Lotem 400v erratic loading plates

[alekbelia]

Hi colleagues
Our Lotem 400v year 2001 erratic load plates. Plate is loaded and clamped well with head gripper. Plate is going well on the drum. Back gripper is open and move to plate well. After all gripper pressure arm not going down and drum not start to rotate.
Manually unloaded plate has small mark near to the middle if back edge of the plate. This error can happen on every plate on some plate sizes. On other size or type of plate this error can be very rare. Any ideas?

 

[PACH]

Hi colleagues
Our Lotem 400v year 2001 erratic load plates. Plate is loaded and clamped well with head gripper. Plate is going well on the drum. Back gripper is open and move to plate well. After all gripper pressure arm not going down and drum not start to rotate.
Manually unloaded plate has small mark near to the middle if back edge of the plate. This error can happen on every plate on some plate sizes. On other size or type of plate this error can be very rare. Any ideas?

Is the Lotem400 a manual loading one or an MCU one?
What is the plate size that you have problems with? What Error messages do you get on the screen?

 

[alekbelia]

hank you for fast responce. Lotem is manual loading. Best results we have with 730x605. Errors on all plates we rich with 675x492.
We see that results depends on different plate stiffness too. Error message is that drum motor can not start in desired time interval. But it is impossible because lower clamps arm not released rear clamps.
I still not discovered is there missing signal for clamp arm releasing or the rason is thrully mechanical block wich make impossible clamp arm releasing.
The problem is that is relatively hard to see what's hapen at this moment and place.
Thank you for any advice or ideas.

 

[PACH]

hank you for fast responce. Lotem is manual loading. Best results we have with 730x605. Errors on all plates we rich with 675x492.
We see that results depends on different plate stiffness too. Error message is that drum motor can not start in desired time interval. But it is impossible because lower clamps arm not released rear clamps.
I still not discovered is there missing signal for clamp arm releasing or the rason is thrully mechanical block wich make impossible clamp arm releasing.
The problem is that is relatively hard to see what's hapen at this moment and place.
Thank you for any advice or ideas.

Please tell me EXACTLY the ERROR messages on the screen when there is a problem.
Make sure that you entered the correct plate size in the Media definition.

 

[alekbelia]

Errors are:
- Drum motor goto position task timeout
- The task drum motor go pos failed
- The task load from drum entry to drum loading system failed
- The task load manager task failed
- Expose task failed
Drum motor is okay. The reason is clearly visible. Lower clamp arm not switch off after pressing and moving back clamp.
Normal sequence is: The clamp arm press and open the back clamp. The drum motor move the back clamp some millimeters. The clamp arm release the back clamp. The drum motor start rotating.
For some reason after closing the back clamp the clamp arm not released.

 

[alekbelia]

Correct size of the plates is checked many times. Time to time machine working well. But especially with plate size 675x492 some time machine stopping on every plate.
Errors depend of type of plates too. We use 650x550 from 2 suppliers. Errors often happen with one of them. But rarely occurs with all type of plates.

 

[PACH]

Correct size of the plates is checked many times. Time to time machine working well. But especially with plate size 675x492 some time machine stopping on every plate.
Errors depend of type of plates too. We use 650x550 from 2 suppliers. Errors often happen with one of them. But rarely occurs with all type of plates.

Please measure the 675x492 plate when you take it out from the box. In your case the 492mm that is important. If the machine is OK with other plate sizes I suspect that this plate was cut down and it is not accurate.

 

[alekbelia]

Plates are accurate. I measured them too many times. At this moment we use 675x492 from another supplier (different stiffness) and Lotem working fine. It's hard to observe lower part around the drum - what's happen when loading. The problem is not easy to fix. This is the reason to post question in this forum.

 

[alekbelia]

Problem solved. I manually increase pressure of rollers on input roller bar. Roller pressure was not able to bend enough the plate on the drum to go under back gripper.

 

[PACH]

Problem solved. I manually increase pressure of rollers on input roller bar. Roller pressure was not able to bend enough the plate on the drum to go under back gripper.

Well done.

 

[erwin]

Hi, how do you increase the pressure manually of rollers on input roller bar?

 

[alekbelia]

Just with bending them.

 

[LUIS AVILA]

Alekbelia, I have the same problem with my lotem 400 manual loading, how do you bending the input rollers, do you know if exist some adjustment to do that. Regards, Luis

 

[alekbelia]

In my opinion your problem is different. Input and output rollers bars bend the plate around drum. You need to see what happen in loading module. It's easy to disassemble it and see quality of rollers, pressure, etc.