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screen printing => Newbie => Topic started by: vwyob on August 14, 2014, 02:53:02 AM
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Hello again.
First off, this site has been an incredible help to me in making my transition from Litho to screen printing. I have spent hrs reading through your posts, many thanks.
I am trying so hard to implement a program of continuous improvement here and getting everyone (from the office right through to despatch) to 'up their game'. The print is the hardest because the guys are resisting the offer of new/different methods. The more I read here on this forum, the more I realise we are somewhat off of the mark. The FPU is now in full use after sitting, covered in dust, for a few years. We are now coating to sufficient EOM on the screens INSTEAD of doing a 1/1 and scraping the print side off (yes I know it sounds crazy but there you go). So improvements are being made. Now I want the guys to nail the white.
Our whites are rough to the touch and not truly opaque. They have been running white jobs on 49 (125?) mesh for the UB and 77 (196?) for the top/highlight white. Squeegee's are red for the UB which I have been told are 60 durometer, and green triple 70/90/70 for the HW/top. On the E-type they are running floods at 10 and print at 6. The pressure is set to 6 throughout. The height/drop is set so it kisses the pallet and then wound on a full turn. Floods set, again, to kiss the pallet and with a slight bulge felt under the mesh - though its lifted a touch with WB/Discharge. Off contact around 3 to start with and angles at 4. They are double hitting the UB. I have got the guys to print with a 77 mesh for the under base but results similar albeit not quite as thick.
I get told constantly 'this is the way we have always done it' and, although they are producing the goods to be fair, looking at many of the garments garments printed by other companies and, indeed, the amazing array of prints I have seen here on TheShirtBoard....we are not up to scratch. It has to change.
Yesterday a job came in from a supplier that had already had a print on the backs. The print was done in China. Although it was far from perfect, it made ours look worse than ever. It was flat to the touch and almost indented, kind of like a heat press look but it was a true plastisol print. Lovely soft hand feel too, very thin. Opacity could have been better but better than ours. I pointed this out to the guys and have been hit with an array of reasons why we will never hit this kind of print. Its frustrating because we have all the kit here but are not using it to its fullest potential.
I have taken some lupe pics. Please advise if you can.
Many thanks as usual.
Tunnel is running at 170C/338F. But prints still have a slight shine on them. The image on the supplied garment was flat matt.
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There are a lot of variables at play here, and I'm sure plenty of others will chime in, but what I see right off the bat is:
1. jagged edges to your print/stencil (likely due to an issue with exposure leaving less than sharp vertical walls to your stencil and dot gain on the print, which could also be from something like overflooding)
2. poor mat down (i dont know what ink you are using, but it could need to be mixed or heated up, your platens may need to be preheated, etc) which is causing issues with opacity and the jagged final print texture. The ink may simply be sticky and needs mixing or heating, or it could be a poor ink for basing, or it could be an issue with how long you are flashing. You may need to run some kind of crushing screen or a roller squeegee if you can figure out how to get a cleaner base.
No way to fix it all in one go without being in your shop really, but these would be some things to look into.
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Great thanks buddy. Its a start.
Image setter arrived a few days ago, so we are hoping for better film work and a more defined and opaque dot. The exposures were check when we upped the stencil thickness using a calculator. However it was some time ago so I will get the guys to recheck exposures. The have tended to underexpose slightly to compensate for dot loss from the epson; hence the image setter purchase.
Stirring the ink!!! lol How many times have I asked them to stir the ink??!! I am met with the, 'The squeegee will do that mate' answer. I have tried to explain that they should still stir them prior to run. What kind of consistency do you aim for with the underbase? At this point I would like to avoid reducer, though we have three varieties here if they are needed. One of the guys uses flow thinner but it can completely hash the ink.
Thanks for the swift reply
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which ink are you using and what kind of screens?
we are on an E-type too and with good screens we run 99% of our jobs with off-contact set at 0 (1mm). If you are running on 3 either your screens are bad (tension should be 20N+) or you are not using it properly.
the coverage and smoothness of the deposit is a function of many things, but the mesh and ink selection will have a huge impact. S or LX mesh will be required to get a nice smooth deposit on the press without rubber on platens.
As a workaround until you get your ducks in the row, I suggest getting a roller from Action Engineering.
pierre
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We do a lot of printing that is white only, one color, no flash.
We use 110 Mesh, firm squeegee, I think it's 70 shore.
Double stroke on the E type and we get the best results with Wilflex Tiger White.
The Chinese often put the garments into a hear press after printing, this gives them the soft smooth finish.
If you paid your workers Chinese wages you could try that. The roller could help.
We don't get a very smooth result be are more concerned about getting a bright white with a single screen.
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We do a lot of printing that is white only, one color, no flash.
We use 110 Mesh, firm squeegee, I think it's 70 shore.
Double stroke on the E type and we get the best results with Wilflex Tiger White.
The Chinese often put the garments into a hear press after printing, this gives them the soft smooth finish.
If you paid your workers Chinese wages you could try that. The roller could help.
We don't get a very smooth result be are more concerned about getting a bright white with a single screen.
Maxie, try the LX mesh. We get better (whiter and smoother) results with one stroke through 150LX then with two through 110.
pierre
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I've tried 150LX in comparison with a 125 and seemed similar.
Seems like we can get more of a film with 110t. Maybe the LXs mesh
isn't up to strength at 20-22 yet though.
The LX coats really weird being almost 'Knucleless" if there is such a word.
Kudo's to Northwest Graphic Supply for upgrading to LX because s wasn't in at that time.
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I've tried 150LX in comparison with a 125 and seemed similar.
Seems like we can get more of a film with 110t. Maybe the LXs mesh
isn't up to strength at 20-22 yet though.
The LX coats really weird being almost 'Knucleless" if there is such a word.
Kudo's to Northwest Graphic Supply for upgrading to LX because s wasn't in at that time.
it is making a huge difference for us!
Comparing 150S/LX to 110T, it is half the thickness and has 20% more open area than 110T. The opening is about 20% smaller, but overall, it should let the ink fall through the mesh a lot easier. I can see ink with high internal tack maybe being impacted by the smaller opening though.
pierre
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How about emulsion, # of coating strokes, tension, squeege dur, angle and speed if you can...
Thx
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I just had troubles last week on a white job.. front went perfect, back was mediocre... no changes at all on press... literally took one screen out and put the new screen in.
couldn't figure out what it was... but after I reclaimed the screens and dried them, I put a tension meter on them.
sure enough.. the good screen from the front was at 22ish newtons.. the 'bad' screen from the back was around 17 or so. wouldn't think that 5 newtons would make that big of a difference, but it certainly does.
2 things to check that might seem basic, but took us a while to understand at the beginning...
1. Are you fully clearing the screen before flashing... if the underbase is rough, anything else is going to be bad.
2. Are you fully flashing the underbase/first layer? If it's not fully flashed that can cause the effect you're seeing... or at least it has in my experience.
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Ok guys I am really grateful for the info.
We are currently testing various whites. This job was with Rutlands 'Best Of Brands' Creamy White. We tested some Tiger the other day and there was slight improvement. Unfortunately we don't use Newman frames, instead we have a large quantity of the aluminium ones and the tensions range from 21 newtons up to 26/7 newtons. Coating is with CP-Tex and we now coat 3/1.
Pierre I had no idea I could change the type of thread. I will look into it. The guys tell me they start around 3 on the off contact because they get pick up quite a lot. I have seen and heard it myself 'clack!'. But it is a separate issue and I am convinced they run the flash way too hot.
Again I thank you for the information and guidance. It is not easy to re-educate printers, or enlighten them that they 'may' have been doing things incorrectly for years. It is quite a delicate situation.....especially when a guy like me, that has come from 25 years in the lithographic industry, joins the team and say 'hey guys...lets change the way you print'
I have shown them some of the samples that you guys are producing, especially you Pierre - as i am aware you have an E-type (in fact it was because of you I managed to get the FPU into service)- and most of them have raised an eyebrow. I really want this to work, passionately, and I will do everything in my power to make it happen.
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get a gallon of EJ Special white Auto from onestroke and test that. we found that to be a great white ink.
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Is it available in the UK? I will have a look.
We have ordered a smoothing/roller squeegee and a double squeegee also. Cheers buddy
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I'm guessing this isn't YOUR shop... Are you the manager or just a team member wanting/knowing you guys can do better?
I'd suggest maybe getting a consultant in there, I bet he could whip you guys into shape pretty quickly. With his guidance your guys could print something awesome right then and there, then that would stop them from thinking they can't do it while at the same time giving them the means to do it!
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No you are correct. I don't own the place. I'm the works manager. I oversee everything from when orders come in, right through to despatch. Every change that has been introduced so far has worked, yet still there is resistance to learn. I went through staff staff appraisals last week. It was interesting reading. I came to the main printers sheets and one of the questions was 'how do you consider yourself as a printer?', he wrote one word..'perfection'.
This was the guy that refused point blank to have the FPU used and the same guy that instructed the pre-press guys to coat screens with 1/1 and then run a dry scoop up the print side to scrape off the excess. He has been a printer for 22 years. I tried to explain to him that knowledge and experience are different animals. No joy. I have urged all of them to join this forum and ask questions; read articles; look at the prints. No joy. We'll get there. Just going to have to try another route. Thanks for the advice :)
My apologies if it seems like i'm ranting. It is merely frustration. There is so much potential here. We have plenty of good, solid kit and the boss is completely genuine and pro-active. Anyway....all good :)
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I definitely suggest to get a consultant in there... Seems like the boss would go for it!
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Hiring a consultant can be a two-edged sword. So much of this is dependant on the workforce. They must be willing to try new things and put the egos aside. We are a finicky group and, since much of what we do is considered to have a high to mid-level degree of craftsmanship and creativity, there is often a degree of pride we take in what we do (hopefully). When Mr. Smarty pants arrives there can be more than a bit of eye rolling, especially if they are seasoned workers. That is the challenge of the consultant. Its all about personality. Being humans, we tend to resist change. And its much easier to make change not work then it is to make it successful.
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It sounds to me like the guy who has been there for 22 years thinks he knows it all, but if you are producing inferior work to cheapo chinese prints (not that these are all bad, but some are including the one in your photo) I would hope he would want to change that. When I see a nice print in a store or on a friend, I tend to geek out and look at it for a while to try to figure out why it is so good. It annoys the hell out of my wife...
I'm not sure if a consultant is worth the money if they aren't expressly open to the idea. I think first you need to explain that even on a forum like this, with some of the best printers out there who have decades of experience, they still have ah-ha moments that they share. That's just how printing is, there is always some area to improve. Based on the image you posted originally, this guys 22 years of experience mean very little as a lot of us have been printing for a fraction of that time and produce superior prints every day. That's not because we are lucky or have better equipment or anything...it's because we have researched and tested and have an enormous drive to become better printers. This forum and others like it are ESSENTIAL to being better as you have the collective knowledge of so many great printers who want to help.
If they are satisfied with their inferior work and don't want to improve, you might want to find new people. Experience is great, but not when it is an obstacle to improvement. Someone without experience, but with motivation to improve will likely have you printing better in a shorter amount of time and with a lot fewer headaches.
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At the very least use a harder squeegee for your underbase, and likely slow down the print/flood until you get the ink flowing.
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I agree completely. Many guys that believe they know the most actually know the least. I was a litho printer for over 20 years before going into management, so I know how easy it is to get stuck in your own comfort zone. I realise it is not the same medium lol. The machine costs for one; the last speedmaster I ran cost 1.4 million GBP and ran happily at 15000 sheets PH, here the E-type was around 40k I think. But people are people regardless of the job, pride I guess. After my last post I spoke to some of the team and I think some progress has been made. Not matter what you do, or how well you do it, there will always be room for improvement. Its starting to sink in that what I am doing is in a capacity of help and good intention.
I have asked them to be receptive; read and understand; read more from other sources and find the common seam in what they have read.....then apply it. Test it. Move forward.
I've gone a tad off topic, my apologies. Thanks again for all of the help. The forum is totally invaluable/priceless
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Mirakami has news letters that always have good information... I print each one out and give it to my production manager and he reads it and puts it in a binder.
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How about emulsion, # of coating strokes, tension, squeege dur, angle and speed if you can...
Thx
Hey Pierre,
Guess I didn't make it clear- did notice above, vwyob had some good specs on his variables.
Was asking you -what would you have on these parameters?
Being seasoned, you have a very good handle on ink lay- Quick White I assume? :)
It will be a great learning tid-bit for all to benefit I'm sure.
Thanks!
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Gary I would love to see how other guys set their e-types.
I have recently got the guys to slow down the flood and print. It was on 11 for flood and around 7 on the print. Now its 5 on the flood and 4 on the print, a little slower on the white. Angle for the white was on 3 but now been changed to 7 or 8. The pressure dial on the side is on 6 for all units. The amount of drop from squeegee to pallet we set with film initially, ignoring the dials. Even pressure established side for side, a firm pull of the film strip with print squeegee in its print position. Flood drop/height is set with a slight bump under the mesh and barely touching pallet. They used to crank everything down and down HARD. They have gone though several pallets with de-lamination. Not good.
After the weekly initial setting we pop in the ink and do a test. The height will have to come down but not by much, slight increments instead of full turns. The lads are too keen to drop the squeegee down to clear screen. A lot of the time they are crushing the garment. Getting them to see and address other variables first has been a toughie! lol
I would be really interested to see how other guys do their initial setup.
Also cheers Gilligan :)