Retrofitting a 1986 Maho MH400E

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23 Jan 2019 14:31 #124668 by hanmon
A fellow sufferer ;-)
B-Axis+spare parts, exactly what I thought when bidding.

@Mark:
The ATX PSU's voltage tolerances according to specs is 5% which equals to 4,75-5,25 V and 11,4-12,6V an should be the same that MAHO requires.
I would try to power the EXE with the PC's PSU again.

Hanno

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24 Jan 2019 09:25 #124719 by RotarySMP
Everyone thinks I am crazy for buying a 1.2 ton unservicable mill. I can imagine your relatives and friends trying to get you committed for buying three :)

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24 Jan 2019 10:18 #124724 by hanmon
I think I can top that.
I bought a fork lift to be able to unload and move my machines.
I just wanted to be independent from my neighbour with his tractor ;-)
My lathe weights 4.5t. That was really crazy to get it into position using two pallet trucks. ....welcome to this madhouse ;-)

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24 Jan 2019 10:22 #124725 by RotarySMP
A forklift. Nice. My basement is too low for anything like that. I moved my lathe in on ion bars.

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24 Jan 2019 10:25 - 24 Jan 2019 10:28 #124726 by RotarySMP
Ion bars is sort of like a warp drive, but slower.
Last edit: 24 Jan 2019 10:28 by RotarySMP.

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25 Jan 2019 00:04 - 25 Jan 2019 00:13 #124778 by drimaropoylos
They can only make comment about the space the mill takes on the floor of your garage (given you are amateur machinist).
But if they ever make comment about the value of the machine, just show them a manual made in china copy (with german quality control) of the machine and then show them the price tag.
www.stuermer-machines.com/metalworking/m...timill-mz-4-3346240/
Attachments:
Last edit: 25 Jan 2019 00:13 by drimaropoylos.

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25 Jan 2019 13:21 #124808 by Glemigobles
Hi guys, lots of interesting posts here, as usual! I was busy with my little business but now I have more time to post. One small update on the Maho that's completely unrelated to LinuxCNC is that I had to replace the gaskets on my DG35 pressure switch. It's a device mounted on top of the hydraulic pump responsible for tool clamping.

The pump would switch on and off in short jumps, making a loud noise as the breaker in the electric cabinet jumped back and forth. Turned out there was plenty of oil in the pressure switch. I took it apart, cleaned the oil and found wear on a gasket mounted on top of the actuator pin, responsible for converting pressure into motion and flipping the microswitch.

Since the gasket is not a standard part (as far as I know), it had to be custom made by a company specialising in machining custom gaskets from polyurethane rubber. This was a once-in-a-lifetime opportunity to also replace the two other orings in the pressure switch (they were a bit flat). I paid around 6€ for all three parts.

Predictably, the pump no longer malfunctions. Replacing the entire pressure switch would have cost me around 120€ (it's made by Hawe). Honestly, the chance of anything happening to the metal parts is almost zero, the mircroswitch inside costs maybe 0,50€ and the gaskets are also very cheap. So there's no reason to replace the entire thing, especially when the machine is used for hobby purposes.

In my case, I've been using my smaller bolt-on spindle exclusively for a few months now, so fixing the pump wasn't a big priority for me. But it got so bad that the switch would flip on and off hundreds of times during one machining session and I was getting worried something else would break as collateral damage.

I also noticed that the label on the circuit breaker in the machine's cabinet was different than what I have in the schematics DMG sent me. It's very likely that the schematics describe the entire class of these MH600s rather than this individual unit. Which means that I probably wasted a lot of money and postponed the retrofit due to a lack of funds for Mesa cards, whereas I could have just gone with the stuff Mark sent me. Well, live and learn.

All in all, I sincerely hope no one else here will ever have to replace the gaskets in their machines' hydraulic pumps, but in case you do, I'm attaching pictures of the parts I described. It's a real slog to clean oil from a microswitch!
The following user(s) said Thank You: RotarySMP

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25 Jan 2019 14:12 #124816 by RotarySMP
Great Input. My switch unit on the hydraulic pump hat the backshell broken. I just epoxied it back on, as there is no sign of other damage.

My drawing set from MAHO is the correct number according to the dateplate of the machine. The only error I found was that the pin out of the EXE output did not match the machine.
Mark

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25 Jan 2019 22:13 #124863 by Mccartymachine1
My pump unit was 3 phase 380v, so I didn't get to keep it when I converted the machine to single phase 240v. I installed a hand pump. It takes three or four pumps to release the tool. Shouldn't be too bad.

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26 Jan 2019 11:53 #124886 by db1981
Hello,

the X-Servo is back from the Motor Service.
the commutator was worn out and had an big unbalance. They turn it a bit down on a lathe and cleanded everything.

Now the hum is about 60% less and the trmeble has gone.
This had also effect on the other servos, now all servos are very soft.

Now i will do an new axis tuning, better start from zero.

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