Holding registration -- what is a reasonable expectation?

[screenxpress]

He's got a Workhorse back clamper like I do.

I'm still curious whether his 1/16th movement is left to right or in to out.

[nobrainsd]

Certainly many very good suggestions here. I have a workhorse 8/8 all heads down. Registration is a bit of an art. I don't over loosen my lock down handles a lot. Just enough to be able to move the screens easily with the micros. Then I lightly lift or kind of bounce the edge of the screen after I initially adjust the micros. What looked like a dialed in by micro setting will be off a little. I always attributed this to friction across the screen on my film creating tension (18x18 platen and film), but what do I know. After I have a pretty solid reg I'll tighten the screen in place with the lock down handles, raise the screen, swing back and forth once lightly, drop and check reg. Usually it is right on. Technique works for me. I'm using large screens and I print long runs with no issues.

Since it is a registration issue rather than a printing issue I would assume that you have the screen positioned flat on the positive. Make sure your print arm is fully down into the registration gate. Flush on the bottom. If it isn't you will get movement as the arm is depressed depending on how far down it goes each time. The screen deflects. It doesn't take much. Easy to miss.

[redwoodtees]

He's got a Workhorse back clamper like I do.

I'm still curious whether his 1/16th movement is left to right or in to out.

Left-right. In-out registration is pretty stable, but I am intrigued by your yardstick idea. I spent the weekend filling potholes, so I did not have time to work on the press. I'm hoping my main issue is simply that the nylon gate bolts are out of adjustment. I'll report back either way. Lots of great info in this thread!

[screenxpress]

If the nylon and gates seem to be snug and you do not see any issues with the tightness of the arms bolted to the spinning platform, you could be experiencing some slight slippage of the screen frame in the back clamp.  If nothing else comes to light, try putting some strips of the non-skid tape (black tape with embedded sand) in the top and bottom of the back clamp to insure no movement left to right when you tighten down on the screen.

Outside of that, I got nothing.

Let us know what you find.

[Northland]

I haven't been following this thread very closely.... but would like to add an observation about "back-clamp" manual presses:
I used a CAPS back clamp for about 10 years & if I got a little too aggressive spinning the screen carousel.. I could push the screens out of left/right registration.
I learned to push the screen carousel closer to the clamps when spinning it. That way you have less leverage to torque the screen out of reg.

I switched to a side-clamp Kruzer a couple years ago and have nothing but praise for it.

[redwoodtees]

So I'm still struggling with this. I have adjusted the gate bolts as tight as possible without binding. I have followed the recommendations of Workhorse tech support (short version - "Tighten everything"). I'm still having this problem where I register the screen, tighten everything down, then simply raise and lower the screen, and it's out of registration by a 32nd to a 16th of an inch side to side. I can repeatedly raise and lower the screen, and the reg is consistently off -- it's not like its moving around. So all I can figure is that something is binding up when adjusting with the micros, and then that something is "releasing" when raising and lowering the screen. I'll put in another call to mfr. tech support in the morning.. I guess I am just venting my frustration here. Of course, if you have the solution, please do share! Thanks for listening.

[screenxpress]

You only mentioned the gate bolts, which I assume you mean the nylon guide bolts. 

I don't see any mention of the bolts holding the screen arm to the carousel or the bolts holding the platen arm to the carousel.  Unless that fell into the "tighten everything" category.

I don't think you answered by earlier question whether Newman frames, Aluminum frames or Wood frames.

Also, if the mesh is really low tension, the image could dance all over the place just by itself.

[redwoodtees]

Yes, I mean the nylon bolts. They are adjusted so that it takes some force to lower the screen, but not so tight that it binds or squeaks. I have tightened everything between carousel wheel and screen. Standard aluminum frames with relatively new s-mesh. I don't have a tension meter, but I don't think low tension is the issue.

[screenxpress]

Thanks for filling in the blanks.  Unfortunately, without seeing the press, I've exhausted any ideas.  Sounds like you have done just about everything possible.  But yet, something must be hiding and a real booger to find.  Good luck and let us know when you stumble across it.

[Frog]

So I'm still struggling with this. I have adjusted the gate bolts as tight as possible without binding. I have followed the recommendations of Workhorse tech support (short version - "Tighten everything"). I'm still having this problem where I register the screen, tighten everything down, then simply raise and lower the screen, and it's out of registration by a 32nd to a 16th of an inch side to side. I can repeatedly raise and lower the screen, and the reg is consistently off -- it's not like its moving around. So all I can figure is that something is binding up when adjusting with the micros, and then that something is "releasing" when raising and lowering the screen. I'll put in another call to mfr. tech support in the morning.. I guess I am just venting my frustration here. Of course, if you have the solution, please do share! Thanks for listening.

With that head and that station, are subsequent strike-offs all in the same position, or does it jump differently each time? And always only side to side?
Also, I forget, did you say that this was a consistent problem on all heads and all stations?
btw, I use a 20 year old Mach VI (not an all heads down version)

[screenxpress]

So all I can figure is that something is binding up when adjusting with the micros, and then that something is "releasing" when raising and lowering the screen.

On mine, I have knobs to lock down the micro adjustment.  Thought they all did.  If yours is like that, how could it be anywhere in the macros once you tighten down those knobs?  I think it's somewhere else.  Frames slipping in the clamps?

[Prince Art]

@ Redwood: Once you've got the print registered except for this unwanted offset, is it possible to adjust with micros to compensate? Is it predictable so that if you go a little "out" in the opposite direction while registering, you'll actually be "in" and stay "in" once everything's locked back in place? I experienced a little of that with our manual. The screen didn't sit exactly the same when loosened for reg as it did when tightened for printing. But once I got used to it, I learned to compensate during reg, and it wasn't a big deal. And once locked in, it printed consistently.

[redwoodtees]

@ Redwood: Once you've got the print registered except for this unwanted offset, is it possible to adjust with micros to compensate? Is it predictable so that if you go a little "out" in the opposite direction while registering, you'll actually be "in" and stay "in" once everything's locked back in place? I experienced a little of that with our manual. The screen didn't sit exactly the same when loosened for reg as it did when tightened for printing. But once I got used to it, I learned to compensate during reg, and it wasn't a big deal. And once locked in, it printed consistently.

Yes, this is exactly what I am experiencing. Thanks for providing a more concise description. The combination of my inexperience and the press being out of adjustment was causing me a great deal of confusion and frustration. I was able to register a job yesterday using the process you describe, and the press stayed in registration.

[Prince Art]

@ Redwood: Once you've got the print registered except for this unwanted offset, is it possible to adjust with micros to compensate? Is it predictable so that if you go a little "out" in the opposite direction while registering, you'll actually be "in" and stay "in" once everything's locked back in place? I experienced a little of that with our manual. The screen didn't sit exactly the same when loosened for reg as it did when tightened for printing. But once I got used to it, I learned to compensate during reg, and it wasn't a big deal. And once locked in, it printed consistently.

Yes, this is exactly what I am experiencing. Thanks for providing a more concise description. The combination of my inexperience and the press being out of adjustment was causing me a great deal of confusion and frustration. I was able to register a job yesterday using the process you describe, and the press stayed in registration.

Glad it helped. I wish I had the advice that would actually make the problem go away. But as said, I got used to just dealing with it. And as long as the prints are consistent & stay in reg once you've got it done, that's what really matters.

[redwoodtees]

I'm back! Setting up a new job, and having issues again. Right now I'm working with one screen on one head, registering to a crosshair on one platen. I'm not moving the platen at all, so I think it's safe to eliminate any issues with the platen. All bolts from where the head mounts to the carousel to where the screen clamp mounts to the head are tight. The nylon gate bolts are as snug as they can be without binding. The screen clamp bolts are gorilla-tight. But still:

If I raise the screen and give it a *very* gentle tug to the right, to simulate spinning the carousel, and then re-center and lower the screen, the registration will be off slightly to the right. If I do the same, but give a gentle tug to the left, the registration will be off to the left. So something is still moving. I spent a couple hours last night trying to figure out what is moving, and I can't seem to figure it out. My best guess is that the screen is moving in the clamp. Earlier in this thread someone suggested applying anti-skid tape to the screen clamp.. That's probably my next move. I was also looking at the clamp design -- The jaw of the clamp on my press is about 3" wide, but the screen is only about 1 1/2" thick. So the clamp bolts have to extend pretty far into the clamp area to contact the screen. I'm wondering if the clamp would be more stable if I used a spacer block, so that the clamp bolts would not have to extend out as far.

Good times!