Tool change was interrupted accidently

Fault:

The process of the tool exchange was interrupted accidentally and the tool on the spindle was stuck on the gripper of the tool magazine.

Remedy:

After restart the axes of the machine still could not be moved.
In the menu Deckel Maho/Manual control/Tool change, Pressed a key by graphic (right one) and heard and saw the gripper was released. Pressed the red emergency stop push button to make off the drives’ power. Turned the lead screw with hand to make the spindle and cutter out of the tool change area.
Turned off and on the machine. Reinstalled PLC. Restarted the machine. Made the axis X return to the reference point. At this moment the small door for tool change closed automatically and the machine restored to normal.

Axes of spindle and rotary table are not coplanar

Fault:

When the X coordinate was zero, the axes of the spindle and the rotary table were not coplanar, and the rotary table could not be used for precise machining.

Remedy:

Fixed two fixtures on the rotary table, as shown in the picture. While the rotary table turned to 0° or the B axis was in 0° position, made them parallel to the Z axis with a dial gauge. Found the center coordinate between the two fixtures through touching, reading and calculation:
while B=0°, X=-151.010;
while B=180°, X= 151.236.
Then:
151.236-(-151.010)=302.246
302.246/2=151.123
151.236-151.123=0.113
Added this 0.113 to the value of the 34090# parameter (REFP_MOVE_DIST_CORR[0], 456.977+0.113=457.090) and restarted the machine. Found the situation was improved.
The difference between the absolute values of the positive and negative X could be very small when the process is repeated. Finally it was 5μ in this example.

Mechanical failure of spindle end

Fault:

The spindle end was jammed on the assembly fixture, and a large deformation and burr appeared in the rim. The spindle was stuck and could not rotate. Each axis could move. No alarm.

Remedy:

After careful observation, found that the end shield were dislocated due to the fact that the shield was jammed by the assembly and was stuck on the bearing end cover, and could not rotate along the axis. Dislocation to a certain extent, the axis would no longer be able to rotate and stopped.
With a plate slightly sharpened, struck the shield along the rim with moderate force and took it down. Now the spindle could turn. Repaired the shield.

Alarm 700112 (Pallet changer not in basic position)

The alarm appears more frequently. Sometimes it disappears by itself, but sometimes it takes a lot of twists and turns. If it is troublesome, can deal with it according to the following procedures:
1. Following the pallet exchange process(see “Alarm 700101+ and oil spill from rotary table”), manually poke the solenoid valve to fulfil each step in sequence. Make a moderate effort to make the lamp light. Can observe the PLC status on the screen to make sure that it is in place. Considering safer, you can poke a valve with another person observing. Press the emergency stop in case of emergency. Can also unload the pallets in advance. This procedure can generally eliminate alarms.
2. If the alarm still exists, reinstall the PLC. If the small door for tool exchange is not closed, can perform manually axis X return to the reference point. After that the door will fall automatically.
Here are two examples.

Example 1:

Fault:
Alarm: 700112 Pallet changer not in basic position.
Remedy:
Following the pallet exchange process found E36.4(pallet changer in 0° position) and E36.5(pallet changer in 180° position) were both “0”. Turned in clockwise a little bit the proximity switch and cable corresponding to E36.5. Orange light and yellow green light were lit at the same time. Restart the machine, the alarm was eliminated.

Example 2:

Fault:
The machining process was interrupted randomly by the alarm 700112. Normal after shutdown and restart. Sometimes the frequency is nearly 1 times per hour.
Remedy:
Following the pallet exchange process, checked PLC status and found that E36.2(Pallet clamped on rotary table) was changed from “1” to “0” when the alarm appeared, and E36.3(Pallet unclamped on rotary table) was always 0″.
A40.2 was “1”, indicating that the system had given the locking signal, the solenoid valve Y40.2 indicator light had been lit, but the corresponding pressure switch S36.2 may not give a signal, making E36.2 become “0”.
Checked and replaced S36.2, the alarm was completely eliminated.

Drives can not be switched on

Fault:

System 840D had run up and basic screen appeared. But the drives could not be on. There was an alarm: Stop No Mode Group Ready.

Remedy:

There is description about Mode Group on the operating manual of 840D. This machine only has one mode group. The alarm can be thought of as the machine is not ready.
While checking, the machine went well sometimes, but bad in other times, irregularly. When pressing the push button Drives On (S45.6) found the status of E45.6 (on the display of console) changed to “1” from “0”. It  showed that the PLC had received the signal sent by the push button through the emergency stop circuit.
According to the electrical schematic diagrams, holding down the button Drives On and checking voltages with a multi-meter, found that there was a 24V voltage of the pin 21 of the relay K17 (page 218) relative to the pin A2 of the relay A170. But pin 22 not. So doubted K17 malfunction. Exchanged K17 and K9 (the same model, optional, not used in this machine) and tried. The machine restored to normal.

 

Alarm 25201 (Axis B1 drive fault)

Fault:

Alarm 25201: Axis B1 drive fault. Machine power can’t be on.

Remedy:

Restarted the control and observed alarms under Diagnosis menu:
3000      13:47:15  Emergency stop
25201    13:47:19  Axis B1 drive fault
300504  13:47:19  Axis B1 drive 4 fault of motor transducer
510300  13:47:26  *** Emergency-stop***
……
700112  13:47:27  Pallet changer not in basic position
So the exact fault should be the motor encoder of the rotary table.
After further confirmation replaced the encoder.  The machine then returned to normal.

Alarm 700101+ and oil spill from rotary table

Fault:

After the pallets exchanged came alarms:
700101 Set-up position not turned to 0 degree.
700026 Pallet has no program/pallet number.
700112 Pallet changer not in basic position.
At the same time oil spilled from around one of the four tapered supports of the rotary table and the bottom.

Remedy:

First removed the outside pallet with crane, and then the inside by six young fellows. Unscrewed the screw on the support and made a copper washer. Re-fixed them with rubber belt. The spill had thus been solved.
Pallet exchanging sequence is as follows:
– Position Z and B axes    B=0    Z=Pallet change pos.
– Pallet unclamped on rotary table       A40.3      E36.3
– Pallet lifted                                         A40.6      E36.0
– Pallet 0° or                                         A40.4      E36.4
–            180°                                        A40.5      E36.5
– Pallet lowered                                    A40.7      E36.1
– Pallet clamped on rotary table           A40.2      E36.2
A (German Ausgang) means output, E (German Eingang) input, both for PLC.
On page Diagnosis/PLC Status both A40.7 and E36.1 were observed as “0”, and A40.5 and E36.5 were “1”, indicating that the sequence was interrupted at ‘Pallet lowered’, and the pallet was not lowered.
Reinstalled PLC, the machine was restored to normal.

Serial Communication Parameter Setting of DMC80H

When the serial communication with DMC80H is not smooth, the possible reasons are improper parameter setting, wrong or poor hardware connection, improper use of software, or errors in transferred program, etc. Sometimes it’s really a lot of trouble to find the problem. To our experience, communication parameters can be simply set as follows:

Baud rate 19200
No parity
Stop 2
Data 7

After such, if still not normal, turn to check other things.