Mix, Mix, Mix

Mix, Mix, Mix !!!!  So often we speak with application engineers having problems controlling viscosity just because the product is not being mixed. Many industries are trying to reduce cleanup time and thus move their pumps from in tank to in line. In doing so the mixing action of the pump, in the tank is lost.

Many mixers run to fast and cannot be throttled to slow flow rates. Often just a little mixing is all one needs.

See the video for an example.

http://www.youtube.com/watch?v=228tGgRkAFM

Do you make pcb's ? Do you use treaters ? Do you use epoxy with acetone solvent ? Do you need to insure consistent impregnation of the fiberglass base ?  Then you need Norcross Viscometers.

Counductive Inks

Do you use silver or gold ink ?  If so you probably have a solvent based suspension. If so you surely pay very dearly for your ink. Most process viscometers cannot measure this because of the metallic content. Norcross can measure and control this with our very clean and easy to use units. If you are printing on medical packaging, flexible electronic circuits or the like then we can help you.

Reactor Viscosity Value - what is it really ?

We often have inquires from companies using product reactors. In the course of discussions we may be advised that the end point viscosity is 30,000 cps.  This may be the case BUT it will be a function of how the product was measured. Usually it has been via a rotating laboratory viscometer on a cooled down sample. The rotating viscometer applies very low shear and most all reactor products are shear sensitive ( ie: thixotropic)
Our viscometers apply a higher shear force and thus what you, our customer, may think is 30,000 cps is only 4,000 cps to us at Norcross.  Both values are right.

So often I will ask the customer to pretend they and I are sitting in the reactor having a cup of tea. During the reaction we dip our tea cups into the product and then pour it out. Tell me, does it pour like water ? warm honey ? milk ? or what. Then we can better sense what the viscosity will be like to the falling piston.

Viscosity Control on Gravure Presses

Just made a YouTube video about viscosity control on gravure presses.  See it here.http://youtu.be/-aJtkL_icfI

Why a Perfect pH Level is Key

When pH levels are too low, the ink could have a faster drying time on the substrate, and increased viscosity, which could lead to filled anilox cells. Also, a difficult clean-up is never fun!

Conversely, when pH levels are too high, ink may not dry at all, in addition to poor water resistance due to entrained amines. Also, odor problems may make for an unpleasant work environment.

Ideal pH and Your Morning

An example of Trapping, courtesy of paperandprint.com

An example of Adhesion, courtesy of paperandprint.com

pH is very important to print quality.  Without it, you could end up with solid chunks of resin and pigments in the bottom of your ink buckets.  This occurs because of a phenomenon commonly referred to in the printing industry as "kicking out", which means that because of low pH, the ink drops out of suspension in the solution, falling to the bottom of the ink bucket. 

There are two other common problems that exist when pH levels are too low; they are called adhesion, and trapping.  Adhesion occurs when the print can be removed by scratching the surface of the material printed. ¹  Trapping exists when one color is superimposed onto another, so that the first color does not lay properly before the next color is printed_.²

It is also important to remember that low pH can cause increased viscosity, which could lead to a dark and dirty print, ink drying too slowly, or small random holes in the printed area.

Also with a low pH, you run the risk of your ink pigments and resins not being soluble, and therefore running in the rain.  This is bad news for newspapers, and could sour anyone’s morning.

*Additional information and images courtesy of FlexoTech 2007 Compendium, Whitmar Publications, found at www.paperandprint.com

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