Laser engraving silkscreen transparencies?

[Weston Porter]

Have any of you heard of someone using a laser engraver to create screen printing transparencies? I have two big items to budget right now, a laser engraver and a large format laser printer, the latter will be used to print the black and white transparencies I need to expose images onto silkscreen frames. If a laser engraver could fulfill that duty, I could afford a better machine.

Now of course I can laser cutout black stencils but that doesn't work for complicated or details designs. I'm wondering if there isn't some clear material that scorches/darkens without cutting or distorting.

A crash course on exposing screens if you don't know what I'm talking about: A mesh screen is coated with light sensitive emulsion and placed under/above a bright UV light with a black and transparent stencil sandwiched between. The areas the light touches harden while anything protected in shadow can be washed away.

[Dan Hintz]

They do make laser-capable screens, but you pay for it...

[Joe Pelonio]

I have made many of them using a plotter and black vinyl applied to clear acetate. Far more cost effective to buy a plotter if you are going to do a lot of screenprinting.

[Dan Hintz]

Guess I misunderstood the question... I thought Weston wanted to expose the screen using the laser.

[Dave Oaks]

It'd probably be easier and less expensive to just print film on an inkjet printer- I use an Epson 1430- We used to use a Xante laser printer but gave that up years ago

[Larry Bratton]

I print designs on film for a local screenprinter. I use an Epson Artisin 1430 also, with a continuous ink system from Cobra ink systems. Some of the designs are pretty detailed but the cost is low and fast. I do the separations in Photoshop CC. I suppose you could cut the stencil with the laser, but a plotter would better serve for that method as Joe said.

It'd probably be easier and less expensive to just print film on an inkjet printer- I use an Epson 1430- We used to use a Xante laser printer but gave that up years ago

[Stephanie Olmstead]

They do make laser-capable screens, but you pay for it...

Hi Dan,
I saw this thread from a few years ago and was wondering if you know where to buy the laser-capable screens???

[Tai Fu]

Sorry to resurrect the thread, I found it on Google.

I am toying with using 250 mesh stainless steel screen, and then putting emulsion onto the screen and expose it fully. Then I would put the whole frame in the laser engraver to engrave it. So far it seems to work. I'm toying around with doing halftone printing this way...

[Dave Garrett]

Tai Fu - that sounds incredibly interesting. I'll have to try it myself! How many screens per design are you doing? Or is the halftone approach not for multi-color? some pics would be nice. :)

[Tai Fu]

You should know to make sure the laser is set to ENGRAVE only and that power level should be around 6% or so (this is for a 800mm long tube, about 40 watts true). On a 80 watt laser you need to dial down the power level really low. If you accidentally use cut mode you will burn a hole through stainless mesh.

I tried halftone, and my laser is still those K40 types (but the larger 50 watt version) that uses the moshi board. I ended up using K40 whisperer driver and their halftone algorithm has worked best so far (rather than manually use CorelDraw's halftone conversion). However, quality has been very inconsistent. I have to charge the screen with ink with only so much ink, too much or too little ink yields poor prints...

https://i.imgur.com/7bP9OOZl.jpg

As you can see the bottom right corner was the best so far, and that was just the first print before everything was charged up. The too dark one was where I used a lot of pressure and loaded the screen with ink... it's like hand pressure and all that all affect the print output. There has to be a better way than this because if I am doing CMYK this is going to result in very inconsistent prints, unless I have a robot hand that can apply the exact amount of ink every pass.

[Ian Stewart-Koster]

I still have a full roll and a half, of 1 metre wide or it maybe 4ft wide translucent red rubylith film.
It's dead easy to plot in reverse and weed, to make screen positives.
I suppose I could cut them on the laser, and have the holes cut fully through, and outer lines just lightly cut- but you do risk it all falling apart when you go to lift it (ask me how I know...)

[Tai Fu]

You need a stretched screen so the film doesn't fall apart when you laser cut them. I have tried mylar film and it doesn't work. The premise of using mylar film is have the laser cut little holes like halftones but I have trouble getting my laser to work this way, so it will basically carve out entire areas instead of burning little dots.

Using stainless screens and spreading emulsion on it as normal, but exposing it fully then using the laser to cut the patterns worked for me. Most CO2 lasers will not affect stainless mesh, but make sure your laser power setting is minimal, DO NOT put it on any continuous exposure mode (cut mode) because even a 50 watt laser will cut straight through stainless steel mesh wires.