Holy Crap Part 2

[blue moon]

so, it's only been few days since Richard left, and the shop is looking better than ever. Everybody cleaned up their stations, organized the tools and storage area and my procrastinating arse installed another dip tank, fixed one of the broken lights in the washout booth, fixed one of the squeegee holders that has been out of commission for about a year, leveled off the manual press and set up a standby platen (this way if we print on a palette we can just swap for a good one that's standing by and clean up the mess without holding up the press)!

Day before yesterday, we briefly tested some of the new white ink and using the settings Richard explained, got it to print 2-3 times faster than we do so far. And on top of the speed, the deposit was thinner, brighter and had less shirt showing through. All of this in less than 5 min of testing! I should also mention this ink was tested and dismissed by us before as the results were not adequate! It just shows there is so much to learn even when you think you actually know something. Even better, no additional equipment was purchased! We just changed the settings on the press and used a harder blade.

There are still several white inks to test as the one we tried does not seem to meet all the specs, but when we are done, we should be printing (stroking and flooding) about 5 times faster than now. As a consequence of better deposit, we printed the order using just two strokes without flashing and without highlight white. The shirts were not black, they were red, but still getting good coverage without flashing is pretty big. I can see the production speed increase significantly and am finally starting to understand how Alan is turning those big numbers with such a small crew!

Richard is coming back on Wed, so stay tuned in . . .

pierre

[starchild]

Pierre when you say the ink you use does not meet all the specs.. Do you mean available specs for that particular ink? Or did you build a spec sheet from general ink properties with specs that you require for that particular squeegee/screen/stencil and print application that you require it to meet?

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[Sparkie]

...And on top of the speed, the deposit was thinner, brighter and had less shirt showing through.

I'd pay just to see how that was accomplished.

Pierre, it sounds like you are well on your way to producing even more spectacular prints than ever before. I can't wait to see some of your new and improved results. Good luck!

[blue moon]

The viscosity drop when printing is not high enough to print faster than on a setting of 6.
We are looking for ink that will let us print on 10 or 11 (12scale).
This was just a first try. And we actually know which ink will, but I am trying to find something that is stocked by our local supplier.

Pierre

[starchild]

Ok.. It's in the ink's rheological properties that are being tuned..
Specially it's Plastic Viscosity.

If it's too high then higher squeegee pressure and lower squeegee angles are required to clear the mesh which introduces slower stroke speeds.

If it's too low, when the ink passes through the mesh, it will splatter onto the shirt.

The ink's plastic viscosity should be at a midpoint where it thins enough to clear the mesh but recover it's body rapidly to hold the image shape  once deposited onto the shirt.. At maximum stroke speed..

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[blue moon]

from what I understand, the viscosity changes when stroking. We are looking for ink that highest difference between the two states which is essentially what you stated above.
Richard was not here for the testing, I was impatient and just ran it myself. He will be back on Wed and is bringing the viscosity meter with him. We should be able to test the inks and choose the one with best results. 'then on to the press to dial it in.

But this is all just a small portion of it. Resources Richard is pulling together to get the results are equally as impressive as is his knowledge. I thought we were a solid 8 or maybe even a 9 on a 10 scale. Seeing what Richard is talking about, makes me think we are probably a 6.5 or so. I am certain that with his help, we'll be able to reach the 9 at the lowest and with our commitment to doing it right, I think 9.5 is a reasonable expectation.

The biggest difference is that everything we have been doing so far has been by the seat of the pants. Richard brings in logic and testing to everything. He backs it up with actual factual knowledge so as we measure and move towards better results it is planable and predictable.

pierre

[GaryG]

What are your screens tensioned at, and how did he help in this area to
keep on top of fibers?
Thx

[blue moon]

What are your screens tensioned at, and how did he help in this area to
keep on top of fibers?
Thx

this was with a screen we burned for a job. I just plopped the new ink and swapped the squeege. It is a regular static frame, probably around 20N.

pierre

[alan802]

That's awesome Pierre.  We did two jobs yesterday that traditionally would have been PFP but we did it with one stroke, white on royal blue, left chest design and then a carolina blue shirt with an easy full front print with white ink.  We got the jobs done with one screen, one stroke and on the belt.  I'd guess we saved at least 10 hours last week compared to our competition if they would have printed the same jobs, maybe more.  We get away with not using highlight whites and doing one stroke prints instead of PFP on a daily basis.  It adds up quickly.

[inkbrigade]

I'm jumping in the middle of this conversation. What ink are you guys talking about?

[blue moon]

I'm jumping in the middle of this conversation. What ink are you guys talking about?

not talking about any ink in particular, just the ink properties. My understanding that the top dog is Rutland's Tidy White (so you can skip the testing and go with what's supposed to be the best choice for this kind of printing).

pierre

[tonypep]

With all due respect to P and R, removing the dye solves many problems mentioned above. Including the troublesome red shade blues. Sorry I can not give out specifics but it is totally achievable given the right circumstances.

[RichardGreaves]

What makes a screen printing ink is a change in it's viscosity (resistance to flow). It's multi-viscosity. When you move it, it flows. If you move it slow - all you do is smash, or push the ink into the stencil holes and we all know more angle forces more ink through the mesh than the mesh can control. A purpose of the mesh is to meter the ink deposit.

If the ink is sticking into the shirt with roots like a tooth - or printing the platen, because you pushed so much  ink through the mesh AND it's not as liquid as it could be, when the mesh peels, the ink splits like a sandwich cookie leaving a poor film - like a hot split transfer. This is a physics problem, but many novice printers reach for the chemistry and add something to make the ink flow better. This kills some viscosity drop and the ink soaks into the shirt defeating the purpose of screen printing ink. The solution is built into many inks - stroke faster.

If you stroke faster, the ink flows into the holes with little or no blade angle and releases easily when the mesh pulls itself out of the ink film. Less ink, but ink on the surface that flows smoothly.

Alas, many textile inks don't have much and are designed for lots of angle, slow strokes.

You all know what every ink manufacturer tells you to do before putting ink in the screen "stir it up". It makes no sense to stroke slower in the screen.

Stiffer blades as straight as possible, low off-contact, fast stroke and finer thin thread mesh at least 25 newtons is what I've 'preached' for 30 years.

Yes, discharge is a way to have the softest prints, "given the right circumstances"

The ink Pierre had in stock had horrible viscosity drop, but speed did increase it's flow.