Registration, Pins and hanging plates

Just switched to register pins on press and are punching plates on ctp. Here is the problem - when hanging plates for a job nothing lines up for registration. We have set up set of plates parallel to sheet and then zeroed circumferential and side to side manually and with console. I have not been able to get a set of plates to register without manually setting up skew for all units and then continuing set up for registration. It is not even consistent moves for each unit, every job is different making a very time consuming job of setting up all units to line up. I would greatly appreciate any suggestions or knowledge of hanging plates for consistency.
Do I need to change anything on the clamps? How do I get the plates to hang in the same position every time?

 

tell us more about the press....

what make / model / age ?
what was done to the press and by whom ?
it may be that you need to set up a basic "0" and move on from that point , but without details....

Meny

 

Thanks for the reply. I am running an adast 755 year 1998, used to be di but we changed over to using ctp, so much better quality. We are running presstek pearl plates right now but are switching to Fugi shortly. Installed pins in plate clamps and also matching pins in ctp. I have set up four plates to fit image and then my boss and I disengaged the motors for side to side and set the console to zero. Also the same for circumferential. Thought that I'd be able to hang plates and be close for image set up but not so. Each job I set up is just like before the pins, in fact I was able to get closer when I hang plates without plates. Really want this to work the time involved is so frustrating. I hope you and some other more experienced operators can help. I have been printing for 30+ years but fairly new (2 years) to larger press formats.

 

Annie, Pins installed by a service guy? Typically, pins will be installed in a predetermined position on each lead clamp and then clamps must be zeroed to each other using a grid to establish a starting point for each, then set to a mechanical stop so they return to "home" position prior to each plate change...think I got this right. If they don't return to the same position each time, how could you possibly get register efficiently???

 

junker1984,

Thanks for the reply. I installed pins on lead clamp, yes holes were drilled for pins from factory so they are set. Can you explain zeroing the clamps to each other and the grid you would use. You are correct that by not returning to the same position the plates do not register. Even when I return all settings to zero with the console I have not been able to get register for each plate change. So you seem to be on the right track, I am just not sure how to set all the clamps to the same starting point.

 

Hey Annie, not familiar with your machine, but on the "gray ones" I work on, with conventional clamps, they're equipped with the physical stops, which returns them to home position when plate is removed. By grids, I mean like one inch grid squares to compare positioning of clamps on start up. You in Mpls area, did you work for IDS?

 

Hi there junker,

Okay, thanks for the info, going to take off clamps and see about setting a home position that is same for all. Will check to see if there is a stop, don't remember seeing anything when taking them off before. I usually just set the console to zero out each unit and start from there. Yeah I lived in Mpls for a long time and now moved to Cannon Falls about 45 miles south, not far enough for warmer weather. I started printing at Dayton's, they had a sign shop and then I moved to print shop where almost all forms were printed and some advertising printing. Then I worked at Blanks USA for quite awhile, that's where I ran my first 26" press a 2-color Solna. This press is a waterless system, it has been interesting to see the difference between conventional printing and waterless.

 

Hi junker1984, I meant to say that the press I am running now is a waterless system.

 

Ok, you at the beacon?

 

No, I have my own shop and in the same building I work for BRC also known as Boldon recycling and converting.

 

Junker...how do you set "home positions" for each clamp using Grid..can you explain to me more details. My press is GTOV...thanx

 

GTO lead clamps are equipped with fixed position bolts, with the hex going through the center web of the cylinder. Suggest you use a feeler gauge set and measure the distance from the top of lead clamp to drop off of cylinder gap to start with. Adjust the fixed position bolts and lock them, making sure the gap doesn't change. Do this at all units, then you'll have to hang plates and using hit miss method, make fine adjustments to the individual clamps. Hard to explain, I don't have a GTO parts book on hand to reference pictures.

 

My suggestion would be to start out as junker mentioned by squaring off the clamps with some form of feeler. Then i would back off the stop bolts about 3mm on each side allowing the plate clamp to pivot on its adjusting bolts. I would then mount all your plates that have been imaged with a fine line grid. These plates should also have both circumferential and lateral register marks to center to the sheet. Im not sure if the GTO is so equipped but if it is you would want to also be sure all units spring loaded register pins located on the gear side of the press behind the cover, on the plate cylinder gear assembly are all in the same of 2 positions.
The next step would be to center all units both circumfrentially and laterally on either the press console or using the hand wheels if not console equipped. At this point you would also want to be sure the headstops are square. I would not trust the headstop gauge adjustment but instead feed a sheet into the first set of grippers and measure the gripper bite with something that will read accurately.
Once all this is done you print just your first unit. At this point you square off and center the grid on your sheet using ONLY the plate clamps. It is recommended that you use the maximum size sheet the press will accept. Once your first unit is both square AND centered you can turn in the stops on the clamps until they just touch the plate cylinder. This will be your "HOME" position!!! Once they just touch you can lock up both sides being very careful to prevent the adjustment from moving when you tighten up the jam nut.
From this point you just strike in all the other units, repeating the above procedure until they are all in register with unit 1.
The time spent getting this right will pay off in the long run with reduced makeready times.

 

That's what I meant to say, Tom!

 

Turbotom and Junker1984...thx guys for your detailed answers...sorry i just read your replies...