No, nothing happened, I just want to know a little more.
What happens if I make a wrong instruction and, say, crash a spindle into a vise. What would happen in reality? It is somewhere in the range between "nothing special" and "explode in a giant fireball". So, in reality, what happens if I crash a running spindle into a vise or something of that sort. Would the mill be ruined permanently?
iIgnoramus11290 fired this volley in news:GKudnfXuHLfrgPLRnZ2dnUVZ snipped-for-privacy@giganews.com:
Ig, it depends entirely on how fast your servo over-current detection or following error aborts can handle the crash.
Hardly anything is "ruined permanently", so long as you're willing the spend the time and money to fix it.
LLoyd
It depends. You will (almost) always kill the bit. You'll scar the vise with the remains of the bit. At that point, either something breaks or the drive system notices that things are not moving and hopefully goes to a graceful error mode (ie, stop trying, shut down spindle if spindle shut down is under program control), rather than making things worse. Otherwise it becomes an "irresistible force .vs. immovable object" game until one of them gives up.
In general, watch like a hawk (with a manual kill switch for the machine
- if you don't have one, make one or more) on any new program or modification. With the router, I also like to "air cut" the whole program with the machine zero raised an inch or more off the table, looking for moves that don't belong. I don't always do this, but I've had some nasty reminders when I don't (ie, trying a particular routine thats supposed to do a circle cut which turns out to ignore z-axis scaling - I was working about 25%, so the bit dropped 4 times deeper than called for and took off smoking, while I grabbed for the kill switch.)
This is one area where having super-fast, super-powerful axis drives can become super-expensive when they crash in a superlative fashion and damage things thought to be sturdy. If your drive logic/control allows for it, setting some limits that are considerably lower than the drive is capable of may help with damage control. You can also put mechanical fuses (shear pins or slip clutches) into the drive train for a non-computer-dependent limit on possible damages.
Possible problems:
Break end mill Injury from flying fragments of broken end mill Big divot in side/top of vise Ruined part Injury from said part being flung from vise Knock head out of tram (maybe not an issue with yours?) Damage tool holder, spindle taper Damage spindle bearings Scrap one pair of underwear Stress from massive surge of adrenaline
Almost any combination of the above is possible depending on the situation. Highly unlikely to permanently damage the mill, but repairs could be somewhat expensive depending what needed replacing.
Most of my mill files are under 1k and I essentially wrote them by hand. I know exactly what is -supposed- to happen. If I have any doubts, I will spend the time doing a dry run to make sure.
Jon
"Crash" is a relative term. Depending on what your feed, spindle speed, tool and "crash" area is it could result in anything from a scuff on the side of the vice before a near instant axis fault shutdown, of it could result in your part being cut out of your vise. Remember that your vise is metal and your tools are intended to cut metal, so if the "crash" results in traveling into the vise at a modest feed rate and depth of cut, nothing bad may happen beyond messing up the vise. The big machines have been known to mill big chunks of vise away without slowing down or generating any faults.
I saw a very high speed machining center at a trade show. Forget the name, but it used a carousel sorta like a Brother or Fanuc RoboDrill. When the tool came out from under the chip shield, it was suddenly just THERE, 50 thou or so above the part. If there was a screwup in offsets or something of that nature, the crash would be over and done with before the brain could fully register what had just happened.
Here's one stellar example...
Jon
Indeed. Look in your software for a modal called "work shift"
Most ..not all ..many...software systems have a M or G code for work shift..which means you say G10 Z3...which shifts ALL Z moves 3" higher than your program tells it to. Use it at the beginning of the program and it remains modal..active throughout the entire program.
Its like setting a universal offset and applying it to the quill. This keeps you from sqewering bugs in your vise if you missed a decimal point.
Every time I write a program for an OmniTurn 2 & 3 axis lathe..I use it to keep the tools AWAY from the workpiece and run the program in single block, then dead slow automatic before actually trying to run a part.
Gunner
Oh..before I let Jon go...I dont suppose he or the other guys here have seen what an OmniTurn does when its fancied up a bit....
Gunner
What I meant was this: say, I lose the spindle so that the spindle is at the level of the vise (and not just the tool) and then I crash it into a vise. What would happen?
Gunner, I was watching this:
Gunner Asch on Fri, 20 Aug 2010 21:20:42 -0700 typed in rec.crafts.metalworking the following:
Single Block - "boring!"
But on some occasions, "bored is good".
"In my experience" the outcome from hitting the vise depends on what else happens. Going fast, and hitting it with an end mill = broken end mill. Going slow (as in single block, and feed rate override turned down to 1%) - the collet hit the aluminum jaws, and melted enough aluminum to wrap twice around the tool holder - before it torques out of the spindle. Which is when it alarmed out. Even at slow, that happens awful damn fast. Oh ... shit! I'm told that was a "mere" $40,000 repair bill. Very expensive education.
pyotr
actually..I have one of each..GT75 and retrofitted Hardinge.
Both are well used and rough, and need me to go through them completely.
Ill sell one for $6-9k, the other for $9-11k.
Shall I take your order?
Gunner
Ive never seen an Omni knocked out of alignment or busted that way. There simply isn that kind of mass there...chuckle and the servos are only 500 in/lb
I did see one cratered by forklift once though.....
that was a $34k bill.....
Gunner
Yeah, an Omniturn can thrash a tool in 1/3 of an eye blink... I've done that a couple times when writing code for back turning, and forgetting a minus sign on the X...
Jon
If your controls are set properly, a near instant axis fault and shutdown. The spindle is designed to handle the high side loads of cutting at the side forces the machine is capable of generating. You could expect some scuff marks on the side of the spindle and vise, and probably little more.
Iggy, its time for you to watch for a lathe to refit. I just tore down a Hardinge HNC for spare parts because I was sure it wouldn't bring $1K. You should have little trouble doing better than that. Hardinge iron can't be beat.
karl
Im wondering when I should repost the message from Iggy where he claimed he wouldnt be buying any more iron....and I laughed and told him he was addicted...and it would not be the end of it.....
Ill wait a couple weeks until he drags something in the door.....
Gunner, who finished up the Helios horizontal tonight and covered it up..next to the other two mills in his shop.....
I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)
Karl, maybe next year, I still have a lot to do. So tell me, those Hardinge HNCs, which I also saw selling for $1k, can be refitted with a new control easily? (easily, to me, means, not harder than my Bridgeport). Docs available? Do they have an indexable turret?
Gunner Asch on Fri, 20 Aug 2010 22:18:42 -0700 typed in rec.crafts.metalworking the following:
THis was a Cinncinati Arrow?sabre. I have come to realize that I am not a Machnist, but an operator. A good one, though, but I am not the sort to wnat to know allthe specs of the machine I'm running. ANd I don't have a :feel: for it. The "sounds right" ability, Feeds & speeds vs alloy, etc. Heck, I've only been at it three years, I know where to put my lunch bucket and how to find the coffee machine, but I still have to look up anything more technical. Which, in itself, is not a bad thing.
pyotr
Hardinge has great docs, and gunner has forgot more about them than you'll ever need to know.
FWIW, I'd start looking now. You get better deals with a long time frame. And machinery is on fire sale now.
Look at gunner's video. That's called gang tooling, no turret. For an omni refit of a hardinge they pull the turret off. Refitting a hardinge to gang tool would be a smaller job than your mill.
If you want to keep the turret, you'll have to learn how to handle more I/O and PLC type logic in EMC. Its a sure bet somebody has already done a hardinge. I like having the turret, all the tools I use are all set up and ready to go, up to 16 is not a problem. You can quickly swap entire turrets out You also can more easily make long parts with a turret.
P.S. Gunner's right, its time for you to eat crow on your words about never needing another machine. Don't feel bad, I'm addicted too. I REALLY want another lathe, got my heart set on a Leblond servo shift
Karl
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