Semi APC issue

2001 Lithrone 626EMP, grrrr! it's just not my week

Unit 3 front plate clamp not actuating, neither when releasing plate nor mounting (we have to go manual). The pneumatic piston fires but the cam that it bears on seems to be swinging freely (more so than the other units). I haven't a parts list for this item (our parts book shows a manual clamp system) so I can't see how it's fitted: grub screw/pinned?

Anyone have any ideas? Paul where are you......Heeeeelp!

 

Some of the early versions used a simple pinch bolt arrangement to lock the cam (lever) to the clamp shaft. If the lever moves freely, check to see if the shaft is moving with the lever. If there is room, hold a mirror to see the shaft or try to feel it with your finger but do not actuate the piston with your finger in there. If a pinch bolt is used, try tightening it but you will need to experiment with the position to get it to lock and unlock the clamp. You can use the other units as a reference. If the shaft is moving with the clamp, there are internal problems in the clamp mechanism. If the lever is slipping on the shaft and cannot be tightened, you may need to replace the lever or shaft or both.

 

Hi klecman, thanks for the info...checked that the pinch bolt is tight on the shaft (which it is), the shaft turns freely and doesn't seem to be held to the clamp mechanism.

Have you got an exploded view, perhaps a pic of the parts page?

 

No, I don't but often the APC parts diagrams are in the back of the parts book under "option". Otherwise, call Komori and have them fax or email you the pages.

 

Yeah I looked there there's everything but the APC.

Cheers for the assist.

Richard

 

HI Richard,
I fly out of here Thursday BA 0056 into Heathrow then Domestic up to Manchester BA1384 arrive about 8.40 am if you would like me to come down and sort the problems you are having either Friday pm or Saturday morning I will be more than happy to just email me.
Kind Regards.
Paul.

 

Hi Richard
I will take my laptop in with me if you need to contact me not sure how much help I will be , Hard to say if you can’t see the problem.

Kind Regards.
Paul.

 

Further to Paul's visit and for other members information - we found a broken keyed joint which sits in between the shaft carrying the operating lever and the plate clamp shaft on the operators side of the press.


Big question: anyone know the procedure to replace this small part?

 

sapc

Richard is talking about part no.34 I am fairly sure after some good info from Andy L that the part can be changed without removing the whole plate clamp but am happy to stand corrected if anyone has any other ideas.

 

I can't help you with the replacement procedure but would want to inspect the part to see why it fractured. Whether it was a casting flaw or resulted from excessive pressure from the air ram travelling to the point of stressing the coupling. In any event, check that the travel of the air ram is not overstressing the holder (34). The air ram travel can be adjusted with the locking nuts on the ram shaft. Try to determine whether it broke on opening or closing and check that the arm (cam) is centered on the shaft so that it does not stress the holder either on opening or closing the clamp.

The usual repair procedure is to make scribe marks on anything that can be adjusted, take it apart and figure it out.

Good luck.

 

Hi Klecman - the press is a 2001 vintage with 74m imps on clock so I expect it's just metal fatigue - the part itself doesn't look particularly robust.

 

Yes, sounds like an old Komori. The parts start falling off but they keep on printing. One pressman told me that they are so solid because they're made from old Chevrolets.

 

Correction: 2001 but 76mil imps, it still makes ready in 15 mins on run of the mill 4 col work and, on the right stock, runs at 13K +.

No shock marks on solids, very tight register between all units, yes even between perfector and subsequent units.

The delivery is the weakest point. On heavily inked work on lighter weights of paper the delivered sheets 'collapse' into a plough shape and scuff the preceding sheet, making a mark about the size of a dollar on the reverse. We can play around a little with downblast and sheet braking but it does compromise the max speed achievable.

Here's a pic (it's mounted on a 300mm plinth btw).

 

Old Iron

I cut my teeth on L640 #102 at Adams Press in NYC back in '89. It had the finiky "B" console and after many years of abuse in a Web plant at Koch Graphics, we took the empty beer cans out of the DBU box and got most everything working. They couldn't get the water low enough to find the dry up point so I installed the newer NPF water motor boards to slow down the pan roller. Then we found the customer was using both alocohol and alcohol substitute. (Go figure) It's sister ship at Northeast Graphics was finally retired a few years back after 350 million impression. Rubber bands holding the feeder head together and all, I think it went to South America or Pakistan and wouldn't be surprised if both are still running. 102 was left uncovered out in the rain after being taken down and for a long time I have wondered where it ended up.

 

Check out the space we have around the press. It's a tad tight but not as tight as the L426 we (FT Neufville BCN) installed in Madrid.

A converted multi-story car park with a spiral access route to the top floor was where we had to build the press up - had to split feeder and delivery away from the print units to get the d**m thing up the access road (usual practice is feeder + 2 units and delivery + 2 units).

When we saw the available space we nearly passed out. The water chiller/recirculators ended up on the balcony outside!

To the best of my knowledge it's still there.

 

Then there was the L440 (Madrid again) zero space for the Royce units.

So some bright spark said put them on top of the drive side running boards...all was OK until they switched them off and the water found its own level. Pretty fountains shooting up the water pan drains.

 

I don't sodding well believe it. Now the 3rd unit APC pneumatic won't fire to release the plate clamp???

It will fire to clamp a plate though, so it's a Friday mystery...where's klecman?

Hey klecman what do you think?

 

First, see if the process will complete itself when only the third unit is selected for plate changing.

I am assuming that you have one of the later generation fully automatic or any one of the semi-automatic plate changers that has only one piston to clamp and unclamp both the gripper and the tail. If you have the older dual piston model, the procedure is similar.

In any event, start the plate changing sequence and when the press stops at the point the pneumatic piston should fire, remove the step and small cover on the operator side toward the delivery of the third unit. You will see the pneumatic cylinder. There should be two sensors one strapped to each end of the cylinder. One of them should show an LED that is lit, the other LED should be off. If both are off, pass a magnet next to each one so that the light comes on and see if the piston fires. I believe it is the sensor toward the delivery end that detects that the piston is retracted. Keep your hands out of harm's way. The computer must detect that the piston is fully retracted before it will fire the cylinder. If it fires, make a reference mark on the cylinder and adjust the band so that the light is on after the plate changing operation is complete. It could be that the sensor is just at the edge of detection and needs a slight bump one way or the other.

Take the press through another cycle to see if the piston fires to both clamp and release the plate.

If the above does not apply, the press may be out of the timing window for the releasing operation to take place. You will need to find the computer input LED indicator for the Varicam output to the Fuji computer input module for "third unit (or process) plate clamp release"; check to see if the computer input status light is on when the press stops to release the clamp. There should be a timing chart with the press or you can deduce which LED indicates the status from the schematic. If the status light is off, compare the timing angle on the chart with the readout on the Varicam. If the Varicam readout is not within the timing window, you will need to adjust the timing window. There are two sets of timing windows, one for the gripper and one for the tail.

It may be that the press is coasting just past the timing window when it gets the command to stop and fire the cylinder. In that case, you will need to adjust the Varicam timing output that issues a main motor stop command. Use the old secret method, adjust it in one direction and if that doesn't work, try the other. Same with the sensor band. Move both ends of the timing window in the same direction by one half degree at a time.

The only variables between the clamp and release operations are the piston position and the timing windows.

When finished make sure that the bearing on the ram lever is hitting the proper spot on the clamp cam by comparing it to another unit and measuring the distance from the bearing to the end of the cam. This is controlled by the Varicam output to stop the main motor for the third unit clamp release command. You may need to work with the two timing windows to get everything right.

 

Hi Klecman, thanks for the info.

First thing this morning I tried taking a plate off and the damn thing worked...confused!

I checked the varicam, the press stops for plate release anywhere (on unit 4) between 306 -309 degrees. Is this variation normal?

Thanks again for the info.

 

That does seem a little wide. I don't know which version of press you have but on some of them the brake is adjustable so I would try tightening it a bit. If it can't be adjusted, clean out the contact surfaces with brake cleaner but avoid getting the spray on any of the wiring. As the brake wears, the press may coast past the timing window. Normal brake clearance is about 0.014 inches or 0.35 mm. Also check that the main drive belt is not slipping.

I would find the timing angle range that the press stops on the troubled unit and record that. If the problem happens again, check the stop angle to see if it has drifted outside of the degree range you found. It is also possible that the piston sensor is just on the edge of detection.

If you would like to, send me a copy of your timing sheet so if this happens again, I would be better able to assist you. ah6k@warwick.net.