How easy to damage a spindle?

Ok, I would like to preface this by saying: I do everything I possibly can to NOT crash my machine. My Haas VF4-SS is the single most expensive thing I own except for my house. Tools are not cheap and I'm not made of money. It's not like the boss will write a check to make mistakes go away, cause I'm the one who has to write the check.

That being said...

Ooops. I was running a proven program today, but it stopped in the middle and told me there was a tool compensation error. Should have checked earlier or caught it in a simulation run, but no big deal. So I hit hand jog, hit Z and then proceeded to spin the dial in the positive direction. Nothing happened. Ooops, need to hit reset. No big deal. Hit reset, error goes away. Proceed to spin the dial in the positive direction, and my end mill moves into the positive Y direction instantly snapping the 1/2 EM with about 2.25in stick out. Not a mistake I will likely make again. Should have just hit Z G28 or hit Z one more time.

I have broken bits before, but this is the biggest. After already stating that the obvious solution is don't crash your machine, my next question is how big of a crash does it take to mess up things? I have heard horror stories of spindles needing replaced. Is this something to worry about? What type of crash does it take for you to worry that damage may have occurred?

Regards,
Alex

Spindles are like cats, they have 9 lives. Hard to say just when they run out of them or what crash costs how many lives. I have had some live through bad crashes and had minor crashes cause a change in the sound they make. What you describe shouldn't hurt the spindle, your collet on the other hand may not be so good.

In a CAT40 spindle, the general rule of thumb is that a 1/2" end mill will be the weakest point in an XY crash and you likely did no spindle damage. Haas tends to build these things extra beefy.

Most of the horror stories you hear on here are standard BT30 machine spindles. The rule-of-thumb limit with them is a 3/8" end mill is the max for an XY crash before bad things happen. This is a combination of the shorter taper, a smaller pull stud, and the fact that these machines move at scary speeds where bad things happen instantly. Big+ helps a lot by strengthening the taper connection.

Crashes straight in Z tend to be 2x less severe than XY crashes.

You just sheared off an end mill moving laterally,we've all done it lol.
It would take a MASSIVE crash in X or Y to damage the spindle.
Now if you did this in Z..... it could easily damage the spindle,but usually only when you rapid something in Z.

yeah you're probably okay. most of us have done such a thing.

I used to go to a surplus store that sold lots of aircraft tooling. They had 55 gallon drums full of 50 and 60 taper holders with 2" endmills broken off flush with the holder. That would probably be a little harder on a spindle than a 1/2" endmill, but 50 or 60 taper machines do have bigger spindles so who knows?

If it was a brother I'd say yer hosed..but it's not, it's a 40 raped machine. It probably didn't even come close of affection it.

plastikdreams said:

If it was a brother I'd say yer hosed..but it's not, it's a 40 raped machine. It probably didn't even come close of affection it.

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Raped? Affection?

Valentines Day?

This was a .062 dia cutting tool with a .250 shank and a MST slimline holder. The spindle WAS a Fidia 24k HSK taper. This was not a crash so to speak, but a missing capped hole on a program that the tool walked down. 19000 rpm's, 200" FEED in the Z axis. Spindle parts went flying. This was over 20 years ago and the holder is on my desk as a little reminder of how easy it is to destroy things.

Hard to say. No real rule but the 1/2" diameter for a 40 taper sounds about right. How fast your spindle is spinning, what diameter and material tool, gage length of holder, etc will all affect how bad a crash is.

Customer wanted to use a 3" shell mill in a BT30 machine. I helped him select the proper holder and shell mill. Once finsihed I reminded him to be careful becaue one misstep with a 3" shell mill in a BT30 machine could be trouble. He said no don't worry. I am just facing 20 thou off the top of a part. Clean up the saw cut.

I asked what steps are you taking to guarantee it is just .020" and not .2 Inches. Are you probing? Are you having the sawcut length double checked before going into the machine. What if the bar remanent is just .1" longer and thrown into the same bin. Being a cnc programmer and being a production engineer that knows how to program are 2 vastly different things.

crane550,
Sounds like you are fresh to this stuff. Good luck with everything and no question is too stupid to ask. If I remember correctly I think in your control you can lock out all rapids to 50%. I would do that if I were you. Cycle times will just be a few seconds longer but crashes will have 4 times less engery ( or something like that).

Booze Daily said:

Raped? Affection?

Valentines Day?

Click to expand...

Autocorrected like a mofo...lol

A wise man once told me, “The axis that moves is the one that’s selected, not the one you’re looking at.” Hahaha, I use that one weekly. Last week had an operator load a part wrong (not down all the way in the vice) and crash a brand new 2” face mill in a puny 30-taper machine....and you think YOU’VE got problems haha! Try not to get too worked up....it will happen again and over time you’ll get good at recovering from it. Good luck!

FWIW.
I broke a few 1/2 carbide end mills on my 1500 lb. hobby milli in XY moves. No spindle trouble.

I did extrude some aluminum on my brother with a 3/8" chamfer mill in Z.
Tool holder was toast, but no other issues.

I ran a tool at full tilt boogie into the spinning sub spindle of my Mazak lathe. Tool stick ruined. Double sided VDI tool holder ruined. Jaws jacked up. Turret way out of alignment. Noticeable wobble in sub spindle that I could not dial out.
Mazak aligned the turret under warranty, think it was because tech was new and he ruined my co ax indicator. I re bored the jaws and replaced ruined parts. Chuck had the slight wobble but all jaw sets re bored, made good parts. That was 20 years ago and 5 years ago my operator got distracted after a change over and I heard the nasty sound because my office is above that machine. Ran the stick in a feed so it was maybe a few revolutions before he Estopped it, or over load alarmed out..
WTF! No more wobble in sub spindle, just damaged jaws, ruined tool stick. Kissed all jaws with a boring bar and still running true.

Just be careful when you run the machine, be happy you got away with this one, and be sure not to let complacency kick in. Worrying about "what if I blow a spindle" is like worrying about getting hit by a drunk driver on your way home. You can be vigilant and careful, but you can't ever eliminate the possibility unless you do everything at 1/100th speed. I've had 4 (roughly) crashes in 18+ years of machining. Once from paying too much attention to a boring bar going into soft jaws and not paying attention to the next tool block on the turret, until it collided with the top of one of the jaws and tore the holder off the turret - knocking the turret out and ripping the threads and a chunk of iron off the turret. That was the worst one.

Had a program I didn't prove out adequately bump the top of the 4th axis housing with the edge of the spindle casting. Machine alarmed out and paint gone from 4th axis housing... I got lucky, I checked my WCS was correct for 1st op but forgot 2nd op used a different WCS and had no M0/M1 in the program.

Had a tap I forgot I hadn't touched off yet and it used the previous tool offset and slammed the tap into the workpiece.

And had a 3/4EM that I pile drove into the side of a 1" aluminum blank at rapid speed (luckily set at 50% but on a small/fast 30 taper horizontal). Buried the tool 3" deep in the blank before alarming out. That happened because I was under pressure to get a part done and went to each tool change to update my WCS number but forgot I did a B-axis move mid-tool that wasn't right after the tool change. I normally would never have run a program without slowing rapids and confirming every move is good, but I had someone hanging over my shoulder asking every 30 minutes "is it done yet? why is it taking so long?" and I put nerves ahead of good judgement and paid for it. Luckily no damage other than to my ego.

I've never killed a spindle or damaged a machine such that it needed repair, other than the lathe crash which I fixed with a drill and helicoil (ghetto I know, but an old machine). I've also heard of people wrecking spindles because they went .020 too deep on a facemill on their 30 taper. So, yeah, you can't really know what little thing you won't get away with amongst the big things you do get away with.

So be careful, stay vigilant and don't worry to the point you don't make parts. Worst case, if a spindle replacement would sink you... you can buy insurance that would cover crashes.

slammed a 3" face mill running at 6500 1." deep into a 3x6 x 2.5 in block of alum on the x axis while running to another vice for the second part put in wrong fixture off set. that was like 6 years ago no problems. Other than reconfigureing my rotation for tool changes
had a alum part come loose on a 3/8" carbide endmill busted endmill that started getting a bit of a whine in the spindle. that was 2 years ago, spindle gets pretty warm so I have a small stream of coolant hitting the spindle case even when I run it with out coolant now it doesnt get warm. been running that way for 2 years had only one issue with z repeatability issues last year then it went away. we run production mostly at 10-12k rpm spindles still kicking and making good parts. repeatability is with in tenths on the z axis except for that 3 day period on that one part. Ran that same part number 4 times since then and have no issues.

I thought forsure I would have replaced the spindle by now, going to run it to it blows. spindles are pretty damn tough but I am sure its how you hit the.

If the sound of your spindle doesn’t change after a crash, it should be OK.

Sometimes you will get a louder spindle after a crash, but this doesn’t mean it won’t make good parts the same as it did before the crash.

And worst case scenario, most vmc’s have modular spindles that bolt in/out relatively easy.

I’m not sure what Haas charges for a new or rebuilt spindle, but it should be relatively affordable compared to Japanese/Korean spindles.

I know you can buy a brand-new spindle for a Fadal vmc for around $3500...probably the most affordable spindle to replace today!

ToolCat

cnctoolcat said:

If the sound of your spindle doesn’t change after a crash, it should be OK.

Sometimes you will get a louder spindle after a crash, but this doesn’t mean it won’t make good parts the same as it did before the crash.

And worst case scenario, most vmc’s have modular spindles that bolt in/out relatively easy.

I’m not sure what Haas charges for a new or rebuilt spindle, but it should be relatively affordable compared to Japanese/Korean spindles.

I know you can buy a brand-new spindle for a Fadal vmc for around $3500...probably the most affordable spindle to replace today!

ToolCat

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On a tangential note here, people often worry/complain about the fragility of 30-taper spindles (I've mostly seen this in reference to the Brother Speedio), but I believe a whole new spindle cartridge is around $6k and can be installed in a couple hours.

Contrast that with the 20k big+ spindle on the Kitamura HX500 I setup/program for a customer, which costs something like $40k to replace. That's one of the advantages of a cookie cutter machine like a Haas... the more expensive and more specialized stuff carries specialized tools, knowledge and calibration procedures to fix them as well as specialized pricing on the parts.

Something we all ought to consider (but usually don't) when choosing which machinery to buy.

Oh hell, I just rebuilt my Kitamura 15k BT30 for $4400 including chroming the taper to build it up after too many regrinds. I had Setco do it and have nothing to complain about. 1 year warranty and no restrictions on who installs it so you can do it yourself. If you need it rebuilt DON'T just get it from the MTB as many don't do the work themselves, they send it out.

A local rebuilder told me Fadal and Haas spindles are their bread and butter as they get so many of them, they just don't last as long as higher quality machines.

cnctoolcat said:

I’m not sure what Haas charges for a new or rebuilt spindle, but it should be relatively affordable compared to Japanese/Korean spindles.



ToolCat

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Hass vf2ss 12k rpms run about 7500 bucks plus exchange as of nov on there(hass) website. I couldnt find them today, dont seem to be on there website anymore.
fadalcnc might have them by now, when I talked to him in nov. he was working on them and hoping to have them avail by jan/feb