Author Topic: Discharge Underbase on Fleece / Hoodies  (Read 1468 times)

Offline ZooCity

  • Gonzo Member
  • ******
  • Posts: 4914
Discharge Underbase on Fleece / Hoodies
« on: June 28, 2014, 10:12:40 PM »
Today I was hoping to get our schedule caught up and run a ≈300 pc repeat fleece job.  Last run we were down about the heavier plastisol hand (client loved them though) and so we had set this up for DC UB + 2 plastisol top colors this time. 11" wide image, very blocky, solid fill spot colors.  Independent AFX fleece.   

Print looked great but registration and running the job was impossible because:
  • Flashing the DC base, which we commonly do on Ts, warped the fleece to the point it could not register (we choke DC UBs 0.25pt, set to inside of base, for typical 10-12" w. x 8-10" h. art).  When I say flash I'm talking about just enough heat to get some water out of the print, not to discharge the garment.
  • Not flashing the base looked promising but when the first top plasti color printed it smeared the DC base in the direction of the squeegee stroke so it peeked out from beneath the last color down.

What a let down and a crappy way to spend a beautiful day, but glad that four hours of r&d happened on a Sat and not when my full staff was here on a weekday.  We've had great success on Ts with this method, was hoping for the same on the always nice to print Indy fleece.  It's possible that our old Gauntlet with it's super great feature of never releasing squeegee pressure is cock blocking us on this by causing the smearing issue and that a modern press that lifts the blade at the end of the stroke for a clean release of the screen would resolve the problem but I couldn't say for sure.

I'm calling this method off for any fleece printing in the future but figured I'd ask if anyone else is doing this successfully and can point me toward where I'm going wrong if so


Offline jsheridan

  • !!!
  • Gonzo Member
  • ******
  • Posts: 2130
Re: Discharge Underbase on Fleece / Hoodies
« Reply #1 on: June 29, 2014, 10:01:17 AM »
Ah yes, the wonderful Indy hoodies. Great fleece to print all inks.

When fleece calls for WB run them through the dryer first to remove excess moisture and to preshink any poly fibers.
 
Drop the OC for the base and raise it for the rest. Sharp hard and fast driving print stroke on the base, kiss on the rest.

web tac.. apply before every-single-sweat and fold back the bottom hem as you load so it doesn't drag in the web.


As for the press, their is an electrical retrofit that allows the mac valves to return to flood position. I know of such a press here in sandy eggo, but the current owner isn't the one who wired it so..  Dan Goldberg from M&R west knows the machine and pretty sure he knows how it was done. I'm sure Rich knows how as well.
Blacktop Graphics Screenprinting and Consulting Services

Offline sqslabs

  • Hero Member
  • *****
  • Posts: 972
  • Work hardened.
Re: Discharge Underbase on Fleece / Hoodies
« Reply #2 on: June 29, 2014, 10:36:08 AM »
Great advice on a tough subject.  Thanks much!
Brett
Squeegee Science
Fort Lauderdale, FL

Offline ericheartsu

  • Gonzo Member
  • ******
  • Posts: 3527
Re: Discharge Underbase on Fleece / Hoodies
« Reply #3 on: June 29, 2014, 01:03:18 PM »
we've had really good luck discharging some of the fleece from INDY.

But most of our fleece orders are usually just black, so the customers tend to go with the Tultex Fleece, which discharge AWESOME.
Night Owls
Waterbased screen printing and promo products.
www.nightowlsprint.com 281.741.7285

Offline ZooCity

  • Gonzo Member
  • ******
  • Posts: 4914
Re: Discharge Underbase on Fleece / Hoodies
« Reply #4 on: June 29, 2014, 05:05:43 PM »
What a great post John.  I read it three times to make sure I didn't miss anything but you described how we print fleece to an absolute T.  The only thing I would add is that I like to smooth the fleece down on the platen in the direction of the squeegee when loading.

The only thing we don't do is pre-run down the dryer, just too much for the hundreds of hoodies we get.  I got a little excited though, thinking that pre-shrinking could be the cure to my problem but then I remembered I had already ran sleeves on these and so they had already made the trip down the 16 ft chamber of our Sprint HO, at a pretty slow belt speed no less.....definitely pre-shrunk.  That just leaves the constant blade pressure as the culprit which maybe could be resolved by running full stroke length (works for Ts when this is an issue).  I'll try it next time but these screens were ganged so that was no-go.  It could also be that the heat of the flash used on the first color down was evaporating too much of the DC base and warping but I'm not 100% on that. 

I'm fairly convinced a better press could run this however.  Maybe next time we'll try a standard plasti/HSA choke on the UB v. the tiny hairline one we use for DC UB. 

So tell me how to get in touch with someone about this electrical retrofit.  Ours is a '92 GT-6 and my understanding was that this wasn't possible since there is only one MAC per head but my thinking says that you could trick it into starting the next cycle as soon as it completes the stroke and then shut it abruptly, just after the next cycle starts to get the carriage to chop over to the floodbar down after the stroke but not go through the whole routine yet. I think it would have to be outside the programming of the PLC and at the MAC valve itsefl though due to the nature of how these machines cycle.  That would solve so, so many issues for us in production! 

Offline jsheridan

  • !!!
  • Gonzo Member
  • ******
  • Posts: 2130
Re: Discharge Underbase on Fleece / Hoodies
« Reply #5 on: June 30, 2014, 03:18:08 PM »
What a great post John.  I read it three times to make sure I didn't miss anything but you described how we print fleece to an absolute T.  The only thing I would add is that I like to smooth the fleece down on the platen in the direction of the squeegee when loading.

 Ours is a '92 GT-6 and my understanding was that this wasn't possible since there is only one MAC per head

that's right.. they only have a single Mac..as soon as you activate the mac it chops and floods. my buddies press is a little newer and has two mac blocks.
I'm sure by now a good work around has been created, what does rich say?

**Edit.. I just talked to dan and they do offer a retro kit to release the pressure. I sent you his contact info via pm.
« Last Edit: June 30, 2014, 03:27:38 PM by jsheridan »
Blacktop Graphics Screenprinting and Consulting Services

Offline ebscreen

  • !!!
  • Gonzo Member
  • ******
  • Posts: 4249
Re: Discharge Underbase on Fleece / Hoodies
« Reply #6 on: June 30, 2014, 07:28:38 PM »
DC Ubase on fleece is a super trick to pull off on any machine. We got the smearing
from time to time as well, and found that we had to have a perfect combination of flash time, penetration,
and also running speed. If we stop for any period of time the base would start to stick to the back of the first plastisol
screen and cause some shifting. If we flashed long enough to get the majority
of the water (and tac) out of the dc ubase then the fleece would contract and the web tack would loosen up.
If we didn't flash at all we'd be fine for a few prints but buildup on the first plastisol screen would start
causing issues, clogging etc.

So yeah, we've pretty much shelved it for time being. It's worth it for those certain jobs but other than that
plastisol is typically only slightly heavier hand, particularly on Independent.

Offline ZooCity

  • Gonzo Member
  • ******
  • Posts: 4914
Re: Discharge Underbase on Fleece / Hoodies
« Reply #7 on: June 30, 2014, 11:41:28 PM »
DC Ubase on fleece is a super trick to pull off on any machine. We got the smearing
from time to time as well, and found that we had to have a perfect combination of flash time, penetration,
and also running speed. If we stop for any period of time the base would start to stick to the back of the first plastisol
screen and cause some shifting. If we flashed long enough to get the majority
of the water (and tac) out of the dc ubase then the fleece would contract and the web tack would loosen up.
If we didn't flash at all we'd be fine for a few prints but buildup on the first plastisol screen would start
causing issues, clogging etc.

So yeah, we've pretty much shelved it for time being. It's worth it for those certain jobs but other than that
plastisol is typically only slightly heavier hand, particularly on Independent.

Well that's comforting!  I was second guessing my decision to pull this method for fleece but your post mirrors my own observations after thorough testing.  And you're right, plasti base through a 225 or 180 yields essentially the same hand to the finished print.  Not to mention that no one can really feel it on the inside of fleece anyways.

I thought about trying it next time with a full stroke to allow the correct snap off/peel of the screen but my production manager pointed out that you gotta stop or go over the kangaroo pocket so that was pretty much the nail in the coffin for this, at least for now, may check it out again someday.   

John, thanks so much for the contact, I'll give Dan a call tomorrow and see if anything can be done, that would be huge for us.