[uli12us]

I had the same problem on a brandnew DMC 63V. After 6 weeks or so I called DMG and they send me a technician, who changed some connections inside the CNC. But I know this only for a Siemens 840D Control, maybe it works on the 810D as well. In the circuit diagram, I have all the changes noticed.

[kevork_gr]

I had the same problem on a brandnew DMC 63V. After 6 weeks or so I called DMG and they send me a technician, who changed some connections inside the CNC. But I know this only for a Siemens 840D Control, maybe it works on the 810D as well. In the circuit diagram, I have all the changes noticed.

Can you specify which cables you had replaced please?

[deckeldoctor]

Most problems are the encoder cable,motor cable.

The problems are also in the connectors, They suck!!

The pins push back in side the connectors, when the machine vibrates it cause intermitent connections causing problem.

Any cables going up to the top of the machine could be problematic and there connectors.

Regards
DD

[uli12us]

No, thats not the connectors. At a new machine the motor connectors are new as well. They have made a fault in the wiring of the CNC and instead of connecting to the customers, they wait until the customers call her. And that was not the only fault in the new machine.

And the connectors of the siemens Motors don't make any problem, I have disconnected the toolrevolver more than 50 times. Never have a problem with this. But the connectors from a dozen years ago are maybe better than the one produced today. Another problem with the machine is the doorlocking, the switch will defective after some years, because of the tremor of the toolchanger.

@kevork_gr and others: If you give me your email adress, I will send you the changes. It works only with the 840D contol.

[kevork_gr]

I have called the dmg service and we cleaned and tightened the connections on the motor cable that leads to the spindle motor(2 orange(1 for power & 1 for information signals) & 1 grey, I think this is for the brake).
The problem stopped for about one day and continued the next day, and continues to this day, again in random times and even when we don't press any buttons(manual move, etc.).
I have noticed that when you start the machine and press the engage button to load(air and/or power?), there is a low frequency noise coming from the back of the machine, like a small compressor working, and then stops. If the noise is heard and lasts for the normal duration(about 5-7 seconds), the machine works normally. If the noise isn't heard, after a small amount of time(~10 seconds) the machine emergency stops, sometimes with a z axis drop and sometimes without. In both cases, following the emergency stop, the air that is loaded is released with a noise. The message that is displayed is "Emergency Stop" & "Emergency recovery module not operative". I don't think this provides many info though.
After that, the machine will hardly start working again if I don't reboot and OFF/ON the main switch at the back.
I would really like to know if anyone knows what's producing the noise on the press of the engage button(noted with the red circle on the pic below).
Thank you all very much for the help.

[deckeldoctor]

There is a very slight delay from when you press the control on button the brake for the z axis that holds it from falling until the electronics come on and the servos turn on to hold the Z axis up until complete power up.

This could be one of the green PILZ safety relays.

I do not have circuit prints at the moment to give you a place to start.

But I would look at that circuitry for the Z axis brake.

Regards

DD

[DCM]

Hi Guys,
I am facing the same problem as Kevork since last week. The Z axis drops whenever we open the Door or when enabling/disabling the axis using hand wheel. There is no change on the controller when this drop occurs and the Z axis axis goes back to its original position with a jerk and big sound when we close the door or operate the hand wheel. I called Fanuc India as well as DMG office. They both suggested that the problem is mechanical and to check the belt , ball screw coupling etc. I have have know bypassed the door lock and machine seems to be working fine. But I am afraid whether it can drop suddenly while in operation and cause damage. Fanuc engineer is expected to visit us in couple of days time. I suspect there is some problem with the relay or servo motor brakes . Plz help guys.......

[markp]

Hi, I just picked up a nearly new DMC103v, only 180 hours, loooong story. Everything works great but the z axis will occasionally drop very slowly after estop is pushed at the end of a run before shut down or sometimes during operation if the door open switch is activated. Only happens once in a while and the brake usually kicks in after a few inches of drop. What was the wiring change you indicated you had made? I would like to try it. Thx Mark

No, thats not the connectors. At a new machine the motor connectors are new as well. They have made a fault in the wiring of the CNC and instead of connecting to the customers, they wait until the customers call her. And that was not the only fault in the new machine.

And the connectors of the siemens Motors don't make any problem, I have disconnected the toolrevolver more than 50 times. Never have a problem with this. But the connectors from a dozen years ago are maybe better than the one produced today. Another problem with the machine is the doorlocking, the switch will defective after some years, because of the tremor of the toolchanger.

@kevork_gr and others: If you give me your email adress, I will send you the changes. It works only with the 840D contol.

[DMGService]

If the Z axis drops when hitting the e-stop button, opening the operator door, or when you finish using the handwheel, the problem is the Z axis Brake inside the Z axis motor.

In each of these 3 cases, the power (electricity) that is holding the Z axis in position is taken off, and the mechanical/electric brake is applied.
The Brake is normally locking the Z axis in place when in e-stop or the operator door is open. When you activate the drives to the 3 axes by closing and locking the door, or by entering hands free mode (Hanswheel) Power is applied to the motor, and a split second later 24 Vdc is sent to the Brakes, releasing them. That is the "Chirp" noise you hear at this point.
The same thing is true when you deactivate the drives by opening the operator door or pressing estop. First the 24 Vdc is dropped from the Brake, and then a fraction of a second later, the electricity from the drives is turned off. This fraction on a second gives the brake time to lock the Z axis in place, before taking off the power to the motor.
If the Z axes drops at this point, it's because the brake is failing to apply fast enough, and must be repaired or replaced immediately. If left like this, it will get worse until the Brake is slow enough to apply that the Spindle crashes into the table.