile on the vise itself.he was duly sacked.

[Guest CNC Apps Guy 1]

I once heard from an OSHA guy that an operator set up a lathe with a part that was 6 inches in diameter and 18 inches in length. He was holding onto about 2 inches(can you see where I'm going with this?) with no tail stock, facing with CSS and no max rpm set. Needless to say it faced a bit, then the RPM's sent the part flying through the window killing the guy. The deceased's (is that a word?) next of kin was trying to say the machine design was at fault. I say the guy was at fault. Bummer.

A guy I used to work with worked in a place where they forged shell casings for the military. They had a 1000 Ton press that to fi you had go get in the machine. Well the maintenance guy was repairing the press, using the proper lock out procedures, he also had a "buddy" outside the press to make sure nobody activated it. The guy finished fixing it, got out and removed the lockout. The "buddy" went on break, the guy fixing it either forgot a tool inside or something like that. Well the break was over, the lockout was removed so the setup guy cycled it. I wont go into gory detail, but they had to cycle it one more time to get him out. This press would make foil out of 55 gallon drums. It was not pretty. Needless to say he did not go home that night to his family or ever again for that matter.

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James M.

Mastercam Enthusiast

[Superfly]

I've seen a few in my day.

like having a turret literally fall off while turning on a 15" dia.,10 foot long roll.

and get this,on that same job,the soft jaws that were being used gave way because the weld wasnt strong enough.

does anyone know what a 5000lb. hunk of steel sounds like when it falls out of a chuck spinning at 800 r.p.m.?

sounds like a howitzer going off.

i've seen my 2 people rapid the turret into the spindle going 3000 r.p.m. on a different machine.

mori-seiki makes one hell of a lathe.

also i have seen someone turning on a long piece of 5/8 dia. stock with it hanging out of the back of the drawbar on a brand new mori-seiki.

he gradually increased the spindle speed until it started to shake a little then backed it off slightly.

well,needless to say,once he started to turn it......KABOOM!!!!

no more fibreglass on the spindle side of the machine.

lol.

[This message has been edited by Superfly (edited 07-18-2001).]

[This message has been edited by Superfly (edited 07-18-2001).]

[Guest CNC Apps Guy 1]

ROFL!!!!! I always wondered why they put that fiberglass there anyway. Looks nice though I guess. Dit it leave pretty spiral marks all along the side of hte machine? ROFL!! ROFL!!!!

I can"t contain myself. I'm totally picturing that and the look on that poor guy's face. Must've been a Kodak moment for sure.

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James M.

Mastercam Enthusiast

[gcode]

A customer of mine had a new Daewoo Puma.

Less than 40 hours on it.

The machine had a 7K spindle and the owner told me to "Use that speed". My program had a 6500 RPM clamp on it.

His operator loaded a 1/2 in. dia. by 7 ft steel bar into it and let her rip. The bar started whipping and gutted the back of the machine. The operator panicked and ran leaving the machine running.

There was big chucks of sheet metal and hydralic components thrown all over the shop.

The were even pieces of sheet metal stuck in the ceiling insulation.

The machine ran for about 90 seconds before the foreman got to the controls and shut it down. The vibration actually moved the machine a couple of inches!

Needless to say it was not a warranty repair!

[This message has been edited by gcode (edited 07-19-2001).]

[Superfly]

if you were able to glue the little pieces back together,i'm sure there were pretty spiral marks all over.

but the fiberglass pretty much exploded.

hehe it was funny because i wasn't the schmuck who pressed the button.

 

[Scott Bond]

Bad bandsaw weld.

Once I broke a weld(my own),on a large doall with 36" wheels it had A 1" thick band saw blade.I didnt have the work piece in yet .So when the rpm's came up the weld broke end of the blade was able to move to the right A little bit,and hit the end of the blade on the table.It broke in little pieces about 1' long, bounced off the table and loudly rained down all over the place.

(This whole thing didn't take a second, but I remember it perfectly, and it was thirty years ago)

Hardway

[This message has been edited by Scott Bond (edited 07-20-2001).]

[Guy]

no more "crash dummies"

every body have a story...

[Fig sign]

Crash -never smthn serious.

Accidents in 20 years saw a lot of blood and that`s not funny.

 

But I want to tell you some funny story a bit O/T also a bit bloody but worth to mention .

Place my home town in USSR .Time -approx. 20 years before.

One of my colleagues was in hospital when she came back she weeped from laugh.

One day all the surgents of the hospital where shoked :

They got a man that by accident on the shoe factory on the machine that put together heel and the shoe had the heel glued and nailed to his hand !

So this was first of this kind urgent operation of the heel disengagement.

They had enough time to say ugh after the operation when they saw another man brought for operation THE SAME CASE A HEEL ON A HAND ONLY THIS MAN WAS NOT A WORKER HE WAS RESPONSIBLE FOR THE PRODUCTION SAFETY OF THE PLANT !!

So after the operation doctors and everybody else were dying from curiosity WTH going on the factory.

This guy refused to tell but there were a lot of witnesses of the case that told :

This clown came to the machine and said :

I can not understand why this happened,this machine has all the nessesary safety arrangements and while he talks PUT HIS HAND ON THE SAME PLACE!

GOTCHA !

 

[ 07-01-2003, 05:31 AM: Message edited by: plasttav ]