question for the auto guys

[mooseman]

what is the the typical amount of off contact on an auto?

mooseman

[Homer]

we use a quarter for t-shirts. . if that helps?

[Frog]

That's the thickness of a 25 cent coin, not a quarter inch!  (just in case, as you never know who is reading, and what they know)

Otherwise Moose, the distance varies with tension, just like on manual screens. Allan's 50 Newton screens can run a lot closer than my old cord and groove or tape and staple antique beauties!

This also assumes for plastisol, right?

[brandon]

And don't forget rollers vs statics. We use rollers and a friends shop uses beat up statics and their off contact is twice if not more than ours. But I'm sure if you keep up on your statics you will be fine.

When we do some really big prints like 2 feet wide for piece printing before sewing those static screens that we have can and do loose their tension faster so we need more off contact. That's just us though so others might have it different.

[brandon]

Then again if you don't keep up on your rollers same thing!

[Nick Bane]

about 1/16in , or about the thickness of a quarter here as well for Ts. 

[tancehughes]

Yep, we use quarters to set our off contact. Using rollers here

[mooseman]

Thanks all for the info.
We try on every job to mimic on our manual (as much as possible) the elements present for an auto.
I am really curious about many things and off contact and the way an auto squeegee addresses the screen are two of the bigger focus areas.
naturally my arms and energy are the greatest uncontrolable elements but fix what you can ..adapt to what you can't.

Our OC is about 1/16 of an inch on every job, i check and modify as necessary.

One of the great variables I am finding is the roller frame job to job, print head to print head all combine to address the platten differently each time a new screen is installed. We find not all of the rollers intersect the square bar exactly the same on each frame as  the square bar is too weak (IMHO) where the side rollers bolt in on our newer frames. The square bar deforms slightly at the side roller footprint which modifies the angle of the fit . Also we find  and not all frames interact with the print head the same depending how deep or shallow the square bar is inserted into the head.
As a result we are managing OC on every setup.

BTW we have only rollers, newer and older versions Newmans, run 230 @ 28 - 30n , 195 @ 36 - 40n and 155 @ 42 - 45n.

At any rate thank you all for the info and replies....mooseman is working hard to make screen printing easy

[tpitman]

One of the great variables I am finding is the roller frame job to job, print head to print head all combine to address the platten differently each time a new screen is installed. We find not all of the rollers intersect the square bar exactly the same on each frame as  the square bar is too weak (IMHO) where the side rollers bolt in on our newer frames. The square bar deforms slightly at the side roller footprint which modifies the angle of the fit . Also we find  and not all frames interact with the print head the same depending how deep or shallow the square bar is inserted into the head.
As a result we are managing OC on every setup.

I've noticed that too. Didn't know what it was, but at least half the time I have to adjust the off-contact. Never occurred to me that it was differences in how the round bar ends engaged the square bar on my rollers.

[alan802]

With screens that tight, you can be at 1/32" assuming your press is calibrated well.  If it's not paralleled precisely then 1/16" or higher will have to do.  I use metric , so 1mm is close to where we are, sometimes half of that if I've got a bunch of 205N's on press at 55 newtons.  I've seen shops using 12 newton statics at 1/4" and even witnessed a shop that had their screens at 1/2", double stroking navy ink on an ash shirt and it still looked like garbage.  The guy got offended when I asked him if he wanted me to help them get away from having to do that, so when I see that type of stuff in other shops I just move along and try to talk shop without getting into all the problems I see.

[Gilligan]

Alan runs some insane OC... barley visible.  I didn't think his screens were clearing the first time I watched him print some white ink.  It was just that it was clearing so well and the mesh was so close that you could easily see the ink like it was still in the stencil!

<super jealous>

[RICK STEFANICK]

depends on the work load and if my pallets are level..lol      somehow we get by..

[alan802]

I've got to parallel our press again.  It's been about 100K imprints since I did it last.  It does no good to try to print with very little OC when your press isn't calibrated to a certain tolerance.  If your pallets are 1/32" out of parallel with each other then you obviously need 1/16" OC to compensate.  I tried getting our pallets to this ridiculous tolerance, .005" if I remember correctly, and putting 10lbs of pressure on some pallets can move the pallet 1/32" easily, depends on the press.  Remember to take into account your press' deflection and how print pressure affects it.

[Shawn (EIP)]

we use the same off contact we would use on the manual

[3Deep]

Moose, back when all I had was a manual press my biggest thing was trying to keep the same print angle....I was working on a tool to fit my squeege in so I could keep the same angle and pressure during printing never finish it though got an auto LOL

Darryl