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General => General Discussion and ??? => Topic started by: inkstain on June 28, 2012, 02:19:50 AM
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Hey guys,
Don't know what its called, if even there's a name for it, but there are times when I'm printing a design and little shadow shows up off the edges of the design. I have to clean the screen on occasion to get that crisp image. I print manually and use plastisol.
I try to have my screen at a minimum above the platen, like 1/8th or so.
Is it cause I'm printing too fast or not using a straight up enough squeegee angle?
Maybe it's even fatigue. Curious.
Wondering if it still happens on an automatic?
Thanks all!
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Need more info because it could be a host of problems or a combination of problems.
Screen tension? Ink viscosity? Pressure? etc. And yes it happens on an auto for the same
host of reasons.
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several possibilities individually or collectively, some stuff to check
off contact is too high + weak tension, the mesh is flexing too much, lower your off contact and check to be sure it is even over all above the platen.
your stencil is too thin, not enough EOM so the stencil does not "gasket" sufficiently.
your ink is thin and or you are flooding to heavily
your press if flexing
mooseman
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Even after you set your OC to the platen you should always check your OC in relation to the material you are printing.
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also try less pressure and quicker stroke, it does not elongate the mesh as much (or so my theory goes!).
If you are running loose mesh, it will register on the top but by the time the squeegee gets to the bottom is has stretched it enough to overlap the colors and create the slight smear.
pierre
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This will also happen when you double stroke as well as all the other reasons mentioned. It's just a matter of going down the long list and eliminating each one as the culprit. How are you cleaning the back of the screen? Most of the time you don't need to completely wipe the screen down with a rag, you can tear off a strip of tape and stick it to the image area and pull it off and that usually gets rid of that ghost. It's much faster than wiping down the screen and works as long as the ghosting isn't ridiculously bad.
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A pic would be helpful, and I didn't catch if this was on one color jobs.
The first thing that comes to me has been mentioned is loose mesh. That, combined with heavier squeegee pressure sometimes, and especially with a second stroke can shift the image slightly in the direction of the print stroke and produce a fuzzy edge by picking up ink from "both locations"
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Thanks guys for all the info. Looks like it could be a number of things.
I'm using newman rollers, tensioned at 35-40N.
The job I just did was on a white shirt with black ink, I double stroked it to make sure it was opaque.
I flood, but not a hard flood. Maybe too much pressure when printing. Off contact is good even with the shirt on the pallet.
Could be the ink viscosity. I thinned out the black ink, but not too much.
Its just one of those kinda things that I see and the client probably doesn't.
It doesn't happen when I'm doing a one stroke, say on top of an underbase.
As for EOM, I do 1 coat on each side.
Thanks guys for all the info! It really helps and my biggest desire is to have top notch quality!
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Thanks guys for all the info. Looks like it could be a number of things.
I'm using newman rollers, tensioned at 35-40N.
The job I just did was on a white shirt with black ink, I double stroked it to make sure it was opaque.
I flood, but not a hard flood. Maybe too much pressure when printing. Off contact is good even with the shirt on the pallet.
Could be the ink viscosity. I thinned out the black ink, but not too much.
Its just one of those kinda things that I see and the client probably doesn't.
It doesn't happen when I'm doing a one stroke, say on top of an underbase.
As for EOM, I do 1 coat on each side.
Thanks guys for all the info! It really helps and my biggest desire is to have top notch quality!
shooting from the hip here as I have very limited manual experience, but I would guess reduce your off contact to about the height of a penny and do a hard flood with a soft stroke and stick to one only. I'd be willing to bet $20 it solves your issue! Any takers?
pierre
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Your screens sound good so I would check the press and pallets. Everything tight?
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1 coat on each side for emulsion might be a problem, it really needs a good EOM and usually one coat per side is not going to cut it unless you coat super super slow.
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Do you flood with the screen down?
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Thanks guys again for the advice.
I don't flood the screen down.
Everything is tight.
I can probably put my off contact down more to the penny height and try flooding harder.
The scenario happened when using 166 mesh (newman panel) and I usually don't flood too hard and I usually
do a double stroke. So I can hopefully flood harder and do a one stroke. Seems a bit hard for me with the 166 mesh.
I don't use anything lower as far as mesh count.
Seems to me that an automatic will be able to consistently flood harder and be good as a one stroke. I'm hoping cause I'm tired
of pushing that squeegee!
I also just did a 1-color black on light colored shirt job using the murakami Smesh 150 and it's soo much easier to use that mesh. I wish
all mesh counts were as easy to print though like the Smesh.
Thanks again for all your help.
*Today was the first day I received a physical piece for my auto setup. My rad looking ingersol 7.5hp compressor and air dryer.
It's slowly becoming a reality!!! Yes!