edge chipping

[jtanner]

need some imput on a problem I'm having with clay coated paper products. I do a lot of bleed trim work and have been having a lot of problems with edge chipping. Can someone please help

 

[D Ink Man]

Change stock if possible to a less brittle CCN. These bastards are notorious for chipping, cracking even with the slightest crease or bend. An ink with a more flexible plasticizer may also provide relief as it forms a tight bond with the clay coat on the topical surface. Of course and you are probably well aware, the sharpest of cuts when finishing also can help minimize the issue. Please provide any further details if my reply hasn't bullseyed the issue. D

 

[akalaray]

Sharp Blade, Also cut with the correct side of the knife

 

[Al Ferrari]

Is this happening with offset or digitally printed stock?

Al

 

[jtanner]

our problems are in our silk screen department printing UV. Thus far, we haven't experienced any issues with litho or digital. I think part of the problem is heat related from the UV reactors. We had an EIT done on our lamps and getting about 100 degree output. Concerning the knife blade, what would be the recommended side, the beveled or straight side?

 

[D Ink Man]

Is the clay coat substrate actually chipping, alongwith the printed ink film? I would blank in some unprinted pieces of the clay coat while finishing and see what result you get. Look at the chipping under magnification, 10X minimum. The key here is that the litho and digital are not doing it, but the silk screen is. Last question, is the clay coat stock the same for all three processes?

 

[jtanner]

First of all I would like to say Thank You for the replies! To answer the question, yes the clay coat is chipping and taking the ink with it. We have already put the edges under a microscope to anylize the edges. As far as the stock, all 3 processes use the same material. We actually print CS1,CS2, 24 and 48 point and also fluted paper board and only getting failure in screen. I'm still in the testing stage of trying different ink lines and playing with flex additives. the flex additives help but kills my opacity. The ink manufacturer is working on developing something that will increase the opacity with the additive incorporated in the formula.

 

[Cold]

Is it possible that the CCN is almost too dry, and once hit with the energy of the UV lamp, it does become too dry and thus chips?

Do you have room to turn down the energy on your lamps and still cure?

Is it possible to keep the stock in a more humid environment?

I live in Arizona, and occasionally similar issues occur here.

 

[D Ink Man]

Ask your inkmaker to incorporate an applicable percentage of latex based material that is compatible with the oligomers in the UV flex formula.

This may help when the critical trim point is executed. The ink may make up for the shortcomings of the clay coat stock.

The key is the other print processes do not cause the problem These ink films have more natural flexibility because of their capabilty to form a flexible ink film because of their plasticizer contents.

The latex could give you that need property.

Worth a try I believe. D

 

[jtanner]

thanks for everyones input! Using the most flexible ink I could find make a tremendous improvement to the quality of the product edges, but the cost is also very high. For the time being this is the route i'm taking and hopefully will find a more cost effective solution in the future.

 

[amgd1972]

Jtanner,

Look at the intensity of your UV lamps, you could be overcuring the ink.
Had same issue on a litho press.

A.

 

[akalaray]

The straight side of the knife is the cutting side. Carbide is the best knife for cutting stock with heavy ink coverage and UV