Blame the Ink

OK, I know you people out there are having problems! Printing problems, that is!

All the major printing processes have dozens of variables that need to be controlled. Do you have an understanding of how the ink, substrate, plates (flexo and Offset), rotogravure cylinders, or screen emulsions, interact with each other? What about process variables like press speed, surface treatment (corona), drying oven temperature, or UV dosage and intensity? What about web tension, or impression roller pressure, doctor blades, Offset blankets, the ink train? What about all the variables that go into making a plate or a screen?

Why do you have trouble obtaining quality printing results? It must be the ink. Maybe, but it is usually a two-way or three-way interaction between the ink and some of the other variables mentioned above. Historically, the print shop would have someone with enough experience to recognize these interactions and make appropriate adjustments to improve the quality of the finished product. If you have that person, keep him or her happy and busy training the younger generation! We need young people in the industry desperately, at least that is what I am seeing.

Now printed products are not always just something to read. They often perform a function like product protection. They are made with films that stretch and shrink. I even was involved with printing on silicone coated films for heat transfer labels. Talk about an ink/substrate interaction! The newest functional print is the budding printed electronic industry, where conductive inks are used to print electric circuits for various finished products like RFID antennas, flexible LED lamps & displays, Electroluminescence, and heaters among other things. This printing niche is expected to grow as the internet of things continues to expand into everyday items.

In these high value added printing industries, the most efficient ways to understand the interaction between variables is by using Design of Experiments (DOE) methods where more than one variable is manipulated at the same time. This should be done during the product and process development stage if possible. I personally use Minitab software for this type of project. What the software helps generate is the process variable range or “sweet spot” where acceptable product is produced.

DOE works by testing variables usually at two settings, high and low. Think of fast press speed and slow press speed, thick film and thin film, or high dryer temp and low dryer temp. or high UV dosage and low dosage. Most people would test each thing individually: press speed, dryer temp. etc in a one variable at a time experiment. Unfortunately this method doesn’t predict interactions between variables. With the help of Minitab, you can vary more than one variable at a time so you can predict the interactions and find that sweet spot where the press is running all of your variables and yielding good results.

Give Functional Inks a call when you want to blame the ink. We can help troubleshoot your printing problems using the techniques described above.

Thanks for reading! Paul Giusto 413-363-0770

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