We previously posted this information on a popular industry forum (T-Shirt Forums), but decided it should be available here on DTG Print Solutions, as well. This is a general overview of some of the things we do in our own production facility at Fusion Logistics Group (our sister company), and should be used as a general guideline for printing with white ink. Of course the first step to achieving a top quality print is selecting the proper garment for DTG printing – you can read more about that by going here.
In order to get the best possible results (on any tee, really), here are some basic pointers:
MAKE SURE YOUR PRETREATMENT METHOD IS ROCK SOLID! This is the most important part of the process; if your spray is inconsistent, splotchy, too light or too heavy, your results will suffer. Nothing else really matters if you can’t nail down this step! We will be putting out some videos of our pretreatment process, sometime next week; hopefully a visual will help some people understand what we do – your process may vary.
- Dial in the pretreatment spray gun to ensure that you are not “blasting” the garment with spray… This is a t-shirt printing operation, not a 1960′s anti-war demonstration; you’re not trying to teach the shirt a lesson – just a gentle spray will do!
- If your pretreatment gun is “sputtering” when you spray, you should probably stop and clean it thoroughly (and also double check to make sure it is still properly dialed in). In fact, we typically pour the contents of the spray gun back into the main pretreatment container about every 4 hours; we rinse the gun with warm water, shake the main pretreatment container then reload the gun. Some might say that is overkill, but our results have been far more consistent than they have ever been since we implemented this process.
- We usually spray “left to right” then “right to left” on the next step down, releasing the trigger on the gun at the far right and far left of each spray; we repeat this until we have gently covered the entire print area with spray, as evenly as possible. If you hold the trigger and simply move the gun back and forth, you will end up with much heavier deposits at the outside edges of the spray area – look for a YouTube video of a professional painting a car with an HPLV sprayer and you can use that as a model for how it should be done. Once the first coat is done we immediately make another pass (moving left to right and back again, while working our way from top to bottom) – two lighter coats provides more even coverage and allows you to use your judgement on a “garment by garment” basis regarding when enough is enough (fleece often requires a heavier deposit, whereas thinner ‘fashion’ style garments will often require a far lighter pretreatment deposit)
- Once the garment receives its two even layers of pretreatment, we use a Wooster 4″ brush to even out the liquid and help push down garment fibers (this step is important!) – we brush “top to bottom”, moving from the left side to the right side, slowly and firmly brushing the pretreatment into the shirt. We have used foam brushes and rollers in the past, and these Wooster brushes provide far superior results in my opinion – we purchase them online: Wooster White Fancy
From the moment we slide the shirt on to the pretreatment board we created to the time we are done brushing the shirt, generally takes about 30-40 seconds. I should probably time it to find out, but that sounds about accurate.
USE HEAVY PRESSURE WHEN PRETREATING! After pretreating the garment, we put it on the heat press, cover it with a sheet of Quilon paper and press with HEAVY pressure for 20-30 seconds (340 degrees). We have found that the heavier pressure during this step, combined with the brushing from the previous step, seems to do a great job of creating a smooth, ideal printing surface; fibrillation is minimized and we get very little “pitting” in the image. We did an installation for a customer a few months ago who had a pneumatic heat press system, which looked to me to be the best thing I have seen for this step of the process; when the time is right, we will definitely upgrade to a pneumatic heat press system (with a shuttle to improve productivity) that will provide consistent and repeatable results during this critical step.
- If there is any resistance when taking the Quilon paper off of the garment, it sometimes helps to press the garment without any paper for an additional 10 seconds; this will ensure that the PT is dry, and will push down any fibers that might have been pulled up when you removed the Quilon paper. This step is not always necessary.
MAKE SURE THE SUBSTRATE IS AS CLOSE AS POSSIBLE TO THE PRINTER, WITHOUT RISKING A HEAD STRIKE - When the print heads are dialed in through the print head alignment process, they are often dialed in very close to the substrate (on the Neoflex, there is a metal bar that is usually set about one dime’s thickness above the print surface, providing the ideal gap) – if you move the substrate further away from the print head for the sake of “safety” (hey, nobody likes head strikes!), the ink droplets will not land where they are supposed to and your end result will not be as crisp… This can range from being “just slightly off” to being obviously blurry, depending on how far away you get. Keep the print head close to the substrate for the crispest possible results!
DURING LONG RUNS OF DARK GARMENT PRINTING, ROLL YOUR WHITE INK BAGS FREQUENTLY - We don’t do this simply once or twice a day – if we are printing non-stop (using white ink), we will sometimes stop and roll the bags in the cartridges every hour or so. This ensures that there is always a consistent pressure level in the system, as this can fluctuate as your ink cartridges empty out. This basic principle is true on probably any machine out there, and I am sure there are a number of ways to deal with it. In our case, we have found that frequently rolling the ink bags creates more consistent results, regardless of what type of garment we are printing on.
MAKE SURE YOU HAVE YOUR MACHINE DIALED IN EACH MORNING, PRIOR TO STARTING YOUR PRODUCTION RUNS – Each morning, you will probably come in to find your white ink may have settled slightly overnight – sometimes it won’t be very noticeable, and you might even fool yourself into thinking that you are getting a “good” white base…. However, if you take the time to really shake all the ink, purge the settled ink out of the dampers and the lines by doing a few sample prints or running a K2 or K3 cleaning, you will sometimes see your white get considerably more vibrant – we don’t notice it until we have something to compare to, then we realize we aren’t getting the best white ink! In fact, it might be a good idea to take your machine on its BEST day and print a few control samples to have handy at all times…. Each morning, use the control samples to ensure that your machine is fully dialed in, then you will know for sure if the issue is the garment or the ink; we do our morning setup on Anvil 980 tees, since we KNOW how good the white ink should look on them – once we have it looking perfect, then we can try printing on another brand (such as a AAA tee) to see what the difference would be. Of course, performing your regular maintenance on your machine is integral to this step, because if you are not properly taking care of things then you will find yourself wasting a lot of effort and ink in the long run.
They are simple things, but any one of those points can cause major fluctuations in print quality…… Rather than banging our head against the wall trying to figure out what the issue is, we just try to follow these steps every day and our results are pretty consistent! With a little practice, you could easily be printing top quality dark garments all day long with minimal downtime and minimal fuss – just keep reminding yourself that the little things makes a BIG difference!