what am i doing wrong? (i.e. help me please!)

[ericheartsu]

Here at the old shop we print a specialty item called slipmats. They are made of 16oz polyester felt, and pretty thin, roughly the same thickness of triblend tee.

we are printing a two color image (base white, highlight white) on a black slipmat. We are flashing in between, and using a poly white ink! The base screen is on head 1, the highlight is on head 10, with the flash in head 3. i have the off contact at about a 1/4".

We just did a run of 1,000 but had to stop every 15 prints to clean the bottom sides of the screens, as we were getting a shadowing effect. i'm about to do another run of 1,000, and i'm hoping to avoid this problem.

At first i thought maybe these are shrinking, so we raised our flash dryer up really high (we are using a quartz flash),  and they were flashing correctly, but still running into that issue.

my screens are roughly around 28 or 29n. the base is on a 156, and the highlight is on a 230.

Any tips you guys can recommend?

[mk162]

can you take a pic of one?  A visual would help

[ebscreen]

Are they tacking correctly?

[blue moon]

is the shadow all the way around or just on the bottom?

I would also look into an off contact of about a penny's height rather than 0.25".

as mentioned, post pictures . . .

pierre

[Doug B]

  I would agree that your off contact is way too high. That will certainly cause that kind of a problem.

[Frog]

If reducing off-contact doesn't do the trick,  here are some thoughts;

do the films for the two images, in fact, line up perfectly? (If using the same film for the base and top, forget this.)

Now, even if "flashing correctly" they could still be shrinking.
How about pre -shrinking by running through your dryer first.

If you are flashing, why is there any ink on the bottom of the screen(s) anyway?

[ericheartsu]

So the offcontact more or less needs to a 1/16" higher than the substrate correct?

we are using the same film for two screens (not how we normally do it, just happened to be how we could do it for that time being)


i plan on trying to "preshrink" these before start these.

Shadowing is only appearing only at the top of the print.







sorry for the HUGE pictures.

[ericheartsu]

oh and iforgot to metion, they are not moving, we are using waterbased adhesive, and it's holding strong!

[jason-23]

to much pressure on a weak screen maybe

[IntegrityShirts]

Ahhh front-to-back (top to bottom of print) screen off-contact could also do this.  Check to make sure BOTH screens in the hangers are set the same off contact at the top and bottom of the screen.  If that checks out, put the highlight in a different head.  Squeegee pressure (or even angle) could be pulling the screen.  Tension levels between base and highlight could also be off.

Most likely screen hanger out of level though.

[cbjamel]

What I have seen happen to much flood pressure on the ink push out the bottom of screen as it floods and is on top edge of design.
Maybe.
Shane

[alan802]

Here is my guess.

Hopefully the image attaches correctly.

[Homer]

What I have seen happen to much flood pressure on the ink push out the bottom of screen as it floods and is on top edge of design.
Maybe.
Shane

was going to suggest the same thing. . .too much flood pressure

[Inkworks]

I'll third the too much flood pressure, particularly if you are doing multiple strokes to clear the screen.

Way too much off contact too, 1/16 - 1/8" max. Just enough off contact to get good rolling snap-off behind the squeegee print.

[Chadwick]

Hmm.

For me, ghosting at the bottom of the print is ( usually ) shrinkage from flash,
and, ghosting at the top is ( usually ) related to angle/pressure/flood/off contact/tension....yeah.

Which is all rather general, but it's the place to start looking.

My first thought is, it's due to a thick substrate causing issues,
but from what I read, they don't sound overly thick...

I'd be interested to see a pic as well.
( I hate when jobs do this, but it keeps you on your toes, eh?  )