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Getting a Maho MH 600 E up and running

akb1212

Aluminum
Joined
Jun 26, 2009
Location
Norway, Vestfold
Hi all,

I have now gone to the drastic step of buying a Maho MH 600E. This is as a hobby project, so I have to use time to get it up and running.

The machine is made in 1991. It has a 20 slots umbrella style tool changer. Unfortunately only a standard square table.

I'd have to say the machine is in a somewhat beat state, and unfortunately the previous owner haven't been to keen on keeping it clean. It has 39000 hours on the power on counter, but I'm not sure how much that is actual spindle hours.

When I took over the machine it had been stored for 4.5 years, the last 6 months outside (but under a roof and with tarp covering it). So there is some rust on it. Hopefully not really problematic though, and from what I have seen so far I’m not too concerned. Just a lot of work to remove it.

I have spent a considerable amount of time trying to get the history of the machine, and I have been able to find out what it have been used for. It’s been used for making molding tools, and that means full 3d contouring. As I understand that means it have the latest version of the CNC controller. It has 500 k memory, and already installed cable for transferring of programs.

Then there is the electronics..... the spindle drive is apparently broken, and repair work have been started but not finished by the owner who owned it before Trond, the guy I bought it from. The actual work was done by a service tech, but was interrupted by a bankruptcy. That put a stop to all work being done on the machine, and it was stored for 4 years before being exchanged for other services to Trond.

While cleaning the machine I discovered the most likely cause of the spindle drive failure. The heat sink was covered in a very thick layer of oil residue and dirt. And the fan blowing air on this heat sink was also totally engulfed in this thick goo. And after cleaning the fan I discovered it was broken. That means the spindle drive haven't had anything close to the cooling it required to work properly. For how long is unclear. Seeing the chips covering very close to 100% of surfaces in the machine (that is including in the back of the machine as well!) I can see that it has been doing some quite heavy cuts.

As mentioned repair was already started on this drive, and a small signal transformer was removed and new ones was supplied with the machine. But using a diode voltage meter leaves me to think a few of the driver transistors are also in need of replacement. But to my relief all the 6 output devices seem to be in good shape. I’m an electronics engineer by trade, and I have built Hi-fi amps many years ago. So I’m not frightened about having a go at trying to get this driver up and running. But searching the net for others trying the same ends up with nothing. Apparently Indramat who makes these drives are keeping all schematics out of public domain. All I got was that the driver stage is usualy what brakes.

My interest in Hi-fi is one of my main reasons for getting this machine in the first place BTW. I’d like to design and develop magnet systems for my own loudspeakers. Magnetostatic compression drivers and bass compression drivers is one of the things I plan on making.

OK, so seeing this brief description on some of the issues I have with the machine I assume you understand why I call this a drastic step. I realize it will not be a small undertaking getting this machine up and running. But as mentioned this is a hobby project, and I do have the time needed to get this machine up and running.

You guys might also comment that this seems like a waste of time, and I should get a machine in better condition. But the situation here in Norway isn’t the same as either central Europe or US. Anyway, the price I paid for it was considerably less than I would get if I crapped the machine and sold the parts, so I’m using this as an opportunity to learn a lot about properly built CNC equipment.

BTW, I have been lurking around with EMC and a Bridgeport clone for almost 10 years now, and realized I would be able to get as much for that if I restore it back to original state as I have now paid for the Maho. And the Maho will be able to do all the things I wouldn’t be able to get my Bridgeport to do anyway. So I couldn’t let this opportunity pass me by.

I have taken a whole lot of pictures of it, and I will post some as soon as I can get them uploaded to a picture sharing server. For the time being I have spent as much of my time as possible trying to clean up and get an overview of the machine. That is, the time I’m not spending finishing building the rest of our house… which my father in law thinks is much more important than fiddling around with old useless machines.

This post is getting more than long enough already, but there is loads of stuff I’d like to share and get help with on this wonderful machine. It really is a nicely built machine, so I’m quite sure I’ll have a good time getting to know it more intimately.

More questions will follow.

Regards,
Anders
 
The schematics for the Indramat should be in the manuals of your Maho.
With a lot of luck, I might have them for your amp. What type is it?

I do have a MH 700C with an spindle drive amplifier that was already replaced by a different brand. The drive on my 700C is a 8kW DC. :nutter:


Nick
 
Do you have a picture of the Maho?I would be surprised if it is really a 1991 600E. Or is it A 600e2?
Yes, we can tell somewhat the year even by the paint colors. For example, if it's green there is no way it's 1991. Since he mentions the "spindle drive" if it's green, it must be an e2.
OTOH, if it's mostly gray, it could be a 1991 600e. Kees, remember by about that time they dropped the "2" designation even though it had VFD controlled spindle.
 
Hi

I am curious as to how much this machine cost you as I am interested buying in a similar one.
FWIW, I have a 1988 Maho MH600e for sale...see here- Procyon Machine

I would think whatever he paid in Norway for one would be a moot point for what they might sell for in North America.

If you need tool changer and VFD controlled spindle I have this one, which is a screamin deal for what it is...

1991 Maho Deckel MH800C - See Video - eBay (item 200526450223 end time Oct-09-10 07:39:09 PDT)
 
OTOH, if it's mostly gray, it could be a 1991 600e. Kees, remember by about that time they dropped the "2" designation even though it had VFD controlled spindle.

My Maho 500E2 was a 1991 machine.I've seen more E2's from 1991, but can't remember I've ever seen a 1992 E2.But I could be wrong about that.
My 600C is also a 1991 machine, must be one of the very first of this serie.While a DMG mechanic thought it was at least a 1993 machine.
 
Ha-ha, so you guys thought I said "I think it is a 1991 model 600E", but the fact is that I said it IS a 1991 model 600E. The CNC part of it might be upgraded to have the full memory and a newer software version. But nonetheless, it is build in the last part of 1990 and very early 1991. All parts also confirm this. As well as the writing on the front door of the machine. BTW, I found several very similar same vintage machines on German ebay, and the all looked more or less like mine. Same paint colors as well. The vertical head swings out to the left when unbolted, and runs on a rail system attached on the left side of the ram to be out of the way. Very neat system in deed:-)

Here are some pictures of the mill:

[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1441.jpg"][/URL]
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1413.jpg"][/URL]
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1396.jpg"][/URL]

A picture to identify the spindle drive in question:
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1384.jpg"][/URL]

I would love to get my hands on the full schematic of that drive Søren. I have the German version of the handbook for the drive, but I'm not that good in German. And I haven't seen anything like a full schematic in it anyway. Most of the documentation is translated in to Swedish which I don't have any problems with (it's very similar to Norwegian). But the only drive I got some documentation on is the spindle drive. The TDM 3.2-20-300-W0 drive for the X and Z axis, and the TDM 1.2-30-300-W0 for the Y-axis aren’t documented at all. Neither is the KDV 2.2-100-220/300-W1 power supply. I'm not sure if all these are original from the start, but they are what are in there now. And I would love to have full documentation and schematics for these as well if you have them Søren!

I paid what comes to about $5000 plus transport. But that price was largely based upon the fact that Trond, the previous owner got it from exchanging goods with the previous owner that hadn't cost him so much. So he hadn't invested so much money in it and was willing to let it go to a suitable owner for what will have to be considered a rather low price here in Norway. This kind of sophisticated machines doesn't go that cheap around here normally. And it was quite clear that this machine would have to be stripped down and rebuilt quite considerably. And I was able to convince him that I was that kind of person to be able to handle that.

Here is a link to more photos of it:
Maho MH 600E pictures by anders_blix - Photobucket

I have loads more pictures of it. And it is now in my garage just outside my house so it will be easy to take more pictures of it if it is particular parts of it you'd like to see.

For the time being I'm just concerned about stripping it down to get it all cleaned up and getting to know all parts of it. I'm not going to power it up anytime soon. I'd like to clean the electronic parts first as well. As mentioned it was this that probably damaged the main spindle drive.

In the long run one of the things on my list to do is to get a hand pendant of some sort connected to it. As it is now with no dials of any kind I'm not too happy about it. This is going to be the only mill I have since I don't have so much space available. But then I'd like it to be able to use in something like manual mode. So that is something I'd like to find out more about. Anyone who have made their own hand pendant and made it work with a Maho?

My Bridgeport clone was set up with EMC (even though I only got as far as rebuilding the X and Y axis). So I have some knowledge of that already. But from reading other posts in this forum I have learned that converting this mill to use EMC2 would be a waist since it would in fact be downgrading and a whole lot of work at the same time. But the thought of not having a way to control the machine without a hand wheel really makes me wonder about what to do about it. So I really hope it will be possible to get something like a hand pendant to work with it.

Ok, I hope the pictures clarify things a bit. And I really appreciate the interest in the thread.
 
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Ha-ha, so you guys thought I said "I think it is a 1991 model 600E", but the fact is that I said it IS a 1991 model 600E.

It's based on the YOM you found on some various parts of the machine, but that does not mean it is the YOM of the machine itself.My 600C also has various 1995 parts in it.What is the serial number of the machine, I can't read it in the photo.
The point is to find out at what time Maho build the different models and made the change to the newer lines.No intention to downgrade you're machine when it comes to the YOM or something.Just want to learn.
About the learning: there are a lot off simularities with my 600C.The only difference I found so far: swivel head, rotary table, tool changer and store and off course the control.
 
Kees,

It's not like I feel offended or anything, I just found it kind of humorous that as soon as I post about my new machine the discussion is a guessing of what YOM it actually is. But given so much variation on how these machines are equipped and the obvious difference in usefulness of the machines I do understand the interest. And frankly that was a big part of my detective work before deciding to buy the machine or not.

I realize I made the pictures to small when I uploaded them, so I'll try to not reduce the size that much next time I upload.

The serial number is 661310. But when I contacted DMG Scandinavia and gave them this serial number the computer system insisted in adding a 3 at the end (making the serial number 6613103). Not sure if that is correct, but if it is it is a 1991 machine, and it was sold in Poland.
I was able to find the owners who had it when it was used in production in Norway. It was Raufoss Industrial Tooling. I even spoke to the workshop manager in this company, and he remembered the machine. He is the one who informed me that this machine was used for making molding tools, and that it was capable of drip feed and full 3D work. But he didn't remember them importing it from Poland. Even though that doesn't mean it didn't happen. He also told me that it had been used extensively for stainless and hardened materials. I suppose that means it have seen quite a lot of load and will be worn. But I hope it doesn't mean it is beyond rebuilding for me.
He even promised me the machine constants on file, but each time I talk to him he forgets to come back to me. I think I need to call him back soon to se if I'll be able to get them. After all it would be much more convenient than having to type them in by hand. And I don't expect the constants to be there since it have been sitting without power for as long as it has.

What I have discovered, not that I didn't expect it I guess, is that I need to disassemble it to a degree that I suspect I might need to do some adjustments I'm not sure I'll be able to do myself when putting it back together. I hope I don't experience this, but if I do I have a Maho tech available about 1 hours drive away. So I'm not all that frightened about it. Even though I was hoping I wouldn't have to spend too much money on getting it up and running. But after all I need to get the whole machine accessible to clean and inspect it. I'm just not comfortable not cleaning it all while I'm at it.

I did read something quite encouraging today though. The company MMD does full refurbishments on old Mahos and sell them with a warranty. To me that mean these machines must be made so well that they are worth refurbishing and given new life. They emphasize the fact that these machines are made before they had started to prioritize the speed of the machines in such a high degree that the rigidity of the machines was starting to come down. This sounds really good to me because my use of the machine doesn't need the super high speed the new modern machines are capable of. But I do wish for as high rigidity as possible from my machine.
Oh well. I do know that I will not tamper with the geometry of the moving axes or anything directly related. If I need to do that I will bring in experienced personnel. But I am discovering that removing the sheet metal coverings are not a small job in itself in this machine! In particular around the ATC. I am hesitant to disassemble too much of that. I don't think a full recalibration of the whole ATC functionality is something I'd like to get in to if I don't really need to.

One more really great thing about Mahos is that the design they use is one of the only full VMC's that doesn't require in excess of 2,5 meters of roof height. As you can probably se from my photos I don't have much spare height in my garage where the machine will be located. So this was one of the important factors that made this machine so suitable for me. Then knowing that Maho is a quality brand made the decition all that much easyer.

Anders
 
Runing it dirrectly on 240 V

I have now done some serious disassembly of the machine! All sheet metal except the electronics cabinet is now removed. All of it was totally full of swarf and some of it had some rust on it that dictated it was better to remove it all.

Anyway, I'm starting to think about moving the different axis now. But moving the y-axis seems to be a bad idea without having the electronics do it. It's not as easy as twisting the screw by had like on the other two axis.

But I have an issue with power supply. In Norway we have an old-fashioned 240 V delta electrical connection. That means that if I'm to use 380V equipment I need a transformer. In all other countries in Europe except Albania all you need to do is to have all 3 phases and you have 380 V.

But the thing is this: The power for the spindle and servos are fed through a transformer that seems to me to transform it back down to 220V (not 240 as used today, but within acceptable limits anyway?). After taking a closer look at it it is clear that it is doing exactly the opposite of what the transformer I would use to feed it with 380 V is doing.

My idea then was to skip the 240V -> 380V transformer and connect my house 240V directly (though the main power switch of course) to the 220V side of the built in 380V -> 220V transformer.

This way the machine gets all the voltages it needs. The 380V equipment will get 380V from the transformer since the secondary 220V winding on the transformer will now act as primary, and the 380V as secondary feeding the equipment wired for 380V (which is not a problem). Alternatively I can reconfigure the hydraulic pump and coolant pumps to run on 240V directly as well if possible. That would mean I can skip the whole transformer entirely.

One thing is that the Indramat system might benefit from having a galvanic insulation from the power grid. And this would be removed if I do what I'm considering here. Alternatively I could use a 240V insulation transformer. But I don't have one big enough for this machine, and buying one will be expensive.

So does anybody have a comment on this? Is it a good or a bad idea?

Anders
 
Nick,

I have checked both the schematics and the transformer itself. First of all I found out that it is an auto transformer. This means that it isn't providing any galvanic insulation from the electric grid.

Secondly it has only tapings for 220V and for 380V. And a neutral, but that isn't connected anywhere.

My conclusion from this is that if I leave everything like it is and just feed the machine through the 220V taping of the input transformer I should be just about right.

I also realize we are in a special situation here in Norway where we use IT-net (delta). This means the documentation doesn't consider this when they are explaining how to use the power supply. All supplies using 220V are considered in need of a transformer to adapt to a normal 380V TN-net.
What I need to know is if it is in fact possible to connect this power supply to my 220-240V network without having extra protection. Most of the supplies made for 380V are specified as possible to connect directly to the grid as they are protected enough to be so. They don't specify this for the 220V versions since they are assuming 220V delta isn't available without a transformer.
I’m trying to assess what is needed on the power supplies that aren’t protected, and as far as I can se they are using an inductor on each line. Then by leaving the auto transformer in place and using this as means to get both 220V and 380V it will also be able to act as the protecting inductor. After all it is how it is connected now, and the only difference will be where on the voltage level in the auto transformer I supply power.
And the fact that we now have 240V and not 220V. The 24V and 110V transformers have + and – 5% tapings to compensate here. So it’s possible I need to make some adjustments on them.

What I was hoping for was a comment on my assumptions. After all it might be really expensive to fix it again if this isn’t something the power supply will handle. But to my knowledge it should be ok to do this. It’s just that it would feel so much better if someone with experience with how these supplies work would be able to give me a thumbs up or not.

Anders
 
First of all I found out that it is an auto transformer.

:crazy:
So it must be OK.

And a neutral, but that isn't connected anywhere.

Not connected? You need that if you want 230 V out of the 400V 3 phase. I do NOT hope that N and PE are connected together. That would trip your RCD (if you have one) in no time.
You should have just a few 380 V consumers. The coolant pump and the ventilator of the milling spindle motor. I think that's it.

I don't understand how your grid works. You say 220 V delta. Does that mean 3 phase and no neutral? So L1 to L2 is 220 V (same for L2 -> L3 etc.).
I'm quite sure that there are 220 V consumers (24 transformer, control, ...).

When my MAHO was built, we had 220 V, now we have 230 V (with less tolerance). If I remember correctly, I do measure 25 V at my 24 V supply. Nothing went up in smoke. But from 220 to 240 V would result in 26 V. Better to buy a new (regulated) 24 V supply, they aren't too expensive.


Nick
 
I agree that it most probably should work. I just hope it's able to take the 240V I have even if it is specked for 220V. That’s my major concern ATM.

Connecting equipment like this is always a nightmare in Norway. No other countries are using this configuration, and we actually have considerably more houses burning down because of this system!
But you are correct, all I get to my house it 2 or 3 of the hot wires, in my case 2. Earth is literally earth! What was done when my house was built was to use the copper pipes for water supply as earth. Then each house has its own earth, and you have the potential for a lot of bad things.....
I'm sure other guys from Norway can share their own stories about all the trouble they have had with this. For example if I touch the earth connector on my TV-cable I can get a shock..... some neighbour has a ground fault. I have to use a galvanic insulator on my flat screen TV to prevent it from starting a fire.

I tried to find an explanation of this kind of distribution net, but on Wikipedia the only languages available was Norwegian, Dutch and German. The name for it is IT-net meaning Isolated Terra, or Insulated Earth.

Oh well enough OT for now.

The hydraulic pump (2.2kW) is also connected to the 400V of the transformer. It is easy to reconfigure the motor. Reconfiguring the wiring inside the electric cabinet might be trickier. But anyway, the transformer is 9kVA. It is also temperature protected, so I think I'll be safe testing it without reconfiguring the hydraulic pump. It's a long time until I will put any load on the spindle anyway.

The 24V transformer have a primary tap for 5% lower and 5% higher input voltage, so I think I'll connect it for 5% higher voltage before testing, and then change back in case it is to low. The voltage is quite consistently about 235 - 240V here.

I have now removed the cooling tray now, so I'm getting down to the bone now! I have taken pictures of the whole process. I would hate to not remember how to put it back together..... I'll try to get the time to post some of them so you can se. Most of my spare time is now spent on reading the schematics and trying to get to grips with them. Maybe even make one or a few big ones myself. I hate when it is spread over 90 something pages. And I need to translate the German stuff anyway. Anyone know if these drawings are available in English?

Anders
 
I have now confirmed that the Indramat power will accept my 230V delta power. My concerns now will be to prevent the RCD from tripping. Everybody I have asked about this has warned me about this. So I will have to talk to my electrician about getting a higher mA unit for my workshop.

I'm getting somewhere within the main drive though. At first I thought it was the driver transistors. Somewhere someone mentioned that these are the ones normally failing. But after finding a dead short after replacing some diodes the previous tech mentioned as bad I started a wider search for bad parts. Electrolytic caps came to mind as possible causes of this kind of error, and behold, I found nothing less than 3 completely busted caps. One had a dead short, 0.0 ohm reading across it. The others two had 20 ohm and 100 ohm or something. Knowing that the price for new ones was so low it absolutely pays off to have them all replaced. So I took out all 12 on the driver board. I think new ones will cost me about $20 for all 12. Then after having done all this I found this thread. Reading this makes me conclude that this is exactly the same components as Milacron had to change out. But instead of just replacing the bad ones I replace them all. After all they are 20 years old now, and the machine has been without power for more than 4 years. So I'm really expecting to have to change out more of these around the machine. I will take out the other drives as well and have a look inside them.
What kind of makes me laugh is the work done by the previously mentioned tech working on this machine. Apparently he thought that the input transformer of the channel he also thought the diodes had failed in was bad. The funny thing being that apparently they were no longer available, and they had to have them custom made at a cost of more than $2000 I was told by the previous owner. I'm not sure if that is what he ended up paying, but I was given 3 of them when taking over the machine. So I guess they must have ordered them. What they actually paid for them I'm not sure about. But after finding the shorted cap in exact proximity to this I actually expect the transformer to not be bad at all. I don't understand how that transformer could fail. And he hadn't found the fault in the cap, so I'm not so sure he knew what was wrong. I don't have the old transformer, so I can't confirm if it is bad. And the worst part is that if it was bad and I had to replace it I know a company I'm sure who would be able to make a new one for a much more reasonable price. BTW, this company is Lundahl transformers in Sweden. He normally makes Hi-Fi related transformers. But he makes all kinds of custom ones as well.

A more concerning issue now is the bleeding resistor in the power supply. I had to take it out of the protective casing to have it cleaned. And that meant cutting off the cables soldered on to the resistor unit. This is how it looked when I took it out: [URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1858.jpg"][/URL]

The bummer was when I was trying to get it back together. I guess it is supposed to be able to withstand high temperatures. And as I found out that meant it was soldered with a higher temp lead. Thinking about it it makes sense. But it proves to be difficult to get it back together.
I have searched for the correct brazing material, but until now I haven't been able to find one that is suitable. I'm not able to make it melt properly without burning the wires. But I have found a silver based brazing with what I hope is a better melting point where I'm getting the capacitors tomorrow.

To give you a little idea of the work put in to it up to now take a look at these pictures from approximately the same angle:
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1362-1.jpg"][/URL]
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1467.jpg"][/URL]
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1560.jpg"][/URL]
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1747.jpg"][/URL]
[URL="http://s865.photobucket.com/albums/ab212/anders_blix/Maho%20MH%20600E/?action=view&current=IMG_1877.jpg"][/URL]

I hope to have the driver and power up and running soon. Then I will finally be able to start testing the functionality and see if everything is in a state that makes this machine worth refurbishing. I'm not too worried yet. But I won't know that until I have tested it. I think I know how to get past the door safety issues for testing purposes. I have spent god knows how many hours studying those schematics now. So I think I'll be able to sort the electronics.

Anders
 








 
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