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screen printing => Equipment => Topic started by: Itsa Little CrOoked on June 24, 2015, 03:51:14 PM
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Those winged flood choppers are pretty danged aggressive, and I get some ink splatters in places I really didn't expect it...mostly behind. The squeegees don't seem to do it.
Is there an adjustment or perhaps some gauges to add, in order to reduce chopper pressure or volume of air through just those circuits?
I searched a bit, but nothing showed up. It is a mild annoyance on some jobs/colors, and worse on others. It makes it all the way up to the backside of the mounting channels sometimes.
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Did you try lowering the pressure (Speed) with the valve at the head?
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Nope. I'll check into that.
Does that adjustment effect the squeegees also? I can't see how it wouldn't...
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Squeegee has it's own adjustment for speed....
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I think larry was getting at the carriage speed, not the speed at which the choppers chop.
Speaking of, I'd also check the hydraulic shocks at the end of the print stroke.
If the head is smacking the back stop it'll toss ink up the back of the flood bar pretty well...
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Yes, I believe you are correct. My choppers SLAM down with authority. It's excessive in my mind.
I have rubber bumpers fore and aft.
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this press has mac valves on it right? .. and all heads chop at the same time?
if so, there should be regulator plates on the front of the valves... I can't remember exactly which way to adjust them right now, but I seem to remember that you back off the nut, and then screw them in for less 'flow', which keeps the same downward or upward pressure, but takes 'longer' to get there if that makes sense?
personally I'd adjust them till they're coming down quick, but not slamming. if you're slamming them, you ultimately could cause ghosting on your prints, and even breakdown on the screens.
-Jason
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Thanks Jason..... yeah, I guess I didn't understand the problem at all...... Stan, do what he said and quit screwin' around!
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Actually, at first I was pretty sure you were right Larry. Now I'm not so sure.
Not to say it's not the reason for what you're seeing, but I'm still scratching my head trying to figure out how you could get ink on the channel from the flood chopping too hard.
I have found high print carriage speed and marginal head shocks will absolutely guarantee this type of press behavior, although the extent of the mess is certainly related to the tack and viscosity of the ink as well.
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I'm going to sit and watch some Quick White when I'm not tending or printing. Quick does it about as bad as any.
And I'm not 100% sure it ISNT at the end of the stroke, but it about has to be. The flood choppers are "UP" of course...at the end of the print stroke.