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Press Settings Made Easy

Press Settings Made Easy
April 29 2019
Whether you are printing on an automatic or manual press, this information may help you out.  I visit a number of shops and I have seen the good, the bad, and the ugly when it comes to squeegees, screens, and settings.  I am really hopeful reading this will help those who truly need help and even those who think things are going pretty well.

So many factors affect the print.  The ink matters.  As always, my go-to ink is ELT-S Series as it is a low temperature ink which is easy to work with on-press.  It’s soft.  It’s stretchy.  It’s very opaque and bleed resistant.  Basically, it is the best thing ever…if you print it correctly.  If you don’t, you may be scratching your head wondering why so many people are excited about this product.

Let us start with the relationship of the squeegee, screens, and off-contact distance.  The goal is to print the ink on top of the fabric.  Not into the fabric.  Certainly not through the fabric onto your platen.  We want the ink on top where it will feel soft and look brilliant.  This is why I typically recommend a medium flex 70 durometer rubber.  Sure, you can go with a harder squeegee and be successful.  However, with the settings I often run into, this causes more problems that I would like to avoid.  The 70 durometer squeegee blade is pretty soft.  It is easy to see if it is bending as you are pulling the ink across the screen.  It should have very little bend if all other factors are set up properly.  Ideal squeegee angle when printing with ELT-S is 15 degrees.  You can certainly use more or less angle but I find this works well.

Squeegee pressure is typically set far too high.  Press operators and manual printers don’t want to run into problems so the force the ink into the fabric at a high pressure to ensure the ink clears the screen.  I promise, you simply need enough pressure to push gently onto the screen and bring it into contact with the fabric or the white base.  Take your finger and push down on the screen when it is over the platen.  Does it take 50 or 60 pounds of pressure to force it to the platen?  I highly doubt it.  With proper squeegee settings, screens, and off-contact distance, you only need a little bit of force.  Manual screen printers, if your arms are tired at the end of the day you are pushing/pulling too hard.  All of the same rules apply to you.  Less pressure is needed if your screens, squeegee angle, and off-contact distance is correct.

This leads us to the screens.  A tight screen is your best friend.  A tight screen allows you to set the off contact distance very low.  A tight screen and low off-contact distance allows you to print with very light pressure.  Having low off-contact with light squeegee pressure will give you the best prints.  The ink will be on top of the fabric.  It will cover dark fabric better.  It will exhibit less fuzz problems.  If you work with low tension screens, you may be forced to use far more off-contact distance so the screen will quickly snap off of the print.  We certainly don’t want to pull the squeegee and see that the screen is still attached.  This is bad for so many reasons.  Think texture.  Think spotty results.  Think registration.  Yes, registration is certainly much harder when your off contact distance is so high.  The loose screen has so much more flex and should be replaced.

Don’t forget about the role of emulsion in all of this.  Some emulsions coat thicker than others.  Others have a slick texture to allow the squeegee to nicely drag across the screen.  I won’t tell you what to use as it really depends on the different type of inks you work with, your exposure unit, and the general environment of your shop (humidity, drying capabilities, etc).  What I will recommend is coating your screens thicker when you need coverage on dark fabrics or polyester.  The more emulsion that is on your screen, the thicker the print will be.  I coat my 110 and 158 screens twice on the fabric side and then twice on the squeegee side.  Always in that order.  Always dry the screen squeegee side up.  With finer mesh I coat once on the fabric side and twice on the squeegee side.  I always use the sharp edge of the scoop coater.

This is all a lot to take in.  If you are serious about quality, order up some ELT-S white and colors.  Grab your tightest screens.  Try to lower your off-contact distance and squeegee pressure.  See how this affects your prints, especially wet-on-wet printing.  The softer squeegee, softer pressure, and tight screens will make this process so much more successful than you have experienced in the past.  It simply works.

fin.

Robb Mears
Director of Product Development

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