Spindle Replacement on our KERN Micro

[@JamesChurchill3]

Sending all the parts that could possibly be needed is such a great idea. I can't tell you how many times I've had a computer tech come out only to have to come back a month later to install the part it actually needed, it must save them so much money in not having to dispatch a tech a second or third time. Also that spindle coming out looked like one of the squid things from The Matrix. Insane how much tech they pack into those things.

[@12345NoNamesLeft]

It looks like she fly's in from USA, maybe Switzerland, her time definitely costs more than parts shipping.

[@nh18343]

We called Haas and said we needed a spindle. The guy shows up and the spindle never was shipped. Then they shipped it and said it will be a few weeks before the guy has time on his schedule to come back and put it in. Almost certain it is more of the people we are region locked into dealing with and not the company as a whole.

[@Sly_MaC]

Man It's been three years?! I remember the Kern being delivered. Shortly there after was the pandemic and watching you in the shop alone running this machine is one of the few good memories I have from back then.

[@JOSEPH-vs2gc]

*scamdemic/plandemic. remember the truckers!

[@GrumpyMachinist]

Yeah it shows how little this man really knows about machining. He should have bought a Haas because he doesn't have the experience to run a machine like this.

[@garyeuscher4499]

You are grumpy. You learn by doing!

[@joshkarpoff3341]

As an engineer that does field service for the high end professional digital sound consoles used for top tier live events, I can't begin to describe the level of frustration I feel when I'm missing one little part to get the equipment back to top functioning. I have actually shipped 90% of a unit, just so that I'll be sure that when I leave, I know that it's all working as expected. Our clients in the live theater market, especially Broadway and touring Broadway shows, can't have any malfunctions that cause a stop of the show. Everything has to work perfectly, each and every performance. When it doesn't, not only do we have over a thousand very annoyed audience members, many who might demand a refund, but it also makes the news. So anything less than perfect functionality and full redundancy isn't acceptable. Seeing other service engineers working on similar expensive equipment that needs to be perfect is always awesome to see. Also glad to see a woman excelling in a male dominated job. Keep up the great work!

[@johanness6545]

DiGiCo?

[@joshkarpoff3341]

@@johanness6545 Yep. Plus Avid, Yamaha and occasionally Studer.

[@mikeobrien4081]

Nice to see another company going "full Grimsmo" in their approach to customer service. A big part of why I enjoy watching high-end machining and engineering content is seeing people put in the work to do things 100% correctly.

[@aj7utu]

On the spindle diagnostic, what is plotted vs. travel that shows the spikes?

[@DanielPerez-bn9bi]

Really cool to see… Kern is an impressive company! Top notch service.

[@max_eley]

Awesome work! Hopefully this spindle shall serve for many more years.

[@karlssonengineering]

How much preload(stretch) does that ballscrew have when mounted? I guess its laser compensated from factory for pitch error, what about that now.

[@Ihorecek195]

I have the same spindle from fisher on my roders mill, definietly getting my pants full when i crashed couple of times, and yes, using high rpms is not forbidden but it will definietly shorten its lifespan

[@coorexz]

We have like 30-ish GROB 350s at work where they change spindles every 3-6 months due to high RPMs in aerospace-grade superalloys. It for sure shortens the lifespan of those poor spindles.

[@frp1276]

​@@coorexzwow, wild.

[@kimber1958]

outstanding job Tina

[@Tubben-tools]

Nice to see they have a verry good service at Kern. What a lot of lines on the spindel. Thats crazy wow Mij 1986 spindel of the mikron has none😂 Cool you can see how the condition of balscrew is. I need also a Tina for my mikron🛠. My z axis not moving perfect . Thank you for your shop update 👌

[@SeanHodgins]

An interesting look into the spindle! Love that its such a tightly packed standalone unit. Spindle replacement didn't seem too complicated(from an outside viewer at least haha) which is good.

[@ryanleib5979]

Thanks for sharing these videos. This is exactly why I subscribe to your channel. Great watch and cheers.

[@bostedtap8399]

That Kern spindle is crazy engineered, 42 k rpm is impressive, love to know how many millions of revolutions it has done. Well done Kern, great video. Thanks for sharing.

[@chrisyboy666]

Trillions

[@ingentingbra]

33 billion revolutions if 50 % spindle time last 3 years.

[@harrisonaero]

Nice update John. Guessing $1USD/rpm to replace. Ouch. But worth it apparently vs running lower RPM for as long as you can. It's a boy? Woulda guessed a girl... for obvious reasons :)

[@user-_-best]

John's T-shirt at the beginning of the video is super!

[@jimsvideos7201]

Three years on the Kern already? Wild.

[@DUIofPhysics]

many $10k's for a *rebuilt* spindle? is that including the offset cost for reselling the old one back to them for rebuilding too?

[@chiseled_face]

Such a beautiful machine - great video as always!

[@SuperAgentman007]

Did you get a brand new spindle or a rebuild the deference would be the price and did you have to pay a core charge for the old spindle?

[@AlMg1SiCu]

They always do rebuilds. Rebuilds are done by Fischer to factory spec and are good as new. The core is always returned and keeping it isnt really an option

[@zeuss194]

could you talk about the speedio ?

[@christobel]

In a Kern service video ? 😅

[@larryblount3358]

Are you going to change where some parts are machined so the wear envelope is expanded?

[@solonanderson7019]

Did Tina have some awesome German work pants and if so what were they?

[@moinky2k]

Engelbert Strauss

[@lord.needham]

Wowzers! That was neat.

[@aserta]

The bottom rubber swole from the liquids. Probably should've had the rubber on the enclosure, not the door.

[@ReactionTime344]

X axis screw is much smaller than I thought it’d be

[@vilts]

Kern has hydrostatic ways, so it takes very little force to move the mass around. I guess that's all the screw they need, and it's probably oversized as well.

[@AlMg1SiCu]

@@vilts This one is not hydrostatic

[@vilts]

@@AlMg1SiCu I stand corrected! I thought all their machines were hydrostatic, but seems not to be the case.

[@AlMg1SiCu]

@@vilts Just the Micro HD and the Pyramid Nano! The other machines are proof that you can still build extremely high grade machine tools even without fancy hydrostatics or air bearings. Fun fact! The Pyramid Nano has a hydrostatic ballscrew. Look those up if you want to blow your own mind.

[@MaX271]

What really got me was the amount of electrical, pneumatic and hydraulic fittings into this spindle. Wow. But, why? Does it really requires to be so complicated? Ps: is it an air spindle?

[@sharkpuffin8286]

its an air bearing spindle

[@felixm.8910]

Well there are: -hydraulic drawbar, -oil to lubricate the bearings -air to pressurize the spindle inside, so that chips don't get to the bearings -coolant for the spindle-bearings -air for the tool (e.g. blowing out chips and coolant when changing tools) - external coolant for the tool -through-spindle coolant -Spindle Power-wires -Spindle Encoder-wires -Spindle Temperature-sensorwires -Drawbar Limitswitch-Wires So at least 12 connections for that stuff alone.

[@igsdannx]

Hybrid ceramic bearings, not air bearing.

[@maikeydii]

@@felixm.8910 and in some cases when there is both through spindle coolant and air/MQL, they are run to the spindle in separate lines. In addition to the sensors you mentioned, I'm quite sure that Kern has specified also a dilation sensor (measuring the axial shaft expansion) and a vibration sensor for that spindle. Also, all bearings have their own temperature sensors, and with a high possibility, the spindle shaft is also cooled with coolant.

[@ianagos4276]

Man how many hours on that spindle before replacement? 3 years seems short but if you are running 20hours a day every day it’s actually decent for a high speed spindle. My integrex needs a new spindle but it’s so bad it’s difficult to rotate. Also how many 10s of thousands? If I may ask just curious vs looking at mine

[@TGC32]

With the ticket price on that machine I wouldn't be surprised if that spindle replacement + labor was upwards of $60 - $70k CAD.

[@ianagos4276]

@@TGC32 I think he mentioned the price at some point and maybe I have the price in my head but it was lower than I expected. 60-70cad sounds about right for a new spindle My rebuild is gonna run about 30k isd

[@paulwood-stotesbury8057]

I think he said in his podcase it had done just under 10,000 hrs. He's doing about 140hrs/week.

[@adriankowalski5492]

I thought that KERN Micro have linear motors axes not ball screws.

[@daight12345]

why is it taboo to say the price of the spindle/replacement?

[@AlMg1SiCu]

Everyone's individual situation is a little different. It's going to change a bit from year to year, and depending on how much travel and labor is needed for the technician to get there and do the job. Also depends on if your core is rebuildable (usually is unless you really smashed it), current currency conversion rates, etc. You just don't want someone in the future to point to a specific number mentioned and whine about why they didn't get Price A when their Price B is based on completely different factors. The price is comparable to a decent new car, but which car specifically and which options on that car depend on the specifics.

[@RoboCNCnl]

Cool stuff buddy.. and about the air solenoid, you might like to read into ‘Root cause analysis’ kind of a cool topic where you basically pointed out to..

[@mofix007]

the X-ballscrew looks a lot smaller then I would have expected. Does anybody know the diameter and pitch? just curious

[@alex_yates]

"it's a boy!" 😂

[@HP_rep_mek]

That was interesting to watch👍

[@CrazedHistorian]

already replacing it?

[@bcbloc02]

I am surprised at the number of wires and hoses on that spindle. Also surprised the manufacturer doesn’t just make the bearing housing slightly larger diameter and the bore to match because having to file the fittings to fit just seems dumb.

[@professorsafari]

Does anybody know if there is an old video where john talks about why he chose the vario over the other models from kern?

[@AlMg1SiCu]

No, but TL;DR the Evo + PyNo are too small and not suitable for his work. The Micro Pro is missing the thermal management system and several other key features. And the HD did not exist at the time of his purchase.

[@professorsafari]

@@AlMg1SiCu oh ok, the pyno makes sense, didn’t know about the other ones and the features. Thanks 👍

[@RoboDriller]

How much did this cost?

[@timogross8191]

8:15 many 1/10 of 1/1000 of dollars... 🙂

[@Nickle314]

You might want to have a pattern that works the left side, then the right, then the left, ...

[@AlMg1SiCu]

X travel on the left side is extremely limited, so it's likely not possible for most parts he does

[@Nickle314]

@@AlMg1SiCu Interesting. I didn't realize it was asymetric.

[@TritonTv69420]

@@Nickle314 Most 5 axis machines have about 75% of the work envelope to one side. The one I work on DMG CMX50U is pretty offset. Any machine that has a rotating trunnion table like this one is like that. The center of travel in x is always skewed towards the side the table rotates more. It makes it really tricky when parts are close to the size of the work envelope. You have to perfectly center the part about the work envelope not the table. It gets weird fast. haha

[@Nickle314]

@@TritonTv69420 For some reason I had the impression they were symetric. On the maths front, there is something called Geometric Algebra. It makes the maths suprisingly easy.

[@rickfearn3663]

Is Kern lacking on basic design? Having to file down the corner of a hex bolt so that the spindle assembly will slide down the tube is surprising. Why not use a socket head cap screw? Or reposition the bolt?

[@genixia]

At least they understood enough basic design to put an electrical fitting where they needed an electrical connection, and not a socket head cap screw that would have been useless in that application. 🤣 There's a lot of different connections there in a tight space. It's likely that the connector used isn't the same as originally designed for, but a running change mid-production. There are several reasons why that might be, e.g. the manufacturer stopped making it or went out of business, or the current favorite: still Covid-backlogged. The engineering supply chain can be very fickle, and sometimes no available replacement is exactly identical. In the vast majority of applications an electrical connector like this would have much more space around it so the physical sizing of the hex just doesn't matter much and its electrical properties are much more important. In a perfect world the spindle designer would have left a circumferential buffer to allow for unforeseen connector changes, but guessing the future of the supply chain isn't exactly 'basic' design. Filing the connector is a bit of a bodge, but compared to the massive engineering costs of a spindle redesign (that would only add to its already sizeable cost), not a bad solution. There's a good shot of it @7:49

[@jeffhughes4277]

what kinda crashes we talking about?

[@M13asan]

Super rad

[@Dwarfgrinder]

My god theres a lot of wires and tubes going into that spindle. It has its own nervous system!

[@HudsonLighting]

Whats incredible to me is the parts you've had to replace after 3 years..which i totally get. It makes me heavily question two things though: 1) what condition spindles and bearings would be on a used machine and why it might not be a good idea to get used... depending on the tolerances you are chasing And 2) How much you need to allow for future maintenance which reqlly makes me think how under priced our products are as we dont have any money for such..hell we barely make wages 😢 Anyway, John you throughly deserve the 400k+ hope you get it! My goal is 30k end of year

[@robertlees2065]

Buying a used VMC with a 6000 - 10,000rpm spindle is going to be very different to something like a Kern, not sure I've ever seen a Kern for sale used in the UK so something we probably don't need to worry about. Used can be just fine as long as you accept there are higher risks for breakdowns, can make the parts you need to on a machine with some wear in it and then put some of the money that you saved over buying new to one side for those repairs. I have 3 similar capacity CNC lathes primarily for the reason that if one breaks down I'm not completely screwed, all bought used, combined costing less than the cheapest of the 3 new. Lathes seem to be a bit more robust overall though, they don't tend to be doing particually high RPMs compared to VMCs or loads of movement for cutting complex profiles, still, if you can budgeting some money for future repairs would be wise as nothing is going to last forever.

[@HudsonLighting]

@@robertlees2065 Thanks, that's some really great advice there

[@andrewclark8225]

For the money you paid for that machine I would expect it to not need a new spindle yet ! Yes if you have crashed it that’s your fault. Hundreds of thousands of dollars worth of machine and you have to remove a washer to get the door to shut properly ! And the x axis ball screw replaced, was that crash related ? Good service time but why was it necessary on a machine that expensive in the first place ? I’ve run old CNC machines (one lathe was a 1978 Hitachi Seiki 4NE 600 , the first cnc lathe in Australia and had a tape reader before retro-fit to Fagor) that machine had shear collars to protect it from crashes and was still making accurate parts till it was retired in 2006 !

[@TrolloTV]

Theres different levels of „accurate“. The precision requirements this Kern meets at the push of a button are either a big headache or straight up impossible on many other machines

[@michaeljuan98]

I assumed the kern was linear motors at that price.

[@igsdannx]

Micro HD is, Micro Vario is not.

[@aurcanis8492]

I thought the Kern uses direct drive linear motors instead of ballscrew :(

[@3.2213]

Yes they do for all axis accept the z axis cause of many reasons and yes they wear off.

[@agg42]

6:20 Determinism is everything in engineering and machining. People who have worked on LODTM will tell you everything is deterministic.

[@car9167]

So paid tens of thousands of dollars on a new spindle but couldn't keep the old one you owned and ask for just rebuilding/fixing it cost?

[@Turnipko]

You didn't wipe the contact surface of the spindle on the machine

[@BerndFelsche]

OMG 3 years already. Tempus fugit.

[@TritonTv69420]

Stop crashing your machine ;) damn 40k that is crazy. My machine at work does 15k. So did she say there needs to be a break in period for the spindle or are you good to go full speed right off the bat?

[@kisspeteristvan]

usually there's a break in period even for the ballscrews , specifics depend of specifics .

[@davidgardener1152]

"tina's an absolute beast" *tina pretends to not hear* 😬

[@alexbike01]

Ballscrew?? It's not linear motors?

[@mkemachineinc.8058]

Only the Micro HD has linear motors and hydrostatic guideways I believe.

[@stevenrichardson7882]

No safety harness while working on top of the machine😱

[@Double_Vision]

It's cool she was squinting.

[@Kveiteson]

You should get a proper simulation and CAM. #hyperMILL

[@Blue.4D2]

⭐🙂👍

[@benthurber5363]

Dude, if I'm working and some client is jamming a camera in my face, standing between me and my work, or otherwise being a nuisance, we're going to have a "come to Jesus" meeting. Props to the bald guy for not being a pest. You could learn something from him.

[@mattiasarvidsson8522]

I like her german accent

[@johnboforsyth5970]

hmmmmmm

[@hall6ppc1]

Should have bought a HAAS 😅

[@spikeypineapple552]

Man gets fleeced for 100k for a lukewarm bearing.

[@davidl.579]

It took you 3 years to fix the door, just saying.

[@dimsum5567]

tens of thousands for a spindle 😂 what an over engineered crap, and still needs a file to fit into the hole 😂

[@TrolloTV]

One of the better CNCs you can buy in this world. You kinda need the overengineering for that

[@Frogyyyyyyyyyyyyyyy]

What a rockie, too much machine for you