Retrofitting a 1986 Maho MH400E

Hi,

I just landed a number of Maho machines (in the US) and was happy to find this topic. Seems this forum has drawn a lot of new Maho owners since there isn't a whole lot out there.

Here is a list of the Machines:

(2) 600p's
(2) 600e's
(2) 400p's that are complete
(2) 400p's that are parts machines

These machines are all from a one owner small shop. He purchased the 400's and a couple 600's new from the factory and it appears there are a number of different accessories for the machines. None are turn key machines, all need repair or to be retrofitted. I'm still in the process of moving the machines to my shop so I haven't really dug into them. I'm hoping somewhere in the stack of books is a detailed parts diagram, would like to see the full working of the P machine travels without having to fully strip them.

Plan A would be to have all machines CNC, plan B would be to mount motors to the P machine hand wheel point and have joystick control with a DRO. We will see what comes of it. I've rebuild a few CNC machines but haven't gone through the process of adding ballscrews and motors to places that don't already have them.

Once I go through all the paper work, I'll try to get any good machine diagrams (if they're there) uploaded.

Hi Chris,

In your troubleshooting post, you state "Capacitors have been replaced." I also replaced the capacitors in my Indramat before I got started. figured it is cheap insurance to get rid of 30 year old electrolytics.

Do you have the set of wiring diagrams? Maho's vary a lot, so you really need to contact DMG and get a set of wiring diagrams specific to your machine. You need this either to troubleshoot the original, or retrofit.

I am not sure how the Heidenhain start sequence works. On the Phillips, you pushed the main Hydraulic start button, and also the on lathcing button.
If you push the Hydraulic start button, and the main contactors don't close, it sounds like your E-Stop chain is open. Have you checked the end stop switches? Pendant E-Stop jumper? The lube oil level sensors are very conservatively set. Make sure that way oil tank is over half full.

If you have the wiring diagram, you could jumper the Control On E-stop chain signal to bypass the Heidenhain, and and provide a control signal to the indramat to check it. However I wouldn't bother. There is no reason to consider faults in the indramat, until you can get the main contactor active. Whether for the Heidenhain or a retrofit, this needs troubleshooting.
Mark

Hi eflor8234,

The x00P is a half way house between manual and CNC. With the complicated clutch system to drive up to two axis at a time off a single motor, they are only capable of straight lines. This is what Thisoldtony has also bought. Maybe he needs some parts. I'd dump those on ebay, and concentrate on the two 600E's, which are much easier to retrofit (if even necessary). I hope you got the wiring diagrams. They are the important document. Parts lists less so.

Those rotary tables are tasty. Shame you are a continent away.
Mark

chris wrote:

Hello Jon

You mention the condition of the Indamat Servo Amplifiers. How can I check this?

Well, examining them for general appearance can be of some value. If they look horrible, darkened areas on the circuit boards, etc. then they may have limitied remaining life. Some others mentioned rplacing electrolytic capacitors, that certainly should be done on 30+ year old amps.

Also, if these are SCR servo amps, they probably should be replaced. Those have limited bandwidth and may not tune easily with LinuxCNC which by default has a 500 Hz bandwidth. Also, the SCR amps are really sensitive to power quality.
In 1986, the SCR amps had mostly been superseded by transistor PWM amps, so likely it is NOT SCR, but just thought I should mention that.

Another thing is if the machine has glass linear scales, you want to figure out what the resolution is, and if they are analog scales (can be determined by the part number on the read head) then there should be interpolators. You want to see if the interpolators can be separated from the CNC control. If so, you can have very high resolution position feedback.
If you can't separate the interpolators (built integral to the encoder input boards) then you end up with really coarse scale resolution.

Jon

RotarySMP wrote:

Hi eflor8234,

The x00P is a half way house between manual and CNC.
Mark

If you are going to the trouble of having motors and encoders on the ways, then it is now insane to NOT go CNC.
Long ago, a CNC computer was hugely expensive, and cost more than the machine tool. Now, computers are in
our pockets. You can ALWAYS do manual machining on a CNC, using a combination of jog buttons and MPG dials.
I do this all the time to clean up the top or edges of a raw part, and the jog buttons (arrow keys) give me a constant
feedrate without having to turn cranks smoothly. The MPG dial gives me precise increments of movement, such as
lower the facemill 0.010" and then plane the top down again.

Jon

Hello Mark
Capacitors have only been replaced in the Heidenhain TNC control.
I do have electrical diagrams and an a user manual on the Maho and the TNC
I have tried to send you my address through the practical Machinist forum private messaging system.
This evening I will try and work out how to send photos to this site.
Thank you and other on this forum for your help and encouragement.
Chris

Hi Chris,

I'm also in New Zealand, down in Christchurch! Also coming to grips with learning LinuxCNC; don't know much but try to help out where I can.

To add pictures, click on the Attachments button:


Use the Add Files... button, or easier just to drap and drop:


You can then put the cursor where you want in your message, then click the Insert button.
Alternatively, you can hit the Insert All button as a batch.


This is something I struggled with at the beginning - could not for the life of me figure out how to add pictures! How this helps.

To Chris mcm
I am glad you have found Mark's thread about his MAHO retrofit. As to posting photos , I figured it out, and I am older than you are! Just take a Burt Munro attitude and getter done.
Two photos that might give very useful information would be interior views of electrical cabinet an a photo of machine right hand side showing the gear change area and the spindle drive motor.

That your MAHO uses a Heidenhain TNC control with a Siemens PLC is interesting in that it may be a updated control design similar to the MH400P machine "Old Tony" ( that old age challenged guy) has vers a MH400E design that Mark retrofitted. Hope you have (or can get ) documentation for the Siemens PLC and how it ties into the MAHO control system.

If you feel electronics challenged, would trying to get some help from the Dave Jones / EEVblog forum (YouTube EEVblog ) be of any use to you? Might ask on the EEVblog/forum if there is any close to you person that could meet up for "High Noon Tea " with a Heidenhain TNC - Siemans PLC cuss an discuss session.

Hope to see some photos and schematics soon.
Bob

To effor8234
I have used the local FEDEX store for getting stuff digitized . Local = Columbus, Ohio
They can digitize 8 1/2 x 11 thru E size paper ,due some image clean up and dump the image to a thumb drive . They can also print stuff from a copy and or thumb drive image. They would even let me operate the equipment and use my own thumb drives. Thought the cost was of good value.
Wondering where you are located ?
Bob

Hi Chris, you have mail. Glad you have the wiring diagrams for your machine. I replaced the capacitors in my Indramat. Not differcult, as it is all through hole and large components. There are only a few boards in their.

I am guessing that the Siemens PLC controls a similar MAHO control relay board as most MAHO's have. The Phillips 432 had the PLC function integrated within it, as does LinuxCNC. Depending how well the interface between the Siemens and the Heidenhain was documented, you might find it easiest to leave the PLC in and command it, or remove it and drive the control relays directly from LinuxCNC. Given your 700C also has the 18 speed gearbox, the software component Sergey wrote should work to control it as well.

Mark