worst crash ever

Hey guys, Worst crash ever for me in my 9 years of owning my own cnc shop was on my beloved Mazak SQT15. Machine was running parts from barstock...I
went to change the retract dimension of the cut-off tool before stocking out for the next part. Well, with Mazatrol, all program dimensions are "+ Z, but, when using TPC to control approach and escape points, you must remember to use "- Z" to get the tool off the right, or clearance side, of the part. Shithead me wanted to shorten the distance the cut-off tool moved off the right side of the part from 6" to 5". I mistakingly input "+5" in TPC instead of "-5". Machine drove cut-off tool into chuck at 1,181 inches per minute (full rapid). Not only do the chuck jaws break off the 8 inch Kitagawa chuck, but the master jaws inside the chuck body are broken and ripped from the chuck as well. Kitagawa chuck body looks like a small nuke was set off inside of it. The VDI-style Mazak cut-off tool holder broke cleanly in half at the shank. Machine turret was knocked 1/8" off center. Turret was knocked out of square on its linear guideways. Spindle was knocked out of line. Spindle bearings were brinelled, forever giving the machine an obnoxious whine with the spindle turning. Figuring $3K for Kitagawa chuck, $10K for rebuilt integral spindle from Mazak, $500 for cut-off toolholder, and about $3K in repair/rebuild labor, plus a weeks lost production, it was a pretty lousy stinkin' mistake!!!
Greg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@naxs.com wrote in

The only bad thing about a Mazak SQT (have a bunch of them)..you aren't fast enough, even if you KNOW you've f*cked up immediately upon 'cycle start' to get it stopped in time to avoid a crash. That big red button is an 'it's too late' button..
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Your 'it's too late comment' made me think of something I've wanted for a long time. A remote e-stop. Wear it like a watch, or clip it to your belt. I mean hell, If I can open the trunk of my car from 100 yards, why can't I kill my machine tool the second it starts whining/grinding? Instead I have to RUN! to hit the brakes.
--
bytecolor


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
bytecolor wrote:

rectally operated would probably work fairly well!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

ROTFLMAO!
--
Remove "nospam" to get to me.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ever noticed how it seems, time wise, like you're running in knee-deep molasses when that happens? <g> --
-JN-
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Anthony wrote:

Doesn't Mazak have programmable soft boundaries to help prevent crashes?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Like anything else...it only works if that wasn't the mistake you made.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@naxs.com wrote:

Bet you NEVER made that mistake again! I keep a collection, right at eye level, of all the destroyed parts & tools I have created. The big goofs, I don't make twice.
ca
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Well, I as working on a vmc and decided to send the Z axis to home while trouble shooting So I merrily go to mdi and and do a G0X0.
I used to program a ASI gantry waterjet and that was what would take the Z to home. Inside the VMC was a 12" cylindrical square and my indicator. Somehow, I missed the square, knocked the handle off of a fixture and trashed my indicator stand. Damn I felt lucky on that one. I could fix that stuff before the end of shift. I hate to think what would have happened if I had hit that square with the spindle nose.
G53 was a command I learned about that day.
I'm supposed to fix em, not break em.
Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
jimz wrote:

I'm really pushing my luck even saying this, but I have never directly caused a serious crash of any type. However, I was on site during three spectacular crashes over a span of 2 years at my previous employer.
#1- A Niigata HN80 HMC (huge, 60,000lb machine with 60 inches of X travel), was running a large part, about 55x48 inches. The program was in the rough facing stage, starting at the right side of the part and cutting all the way to the left side. Unfortunately, the left side X axis way cover fell off during the cut. When the machine decided to rapid at 787ipm all the way back to start the next pass, the X axis cover that had fallen off bound up and blew the whole left side of the machine out, knocking down the inspection table positioned directly outside of the machine. It sounded like two Honda Civics hitting head on at 45mph.
#2- An operator running production parts on a Niigata SPN63 high speed horizontal decided to make some program changes without asking me for help. He actually did a good job restarting the program where it left off, and he walked through the first tool approach nice and slow. Unfortunately, at the next tool change, instead of a 4 inch long chamfer tool, the ATC brought in a 12 inch long, $3,000 Tecnara boring head. It rapid traversed at 1,575ipm directly into the 90 degree face of the part. This machine is so rugged, it wasn't even phased. It sheared the six 1/2-13 bolts right off of the tombstone, sheared one of the 1/2-13 studs holding the Kurt vise, and bent the other stud. Meanwhile, the machine is in circular interpolation with half of the boring head down in the conveyer. I don't know what was worse that time, the sound of the crash, or the sound of the owner yelling.
#3- A nearby shop was running their brand new, two machine, Mori Seiki SH5000 FMS, Somehow one of the setup guys rammed a 4 inch face mill into the tombstone at full rapid, either 1968ipm or 1654ipm. He basically destroyed the whole machine. Tens of thousands of dollars in damage to the B axis just to get the machine running again, and a permanent spindle runout of .001.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Had an H-400 Mazak that decided of it's own accord to plunge into the tombstone. Never did figure out what happened to cause it. Tool was spinning at 10,000 rpm. Broke the clamp deal and knocked the tombstone off, along with ruining the spindle. Fortunately, no parts escaped the machine.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Anthony wrote:

That reminds me of a situation that happened to a fellow Mazak user about 45 minutes from me. One of his FH4800s was shredding along at 12,000rpm in aluminum when the pull stud decided to break in half. If I remember the numbers correctly, it was about $21,000 for the spindle, and $4,000 for the labor to repair it. This is why nobody should ever own a high dollar machine without insurance for operator error or other such problems. His insurance covered almost the whole bill.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yup..spindles are not cheap....no matter the brand.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wow
This stuff is mind blowing to me
Out right night marish....................
Its pretty hard to crash a CNC with your eyes open.
Wow
Joe788 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
MSI wrote:

<<Snip>>
Really? What's the max programmable feedrate on the machines you run? What's the rapid rate? Get one going 900 IPM or more, and you won't have time to close your eyes before the turret indexes the part right out of the chuck and destroys the safety glass you've got your nose pressed against. Damn, but that guy was glad it was a good window.
Later,
Charlie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Right Charlie, my Yang gang tool that you saw has 1,181 IPM rapid. I never have crashed it since I bought it new in 1997. But you would NOT be fast enough to stop it. I'm very careful setting it up at rapid on 25% .
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Exactly the same situation on a Mazak Squirt. 1181 IPM rapid. You don't have time to even think before bad things can happen. Add in robotics..and it can get ugly in a hurry.
--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Best thing about a CNC, it does exactly what you tell it to. Worst thing about a CNC, it does exactly what you tell it to.
Tom
MSI wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ha-Ha. Maybe some day controls will look at the code & flash a warning on the screen. "your going to CRASH dumb ass".
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.