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screen printing => Screen Making => Topic started by: Rockers on April 24, 2022, 03:53:39 AM
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Ever since we have an Exile Spyder we are having problems setting up screens on press. Almost non of the jobs sets up in registration. We would have to micro at least a couple of screens with each setup. I checked if I can take a screen print registration marks and then remove it from the Spyder and then repeat the process over and over again. The regi marks always fall in the same spot on the same screen. Where else could the problem be located. We had this issue while we still had our M&R press and now it continues with our ROQ Next. I feel like there is too much pressure applied by the clamps on the Spyder which might pull the mesh too much? The stop blocks on the tri loc do not match the position of the stop blocks on the Spyder either by 100%. I assume this could as well be an area of concern.
I still got screens sitting on a shelf with images that were made using film. Those screens register on press without problems.
Advise would be more than welcome.
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I was told that for every millimeter of stretch that the drum pushes on the mesh, the tension changes by 4 newtons. First I would shim the Spyder to get the drum to barely touch the mesh. Second, if the blocks on each don't match 100% you are unlikely to ever get perfect reg with out some modifications to the entire system.
This is just one of reasons why we choose MHM. All of those variables go away with their pin system.
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I was told that for every millimeter of stretch that the drum pushes on the mesh, the tension changes by 4 newtons. First I would shim the Spyder to get the drum to barely touch the mesh. Second, if the blocks on each don't match 100% you are unlikely to ever get perfect reg with out some modifications to the entire system.
This is just one of reasons why we choose MHM. All of those variables go away with their pin system.
The pin system is a nice option to have, and ROQ got as well a pin system which is slightly different to the MHM pins. Thing is you can`t get an attachment for the Spyder for the ROQ pin system.
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Look at you Dave, giving sage comments. Kudos to you. As said, there are the always present interdependant variables that mix up the process of producing a perfectly registered print from the first strike off to the end of the run. With regards to the MHM pin system well, it originated with old school (still used) table print systems.
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I was told that for every millimeter of stretch that the drum pushes on the mesh, the tension changes by 4 newtons. First I would shim the Spyder to get the drum to barely touch the mesh. Second, if the blocks on each don't match 100% you are unlikely to ever get perfect reg with out some modifications to the entire system.
This is just one of reasons why we choose MHM. All of those variables go away with their pin system.
The pin system is a nice option to have, and ROQ got as well a pin system which is slightly different to the MHM pins. Thing is you can`t get an attachment for the Spyder for the ROQ pin system.
Yes, we use to have ROQ's with their pin system and it's terribly flawed, in so many ways.
bimmridder gives you some very good advise.
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Rockers, the DTS systems I have worked with (Kiwo), we printed the image upside down at the bottom of the screen for it to match the tri-loc system. Are your screens imaged that way?
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Dave hit the nail on the head.
I've been trying for a long time to get perfect registration with MHM and Douthitt.
I get close but not 100%.
What I can say is my registration is very close, and a slight adjustment by a experienced printer gets registration 100% quickly.
Much faster than when we had film.
My feeling is that the time I have to spend trying to keep the whole system perfect is wasted, I'd rather make the small adjustments.
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We have an I Image and the Tri Loc to match. I found no matter how tight I make everything there will always be a little mis reg here and there. It comes down to clamping pressure, slight bows in the frame, mesh tension differences, on and on. To many things to chase down. A tiny 2 second adjustment of the micro regs is all it takes. Of course it still pays to get as close to perfect as possible but diminishing returns comes to mind.
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Jeffery has a way to improve this, aka jepaul.
I'd post more of it if he gave permission but maybe reach out if he's still out there as he has videos as well.
Basically the concept is the tri-loc system is flawed because the contact points are too large, and don't match up exactly with the tri-loc jig on press to the CTS,
If you can reduce those contact points to be smaller and more mirrored from CTS to on Press then you can get closer to perfect registration on press.
However we have not implemented that internally although I'm sure we would see huge improvements for not much modification needed.
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I can see that as helping quite a lot. However it would require the point of contact to be the exact same spot from the CTS to the tri-loc.
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The smaller points of contact would definitely have to help but as inkman mentioned would have to be in the same spot on both cts and triloc. I've noticed here that when using roller frames and the rocket launcher that you have to be super careless to be off registration when they are maintained. I'd say we are 95% spot on with the rollers. Also the rollers have smaller points of contact as well.
Another thing is that we use mainly shurloc frames and when we do a test print and notice one frame is a touch low off that before we start screwing with the micros, I make sure that the squeegee pressure is relatively the same on all heads "enough to clear but not excessive". It has been as simple as lowering the pressure of the problem causing screen to fix the registration. I know that is a tension issue. All good points mentioned above.
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Jeffery has a way to improve this, aka jepaul.
I'd post more of it if he gave permission but maybe reach out if he's still out there as he has videos as well.
Basically the concept is the tri-loc system is flawed because the contact points are too large, and don't match up exactly with the tri-loc jig on press to the CTS,
If you can reduce those contact points to be smaller and more mirrored from CTS to on Press then you can get closer to perfect registration on press.
However we have not implemented that internally although I'm sure we would see huge improvements for not much modification needed.
Yeah I`m going to try this, should be easy enough to make those changes. Plus we will grind down the drum in height a little, maybe by 2mm.
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All around excellent advice here.
It sounds like you did so already but, in case I misread- ensure that the CTS itself can repeat registration. i.e., is it printing the reg marks in the same place on each screen if you print twice without removing the screen? It's very possible to have an x or y axis alignment or repeatability issue with the CTS itself. Rule this out before you go chasing your tail downstream.
If it repeats without removing the screen, see if it will repeat if you remove the screen and reclamp. It could be an issue with how the screens are loaded and clamped.
If everything is repeatable at the CTS itself, do a decent size control batch to make sure it's 100%. If it is 100%, then start looking at the jig you are using on press and ensure you are matching the exact three points of contact from CTS to press. Procedure in loading the frames is important here and will make a difference in registration success.
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All around excellent advice here.
It sounds like you did so already but, in case I misread- ensure that the CTS itself can repeat registration. i.e., is it printing the reg marks in the same place on each screen if you print twice without removing the screen? It's very possible to have an x or y axis alignment or repeatability issue with the CTS itself. Rule this out before you go chasing your tail downstream.
If it repeats without removing the screen, see if it will repeat if you remove the screen and reclamp. It could be an issue with how the screens are loaded and clamped.
If everything is repeatable at the CTS itself, do a decent size control batch to make sure it's 100%. If it is 100%, then start looking at the jig you are using on press and ensure you are matching the exact three points of contact from CTS to press. Procedure in loading the frames is important here and will make a difference in registration success.
I totally appreciate all the advice I get here. You are right we did all those steps as described in your reply. No issue with the Sypder. Still, I remember seeing a post from Denver Print House in which Danny said he did grind down the drum itself as it is putting too much pressure on the mesh once the clamps hit. That and the fact that there is a too big contact area on the stop blocks will for sure have an effect on the registration. I bought some rivets, like you find on denim trousers, and will stick those with double-sided tape to each stop block. Then mirror their position on our regi pallet. This will reduce the contact area on each block to around 2mm in diameter.
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Yer on the right path! Match the points on both cts and jig and then establish a very specific sop for screen loading at both points. Include how the on press registration jig is loaded and locked in this sop as well.
Exile has world class support and also some serious parts making resources. They probably can get you blocks that are exact match to the points on your on press jig.
I would consult with their team before reducing the drum height, there are some techy details with tension that need to be considered I believe.
There are 1,001 other variables and ways to reduce setup times but establishing this baseline will be a big step. Remember to zoom out periodically and see what's really holding up the setups, it's not always reg time.
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as someone who has been working on this (with and without danny) for over 3 years, and 2 of those 3 years was with an SPYDER III, here is what i recommend:
-Ask them to send you a new drum, that matches the specs that Danny requested.
-Ask for their new blocks, which have more precise contacters. You want pin point blocks touching your screen, not the broad blocks they typically come with.
-You need to make sure your blocks on your CTS hit in the EXACT same spot as your reg board.
-Make sure screens are at similar tensions (within a job).
-Make sure all your frames are the same thickness. This seems trivial, but it can be an issue with the drum/tension of the mesh.
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as someone who has been working on this (with and without danny) for over 3 years, and 2 of those 3 years was with an SPYDER III, here is what i recommend:
-Ask them to send you a new drum, that matches the specs that Danny requested.
-Ask for their new blocks, which have more precise contacters. You want pin point blocks touching your screen, not the broad blocks they typically come with.
-You need to make sure your blocks on your CTS hit in the EXACT same spot as your reg board.
-Make sure screens are at similar tensions (within a job).
-Make sure all your frames are the same thickness. This seems trivial, but it can be an issue with the drum/tension of the mesh.
Thanks for all the advise.
May I trouble you to elaborate a little on some of those points you have made.
So the "new" blocks are standard issue now or a secret menu item so to speak?
What makes Danny`s drum different to the standard drum?
Screen tension is not an issue I`m worried about as we have that locked in.
Thanks for your help.
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Danny had them make changes to the reg. blocks on the unit. This was in the last year, so i'm not sure if they are now standard.
Same thing with the drum Danny had them shave it down, so it didn't put as much tension on the screen.
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All around excellent advice here.
It sounds like you did so already but, in case I misread- ensure that the CTS itself can repeat registration. i.e., is it printing the reg marks in the same place on each screen if you print twice without removing the screen? It's very possible to have an x or y axis alignment or repeatability issue with the CTS itself. Rule this out before you go chasing your tail downstream.
If it repeats without removing the screen, see if it will repeat if you remove the screen and reclamp. It could be an issue with how the screens are loaded and clamped.
If everything is repeatable at the CTS itself, do a decent size control batch to make sure it's 100%. If it is 100%, then start looking at the jig you are using on press and ensure you are matching the exact three points of contact from CTS to press. Procedure in loading the frames is important here and will make a difference in registration success.
Thanks for your input. We indeed made sure the CTS can repeat registration, we did several tests. No problems there. We did with and without removing the screen, both times the registration is bang on. My money is on the drum causing too much tension on the mesh and the fairly big contact area on those stop blocks,