Thanks for the response Adam, it's relieving to hear you don't think humidity is an issue.
We use InkCups Cobalt Steel Back Laser Platers - shown at bottom of page here
Laser Plates, Laser Engravable Plates | Inkcups Now
We order the imaged plate directly from InkCups, we don't do any plate making in-house
Our consistency problem is that we load ink into the cup, start printing, and the first few prints will look fine but then we'll gradually start to lose parts of the image on the printed shirt. No ink will be stuck to the pad but the missing parts of the image will collect in the cliche.
We're pretty sure we can just adjust the ratio of ink/solvent/hardener, but are in the process of making adjustments and haven't yet been able to dial it in. This would require more solvent, less hardener, I think.
Ok. So it is definitely not plate.
It will be ink/solvent/hardener
First hardener
You should not be altering amount of hardener. You should always put exact proportion as recommended by ink manufacturer and in your case is 1:10. Why would you use hardener at first place for textile? I would imagine that you would use hardener on substrates there ink has problems bonding to.
Do you use scale? Scale is very important.
Tell me what is average temperature in that part of building? Is it to hot?
By your description you have problem with solvent evaporation. It evaporates way to quick. It is dry before pad pick up ink.
What solvent do you use? Fast or medium?
I would say that problem at this stage could be
- You are using fast evaporating solvent but you are not running machine adequately fast.
-If it is to hot in your factory it will just add on to solvent evaporating even faster.
- If you do not use scale there is chance that you don't put enough solvent as well.
Pad printing process works by solvent evaporation-
Ink cup inks image on plate, solvent evaporates little bit, just enough for ink to be tacky to stick to the pad. By time while pad moves forward solvent evaporate little bit more and ink becomes even tackier, just enough to stick to substrate you print on.
Correct solvent, correct amount of solvent in ink and speed of machine have to be in sync otherwise you wont get good print.
If solvent is to fast and you don't run machine fast enough, it will evaporate before pad comes down and it wont be able to pick up all of ink.
On other hand, if your solvent is medium and you run machine to fast, it won't pick up whole image as well as solvent did not have chance to evaporate enough for ink to become tacky enough to be transferred to the pad.