UV spitting due to anilox

[DMan]

Hello

I have issues related to UV ink spitting on press.
I notice that the anilox can be the issue since changeover to other supplier solves the purpose. (screen/volume/hex 60 Pattern) same.
Can some one (anilox expert) suggest why the anilox behaves so. Trying to explore all reasons.
Regards

[dkelley]

I have found ink spitting is more related to ink viscosity than an anilox. A Lamella Tip blade will help or use a UV reducer in the ink. If you are running a MA P Series press you can order a smart blade, These work quite well.

[The Dude]

I use a heaterband on my 5 gallon bucket.... reduces the visc greatly

[Frank Burgos]

UV inks are notorious for spitting. The ink accumulates on the back of the blade ("back-doctoring") and, every now and then, the accumulation touches the anilox surface and gets catapulted onto your customer's product.

It's a challenge. So, in the meantime, consider a way to catch the droplet so they don't make a mess and you'll buy time to see if you can come up with a permanent solution.

Mud flaps. They do a UV printer good.

[wdustin1]

Have you tried the plastic doctor blades. We have noticed the same thing there is a particular anilox in our shop that spits no matter what you do. If anybody is going to be using that one they switch over to the plastic dr blade and it goes away. The plastics don't meter as well as the metal ones so it does lay the ink down a little heavier but its better than constant spitting!

[vandium]

I am thinking your previous anilox was dirty, and probably not retrieving/releasing the ink, as with the new anilox.
Especially if they are engraved the same.

Everyone nailed it here...

1) Blade needs a rigid base, but the edge needs to be fine for clean metering.
So you may want around a 10 to 12 mil base (usually 10 is fine), and a lamella edge profile (which is usually around 6 mil on a 10 mil blade)

Thinner bodied blades will flex and rippled when the more viscious ink comes against it.

But remember, when that lamella tip is worn off, it will meter from the 10 mil base steel... This will meter very poor and inconsistent.. Change the blade..

Sometimes I have seen people run the lamella blade backwards to create a channel for the ink to flow out of the sides...

2) Reducing the ink slightly (not extending, as that will change color quicker than reducing it) can help too.

3) As speeds change, so might your blade pressure... be aware of that too.