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How easy is it to kill a Haas VMC spindle?

prime_mover

Aluminum
Joined
Jul 3, 2017
Recently the spindle in my 2013 Mini-Mill went out. I got 8 years of use out of it, maybe a few thousand hours of spindle run time. I don't know exactly how many hours because the mobo battery died and the hours reset. It still shows total hours in parameters but not spindle hours, I think. The first sign of trouble was when the sound signature suddenly changed from normal to something more akin to a table saw being fed some plywood. It would bounce back and forth between normal sounding and the table saw sound before eventually always sounding like the saw. Over a couple of months it sounded worse and worse until eventually sounding like a plastic bucket filled with rocks, and finally one day the surface finishes on my parts degraded, and so I decided it was time for the rebuild. I had the spindle rebuilt by a reputable spindle rebuilding company for $5k. It's been up and running again for two weeks now, maybe 30-40 hours spindle runtime, and has started making the table saw sound again.

I am hogging aluminum with a stubby 3/4" 3 flute end mill, but it's only pocketing and profiling at less than 1x axial depth, and usually 10-20% radial, and .004 to .007" IPT, depending on how much radial engagement there is. Always 6k RPM. The end mill is being held in a Schunk hydraulic holder with 2.5" gage length. The spindle load is always well below 100%, usually 40-60%. As the cutter wears the sound of the cut gets louder and there is a fair bit of vibration going through the machine, then I swap the cutter for a fresh one. The other roughing I have done is slotting aluminum with a 3/8" end mill. ~.270" depth of cut, .005" ipt, 6k rpm, sk16 holder with 2" gage length. It's a moderately loud cut and the spindle load is at about 60-70%.

I would not think that those cuts in aluminum would cause spindle bearing damage, especially after 30 something hours of run time. The rebuild has a 1 year warranty, so presumably I am covered if it is on its way out again. I've still got 1500 parts left to make to complete the current job, so hopefully it makes it at least that far....
 
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Who rebuilt your spindle? I had one done a couple months ago. I was not happy with what I got back.
 
You could validate that your oil air is working. I guess you are careful about keeping coolant away from the nose when the air clicks off? This of course assumes it is not the greased spindle.
 
As the cutter wears the sound of the cut gets louder and there is a fair bit of vibration going through the machine, then I swap the cutter for a fresh one.
Where's the wear coming from? I get many months out of an endmill in aluminum, 99% of the time they go bad when hit a vise/clamp/etc
 
Thanks for the replies.

@triumph406 The cutter wear is from making a couple hundred LB of chips. The mill can vibrate pretty heavy when the 3/4" cutter wears despite being in a hydraulic holder. Sounds like a horn and stuff falls off of the chintzy little shelf. I've got downtime at the moment because I'm waiting on new 3/4" cutters to arrive. oops.

The Haas price is $6k with a core exchange, $7k without exchange. I saved a few thousand by going with the rebuilder and I figured I might get better results in the end. I also thought, because of the "exchange" thing, that replacement Haas spindles were rebuilds. I am probably wrong.

The mini spindle has greased bearings, so no oil air.

The toothed drive belt is new. I had a local machine tool servicing company perform the install. The belt was tensioned by feel.

I received no test data or anything from the rebuilder. The spindle I sent had totally shot bearings, so not much to test there. They said it was all packed with rust too so they sandblasted the inside of the housing.
The spindle taper was not reground. The rebuilder said it tested at .0001" runout at 10" so it was already perfect.
The belleville washers were replaced. I think the drawbar bearings too but I'm not sure.
They performed an in-house run in of four hours.

I called the spindle shop and they said if I have any issues at all they'll rebuild it again no problem. Not sure if I'll get reimbursed for the shipping or reinstall labor. That'll end up costing me another grand in total. Oh well.
I'll keep running it and see if the sound gets worse.

On the plus side, the total downtime during this rebuild process was minimal. The local machine service company came out within a couple days for both the pull and re-install. The rebuilder gave my spindle back inside of a week.
 
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I have confidence in the spindle rebuilder.

I am just wondering if any of you guys push your Haas mills real hard and have killed spindles quicker than expected as a result.
 
I have noticed 1/2” endmills sound alot smoother on 40 taper machines. Are you able to do what you need with one of those?
 
Thanks for the replies.

@triumph406 The cutter wear is from making a couple hundred LB of chips. The mill can vibrate pretty heavy when the 3/4" cutter wears despite being in a hydraulic holder. Sounds like a horn and stuff falls off of the chintzy little shelf. I've got downtime at the moment because I'm waiting on new 3/4" cutters to arrive. oops.
I'd expect to fill 6-12 55gallon drums with chips using a 1/2 YG-1 Alu-power, and still get as new finishes.
 
I have noticed 1/2” endmills sound alot smoother on 40 taper machines. Are you able to do what you need with one of those?
Yea, and especially in the Mini-Mill.

There are a couple reasons I have been using a 3/4" endmill. The parts feature a series of circular pockets which are not much larger than 1.5" so most of the pocketing is done with the spiral entry alone, then it just cleans up the sides in one pass. There is a cosmetic finish pass in the bottom of the pockets that require a nice and sharp 3/4" endmill so what I have been doing is swapping the 3/4" 'floor finisher' into the 'rougher' position each time I replace the rougher. This keeps the floor finisher rather new.

I've revised my machining strategy. There is a 3/8" endmill in the program already and those are cheap and I have a lot of them on hand. I've removed the 3/4" 'rougher' which opened up a pot in the tool carousel, which saves me from performing a manual tool change during the cycle. The op requires 11 tools and I've got 10 pots.

I can push the 3/8" pretty hard so the change only added a minute to a 45 minute cycle time. Most of the program is finishing work.

I'd expect to fill 6-12 55gallon drums with chips using a 1/2 YG-1 Alu-power, and still get as new finishes.

I'd wager that your cutter is pretty dull. It can be hard to see the wear, especially if you aren't looking at it through a 10x loupe. ZRN coating makes the wear easier to see, although the coating itself doesn't seem to offer any benefit in my experience. I'd rather have TiB2. The wear can be seen on the end of the cutter but is hard to see on the flutes unless the edges are chipped.

I tend to use 'Helical' brand variable helix 40 degree cutters. Ordered some YG1 Alu-Power cutters the other day but haven't tried them yet. I'd like to try some MA Ford cutters next.
 

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I'd wager that your cutter is pretty dull. It can be hard to see the wear, especially if you aren't looking at it through a 10x loupe. ZRN coating makes the wear easier to see,
i run uncoated YG-1 Alu-powers and they aren't remotely dull after filling 6-12 55g drums. I've had endmills last a year or more, used every day, it's the stupid crashes that wipe them out

And my experience isn't unique, maybe yours is?
 
I'd wager that your cutter is pretty dull. It can be hard to see the wear, especially if you aren't looking at it through a 10x loupe. ZRN coating makes the wear easier to see, although the coating itself doesn't seem to offer any benefit in my experience.

I tend to use 'Helical' brand variable helix 40 degree cutters. Ordered some YG1 Alu-Power cutters the other day but haven't tried them yet. I'd like to try some MA Ford cutters next.

There's one job I do where in total I remove 180cuin of 6061 with a 3mm endmill before it gets changed out. At that point it starts to feel dull. But that's about the only time I change a YG-1 due to wear
 
i run uncoated YG-1 Alu-powers and they aren't remotely dull after filling 6-12 55g drums. I've had endmills last a year or more, used every day, it's the stupid crashes that wipe them out

And my experience isn't unique, maybe yours is?
If you were saying this about brass I'd agree with you, but 6061 aluminum wears cutters. I've worn out dozens upon dozens, maybe hundreds, in my 12 years working as a machinist. Coated and uncoated, cheap ones and high performance, and from many brands. The character of the wear differs. For small cutters, they eventually just break. They break because they get dull. For other cutters, they produce a burr. Replace it with a fresh one and the burr goes away. As cutters wear, deflection occurs and features grow in size and walls take on some taper. This is measurable and hard to ignore over a run. The sound of the cut gets louder. The finish becomes less shiny or takes on a less than uniform character. Many cutters get chipped over time and will leave hairline scratch looking lines on your profiles. This even happens with cutters that only finish freshly exposed aluminum and haven't had to cut the exterior skin of the extrusion. Sometimes a hairline scratch will appear when the cutter has seen very little cut time.

I do use full synthetic coolant in my shop, as have some of the shops I've worked at. It is less lubricative than semi-synthetics but the sump life is infinite and it doesn't go rancid so it's worth it.

That's my experience. I've used plenty of YG-1 cutters in steel but not aluminum. But they are carbide cutters like any other.
 
The YG-1 cutters arrived. They are very shiny, but some negative qualities are apparent. The usable shank is about 37.5mm long which is the shortest shank I've ever seen on a 3/4" end mill. The minimum clamping depth of a 3/4" Schunk Tendo E Compact hydraulic holder is 41mm, so it's about .135" short of that. Maritool's new hydraulic says 1.5" minimum clamping depth, and the YG-1 shank is about .025" short of that, but it would be fine to insert the flutes .025" into the holder to make up the difference. But I don't own a 3/4" Maritool hydraulic. I'll have to use these in a side-lock holder.

The other negative is that the ends and corners are dead sharp with high positive rake. Geometry resembling a hook. I've always found that this hook corner geometry takes damage pretty quickly when run aggressively. The corners break off. Many manufacturers grind the gash so that it creates a small flat on the ends and corners for this reason, and it does eliminate the corner breakage issue. I've never ordered one of these hook geometry end mills a second time because they do not last.

I just tested the 3/4" YG1 45 degree ALU-POWER to cut the "cosmetic pocket floor" feature of the parts I'm currently making. While the machining marks look good and are uniform, that high rake hook geometry creates a less smooth floor finish than the Helical cutters I normally use. With the YG1 I can feel the grooves with my fingernail, feels grippy like sandpaper. With the Helical it feels smooth. The 40 degree helicals have a wiper flat. The 35 degree Helicals don't have a wiper flat but still create smooth floor finishes.

Anybody want to buy some really shiny end mills from me at a discount?
 

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If you were saying this about brass I'd agree with you, but 6061 aluminum wears cutters. I've worn out dozens upon dozens, maybe hundreds, in my 12 years working as a machinist. Coated and uncoated, cheap ones and high performance, and from many brands. The character of the wear differs. For small cutters, they eventually just break. They break because they get dull. For other cutters, they produce a burr. Replace it with a fresh one and the burr goes away. As cutters wear, deflection occurs and features grow in size and walls take on some taper. This is measurable and hard to ignore over a run. The sound of the cut gets louder. The finish becomes less shiny or takes on a less than uniform character. Many cutters get chipped over time and will leave hairline scratch looking lines on your profiles. This even happens with cutters that only finish freshly exposed aluminum and haven't had to cut the exterior skin of the extrusion. Sometimes a hairline scratch will appear when the cutter has seen very little cut time.

I do use full synthetic coolant in my shop, as have some of the shops I've worked at. It is less lubricative than semi-synthetics but the sump life is infinite and it doesn't go rancid so it's worth it.

That's my experience. I've used plenty of YG-1 cutters in steel but not aluminum. But they are carbide cutters like any other.
I would comment on your opinions on coolant, but i wont. I was going to say ive had 585XT (semi-synthetic) in the sump for 6-7 years and its only now starting to smell a bit. But I‘ll refrain. Evidently your from a different planet
 
The YG-1 cutters arrived. They are very shiny, but some negative qualities are apparent. The usable shank is about 37.5mm long which is the shortest shank I've ever seen on a 3/4" end mill. The minimum clamping depth of a 3/4" Schunk Tendo E Compact hydraulic holder is 41mm, so it's about .135" short of that. Maritool's new hydraulic says 1.5" minimum clamping depth, and the YG-1 shank is about .025" short of that, but it would be fine to insert the flutes .025" into the holder to make up the difference. But I don't own a 3/4" Maritool hydraulic. I'll have to use these in a side-lock holder.

The other negative is that the ends and corners are dead sharp with high positive rake. Geometry resembling a hook. I've always found that this hook corner geometry takes damage pretty quickly when run aggressively. The corners break off. Many manufacturers grind the gash so that it creates a small flat on the ends and corners for this reason, and it does eliminate the corner breakage issue. I've never ordered one of these hook geometry end mills a second time because they do not last.

I just tested the 3/4" YG1 45 degree ALU-POWER to cut the "cosmetic pocket floor" feature of the parts I'm currently making. While the machining marks look good and are uniform, that high rake hook geometry creates a less smooth floor finish than the Helical cutters I normally use. With the YG1 I can feel the grooves with my fingernail, feels grippy like sandpaper. With the Helical it feels smooth. The 40 degree helicals have a wiper flat. The 35 degree Helicals don't have a wiper flat but still create smooth floor finishes.

Anybody want to buy some really shiny end mills from me at a discount?

Make sure you pass your findings along to YG-1. im sure theyd like to know theyve been making substandard endmills. Must admit im shocked, shows you how much i know
 
I would comment on your opinions on coolant, but i wont. I was going to say ive had 585XT (semi-synthetic) in the sump for 6-7 years and its only now starting to smell a bit. But I‘ll refrain. Evidently your from a different planet
If I had semi-synthetic in my sump I'd try to keep it as tolerable as possible, maybe with bubblers and filters and stuff. Maybe I would succeed. But on the planet I'm from, most but not all of the shops I've worked in that used semi-synthetic coolant had some pretty cheesy sumps. At the last shop I worked at I was pulling huge blob like growths out of the tank. These things had some serious mass to them. From a single Mazak VMC I filled up a 5 gallon bucket with cheesy blob creatures, fishing them out with an actual aquarium fish net, a big one, which the shop just happened to have on hand. As I was doing this it occurred to me that breathing the vapor from this fucking sump was quite possibly a health risk. As for the shops with clean semi-synthetic, it's a tolerable smell, one that permeates all of my clothes and my skin and I even smell like it a little after a shower. Non-scented full synthetic coolants barely have a smell at all. They also don't have any separation issues and are nice and clear. One downside to full synthetic coolant is worse performance when tapping aluminum, but buying DLC coated taps (Emuge GLT-8) completely resolves this.
Make sure you pass your findings along to YG-1. im sure theyd like to know theyve been making substandard endmills. Must admit im shocked, shows you how much i know
YG-1 already knows. Take a look at the geometry of their ALU-POWER HPC series.
 

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On the coolant front, I use Hangsterfer's 5080 (used to be called 787), and it has indefinite sump life. I had one batch for four years before I decided to clean the tank just to get the fines out. Mix it with clean water (DI or distilled). Never smells, never had a skin reaction, even splashed some in my eye a couple times, no reaction and it didn't even sting. I've used it on everything from aluminum to titanium with good results.
 
That Hangsterfer 5080 sounds pretty good. What does it smell like and how strong is the smell? Does it have water separation issues? I wonder if they'd give me a bucket to try.

I have to buy a new pail of coolant within the next couple of months. Been using Castrol Syntilo 9918 for years and it's great for its tolerability, practically no smell, not greasy feeling, it's almost clear, infinite sump life, no bacteria, no separation, but it's possibly not as good as some other coolants at preventing rust under vises, or tapping aluminum with non DLC coated taps. It's definitely not as lubricative as mineral oil based semi-synthetics. I've tried two other coolants in my machine over the years but both times I immediately switched back to the 9918. Having practically no smell is a major benefit of this coolant. By "practically no smell" I mean even after a cycle, with my head in the machine, it has practically no smell, and I am running it pretty rich. When I top up the tank with some fresh concentrate it has a stronger smell for a little while, maybe a few hours, then it goes away again. A negative in regards to its tolerability is that it irritates my sinuses a bit and makes my nose run. My machining processes don't tend to generate much fog though so it's not much of a problem. A mist condenser could solve that.

There are a lot of formulations of coolant that I have never been exposed to. Around here a lot of shops use mineral oil based semi synthetics from the likes of Blaser and Qualichem. They all look milky and smell pretty much the same, a kind of creamy chemical smell that I don't particularly like. When you walk into those shops it's what you smell. Yuck.
 

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pay me now or pay me later
I have a spindle on the way out, i'm debating how successful a R&R will be. might be worth it just for the learning experience, but talk about masochism...
 
I am sure Hang's will send you a test bucket, they sent me one years back. Can't remember what specific one it was. I think we switched to Qualichem to try and get more life since most of what we turn in the lathe is stainless. Trying out Sterling Cool in it currently just to see, that machine is basically our guinee pig for coolants.

After 4th of July weekend, I will probably walk in and be able to smell the shop again. The middle schoolers that came out to see what machining was all about said my shop smelt good. :) Funny watching a kid's eyes the first time they see a tool change.
 








 
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