Exposure time for Murakami SP-Pro with M&R Starlight UV LED Screen

[Rubysky]

Hello,
What is the exposure time for Murakami SP-Pro with M&R Starlight UV Led Screen exposure system.

Thank you so much.

[Frog]

I'd suggest a call or email to Murakami, to get a base approximation of time (since LED may not be included yet on the tech sheet ). Then, use an exposure calculator or use their instructions on how to perform a step test

Keep in mind, that though all exposures made with the Starlight will be fairly quick, mesh count and coating technique will change times.

[244]

Hello,
What is the exposure time for Murakami SP-Pro with M&R Starlight UV Led Screen exposure system.

Thank you so much.

This is not enough information to go on. Mesh count, color of mesh, how you coated, manually or with an automatic, EOM of emulsion or how many coats will help.

[Rubysky]

Hello,
Thank you so much for the reply. I am planing to use this mesh count;

110 (white)
155 (white)
230 (Yellow)

Nittoku/ Murakami S Mesh in USA 225S (Yellow)

Coating; 2x printing side, 2x T-shirt side.

Emulsion type; Murakami Diazo Type Sp-pro

Murakami told me to start at 60 sec.

But the exposure machine I use is M&R Starlight and I heard it expose screen very fast.

Please advise.

Thank you.

[Dottonedan]

Hello,
Thank you so much for the reply. I am planing to use this mesh count;

110 (white)
155 (white)
230 (Yellow)

Nittoku/ Murakami S Mesh in USA 225S (Yellow)

Coating; 2x printing side, 2x T-shirt side.

Emulsion type; Murakami Diazo Type Sp-pro

Murakami told me to start at 60 sec.

But the exposure machine I use is M&R Starlight and I heard it expose screen very fast.

Please advise.

Thank you.

The Starlight does expose (as fast as you may want it to), but the different emulsion have different times needed to fully cook the emulsion and cross link completely. So, lets say, maybe the Murakami does not expose (as fast) as other brands. Theirs may need more time for a full cure. That is not a bad thing.  Even 60-80 seconds can still be shorter than a 3-5k MH. depending.

Your real goal, should not really be (fast exposure), but accurate exposure.  Sure, everyone wants it done faster, but you really want a "good" exposure. So just expxose a tad longer to get it to fully cook.

Some people expose for X time such as 50-90 seconds and then will post expose (or expose again).  All of that (number of seconds) pertains to (how) you coat. One persons 1:1 will be different than another persons 1:1. You, also on the other hand, are coating 2:2.   That will also add time no matter the technique.  I myself, like a good thick stencil, but it can be (too much) some times.

That 230 mesh, now that I looked at it, really should not need a 2:2 coat. That is too thick for a 230.  Some people will do as little as a 1:1 on that mesh...to hold good detail. 

Also, (if printing your images from a DTS), and burning on a Starlight, and you do a stouffer's step test, the more accurate exposure # you want will be a 6.  If on films, you want a 7.  With a DTS, you are removing two variables. Films and Glass. So a 7 is not the desired number.

[Rubysky]

Hi,
Thank you so much for the detailed reply. I'm just starting out with silk screen. My past experience is Digital Printing. But I want to shift some of the production to silk screen for bulk order. DTG printing takes very long to print one t-shirt and the ink cost is unbelievable.

Mesh 230 1;1 noted.
230 lower mesh I will try 2;2
Murakami advise me to do 2;2 let it dry then 1;1. But I think that much emulsion on the screen might be too much.

I don't think the Murakami in Japan has seen M&R LED exposure machine yet. Last I check only 2 vendors is using this machine so the number they gave me might not be accurate (60 second exposure time). That is why I come to this forum to seek an answer. I will coat several screens today and set the time to 60 sec to expose the screen and see how it goes.

Can I use a liquid dishwasher to degrease a new screen? Murakami here told me to just use sticky roller tape to pick up dirt from the screen, no need to wash.

I hope the end of this year I can buy auto coating machine and auto press. Doing a lot of research now for those

Thank you so much, guys.

[Dottonedan]

I think you might be either misunderstanding what they are telling you...or they are misinformed themselves and (they) should be the least uninformed about their emulsion.
You might want to review with them again. For example, one would not normally coat a screen 2:2, let it dry then coat 1:1 unless you were going for some high density printing to where the ink is put down very thick. Stacked.
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[/size]Forums are great... and ours is the best, (we now have an award to prove it). but "typically", if you want the best information about the best methods of using a specific product, you want to contact the manufacturer or the specialist in the suppliers screen printing department.[size=78%]

[jvanick]

Can I use a liquid dishwasher to degrease a new screen? Murakami here told me to just use sticky roller tape to pick up dirt from the screen, no need to wash.

I highly suggest not using a liquid dishsoap as most of them contain lanolins which will cause adhesion issues with the emulsion.  Some ink degradents (Easiway 701) contain a degreasing component in them, others require it, still other people who use mostly lower mesh counts don't degrease at all.  At our shop, we use Saati products (Ir26 for ink degrading/dehaze, followed by DirectPrep2 for degrease) this combination gives a killer screen result with next to 0 imperfections in the coating.

If the Murakami SP Diazo is roughly equivelant to their SP1400, our exposure times for a 156/64 white mesh screen were around 70 seconds to a solid 7.   Best advice is to get yourself a Stouffer strip and do some testing.

Generally speaking, the LED exposure units are super fast on pure-photopolymer emulsions, not so much faster on diazo's.

[244]

Hi,
Thank you so much for the detailed reply. I'm just starting out with silk screen. My past experience is Digital Printing. But I want to shift some of the production to silk screen for bulk order. DTG printing takes very long to print one t-shirt and the ink cost is unbelievable.

Mesh 230 1;1 noted.
230 lower mesh I will try 2;2
Murakami advise me to do 2;2 let it dry then 1;1. But I think that much emulsion on the screen might be too much.

I don't think the Murakami in Japan has seen M&R LED exposure machine yet. Last I check only 2 vendors is using this machine so the number they gave me might not be accurate (60 second exposure time). That is why I come to this forum to seek an answer. I will coat several screens today and set the time to 60 sec to expose the screen and see how it goes.

Can I use a liquid dishwasher to degrease a new screen? Murakami here told me to just use sticky roller tape to pick up dirt from the screen, no need to wash.

I hope the end of this year I can buy auto coating machine and auto press. Doing a lot of research now for those

Thank you so much, guys.

on a one and one coat or a 2 and one coat on white start a 30 seconds on white mesh and 50 seconds on yellow. On the 230 yellow S try 60 seconds.

[tonypep]

Bears noting that post exposing a diazo may make you feel better but accomplishes nothing. Not so with PPs though

[ZooCity]

LED units, including the Starlight, expose diazo sensitized emulsions much slower than a 5kw metal halide.  So slow, that some core components overheat as the units are not cool running either.  Ours is 109˚F on the outside of the blanket during screen production for an example.

It's unfortunate that many manufacturers sell the units on characteristics that do not apply to fully exposing diazo emulsions.  If you are zapping PP emulsion for 1 second because you print plastisol and don't need to correctly expose your screens then some of those claims might ring true but for the rest of us, by and large, it's bunk.   You can get acceptable and even very good results from LED but it's a downgrade form MH in every way but power consumption.  We run LED because of power constraints. 

On our starlight a 225/40 Murakami S screen coated 2/1 thin side of coater with diazo sensitized emulsion (not yours but this should be an ok starting point) exposes at 75 seconds CTS/no glass and 140 seconds with film and glass.  This is 7 steps on the stouffer strip and acceptable resolution.   

Hope that helps.

[Dottonedan]

LED units, including the Starlight, expose diazo sensitized emulsions much slower than a 5kw metal halide.  So slow, that some core components overheat as the units are not cool running either.  Ours is 109˚F on the outside of the blanket during screen production for an example.

It's unfortunate that many manufacturers sell the units on characteristics that do not apply to fully exposing diazo emulsions.  If you are zapping PP emulsion for 1 second because you print plastisol and don't need to correctly expose your screens then some of those claims might ring true but for the rest of us, by and large, it's bunk.   You can get acceptable and even very good results from LED but it's a downgrade from MH in every way but power consumption.  We run LED because of power constraints. 

On our starlight a 225/40 Murakami S screen coated 2/1 thin side of coater with diazo sensitized emulsion (not yours but this should be an ok starting point) exposes at 75 seconds CTS/no glass and 140 seconds with film and glass.  This is 7 steps on the stouffer strip and acceptable resolution.   

Hope that helps.

I say that holds true.."for your shop" and of course others (but not all discharge waterbase users).  You might do things differently than another shop using the same emulsion and exposure unit on the same exp unit. LED is not bunk for all who use diazo. I know this.  I've seen it, been at many shops doing/have been doing it all the time.  What is their quality?  I really didn't pay that much attention.  I've also been in one shop using a 5k MH exposing 4 screens up at a time...on 110's needing exposed for 8 minutes while The I-Image was clicking away right next to it with the same emulsion, same coating. True story.


Have you tried looking at a step 6 without film and glass?  It's being said many emulsion suppliers (and myself), that the 6 is where you should be for dts no glass, no film.


I say, it depends on the shop.

[DannyGruninger]

I agree 100% with Chris on this topic of led vs metal halide. I've tested a ton of units and nothing led wise has been better then my trusty ole nuarc metal halide regardless of what test that is. Led has its place for 90% of users out there but my opinion is if you want repeatable top quality screens metal halide has an edge in everything except power consumption/bulb life. Led can produce some great screens but from all my testing I'll still take a metal halide unit over led.

[ZooCity]

No, it does not depend on "my shop".  M&R, professionals they are, confirmed the times using same mesh/emulsion/coating to make sure there wasn't something off with the unit or with our process. 

And yes, if you are using diazo added emulsions, the claim that LED is faster and cooler is absolutely bunk.  Apparently nobody tested that prior to selling the units and they weren't aware that certain diazos would have such long exposure times.  The units overheat at the times needed to shoot diazos- our entire array needed replaced due to a heat warped board. 

I'm hesitant to address your comment about an i image working faster than a 5k MH shooting multi up....I'll say that I love the concept of "insert screen, image, expose, resolve".  I think that's great and a very natural workflow.  But it is not faster than standalone imaging and MH shooting multi up. 

Again, we use LED so it's not that I'm against it.  Just putting down some facts.

[TCT]

So I hesitated for a while on led units, actually returned 2 units because they didn't work on diazos(sp-1400). I had swore them off, very happy with our 5k unit. After running a dozen screens that I coated, imaged and then exposed on a LightSpeed LED unit, I bought one. Now we don't have 5 sec exposures, 55sec - 1:16sec. But I personally haven't noticed any difference from the quality screen we were getting from our 5k unit. I have not and will not use hardeners, I just refuse to.

I think you guys know me enough that if there was a issue, I'd be the first one to bitch