Big Crash

[Guy]

Hi everybody

I would like to know if some of you have a crash's story to tell !!!

Mine: last week one of my guys put the turret in the chuck in rapid feed. Imagine the tools...

[Michael Reynolds]

When I was first learning to set up -n- run cnc lathes, I was setting up a reverse-work piece job, and forgot about the second workshift. 900 inches/minute, 5000 revs straight into the spindle. Brand new machine, first (attempted) set up.

Sooo, I single handedly turned a NEW Hardinge Conquest SP (super precision) into a normal, everyday Hardinge conquest.

How's that?

Mike R.

[gstephens]

I had program a VERY complex (7 different part numbers with variable switches to turn each part on or off individually) tombstone setup. Anyway, the operator had to replace a broken tool. He also replaced the part that the tool broke in. When he restarted the machine, he neglected to cut the replaced part in a different rotation (roughing op) before re-running the current rotation's sub-program. 12000 RPM + plunge at 200 IPM into an area that hasn't been relieved at all = smoked $25,000 spindle (and a sound taht was heard in the offices 2 doors down).

[Michael Reynolds]

Gstephens, is that operator still working with you???????

Mike R.

[Guest]

Mine is not a crash story, however it was a very close call. One of my mill operators was starting to indicate a part in with a dial indicator. The machine was a Tree VMC840, he had the safety doors open. He punched in to the control “M3 S25”. However, when the spindle came on it started at the spindle speed of the previous operation and then shifted down to low gear to get to the 25 RPM. The previous operation was engraving. The spindle came on at 8000 RPM and whipped the dial indicator off in a millisecond. As he was ducking to get out of the way, the indicator flew right past his head and embedded in the drywall right next to the time clock which was about 20 feet away. It left a perfect cut out of the indicator, point and all, in the drywall. And believe it or not the indicator still worked. I used the cut out in the dry wall as an example during my safety meeting from then on.

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[This message has been edited by mlindsey (edited 07-05-2001).]

[lovell110]

Here is mine,

I was stepping into the field of unmanned machining. I programmed my Mazak SQT8 to have the tool eye come down and check the tools for wear and breakage. In my haste I forgot to tell the tool eye to go back to its home position. Needless to say, I now know how to replace and calibrate the tool eye on Mazak lathes!

[mopar]

This is more of an accident than a crash. I was teaching a guy how to rapid the table on a 1985 Mori-Seki mv45/40 and on the front of the table there were three steel "tee" pipe fittings and screwed vertically into the top of these were 1/2 x 8 capscrews. These were put there by the previous guy in a attempt to attach a piece of lexan to keep the coolant from spraying everywhere. Table goes to home from G30 and a bolt and fitting swing down and catch the diamond pattern way guard breaking off and shooting out and into the air and into the left lense of my eyeglasses. Lense pops out and into my face, frame cuts my left brow and I'm bleeding. Luckily I have polycarbonate safety lenses and titanium frames or I would not have a left eye. I clean up and bandage and go to Westec a hour later to look at more machines.

[Kenneth Potter]

Heres a story

On Fadal a guy fashioned a 12inch heavy 30lb face mill to a 40 taper tool holder to one pass face off some aluminum stock at 5000 maximum spindal rpm .375 depth & 100. ipm. the tool holder & mill ripped out of the spindal & danced around like a ping pong ball putting sleadge hammer dents in the metal guards around the machine. Spindal was trashed & table top had chunks of metal missing.

He got fired.

 

[Guy]

WOW

Nice story everyone.

Have a nice day

[Brendan O' Regan]

While we were training in our training centre we were using Maho machining centres. One day one of the lads entered the z value wrong with a rapid traverse and sent the table of the machine up into the spindle and did some major damage. Boy did he go RED !!

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Brendan aka ruffmut

Faul Precision Eng.

"Remember pressure is for tyres."

[Guy]

Hey, you people don't have any more nice story???...I'm not so sure about that.

once ,on Okuma milling center, instead of writing -0.005" , I wrote -0005" . So my 6"facemill crash down in rapid into the tailstock for my fourth axe.

OOOO!!! 3000$...

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Guillaume Côté

Hexco inc, Montreal Canada

Stainless steel specialist

[This message has been edited by Guy (edited 07-06-2001).]

[cadcam]

Ok along time ago back in my beginnins,

I was work on a horz with a tompstone,i was loading a " endmill the spindal touched it off and of course for got to enter the value.

Hit the nice little green button & in rapid mode it ran right across my part about half walf way thru the tool.

thank god that machine was a large 50taper Prat & whinty snap that tool right off and kept going like it was just cutting thru the part at 10inch min.

i thought for sure the boss was going come over & tell me to have a nice life.

No damge to the mahine.

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jay/ aka cadcam

Precision Programming

cnc programming &

Predator & mastercam reseller

email: [email protected]

web: www.ppcadcam.com

[garyg]

YOU GUYS SCARE ME......

[cadcam]

Now why do you say that?

(Want some candy little boy, ok lets not go there)

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jay/ aka cadcam

Precision Programming

cnc programming &

Predator & mastercam reseller

email: [email protected]

web: www.ppcadcam.com

[Bill]

Way back in the day when we were writing macro on a shibaura it was always fun to see if you could scare the tar out of whomever happened by after a set-up was complete. To see the look on the owners face when the tool in rapid would head screaming for the table and then up to loopty-doo at the edge of the part moving back into the air before cutting was, I must say, "priceless". I thought one time he was going to pass out.

As for crashes, I don't do that yea right!

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B. Henderson

OMEGA PlASTICS

[email protected]

opinc.com

[Guy]

thank you for all your stories folks...

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Guillaume Côté

Hexco inc, Montreal Canada

Stainless steel specialist

[kathy]

This story isn’t really a ‘crash’ story – just one that will go down in the books as “Not everyone should be a programmer.”

About 7 years ago we had a tool designer under contract who thought programming was a piece of cake. He sweet talked the powers to be into letting him a go at it.

He buried a 1.0 inch diameter 5 flute roughing ball end mill into a block of MIC-6 aluminum 30.0 x 50.0 x 6.0 thk sitting on a vertical Fadal at 10 IPM. The tool got down about an inch, inch n’ half, before it loaded up, grabbed the material and spun that block enough the break it lose from the clamps and stop the spindle.

Needless to say, he’s long gone!

Kathy

[cadcam]

Ok kathy now what have you done? come on cough it up you to bill...

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jay/ aka cadcam

Precision Programming

cnc programming &

Predator & mastercam reseller

email: [email protected]

web: www.ppcadcam.com

[This message has been edited by cadcam (edited 07-06-2001).]

[kathy]

Okay, Jay - this one was all on me!!

I had programmed a SubNaidr panel – the big daddy of all our panels. Lots and lots of holes (over 3,000) in a bonded panel with embedded ammonia filled heat pipes through out the panel. After three shifts on the machine, the machinist was making his last passes. When we profile out our panels, we only go through the facesheet and just into the core, typically only -.1Z. On the first side of the panel, there was an area along the front edge where the heat pipes exited the panel about .25. I routed along the top of the fitting just fine. But ----- getting back to the passes on the other side of the panel at the same area, I forgot to raise the cutter up! At -.1Z, the cutter started to mill through the aluminum plates on top of the fittings. Remember, the last cut on a piece of flight hardware that costs, well, I could buy several houses for that price. And I’m milling into it! I didn’t sleep or breath for three days until the customer dispositioned the PA to re-work the plates! (They weren’t that thrilled about scrapping the panel at the point either).

This was back in the Smartcam days. Now, in Mastercam, I solid model all my critical fittings so I know exactly where they are!

Kathy

see http://www.aascworld.com

[This message has been edited by kathyric (edited 07-06-2001).]

[Bill]

Ok Jay, I have welded a few tool holders to workpieces in my day.

I guess the worst was when I neglected to cover a lifter slot on my core surface data. I was lucky on some accounts because it was P-20 and the cutter didn't make it far out of the gate. The damn machine was more determined, though. I brought the machine to its knees not to mention our cnc operator. I blew every overload switch I think it had.

Well a couple of hours later when we FINALLY got the spindle to cough up the holder and added about 10 pounds of weld to the core and covered that damn hole on the data noone was the wiser.

I have similar stories but nothing even close to Kathy's. Sorry about your luck Kathy.

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B. Henderson

OMEGA PlASTICS

[email protected]

opinc.com

[kathy]

Bill!

Thanks for your concern!

But it has nothing to do with luck! I just have to check everything very well. Bear in mind though, I've programed about 30 plus of these panels without anything going wrong. Very labor intensive. We run 'wood proofs' of these panels on the machine, but we can't check the depths. I just have to do it right the first time around.

Kathy

[lou]

THIS IS A GOOD ONE!!!!!!

Ok, Mine was back when I worked in a die shop through CO/OP in high school as a Die Setter. I just set a die in a 2 ½ story press and we had customers in that day to see it run. As we were changing things throughout the day we moved the heal block back to far. I didn’t notice it and the boss was standing there and didn’t notice it. I hit the buttons to close the press. IT WAS LIKE A BOMB WENT OFF!!!!!!! Chunks of steel went flying everywhere. People ran for cover (including the customers) hiding behind anything we could. With all the pressure there were chunks of steel were popping off left and right. We had to wait until it stopped to get close enough to the press to take it apart to reverse the travel. In all that mess only one guy went to the hospital to get stitches in his arm. He was hit with one of the flying pieces of steel. Good thing the boss was there and he took full reasonability.

Have a good day.

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Lou Wilson

Cnc Programmer

OMEGA PLASTICS

[email protected]

[Guy]

that's lucky... or having a very good boss...

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Guillaume Côté

Hexco inc, Montreal Canada

Stainless steel specialist

[lou]

Not that good. Because he laid me off about a month later. I am glad he did because that is a dangerous trade.

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Lou Wilson

Cnc Programmer

OMEGA PLASTICS

[email protected]

[ferdelance]

I have one from a few months back. Had some kid running one of the horizontal machines doing a small vise job on a tombstone. He made an error with tool numbers and used a 2-1/2" insert drill that was about 17" long instead of a 1" brazed carbide drill about 10" long. It made alittle noise and left a scratch to remember. He kept saying that nothing was wrong with the machine, but when maintenance took a look, the z-axis bearings were in pieces. They literally fell apart. The machine was down for better than a week and he doesn't run CNC's anymore!