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390 mesh for PET bottle -- smallest line width?

Posted: Fri Dec 11, 2009 12:04 pm
by radioboy
Perhaps this should go in newbie, because I'm a newbie. But...

We're preparing artwork for a PET bottle screen print. The printer is using 390 mesh.

I know I should get all the details from the printer, themselves about minium feature size, details of the mesh, etc., but I'd like to educate myself and try to get it right -- at least very close.

The design is very simple, black only, sans-serif letters -- but, there's a registered trademark symbol (R) which we want to make as small as possible. It's not the most critical part of the artwork, by any means, but it should be recognizeable upon close inspection and not just a black dot.

Can anyone provide some advice on what would be the minimum line width for the lines in the R and the circle around it?

I did see something recommending 1 mesh opening, plus 0.5 filament diameter. It looked like 390 mesh typically has ~30 micron opening, and ~30 micron filament diameter, which would put it at 45 microns. Currently we made it 66 microns to be safe. How does this sound?

Thank you!

Re: 390 mesh for PET bottle -- smallest line width?

Posted: Wed Dec 16, 2009 3:51 pm
by geneh
My advice would be to see what the printer is using is it a true 390 mesh or a 380 mesh which a lot of printers will call a 390 and what the thread diameter is. You said you made your reg. mark at 66 micron which is 2.5 thousands it can be done with the correct film or emulsion and exposure unit. But if I was the printer I would at least ask you to open it up to double your current line with. Due to the fact you always get some undercutting when exposing a screen a minium of 1 to 2 thousands. and if you are only working with 2.5 to start with you are not going to get good results. You would probably wind up with just a dot.