Retrofitting a 1986 Maho MH400E

On my machine, the coolant flow control has become sentient. I think Maho just went to the hardware store and bought the smallest household tap they could find. Mine changes flow settings at random. Probably tied in with the fact that I haven't cleaned out the coolant tank in the foot casting, and it was full for at least a few years before I got the machine. Draining and cleaning it are on the to do list, under the sub heading "shit jobs"
Mark

Oh, okay then. Mine came with a separate, steel box for coolant and a rather nice, if cosmetically beat up pump (tbh the entire machine is beat up). The box was empty of course. It's still worth it to clean the coolant reservoir IMO though I see how given your situation you might prefer installing something else altogether and forgetting the original system is even there. Especially since you can cut a lot of steels and cast iron completely dry with a bunch of carbide, cermet and CBN tools.

I had a lot of fun machining cast iron on my MH600 with a 16mm 6 flute carbide endmill. It didn't feel much different than cutting aluminum had which I thought allowed the machine to show its strengths well.

I should be easy enough to move the coolant to a separate container. The Maho pump is mounted on a loose sheet metal cover over the foot casting.

Hello Mark and Friends
I have a Maho 700 C. imported from Switzerland . I live in Auckland, New Zealand.
The machine has had little use as evidenced by the condition of the slide ways.. When the machine arrived the electrics worked but the Y axis would not work. This was due to broken Aluminium coupling. That fixed the machine worked well for a while then failed. A good friend in Germany helped. We sent a circuit board back to Germany and had the Eproms replaced. The machine ran again for a while. Now the machine is out of action again. My contact in Germany wants me to send the whole Heidenhain TNC 135 unit back to Germany for service and also renew the screen. This will be expensive and I wonder what next will fail. This machine is in a private work shop. I am trying to finish building a steam Launch engine. The TNC or CNC feature would be nice but I really just require a regular accurate milling machine with power feed.
The Maho has Indramat DC Servo motors driving 49mm ball screws on the XZ and Y axis. The amplifier is also made by Indramat. This 35 year old electronic equipment can only be serviced by the factory at huge expense.
Can anyone on this forum tell me how I can by pass the Heidenhain TNC and get my machine running again. I don't trust the original 35 year old electronics. The machine came through the tropics in a container. My guess is the heat from the sun has helped break down the plastic electrical components. My friend in Germany has a similar machine and it has given him no trouble.
Can you please advise me in what I should do. My age is 75. I don't want to scrap this superb machine. Thank you

Welcome Chris. I am also a Kiwi. I have assembled what I have learned so far in my Maho MH 400E conversion into one draft document. If you give me you email address I'll sent it through. Unfortunately you cant do private mail on this website, but I use the same user name on CNCzone, Practical Machinist, Madmodder etc, so just drop me a line with your address.

You said it stopped working again. What is the symptom this time? Is your 700C equipped with a fourth axis? Please post some pictures of the machine and its control cabinet innards.

The MAHO's are very modular in their electrical/electronic architecture. I found it quite easy to keep the bits which work (power switching/ relais control / motors and Indramat / Axis encoders) and only lobotimise the old 1980's brains. I had little knowledge when I started.

If you have existing faults, but don't trouble shoot them, it can make the conversion more differcult. I had to go that way, as I couldn't get a video signal on my old Phillips. In the process of the conversion I discovered an intermittant fault on the relays board edge connector, and two faulty Heindenhain EXE's.

It should take the same minimum equipment to convert your 700C:
- A PC running LinuxCNC
- Mesa motion cards .I used 5i25/7i77/7i84. If doing it over I'd add a 7i74 and 7173 as well, to reduce the discrete wiring a little.

I am assuming your MAHO also has Heidenhain LS-403 encoders for the axis position feedback, and probably has some flavour of Heindenhain EXE to do the analog / digital signal processing. However, if this A/D conversion was done internally in the TNC 135, you might have to buy three 602 EXE's off Ebay to interface the encoders with the MESA cards.

Does your 700C also have an 18 speed gearbox, and single speed spindle motor, or is it the two speed gearbox with the electronically controlled motor?
Mark

chris mcm wrote: Hello Mark and Friends

The Maho has Indramat DC Servo motors driving 49mm ball screws on the XZ and Y axis. The amplifier is also made by Indramat. This 35 year old electronic equipment can only be serviced by the factory at huge expense.

It is not sensible to maintain a 35 year old CNC control. Not only are modern controls better in operation, but theay are more relaible and much less expensive to fix.

One option is to use the Pico Systems PPMC to control your existing Indramat servo amplifiers. The PPMC is a set of boards for interfacing to analog servo drives and the machine's encoders. Of course, you have to take a look at the condition of the Indramat servo amplifiers and decide whether you want to keep those.

You could replace them with AMC, Copley or Servo Dynamics servo amps, or possibly, depending on the motor ratings use the Pico Systems PWM servo amplifiers and PWM controller. One issue is that for best results with the PWM system, you want to have higher resolution encoders that was typical with machines of this vintage.

Also, your machine may have Heidenhain interpolators for the encoders, you want to keep those if you remove the rest of the
TNC 135. I **THINK** they are separate modules in that system.

Jon