User login

Taking Control of Screen Coating

(May 2009) posted on Wed May 20, 2009

The stencils you use for printing are only as good as the coating procedures you follow to produce them. Here you


By KIWO Technical Support Department

click an image below to view slideshow

Fine detail can be taken to mean any artwork in which the finest elements are equivalent to the width of two threads and two mesh openings of the particular mesh fabric being used. You can test this concept by laying your film positive right on the screen and looking through a 50x microscope to see how many mesh openings and threads your finest design elements span. If your smallest dots or lines are not much larger than two threads and two mesh openings, you have fine detail. With such details, if you do not have enough EOM, the threads will create a dam around open areas in the same way that a stencil does. In halftone printing, such low EOM leads to dot loss as the highlight dot is cut into pieces by the threads (Figure 2). (Figure Reference: With insufficient EOM, the mesh in open areas of the screen can make direct contact with the substrate during printing. As a result, the knuckles of the mesh serve as dams that prevent ink from spreading through the entire open area. The result is dot loss and poor dot reproduction.)

Stencils with low EOM also likely suffer from high Rz values. The incomplete gasket caused by high Rz allows the ink to push beyond the image edge and leak into the valleys of the stencil. This results in dot gain. At the same time, the low EOM leads to dot loss and sawtoothing. High Rz and low EOM are both the result of poor coating techniques. However, these conditions can be eliminated by observing the screen-coating pointers we’ll consider in the next section.

All stencils must have some EOM for proper printing. But, a stencil can be too thick as well. For many printing inks, stencils perform well with an EOM that is between 10-20% of the mesh thickness. For finest detail printing, including four-color process, the EOM should not exceed 10% of the mesh thickness. If the stencil becomes thicker, problems such as ink piling, skipping, and skewing can occur when printing with UV ink. Moreover, highlights may not open up, and ink transfer becomes difficult. For excellent printing on most substrates, the stencil will also need a low Rz value (approx. 6 microns if possible).

 

The coating process


Terms:

Comments

francissy says: Youre so cool! I dont suppose Ive learn something like this before. So nice to seek out anyone with some authentic ideas on this subject. realy thank you for beginning this up. this web site is something ...

Youre so cool! I dont suppose Ive learn something like this before. So nice to seek out anyone with some authentic ideas on this subject. realy thank you for beginning this up. this web site is something that's needed on the web, someone with a little bit originality. useful job for bringing one thing new to the internet!
Buy cialis by mail juxtapyloric Buy Meridia hardily

posted on: Wed, 10/19/2011 - 11:49am
donlangwe says: GenF20 large prototype HCG Diet teratic wield Levitra moins cher revalorization transistor posted on: Wed, 02/01/2012 - 11:12am
isaacbvrogelio says: iiaqczce payday loans UK yrSQcX payday loans %-[[[ instant cash advance OQnYv posted on: Thu, 02/02/2012 - 7:25am
isaacbvrogelio says: exbnbvt viagra 3647 cialis kjqoVr cialis >:-OOO cialis kaufen >:]] viagra %-[[[ viagra online BpgQw posted on: Fri, 02/03/2012 - 6:30pm
isaacbvrogelio says: iogwnpa accutane >:-[ generic viagra OLwiUk propecia =-] generic cialis 4119 posted on: Fri, 02/03/2012 - 7:15pm
isaacbvrogelio says: datyqj viagra 8]]] viagra 9263 viagra YpIEpP ジェネリック・シアリス 8]]] viagra >:]] viagra generic YoANyh posted on: Tue, 02/07/2012 - 5:40am
isaacbvrogelio says: ropabr payday loans 3238 cash advance tcOoUZ cash advance EuVGH payday loans >:-[ posted on: Wed, 02/08/2012 - 7:22pm
isaacbvrogelio says: vrtafm Viagra Génerique %-[[[ Cialis >:-OOO viagra billig ZQTSc viagra XNByv propecia lDPYJ posted on: Thu, 02/09/2012 - 7:48am
isaacbvrogelio says: vnmsxwzm payday loans =-] payday loan 0342 payday loan 0707 posted on: Fri, 02/10/2012 - 3:24pm
isaacbvrogelio says: ucdvnu cialis 7404 cialis prices ekqRh viagra 9648 generic viagra =-] posted on: Tue, 02/14/2012 - 4:20pm

Did you enjoy this article? Click here to subscribe to the magazine.