TSB
screen printing => General Screen Printing => Topic started by: Dottonedan on November 28, 2016, 05:58:34 PM
-
Ok, let me set the scene and start this with (The lead printer/production manager) already knows he's not well versed in all the different ways of printing. He's very new to it (4 years) and self taught. Very very nice guy. He's grown with this Co. from it's infant stage but in truth, really wasn't forced into needing to know much more than he does. Pretty down to basic bare knuckles printing.
We have one 8 color auto and a 6 color manual. They have been printing solid over solid for everything in the past so I've been introducing them to halftones and registration. So I've been noticing they don't adjust off contact between tees and sweats. He said he's tried once, but didn't see a difference. So, for tees, lets say the off contact is set at the install of 1/16" or maybe 1/8th (I'm not sure what M&R's default off contact is). I'm assuming it was set up for tees at a default setting and whatever it was set up at, is where we are now and that must be what we are using on lofty sweats as well.
So, the printer doesn't adjust pressure either. We stay at 50lb on everything he says. oh yea, 50lp?. Yea, so, he said, well, we do go a little higher sometimes for tee shirts. Is it just me, or am I living in Bizaro world?
Now, I know of one guy that was recently showing how you can print nicely with just 5lb's of pressure. He was gloating a little for gloating's sake, but sure, it's extreme. Lets say maybe a good low is 10 lbs? I don't know. I've not ran/setup auto's so I guess I'm going to get into it. So, I am curious to know what the rest of you'nze guys/gals are doing (on average). There's probably a middle ground on pressure for most things but I'm guessing it jumps when you jump to sweats.
Must guess is that 50lp's of pressure is just one other reason why they print 2-4 strokes on the same color. ;) Hey, I'm just observing. I'm only an artist.
-
The default off contact for tees is 1/16. They should be adjusting for sweats to the same off contact. The squeegee pressure with the knobs for squeegee pressure all the way up should be around 30-35lbs of pressure with a average 25 degree angle and sharp squeegee. The pressure should never have to go over 50. If you have to something is wrong.
-
OK. We are really talking 2 things. Squeegee travel and PSI. I have always shied away from PSI and worked with travel. The issue you will have is that different shops use their air differently. Someones 50 psi might be equal to someone's 35 psi. I would set my psi to whatever I wanted and dial in with squeegee vertical travel. If you want 25 psi then set it and dial in the pressure with adjustments in the vertical travel. Call me and I'll be happy to talk you through it. Also I would recommend "one" angle set squeegees. Smiling jacks or double bevels. 404-895-1796
-
Dan, pressure read out is not an accurate metric shop to shop, even press to press. If you chase after figures others toss out you'll be going in circles- too many variables effect it.
Just have him print at the minimum pressure needed to clear. Give him perfect screens, the best ink available and quality, sharp blades. Parallel the press and check it regularly.
He's onto something regarding leaving a setting static to speed setups but pressure isn't something you want to typically leave in one place for every job.
-
One shops perfect numbers is another shops nightmare's, I'm with Zoo on this just to many variables to deal with, but it's a good start to get where you want to be.
-
Yes, see the whole spat over the Lava white ink. My Roq is 3-4 years old....we have to run our pressures up in the 50's...the new ones are all in the 30's. My guess is we are not getting a true reading as the CFM is low and the way the scissor system works. I've been in shops where the presses were all installed at the same time and none have the same readings. It all starts with great screens and the right squeegee and then work from there.
-
Everything is subjected to change with so many variables, but these are good starting points for us. We often print with 20-25 psi, and yet other times it maybe higher, it really all depends on the variables of the job.
30-35 psi for a standard coton tee's.
M&R sportsman's.
One stroke. ( standard plastisol )
150-48 mesh up to 300
A good squeegee.
Good ink.
Murphy
-
Dan, pressure read out is not an accurate metric shop to shop, even press to press. If you chase after figures others toss out you'll be going in circles- too many variables effect it.
Just have him print at the minimum pressure needed to clear. Give him perfect screens, the best ink available and quality, sharp blades. Parallel the press and check it regularly.
He's onto something regarding leaving a setting static to speed setups but pressure isn't something you want to typically leave in one place for every job.
Amen. This is screen printing! Then you add 4c process, Discharge inks and the list goes on. Dan, I wouldn't focus so much on a standardization but more on teaching him some fundamentals as that will go miles. I always like auto printers that have manually printed for a while as they understand mesh, squeegee angel-speed and off contact so much better.
-
We are averaging 35psi with s mesh and really sharp squeegees.
-
More agreement with what Zoo said.
At the auto shop I last worked, we adjusted squeegee pressure via travel; adjusted angle & speed; and swapped between different duro squeegees, all based on the needs of the job at hand. We also kept squeegees sharp, and had general guidelines for how we selected mesh based on art/ink color/garment color. Single or double stroke; if it got hit more than that, it was a p-f-p. In all of that, we never gave the actual psi a second thought, never changed it based on job. (We also never changed off-contact, but fleece was rare for us.) That shop wasn't going to win awards, but had basics down, and turned out quality work.
Maybe your guy just needs some encouragement to branch out a bit. Perhaps not "try to meet this metric," but "what can we do to make this work better, make production move faster". Can his comfort zone be broadened, rather than challenged?
-
Printing single pass ultra low pressure is great, and something to strive for...... but, before you do, you need:
Staff that really buys into the idea without being forced
S-mesh
sharp squeegees
tight screens
very tight tolerance press leveling
good inks
good flood processes.
If you are even somewhat questionable on any of the above, look at getting everything else up to snuff first. If someone came in here and said we should be printing at 5psi and started pushing for that, they'd be shown the door..... A little bit of information is a dangerous thing.
-
Why not offer him to read through the threads here? Great stuff to be learned!