chasing my tail...squeegee angles, pressures, and stroke speeds

[Du Manchu]

I just installed my first Auto.  So I'm running my first good batch of jobs on it today with visions of finally knocking out jobs like I've been dreaming of for years, but instead, nothing but frustration.   Could someone chime in with some basic tips on  squeegee pressures, stroke speeds, and depth settings.

One specific question about depth/squeegee pressure....so if the table is raised, and you lower the squeegee on the outside tip of the pallett,  should you see any deflection on the pallet arms.  When I look the the depth setting from the previous owner, they all seem excessive, yet those guys produced some awesome prints.  OR should you set the depth to just kiss the shirt/pallet top?

Any tips would be greatly appreciated. 

Dewey

[ScreenPrinter123]

Hey Dewey,

You must have a rhino :-). (Brian here). We took our cue with the settings from Alan that you can play around with the depth/pressure all day, but he saw no significant improvement of just lowering the squeegee to produce a little deflection on the pallet with very little pressure (I think if u bring it to 0 the floodbar won't even go down). So we lowered the "depth" and then used as little pressure as possible to clear the screen. Maybe Alan can clarify anything I've said. What headaches are you encountering?  Opaqueness issues? Clearing screen issues? Etc ?

[Du Manchu]

Hey Brian!  It sounds like you must have owned a Rhino at some point...haha.   My problems are multiple, mostly attributed to running this beast.  A manual press is nice and slooooow and you can choose what your next step is after every print.  The auto is just a lot to take in at once, but man is it going to be nice once I master it.

My last problem of the day was printing black ink on a white shirt.  Simple huh?  But I just couldn't get a good solid print, with out hitting it twice, which I assume is ridiculous.    Running about 26 pressure. depth about 38?(yours were at 40-40.25), and 110 static screen.  I didn't look at the screen to see if it was clearing.  Good point.

My theoretical question is that if the squeegee depth is so deep that it is bowing the pallet arm downward, what good can the pressure setting be, since it would seem to be at 100% pressure.  Yet when I decrease the depth, I end up with a light print. 

My other questions is probably a stupid one, regarding placement. ...I typically print about a hand below the collar on most prints.  However, this placement seems to always max out the forward stroke and has my squeegee extending past my pallet.  I keep finding myself increasing the angle of my flood bar (to flood the image) and decreasing the angle of the squeegee to keep it on the pallet.  The only solution I see is to reposition my pallets outward, and have the  shirt collar on top of  the pallet.  Come on... there has to be a simple answer I am blinded to.....

Many thanks.

[ScreenPrinter123]

<<Hey Brian!  It sounds like you must have owned a Rhino at some point...haha.   My problems are multiple, mostly attributed to running this beast.  A manual press is nice and slooooow and you can choose what your next step is after every print.  The auto is just a lot to take in at once, but man is it going to be nice once I master it.>>

Yes, it will be very nice.  You will be very happy very soon once it all starts coming together on press.  One thing I would mention, as I'm not sure where you are in getting all of the pieces of your puzzle together, is that now that you have the major stuff in place (dryer and press) don't cheat by not getting the peripherals that will make your life a lot easier that are a lot cheaper in comparison -- in particular, good squeegees, good mesh, and maintaining good tension (or getting new statics relatively often) (and a good exposure unit if you haven't found one, but I think you mentioned you did find a nuarc, right?).  The little things, I've found, can have a great impact on your "throughput" at the end of the day. And, as of late, since we're a two man-show (as you know), we've been trying to implement as many of those little things to streamline our weekly printing so we can move on to other things. 

<<My last problem of the day was printing black ink on a white shirt.  Simple huh?  But I just couldn't get a good solid print, with out hitting it twice, which I assume is ridiculous.    Running about 26 pressure. depth about 38?(yours were at 40-40.25), and 110 static screen.  I didn't look at the screen to see if it was clearing.  Good point.>>

Well, with a 110 you should definitely be getting clearance with one pass ... but you definitely shouldn't be using a 110 on a white shirt -- it will feel far more "vinyl-y" than you would want, I imagine.  We shoot for 225's with black on white shirts, but if it's got a decent amount of open area, we would go with a 180 (s mesh for both).  My "recommendations" (i.e., what I would do) is the following if I were experiencing your problem:

(1) Definitely confirm or dis-confirm whether or not it's clearing on the first pass -- but it seems like you imply it's not - otherwise, why need a second pass?  [Btw, if you have a smaller order (like 100-200 piece shirt job) and it's a black print on a white shirt and it's not clearing for some reason you can't explain in an isolated situation -- just double stroke it and get the job done!  You'll waste more time trying to figure out what the problem is -- do that when you are done with the job and have all your equipment turned off and you have spare time! :-)]

(2) What's the status of your squeegees?  New?  Used?  Are they firm?  What kind've squeegees are you using?

(3) What's the status of your screens?  What's your tension like?  Shouldn't matter too much with black on a white shirt, but better tension would obviously help, and the same consistent tension all the time, whatever that may be, would be optimal.

(4) Make sure your screen is parallel with your pallet from front to back (same off contact on the front as there is on the back)

(5) Try slowing your print stroke down a little.  Or, if you want to go fast, my experience was that you had to increase the pressure quite a bit so that the pressure would off-set the heightened speed to give the ink a chance to flow through the open areas of the stencil.  When we were really moving on certain jobs (especially where we were printing a black ink, for instance, on a maroon shirt where opacity or lack thereof won't even be noticeable), we'd ramp up the psi between 40-50 and have the valve nearly wide open.  But i'd never do that with a lighter garment and darker ink, since the contrast between shirt color and ink color is so great that if the opacity is lacking, it will obviously be noticeable.

(6) Spend about an hour or two on the following, and you'll pat yourself on the back over the next year on the time it save you: Shoot out 5"x5" block on all of your mesh counts.  Lower your off contact to where the screen is touching the shirt.  Raise it by .06 - this should give just a little off-contact and probably far less than you're used to when using the manual press.  Find the right angle (I'd start at about 10 degrees -- a little bit of an angle), speed, and pressure (start at 25 psi with the dark color inks that are thinner and work your way up in 5 psi increments; i'd start at 15 psi with white inks and work your way up if need be) that clears the ink with the opacity you want with one stroke - that way on artwork with thinner lines (which is probably most of the time and not a 5"x5" block of ink!) you'll be good.  I've found that the less off contact I have (within reason of course, as a little is desired) the more opaque the dark print on a light garment is (and you'll need far less off-contact than what you thought you needed coming from a manual).  With the white ink, i'd go a little higher with the off-contact -- but once the white ink is really flowing, it probably wouldn't make a difference (though with thicker standard plastisol inks, I find that less pressure is needed than with the thinner inks).

(7) Consider, if you haven't already, triple durometer squeegees or maybe even give a go at the smilin' jack.

( Consider going the "s" mesh route.  Sorry, but I've become a smart mesh (by murikami) junky once we started using it.  The difference in clearance of the ink was very impressive.  Since I first encountered this at an SGIA show in New Orleans back in 2008 I think it was, I always shelved this aspect as a "yeah, that is kinda nit-picking -- I don't think the thickness of this mesh's strand vs. the thickness of that mesh's strand will make that big of a deal" -- boy was I wrong.  It's expensive mesh up front, but if you have the jobs to justify getting some, it's a smart investment -- just handle the screens carefully and stick to the suggested range of tension.  Worst case scenario, order enough mesh for one or two screens (use the mzx's) of the 180 smart mesh or 225 smart mesh and compare it to the clearance you're getting with 110 mesh you're currently using.   


<<My theoretical question is that if the squeegee depth is so deep that it is bowing the pallet arm downward, what good can the pressure setting be, since it would seem to be at 100% pressure.  Yet when I decrease the depth, I end up with a light print.  >>

Well, you can work with two variables or one.  You can lower the squeegees to where the pallet is flexing and leave it there -- then all you have to worry about is pressure.  Or you can play with two variables of adjusting the squeegee height and pressure constantly on different jobs (though I guess you can keep the squeegee's higher and just continue to ramp down on the pressure).  Life's complicated enough, and since Alan mentioned he had the best results (or at least no better results from the other methods) lowering the squeegees to where the pallet just started deflecting and then using as little pressure as possible, that was fine by me to operate off of -- and since it seemed to work just fine for us, we didn't look back in trying to raise the squeegees and compensating with more pressure. 

If you lower the squeegee down all the way -- try lowering the pressure down to nada (or to where the squeegee will just be forced downward - prolly around 10-11 psi just starts getting the squeegee to be forced downward) -- I bet the ink doesn't clear.  You need some pressure with the air cylinders, if memory serves correctly, even if you have the squeegees all the way down in the "depth" category.  We found the above to work just fine - lower to just starting to deflect the pallet then use as minimal pressure as possible.

<<My other questions is probably a stupid one, regarding placement. ...I typically print about a hand below the collar on most prints.  However, this placement seems to always max out the forward stroke and has my squeegee extending past my pallet.  I keep finding myself increasing the angle of my flood bar (to flood the image) and decreasing the angle of the squeegee to keep it on the pallet.  The only solution I see is to reposition my pallets outward, and have the  shirt collar on top of  the pallet.  Come on... there has to be a simple answer I am blinded to.....>>

(A) You don't have to keep the squeegee on the pallet.  Ideally yes, but not necessarily.  I'd recommend just taping (we use masking tape when this happens) where the squeegee will be pressing the mesh up to the edge of the pallet right as it rides up on to the top of the pallet.  Never had a screen pop -- even the s mesh -- when taped -- nor have we ever had any image/ink smearing when the squeegee ran past the pallet.

(B) You need to find the right balance between where to extend the pallets and where to burn your screen.  I believe we were doing 6.5"-7" down from the outer diameter of the screen.  You don't want to go to far out with the pallets because then the shirt won't go down far enough and you'll be printing on the stomach and not the chest; but you don't want to be too far in with the pallets because it's not optimal to have the squeegee dropping in front of the pallet if not needed.  So, just find the right location for the pallets and log it if you should need to swap out sleeve pallets, junior pallets, etc. in the future.

Hope some of those things help.  If not, it's all Michael's fault.

-Brian

[Du Manchu]

Thanks for taking the time above Brian.  All good points, and I'll apply and post results.  Below are answers to a few of your questions:

Squeegees: all new 70/90/70 from Action, along with winged flood bars.  I even went all out and bought that Roller contraption they are advertising so heavily.  I'll let y'all know how it works, as I've got a 450pc repeat job,  white on navy to print this week

Mesh: I'm waiting on a tension meter (used) to arrive next week, so I can mesh up those 6 screens you gave me.  I've waiting to experiment on those, and the pin reg system, before I make any further investments/decisions.   I've got one 225 roller screen with decent tension, that I've burned for the white on navy job mentioned above.   Typically I wouldn't put 110 on a black shirt, but I was so ambitious about printing 5 jobs yesterday, I burned all of my higher mesh screens.   The black ink on white shirt mentioned originally is a give-away event shirt, so it got the lowest quality priority.

Image setter: Nuarc

New Question.  For the white on navy.  With one 225 roller, would you locate that as the under-base screen, or the finish screen.  All my others are static  110,160,196.
 

Thanks again, and you are right.....it is all Michael's fault!

[Printficient]

OK First things first.  Is the press installed properly?  Is it level and plumb?  The perfect squeegee pressure for printing is 0.  I always recommend using the "physical" (adjustments on the carriage) not the air for adjusting pressure.  The Triple duro's are a good start.  The object is to dial in the surface area of the squeegee to the screen.  The minimum is what you are looking for.  If you are deflecting the table then you have way too much surface area.  The squeegee should not roll under.  You are trying to just use the edge.  Remember your chopper movement is vertical.  Your squeegee is angled.  Therefore your squeegee is being pulled down to the screen from the top backwards.  All goes back to all the platens being level and plumb to each other.  If they are now and you do not relieve the table deflecting pressure then they will not be level and plumb for long.  Start there.  Merry Christmas from all of us at Xenon.

[Binkspot]

I know what works for us. 20-30 psi just past vertical, maybe 3-5 degrees on the squeegee, triple for white and thick inks, 70's for all the other colors, just enough pressure to clear the screen. Firm flood but not so much to produce a ghost image. Little off contact with tight screens, more with soft, just enough for the screen to lift off the garment as the squeegee passes. I print with pressure and rarely do the stops ever touch on the choppers, more of a floating of the squeegee.

Depending on how your press was set up the actual numbers or travel distance on the choppers may not be the same between two presses. The distance between the bottom of the squeegee, screen and pallet will vary machine to machine and can only be used as a reference, need to visually adjust your settings to your needs. 

Black in a 110 should almost leak through the screen.

IMO its not the set up but the emulsion on the screen, not thick enough stencil to leave a good deposit of ink. We have been struggling with trying new emulsion for the past few weeks and when I have coated to thin we need to double stroke, just not enough ink in the stencil.

I would run white on navy on a 160 with a thick stencil and try to pull off a one hit white or two 160's but a lot has to do with the ink you are using and how well it moves through the screen.

Just my two cents.

[inkman996]

I would love for sonny to clarify what he means by zero pressure being ideal? Is their some magic I am missing.

Sonny sometimes you come out with the most odd ball things ever, and sadly it could be real damaging info for someone new to a press if they decide to chase your idea of ideal. Everyone else that gave advice here are real day to day printers and they know best, stick with selling products and stop stating stupid things like zero pressure.

[Printficient]

I would love for sonny to clarify what he means by zero pressure being ideal? Is their some magic I am missing.

Sonny sometimes you come out with the most odd ball things ever, and sadly it could be real damaging info for someone new to a press if they decide to chase your idea of ideal. Everyone else that gave advice here are real day to day printers and they know best, stick with selling products and stop stating stupid things like zero pressure.

The zero pressure comes from Joe Clarke who is an undisputed Guru for printing.  The math he uses is beyond me and the "zero" is the goal.  Get as close as you can.
1.    “Pressure” equals force divided by area [F/A]

2.    The ideal pressure on the T-Shirt platen [or press bed] is zero

3.    The goal therefore is equilibrium between blade pressure [F/A] and mesh tension AT ZERO GAP

4.    Rough estimate ~2N/cm² gain for every 16” of off-contact gap

5.    So a 110/80 mesh at 25N/cm² screen at 1/8” gap prints around 29N/cm²

6.    The ideal blade edge during the stroke ~250m and 16” in length = 0.16in²

7.    This mesh uses 231pL [picoliters] of ink [not including the garment]

8.    More ink delivery causes wet artifacts, less causes dry artifacts

9.    Therefore buckling is inadvisable – causes image drag and pressure on platen

10.  Multiply dynamic N/cm² by 1.4503 to find PSI = 29N/cm² * 1.4503 = 42PSI

11.  The ideal force on that blade = 42 * 0.16 = 6.7lbs of force

[ScreenFoo]

This is the best post I've read all week. 

Just to make an analogy about what was said about 'zero pressure'--how hard do you have to push on the ink inside a bucket to transfer the ink to your finger?   

Also, note that he places the 'footprint' of the squeegee at .01" (actually it'd be 254 microns, but for the sake of easy math...) times the length. 
This is the variable that wildly affects your prints when squeegees are dull.

[ScreenPrinter123]

Dewey,

As I mentioned before, you will have to bump the pressure up on the rhino to at least 11-12psi for the squeegee to even go down to reach the pallet. Just fyi

[inkman996]

Fantastic lets all start measuring our pick liters and look for wet artifacts, get frigging real and join the real world.

[alan802]

Crank your barrel adjusters to where the squeegee will go down like Brian said.  Sonny may not have communicated to us what he really meant by zero pressure.  He means zero pressure on the pallet, I do believe. 

Use the air squeegee regulator to provide that print pressure variable and leave the other variable constant.  If you make sure your blade goes down far enough, then you only use enough pressure in the chopper cylinders to shear the ink, then you'll always be using the proper amount of print pressure. 

Technically speaking, in a perfect world, proper press calibration, you would have zero pressure on the pallet.  The chopper cylinder/squeegee pressure has to overcome screen tension, ink, and off contact so technically speaking zero squeegee pressure will not give us the opportunity for the ink transfer to take place.  In a real world scenario, you'll never be able to print with zero pressure, but you want to try to eliminate pressure on the pallet.  Zero pressure won't be enough to overtake the mesh tension and off contact, so you need enough pressure to put the stencil into contact with the substrate so the transfer of ink can happen, yet not have measurable pallet pressure. 

I've used both squeegee height and chopper cylinder pressure at the same time but now I've adjusted all of our squeegee/barrel adjusters all the way down and locked them there.  If I were setting up a shop, I would not use Sonny's suggestion, it's just adding another variable that really doesn't need to be there.  If you use Sonny's method, there will be a higher likelyhood of printing with too much pressure than using the other method I mentioned, and I doubt the press is calibrated enough for either method to produce perfect results.  You'll also be adjusting the barrel height on every setup, just like adjusting the pressure regulator, but getting the air pressure in the cylinders right is easier than trying to get the squeegee at the perfect height.  Say you get the squeegee the right height, but 60 psi is in your chopper cylinder, you're still printing with 60 psi when you shouldn't be.  With your squeegees all the way down, and 25 psi in the chopper cylinder, you're printing with 25 psi, plus the gravity of the weight of the squeegee assembly.  If you adjust the squeegee to just the right height to make the mesh touch the substrate while not putting any pressure on the pallet, your press better be calibrated to a very high tolerance or you'll see inconsistent results and you'll still have to insure that you aren't using excessive pressure in the chopper cylinders.  With using the air pressure in the chopper cylinders only as your variable to shear ink, it allows you to print with less pressure and setup faster than playing around with squeegee height.

That's my take, I don't doubt the validity of Sonny's claims, he's taking Joe's suggestions which I have always found to be as good as it gets, but he's also not telling the whole story.  The math doesn't lie, but it's nearly impossible to measure some of the variables that go into that math so in the real world, you'll not see the results that the math says will happen.

[ScreenFoo]

Certainly, squeegee air regulation can help overcome print issues caused because of head linear and planar calibration problems, but is that the ideal solution?

Everyone jumped on Sonny saying 'zero squeegee pressure won't print' even though he clearly states in his second point he's talking about pressure on the print bed or platen.

One more time--how hard do you need to press on the ink in a bucket to transfer it to your finger?

[inkman996]

I jumped on Sonny because he has a way of giving advise that in reality does not help. Even tho his theory (Joe Clarks) makes sense in theory it is not practical for the day to day printers, and absolutely wrong to put someone new to an auto on that road. We can sit here all day and talk about ideal parameters and yet next to no one here will have any of them dialed in and working. I personally set my squeegees to the point of just kissing the platen. I then add pressure up or down from there, once a screen is in the head the squeegee needs either more or less pressure to make contact with the platen. Point is by mechanically stopping the squeegee from pushing down to far it wont nor cant deflect the platen or put excessive pressure on the whole print head.