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screen printing => Screen Making => Topic started by: SI on January 15, 2016, 06:31:34 PM
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I hate to post this cause i feel like the Newb that I am but,,,,
I have been printing for about a year now. Up until 1 week ago I have been using a DIY exposure unit consisting of a 1000k watt metal halide lamp I got from Menards. The distance between lamp and glass is correct, etc. I did a lot of research on it when i built it. So my exposure time for photopolymer was 30-35 seconds, and time for SP-1400 emulsion was 90 seconds roughly. I didn't experience any slime inside the screen when washing out and I really never had any problems with this system. The issue i had is the lamp has to be always on and its just a pain getting the vacuum on my DIY system I had. So i found a really good deal on a older MSP 3140, pre M&R version with the 4 posts. It has a light integrator and everything appears to be working.
The issue I have with it is when doing either emulsion, if I leave the screen on long enough so it properly exposes, i lose all detail. In order to get all my halftones and the correct amount of detail I have to basically expose the screen for half the required LTU, and then wash it out, dry, and post expose. But this leads to issues with slime on the inside of the screen and I know it will cause problems if I get to any jobs over 100 shirts or so. I do mostly WB and DC so I know ink sitting in this screen will probably lead to issues on a long run with losing so much emulsion.
So, Has anyone have any advice on this? I am thinking maybe the lamp is going out, just seems weird that a $30 MH lamp from a hardware store would outperform this, but possibly I am doing something wrong that i don't realize as well.
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What film type?
Shane
Sent from my SAMSUNG-SM-G890A using Tapatalk
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this is the film i am currently using:
http://www.tandjprintingsupply.com/productdetailI2.aspx?dataid=SVTJWP517100 (http://www.tandjprintingsupply.com/productdetailI2.aspx?dataid=SVTJWP517100)
I can tell where the film was on the emulsion after washing out the image, where with the DIY unit i don't have that issue. I'm leaning towards thinking the lamp is just weak.
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Maybe they put a different bulb in than what is recommended to small wattage.
Shane
Sent from my SAMSUNG-SM-G890A using Tapatalk
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many things to look at here, but without a doubt your exposure times are too short. We were at 90 seconds+ for 305 mesh and 110 was almost three minutes on our 3140.
problem you are having with halftones closing in has to do with your films not being dark enough. The light is burning through it and exposing the emulsion. what kind of ink are you using? what kind of printer? RIP?
pierre
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Epson 1430, Stock ink from Epson. I haven't bought a rip yet, I am using ultraseps plugin for photoshop. I am suspecting (film not dark enough) as well after reading your comments. Im going to download a trial of accurip and try a test of that compared to using ultraseps utilizing your test file from here:
http://www.theshirtboard.com/index.php/topic,8018.0.html (http://www.theshirtboard.com/index.php/topic,8018.0.html)
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Now I feel silly, Ultraseps is definitely not good enough to be printed from directly. Looks like I'll be buying the full license of Accurip unless there is a cheaper equal option out there? I'm posting the 50% opacity pictures, obviously the crisper square blocks are from accurip. Not to mention the ink itself is more opaque from the accurip print, I don' know why i thought for some reason that Ultraseps could replace a RIP, luckily almost everything I have done so far has been logos and nothing with half tones. Back to exposure time testing. Is there a huge benefit with going with the black pearl all black ink kit for the epson printers?
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Speed, but you sacrifice detail.
Almost everyone opts for detail over speed and just runs a single black.
It's been discussed a good bit on here before.
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Now I feel silly, Ultraseps is definitely not good enough to be printed from directly. Looks like I'll be buying the full license of Accurip unless there is a cheaper equal option out there? I'm posting the 50% opacity pictures, obviously the crisper square blocks are from accurip. Not to mention the ink itself is more opaque from the accurip print, I don' know why i thought for some reason that Ultraseps could replace a RIP, luckily almost everything I have done so far has been logos and nothing with half tones. Back to exposure time testing. Is there a huge benefit with going with the black pearl all black ink kit for the epson printers?
Lok at cadlinks filmaker.
Shane
Sent from my SAMSUNG-SM-G890A using Tapatalk
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Okay, Epson 1430 folks, are there no settings to tweak with the printer itself to obtain decent black films?
On the old 3000, it was set for backlit transparency or something.
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As far as the exposure unit, make sure you have a new bulb and also make sure you have the correct line voltage selected INSIDE the machine. If you're not sure of this, consult your user manual or call service as this is very important to get proper voltage to the bulb.
Also, check your glass on the unit and see if it's been replaced. If you look at the edge of the glass and it has a very green hue to it, chances are it's been replaced with regular plate glass that can block the UV light causing longer exposure times.
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Okay, Epson 1430 folks, are there no settings to tweak with the printer itself to obtain decent black films?
On the old 3000, it was set for backlit transparency or something.
I just have it set to Best Photo and Epson Premium Glossy Paper. Using Cobra CISS all black ink. I can print dark spot color films straight out of photoshop.
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Cobra all black dye ink in refillable carts for our 1430 and we love it...Really dark films. I have a 3140 as well.
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If you can see through the black area of the film, then light will be getting through as well. Some dye type inks can pull this off, but halftones need good opacity. You are only getting a dozen or so pico liter dots on halftones below 10%. You can also double up your films until you get a good RIP which has more control over opacity. Definitely get a new bulb from M&R to start with.. The new ones have stronger light IMO than the older ones from years ago.>
Pierre's advice is sound, your times are quite short to properly expose the emulsion. Run a step test, or emulsion calculator on each mesh count. Get some baby powder to put on the print side of the screen. It will save your black imagery. Once the glass heats up film tends to stick to emulsions.
Al
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Now I feel silly, Ultraseps is definitely not good enough to be printed from directly. Looks like I'll be buying the full license of Accurip unless there is a cheaper equal option out there? I'm posting the 50% opacity pictures, obviously the crisper square blocks are from accurip. Not to mention the ink itself is more opaque from the accurip print, I don' know why i thought for some reason that Ultraseps could replace a RIP, luckily almost everything I have done so far has been logos and nothing with half tones. Back to exposure time testing. Is there a huge benefit with going with the black pearl all black ink kit for the epson printers?
google t-biz network and get a copy of Scott's RIP (T-RIP I think it's called). It's the best bang for the buck when starting with RIP software and I think it's priced the same as AR.
pierre
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Getting the Ink solid helped a lot, I now know what my correct exposure time is. I checked the glass and it is the original or appears to be. I have yet to check the voltage, that is the next step. The exposure time on it is 81 LTU on white 180 mesh with SP-1400 emulsion. Going to have to get a new lamp for it ASAP as 81 LTU is a burn time of 9:20. So either the voltage taps are incorrect or it is in serious need of a lamp.
Pierre I wil try out the T-rip, but that means breaking out the windows machine, and Windows hasn't made a good OS since XP as far as i am concerned. But if it lets me do custom film size it would be worth it. I didn't see where I can do custom Film sizes with Accurip, unless the paid version adds that feature.
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Getting the Ink solid helped a lot, I now know what my correct exposure time is. I checked the glass and it is the original or appears to be. I have yet to check the voltage, that is the next step. The exposure time on it is 81 LTU on white 180 mesh with SP-1400 emulsion. Going to have to get a new lamp for it ASAP as 81 LTU is a burn time of 9:20. So either the voltage taps are incorrect or it is in serious need of a lamp.
Pierre I wil try out the T-rip, but that means breaking out the windows machine, and Windows hasn't made a good OS since XP as far as i am concerned. But if it lets me do custom film size it would be worth it. I didn't see where I can do custom Film sizes with Accurip, unless the paid version adds that feature.
If the emulsion is dual cure, your 9 min exposure time is probably not that far off. They usually run several times longer than then pure photopolymer.
Pierre
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something sure isn't right.. I've shot hundreds of thous of screens on a 3140 with diazo based and never exceeded 5 mins exposure.
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1 LTU should ~= 1 second.
I can't remember if the integrator has an adjustment or not, but something is way off.
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1 LTU should ~= 1 second.
I can't remember if the integrator has an adjustment or not, but something is way off.
Light Units are used in place of seconds (time) because time isn't important, LU's are. As a bulb ages it will put out less LU's so it will take longer.
That said, on my 3140 with a "fresh" bulb I get about 1 LU = 1 second... but that's more of a coincidence than on purpose.
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That's my point, something is waaayyyyyy off.
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50% EOM on a 110 with Diazo emulsion could be in 9 min range with an older bulb that still exposes correctly.
How are you coating the screens?
pierre
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Right, the time might not be off for a correct exposure, but the LTU reading for it certainly is.
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I am using the Glisten method, shirt side first, rounded edge of coater, nice and slow, then one coat squeegee side the same, 2nd coat shirt side. Dry in rack shirt side down. Just got done ruining some shirts, going to check the voltage taps shortly.
1 LTU is def not one second on this thing. maybe .1 LTU = 1s, and I don't even know if that is correct. I can expose two screens at a time, and when i pull them off i have enough time to wash both screens out, dry them, and take a break before the next set of screens are exposed. I think its either a voltage issue or lamp issue at this point. I appreciate all the advice, Thank you Pierre for pointing me towards a Rip, that was definitely one major issue I had. Films are printing like a champ now at least.
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I am using the Glisten method, shirt side first, rounded edge of coater, nice and slow, then one coat squeegee side the same, 2nd coat shirt side. Dry in rack shirt side down. Just got done ruining some shirts, going to check the voltage taps shortly.
Using the glisten method to achieve the needed EOM involves finishing on the squeegee side. That's what pushes the emulsion through to the shirt side where it does its good.
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I am using the Glisten method, shirt side first, rounded edge of coater, nice and slow, then one coat squeegee side the same, 2nd coat shirt side. Dry in rack shirt side down. Just got done ruining some shirts, going to check the voltage taps shortly.
1 LTU is def not one second on this thing. maybe .1 LTU = 1s, and I don't even know if that is correct. I can expose two screens at a time, and when i pull them off i have enough time to wash both screens out, dry them, and take a break before the next set of screens are exposed. I think its either a voltage issue or lamp issue at this point. I appreciate all the advice, Thank you Pierre for pointing me towards a Rip, that was definitely one major issue I had. Films are printing like a champ now at least.
Our older 3140 is at 90 sec for 2 LTU. This is the first gen, prior to M&R.
1+1+1 with Aquasolv, dull edge and 5 seconds per coat would produce at least 40% EOM. 3 sec per coat, Aquasol HV with glisten method is about 25%.
Pierre
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coating technique also depends on what screen mesh he's using, as well as the viscosity of the emulsion.
a 1+1 in our shop results in nearly 50% EOM on a 150S
in order to have EOM in the 20% range, we do 1 coat on the shirt side, nothing on the squeegee... having 45-50% EOM was causing us all kinds of issues for us in both exposure and printing.
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I have no idea what my EOM is, have yet to buy the tester for that. I forgot that on the last batch of screens i just used a 1:1 coat of SP-1400, second coat on squeegee side. as far as thickness though I couldn't tell you. The tester is on my purchase list, along with 100 other things I still need to get. The more posts I read on here the more stuff i seem to need to purchase :-\
All I know at this point is it takes forever to expose the screen, but with the proper films now, I am getting good exposures, no more pinholes in the screen during printing, and sharp detail. So long exposure times are a small price to pay at the moment for good screens. I opened the Expo unit up and the wiring has been worked on some, lots of splices. I will have to contact M&R to see if I can get a wiring diagram for it.
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I opened the Expo unit up and the wiring has been worked on some, lots of splices. I will have to contact M&R to see if I can get a wiring diagram for it.
That's not good.. Lets hope it's not to bad of a rats nest in there.
Anyone got a 3140 manual around they can scan in the diagram for our friend here?
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Just opened the other side up. Looked closer at the wiring, really only two wires with splices, not how i would have done them so i will redo them properly, but they are working.
So as for the testing. Ran the unit for 1 minute and checked the line voltage, 120V even, wires were on the 125V tap. moved to the 120V tap. Noticed the LTU were moving much faster. Did a full 81 LTU test. Prior results on the 125V tap was 9:20. New results moved to the 120V tap at 81 LTU is 6:54. Good improvement. At this point I will be getting a new lamp. This is just times for the integrator to see 81 LTU, not actually exposing a screen.
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SI, if you will call or email me with your serial number I can get you the correct wiring diagram for your unit and answer any other questions you might have on the your MSP3140.
Ron Hopkins
NuArc Sales Mgr
M&R Sales and Service Co.
ron.hopkins@mrprint.com
847-997-2487
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So as for the testing. Ran the unit for 1 minute and checked the line voltage, 120V even, wires were on the 125V tap. moved to the 120V tap. Noticed the LTU were moving much faster. Did a full 81 LTU test. Prior results on the 125V tap was 9:20. New results moved to the 120V tap at 81 LTU is 6:54.
Boom!
that time sounds about for a 120 line. I've always had it on 230 which gave me the 5ish minute exposure.
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Well I exposed two screens today at 81 ltu after the voltage change. Exposure time was 6:40. But both screens were underexposed. So while the ltu seems to be going faster, I think the screen still needs to be exposed for 90 minutes. Going to order a new lamp from m&r
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New bulb for sure, start any calibration with a factory bulb from M&R. That way you know that variable is starting from the optimum point. Set taps correctly first.
I believe you can set the LTU to Seconds on your control panel. Ron?
1 ltu = 1 sec. this way downline you can run off a 60 ltu test to see if it equals one minute. When the times start getting to 50% more like 90 sec = 60 ltu its time to replace the bulb.
John is right on the taps, you need to have it tapped to your voltage to get strong light.
Al
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Well I exposed two screens today at 81 ltu after the voltage change. Exposure time was 6:40. But both screens were underexposed. So while the ltu seems to be going faster, I think the screen still needs to be exposed for 90 minutes. Going to order a new lamp from m&r
I think you are saying 9 minutes correct? typically with a new bulb ltu and seconds are pretty close to the same.
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Do the LTU count down very slowly?
I have this in winter. Our new screen room is very cold inside, and upon start up of the exposure unit the LTUs count down very slowly until the lamp reaches it full temperature. I assume there has to be a connection between low temperatures and UV output of the bulb. On our LED unit it`s even worse as they don`t get warm really. Have to bring in a big stove first to heat up the screen room, once that`s done there are no issues with either of my units. So I guess if you notice the LTUs counting down very slowly you have to change the bulb as I don`t expect your screen room to be as cold as ours. It`s very likey an old bulb issue.
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exposure unit is in a heated space so it's not a temperature thing. The LTU is about 1 LTU per 6-7 seconds. so slightly faster than .1 LTU per second. I could take a video but I think at this point it just needs a new lamp. Ill get around to it, still a small time shop so it has to work its way down the priority list. Definitely on the to do list once business picks back up
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7 seconds per LTU is indeed very slow.
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Update:
Well I finally got around to ordering a new lamp for it. Just did a test on the old lamp before removing it. 85 LTU at just over 9 minutes.
New lamp from M&R, 85 LTU in 3:52. Definite improvement. while I had it apart I did some preventive maintenance on it as well, double win!
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The new lamp as of March 5th was exposing 90 LTU right at 5 minutes. I haven't really been timing it but a few days ago i noticed it seemed to be taking longer than normal. Today I timed it and it is now back over 9 minutes. Lamp is one month old with around 200 cycles on it and no better than where i started. They shouldn't be losing this much efficiency this fast should they?
I am thinking there is something else wrong with the exposure unit causing the lamps to wear faster than normal.
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The new lamp as of March 5th was exposing 90 LTU right at 5 minutes. I haven't really been timing it but a few days ago i noticed it seemed to be taking longer than normal. Today I timed it and it is now back over 9 minutes. Lamp is one month old with around 200 cycles on it and no better than where i started. They shouldn't be losing this much efficiency this fast should they?
I am thinking there is something else wrong with the exposure unit causing the lamps to wear faster than normal.
There is definitely something wrong but without seeing the unit this will be next to impossible to diagnose. First ther should of been around 90 LTU in about 100 seconds with a new bulb. That says something is not right. Could be the actual power into the unit being too low or too high. I don't know where you are but I would suggest someone from M&R see your installation and check out the machine.. You might want to schedule a service call