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Hermle C400U vs Grob G350A

TJHell

Plastic
Joined
Aug 2, 2020
Singled my machine choice down to 2 options. Price is negligibly different. Obviously two pretty different machines. This is my entry into 5AX. I am a small one-man shop taking the plunge without a whole lotta work lined up. I want to be pretty open to going down whatever road in the future. Running Hypermill. I have no strong opinion on the control. The Grob's ability to handle long tools isn't super important to me. Really concerned about long-term build quality. The Grob beats Hermle on paper in most aspects, but I need some more real-world opinions.

Hermle C400U - Heidenhain - 38 tools
18000k spindle - waiting on some more spindle info


Grob G350A - Siemens - 50 tools
Higher stated positional accuracy .006 vs .008
16000k air spindle

I am mostly concerned with who is going to last longer(cost of ownership down the road). I am out of WI, so Hermle definitely has a slight leg up in support.

Let me know what you guys are thinking. I don't hear a lot of shit-talking about either, it's hard to garner an opinion. Couldn't find any straight-up comparisons.

Probably going to pull the trigger in a week or two. Thanks a lot in advance.
 
Singled my machine choice down to 2 options. Price is negligibly different. Obviously two pretty different machines. This is my entry into 5AX. I am a small one-man shop taking the plunge without a whole lotta work lined up. I want to be pretty open to going down whatever road in the future. Running Hypermill. I have no strong opinion on the control. The Grob's ability to handle long tools isn't super important to me. Really concerned about long-term build quality. The Grob beats Hermle on paper in most aspects, but I need some more real-world opinions.

Hermle C400U - Heidenhain - 38 tools
18000k spindle - waiting on some more spindle info


Grob G350A - Siemens - 50 tools
Higher stated positional accuracy .006 vs .008
16000k air spindle

I am mostly concerned with who is going to last longer(cost of ownership down the road). I am out of WI, so Hermle definitely has a slight leg up in support.

Let me know what you guys are thinking. I don't hear a lot of shit-talking about either, it's hard to garner an opinion. Couldn't find any straight-up comparisons.

Probably going to pull the trigger in a week or two. Thanks a lot in advance.

To be honest that's not a lot to go on.

Dennis of @dstryr "fame " runs / bought a number of Grobs - seem to love them.

The stated volumetric blanket stated accuracies are worst case scenario ten years from now not very descriptive "Metrics".

Things like laser plots - straightness of travels , plots for circularity (like ball bar plots) in XZ, YZ and XY planes are more meaningful + actual measurements of build geometry.

+ positional accuracies for rotary table / axes. [Rotational plots versus "Brochure" values that show uni-directional and bi directional (rotational repeatabilties).

+ actual measured test parts and 5 axis cone test.



The layout of the Grob 350a really seems amazing (horizontal 5 axis).

I reckon the Hermle might give you more options for size of work pieces more like a "Universal". I.e. larger flat 3 axis type work pieces.

For Hermle The C400 is not their HIGH production model and hence might have one of the linear rails removed, and if memory serves me right spindle chiller is not an option nor are scales... The worm gear arrangement needs to be replaced at some point for A axis. - Other wise the build geometry and long term accuracy is supposed to be good.

the C400 "Entry" machine is slower 'cus it's "entry".

Hermle use mineral castings (epoxy granite) so good surface finishes/ vibration dampening.

Hermle use CRASH bushings in their spindle that are cheap to replace compared to a whole spindle cartridge replacement 50% chance of dodging a bad crash.

the GroB looks better for complex very three dimensional somewhat smaller mechanical parts / work pieces. Seems like it would be more production oriented / faster for the same $.

Grob 350 a layout 1.jpg

^^^ Spindle go Hurrrrr not Burrrrrr. {Click to "Blow up".

Some rando points -nothing comprehensive. - help get the ball rolling a bit.

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I think the Hermle C400 comes in around $400K so is that same for a Grob350a ?

@TJHell - what options do you get with the Grob350A [I've seen these second hand also , or similar from grob.]. The Hermle entry level models like the C250 and C400 and C600 are fairly paired down (option wise) compared to C12, C22, 32, 42, 52 , 62 .

So does that Grob 350a have...

Linear scales ?

Direct reading circular / rotational scales ?



Spindle chiller ?

Coolant chiller ?

DD rotary motors on rotary table or worm gear or zero backlash roller gear cam ?

Thru-spindle coolant option ?

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DMU 50 3rd gen might be worth a gander (given your envelopes of C400 and Grob 350a ), assuming you don't have a personal vendetta against DMG Mori.
 
If you're looking at those, as a one man shop please give me the lowdown on how you managed THAT feat!??!?!? Congrats on that point!

Anyhow, if you are looking at this class of machines, you should also be considering Mikron. In my not so humble opinion you might want to be looking out for lowly grease-pack spindles on the ones you listed. Most all Mikrons have the best available lubrication design with there Step-Tech's that can see tens of thousands of hours @100% rpm duty cycle, not 8000hr grease packs. All modern Mikrons have torque motor direct drive rotaries, whereas most (if not all) Hermles have gear drive. (Anyone more knowledgeable please correct me on Hermle specs). I'm not sure if your list OEMs are available with linear motors, but some Mikron lines are.
Milling machine | 5 axis | Mikron MILL P U Series - concept of modularity
I've seen some pretty scary-good accuracy out of this line of machines, from tiny mills to <2 meter stroke, that I've posted about here on PM in the past.
 
BTW, Hypermill post for Heidenhain are superb!!!!!!!! They post HH cycles where applicable, which is pretty sweet. And their machine simulation is really great.
Heidenhain really makes the 5 axis almost as easy as setting up a Haas 3 axis. Feed rate planning in HH for 5 axis is second to none. So post your code the machine will sing, no futzing with 'the right' combination of fanuc g codes to get things to work. Don't get me started on the great built-in probing routines....
 
Thanks, this is exactly the kind of input I am looking for.

I think the Hermle C400 comes in around $400K so is that same for a Grob350a?

Yes, staying under $400k. Grob is like $385k but waiting on a firm quote. DMU 50 is like $315k

DMU 50 3rd gen might be worth a gander (given your envelopes of C400 and Grob 350a ), assuming you don't have a personal vendetta against DMG Mori.

I was heavily pursuing the DMU 50 3rd Gen, but I got turned off by hearing about many little things breaking with DMG. It is substantially cheaper, has a 20k spindle, but only 30 tool pockets. Is the DMU 50 in the same league as a C400 or G350?

All machines I am looking at have TSC/TSA, spindle chiller, table drives are all a little different.

Drive
Hermle - worm
Grob - waiting on info
DMG - Direct

Scales
DMG - all axis
Hermle - No
Grob - Yes


Good to know about Hypermill/Heidenhain, definitely leaning that way

I'll post some better info when I get some better Grob documentation.


I am not really interested in Mikron due to support. It doesn't feel like they are as committed to the US as DMG or Grob. Hermle USA is close to me.
 
Hope you like the sound of gear whine.. You're gonna love the Hermle. The Grobs can have the same geometry issues as Mikrons S line with the cantalevered trunnion, but on a much larger scale due to obvious size difference.
You could get a Mikron machine demo in Illinois or Toronto, among others. But if your more comfortable buying from general motor than ferrari, nobody's gonna change your mind. GF has been around since 1802, btw. And has a large worldwide footprint.

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Thanks, this is exactly the kind of input I am looking for.



Yes, staying under $400k. Grob is like $385k but waiting on a firm quote. DMU 50 is like $315k



I was heavily pursuing the DMU 50 3rd Gen, but I got turned off by hearing about many little things breaking with DMG. It is substantially cheaper, has a 20k spindle, but only 30 tool pockets. Is the DMU 50 in the same league as a C400 or G350?

All machines I am looking at have TSC/TSA, spindle chiller, table drives are all a little different.

Drive
Hermle - worm
Grob - waiting on info
DMG - Direct

Scales
DMG - all axis
Hermle - No
Grob - Yes


Good to know about Hypermill/Heidenhain, definitely leaning that way

I'll post some better info when I get some better Grob documentation.


I am not really interested in Mikron due to support. It doesn't feel like they are as committed to the US as DMG or Grob. Hermle USA is close to me.

this is gonna be a tough one...
if C42 is not an option i think i'd go with grob, the layout is just SICK imo.
we have a C12, Mikron mill 700 u and matsuura 5 axis machines, the C12 is incredible, but as cameraman mentioned, 400 will not have scales. that would drive me towards the grob. on the mikron side, we've had GREAT support from both ellison and GF directly. nothing but great things to say.
either way you're gonna be very happy, both are great options that will serve you great!
i'm partial to heinyhein, i believe Grob does mostly siemens, but can do HH as well.
oh ya, Hermle spindle will be grease pack, not a huge deal, just a bit more maintenance. they are very robust! the replaceable union for collisions are a great feature also.
 
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Good to know about Hypermill/Heidenhain, definitely leaning that way

I'll post some better info when I get some better Grob documentation.


I am not really interested in Mikron due to support. It doesn't feel like they are as committed to the US as DMG or Grob. Hermle USA is close to me.

Yup, for many years Hypermill and Heidenhain on the Hermle platform have been working together.

@Empwoer had some some issues with Hypermill for roughing and other issues but his outfit more recently purchased a Hermle AND a Mikron at auction - I was trying to give him some hope that Hypermill and Hermle/ Heidenhain dove-tail more seamlessly (sp). (than what he had previously been experiencing.).

I believe there are further enhancements for programming i.e. what tools are in a particular machine are reflected back to the CAD/CAM station.

With Hermle in WI + Heidenhain; normally anyone that properly supports the Heidenhain control can receive proper training / formal training at one of their training centers.

The other advantage is there are fewer dots to connect with Hermle in terms of technical support. If they can't answer it locally immediately it goes to their team in Germany - good phone support + they can offer tooling / cutting advice also for particular applications or projects. Given they only make "One thing" they are well positioned to help solve or advise on specific cutting issues.

The "Peeps" in WI I have found to be extremely knowledgeable and know each model of Hermle inside out - EVERY nut and bolt just about.

There's one guy there "Pascal" (if he's still there) he grew up in Gosheim (Home of Hermle) and went through the whole training program for many years. Very knowledgeable, smart and talented and knows his onions and if there's something deeper or more tricky he can connect the dots to Germany for a "Deeper" bench if need be.

Long term Hermle have parts and support for some machines older than 15 years old.

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Grob vs. Hermle - first 5 axis machine + job shop work ~ Kinda depends what you want to be known for ?

I think @dstryr has at least 3 Grob machines is using NX and is banging out complex aerospace / DOD type parts (I believe).

Complex high value parts. I'm sure he'll say Grob blows the doors off anything else.

The Hermle C400 is slower but more "general" / universal and not bad at mold-ish work 3 to 5 axis type of work with nice finishes.

The Problem being that longer cycle times for card carrying mold-work of the order of 8 to 15 +++ hours cycle time - thermal management is critical vs. shorter cycle time mechanical components.

The Hermle C400 -ENTRY LEVEL MACHINE :-) has (digital) thermal compensation at the control with temperature sensors at various points in the machine and spindle but no direct spindle chillers. I.e. no direct way to transfer and dump heat - its just has to roll with whatever thermally is going on. Maybe a bit like Okuma's "Thermo friendly " concept and similar to MAZAK (in some instances). + no scales so wear on the machine will degrade positional accuracy eventually. But other wise very accurate.

Heat build up + the environment of your shop may be an issue for ultra precise 3d contouring.

The non-entry level Hermle(s) "High Production" have all the things a production card carrying 5 axis mold level machine would want.

OTOH the synthetic granite is less reactive to thermal changes as compared to meehanite - gray cast iron , but bear in mind the trunion AND the overhead 1/2 gantry is also made of cast iron but at least the machine is very symmetric and the large diameter worm gear on the A axis can handle a fair amount of counter torque "In-cut".



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DMG Mori DMU 50 3rd gen really IS a substantial improvement over the second gen.

You are not limited by any options per se.

So 60 tools is an option. + scales all axes (linear and rotary) + higher rpm 20K spindle + 3 years spindle warranty (no questions asked)

IS a pretty good all rounder. Decent surface finishes and GOOD thermal management on bearings, and spindle and ball screws.

Heidenhain is or can be an option.




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Grob are based in Ohio, German company on US soil but integrating with Taiwanese iron - nothing wrong with that.

If you were looking to scale quickly and get really into production at scale for super complex high mix low volume (high value parts) Grob seem pretty excellent - probably a bit less hand -holding + steeper learning curve with Grob (maybe).
 
Pulling focus on the type of work and materials and markets you want to serve will have you looking VERY closely at various spindle torque diagrams + type of spindle.

It's very tricky to get a spindle with useful or significant grunt at lower rpms / torque for the Titaniums and nickel alloys and even roughing various 'Steels" that are higher than 20K rpm.

If you have to do mold work or have fine finishes then lower spindle runout more fragile / flossy spindle might be required - 30K rpm. but you have to give up roughing out tough / hard to machine materials for larger components.

Hard to get it all on one machine...
 
I run a Hermle C42 here in WI, couldn't be happier, however it's in a different class as what you mention. I would certainly put Mikron in the game, we have a 600 here and are extremely happy with it, what ever you decide on, make sure a Heidenhain drives that thing, Heidenhain+Hypermill=Happy. BYW, what part of WI are you in? we are always looking for outside help with mold work.
 
this is gonna be a tough one...
if C42 is not an option i think i'd go with grob, the layout is just SICK imo.
we have a C12, Mikron mill 700 u and matsuura 5 axis machines, the C12 is incredible, but as cameraman mentioned, 400 will not have scales. that would drive me towards the grob. on the mikron side, we've had GREAT support from both ellison and GF directly. nothing but great things to say.
either way you're gonna be very happy, both are great options that will serve you great!
i'm partial to heinyhein, i believe Grob does mostly siemens, but can do HH as well.
oh ya, Hermle spindle will be grease pack, not a huge deal, just a bit more maintenance. they are very robust! the replaceable union for collisions are a great feature also.

Oh hey - just saw your post / posts crossed.

Is or does Hypermill play a bit more nicely with the C12 ? - Nice machine BTW. Actually really nice.

__________________

Just saw @5 axis Fidia guy's post.
/ posts crossed.
 
If you're looking at those, as a one man shop please give me the lowdown on how you managed THAT feat!??!?!? Congrats on that point!

Anyhow, if you are looking at this class of machines, you should also be considering Mikron. In my not so humble opinion you might want to be looking out for lowly grease-pack spindles on the ones you listed. Most all Mikrons have the best available lubrication design with there Step-Tech's that can see tens of thousands of hours @100% rpm duty cycle, not 8000hr grease packs. All modern Mikrons have torque motor direct drive rotaries, whereas most (if not all) Hermles have gear drive. (Anyone more knowledgeable please correct me on Hermle specs). I'm not sure if your list OEMs are available with linear motors, but some Mikron lines are.
Milling machine | 5 axis | Mikron MILL P U Series - concept of modularity
I've seen some pretty scary-good accuracy out of this line of machines, from tiny mills to <2 meter stroke, that I've posted about here on PM in the past.

That Mikron P U machine has pretty much everything anyone could hope for leaning in that direction... + their crash prevention strategy.

But - the machine IMO is in a different price bracket ? like $500K to $600K territory ?

Like @TJHell I have the same "reservations" about Mikron for support where we are. - Seems solid on the West Coast though ?

If I was based in Europe I'd be pretty sure that Mikron / AG would be my "Jam" for tiny intricate machine parts.

_________________________

Hermle do have DD motors for C axis as an option and they have some kind of "Torque" drive option for Tandem driven trunnion. Just not available on your C250 C400 C600... Entry level machines.

Hermle C42 torque vs Worm.jpg

^^^ Click to "blow-up" worm and no worm on C.
 
I really like Hermle, but I wouldn't even consider the C400U. There is no way I would buy a new 5 axis with <50 tools. We have some parts that use more tools in one OP than the Hermle can handle. The 18k grease pack is a known weak point, but the scales issue would be an absolute deal breaker. Shouldn't even be an option on a 5 axis.

For me this would be a decision between the GROB and a DMU50 3rd gen. The latter has a much better spindle (the 20k option), and the option for 60 tools. The DMU50 also has a nice steel casting instead of the cheesy weldment. However, in addition to fabulous kinematics, the GROB does have a certain *appeal* that is very unique. I'd love to be the first guy in the area to announce I just bought a GROB. :D

Just checked the clock on our DMU50. I bought it in 2018, and it has almost 6000 hours on it. Besides a couple hiccups in commissioning, we haven't made a service call yet.
 
Oh hey - just saw your post / posts crossed.

Is or does Hypermill play a bit more nicely with the C12 ? - Nice machine BTW. Actually really nice.

tbh only fed it hypermill code twice since we've had it, and its done really well! i find myself using fusion for about 90% of the stuff we've done so far. its just that much easier to do simple things like 3+2/basic surfacing etc.

anything complex goes hypermill. but yeah the machine itself is simply incredible. i think our spindle might be on the way out, quite loud - at 10kish rpm sounds a bit louder than our LX at 40k... but for the amount of money we paid for it, we'll still be WAY ahead after spindle replacement.
 
I really like Hermle, but I wouldn't even consider the C400U. There is no way I would buy a new 5 axis with <50 tools. We have some parts that use more tools in one OP than the Hermle can handle. The 18k grease pack is a known weak point, but the scales issue would be an absolute deal breaker. Shouldn't even be an option on a 5 axis.

For me this would be a decision between the GROB and a DMU50 3rd gen. The latter has a much better spindle (the 20k option), and the option for 60 tools. The DMU50 also has a nice steel casting instead of the cheesy weldment. However, in addition to fabulous kinematics, the GROB does have a certain *appeal* that is very unique. I'd love to be the first guy in the area to announce I just bought a GROB. :D

for me, if it was a question between Grob and DMG, i'd run as far away from DMG as possible. IMO Grob is a MUCH better machine in all aspects.
 
IMO Grob is a MUCH better machine in all aspects.

Why? I completely understand the issues people are having with DMG MORI service, but the DMU50 specs out really nice. It beats the GROB on a lot of key metrics. The spindle issue alone is absolutely massive for us - having a 16k spindle (instead of 20k) would be a huge step backwards, and the 24k spindle on the GROB is really anemic.

Not saying the DMU50 is a clear winner, but it is almost certainly the best value in 5 axis machines available right now. The next closest competition for price/performance is probably the DMU75.
 
Why? I completely understand the issues people are having with DMG MORI service, but the DMU50 specs out really nice. It beats the GROB on a lot of key metrics. The spindle issue alone is absolutely massive for us having a 16k spindle would be a huge step backwards, and the 24k spindle on the GROB is really anemic.

Not saying the DMU50 is a clear winner, but it is almost certainly the best value in 5 axis machines available right now. The next closest competition for price/performance is probably the DMU75.

the layout is huge, chip management, tool versatility. granted we dont do crazy alloys so spindle power/torque isnt as huge of a concern to us. what metrics does the dmg beat it in?

me personally the #1 thing that steers me away from DMG is their reputation.
 
I really like Hermle, but I wouldn't even consider the C400U. There is no way I would buy a new 5 axis with <50 tools. We have some parts that use more tools in one OP than the Hermle can handle. The 18k grease pack is a known weak point, but the scales issue would be an absolute deal breaker. Shouldn't even be an option on a 5 axis.

For me this would be a decision between the GROB and a DMU50 3rd gen. The latter has a much better spindle (the 20k option), and the option for 60 tools. The DMU50 also has a nice steel casting instead of the cheesy weldment. However, in addition to fabulous kinematics, the GROB does have a certain *appeal* that is very unique. I'd love to be the first guy in the area to announce I just bought a GROB. :D

Just checked the clock on our DMU50. I bought it in 2018, and it has almost 6000 hours on it. Besides a couple hiccups in commissioning, we haven't made a service call yet.

I think the Grob has some appeal for extending that Horizontal machining idea of gravity and not re-cutting so many chips. So that inversion capability seems nice + seems really well geared for reliable automation.

Mikron are certainly pushing their automation / pallet systems even on their entry level universal.
 
I think the Grob has some appeal for extending that Horizontal machining idea of gravity and not re-cutting so many chips. So that inversion capability seems nice + seems really well geared for reliable automation.

Mikron are certainly pushing their automation / pallet systems even on their entry level universal.

we just started running our mikron lights out, been working out really well so far!
 








 
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