How To Maximize Digital Direct To Garment Production On Custom T-Shirts (Part 1)

By Kevin Kelly

The key to having any decorating process be profitable is setting up your shop so that the layout and work flow are as efficient and productive as possible, and this certainly holds true for digital direct-to-garment production on custom tee shirts.

If you are a smaller custom tee shirt shop doing onesie-twosie orders, then speed is not going to be a big issue. However, if you are approaching direct-to-garment printing from an industrial perspective, you need to be concerned with fractions of minutes in production time.

In your pursuit of speed, you also have to take care that you don’t sacrifice quality. If you sacrifice quality, it doesn’t matter how fast you go when you start losing customers. So the ultimate goal is to find that balance between the efficiency of speed and quality.

I have been running multiple digital printers in my shop since 2007, and over the years we have constantly tried to push the equipment, but you can only push the equipment so far. What it mostly comes down to is technique.

Shop Layout
Before I brought in my first Kornit printer, I did some research and put a lot of thought into where I would house my digital equipment.  For direct-to-garment printing on custom tee shirts, you should have a dedicated, clean area to house your machine. You can't put it in the same area as your screen printing presses, because you need control over the heat and humidity; and you shouldn't put them near your embroidery equipment due to lint from tee shirts and other apparel.

Our digital printers use phthalate-free water-based inks, which are sensitive to the environment. I custom built a 1,200-square-foot room inside of a 2,300-square-foot room, and planned for enough space to add five more machines if needed. Although we can't air condition the rooms, we continuously pump in cool air and keep the humidity ramped up.

To prevent the dryers from heating up this area, we positioned the gas ovens outside the room, which is heat shielded except for the residual that comes off the belt. So we have only the feed belt of the dryer accessible to that room. Typically, if you run a gas oven at 250,000 BTUs, you'll heat up any room by 25 to 30 degrees within two hours.

Our tee shirt dryers are the return-feed type. The operator places custom tee shirts on the top belt and cured tee shirts return on the bottom level back to the same operator. The dryer belt is positioned between the two printers. Each operator can remove a tee shirt from a pallet, and take a half step to put the shirt on the belt.

It’s also important to have a dedicated dryer for your digital production. It’s not production friendly to run screen printing inks simultaneously with direct-to-garment inks, because one is plastisol and the other is water, and they require different belt speeds.

Design and Printing Details
Most of our direct-to-garment printing of custom tee shirts involves moderate-size full front and neck prints. Lately, we've done a lot of branding on the back of the neck. It's a popular print location we love, because it's smaller than the left chest and is roughly 30% more profitable than a front print on the same shirt.

When it comes to custom neck prints, we often print one-color designs, but even if we print full color, the design is typically so small that there are very few indexes of the print heads so the print time is significantly reduced.

If we print at standard production speed, we can print in excess of 100 dozen custom tee shirts per day if the designs are not too large. But if we ramp up to high speed, we can increase production by about 13%. With our industrial equipment, we can alter the machine parameters that control electronic functions such as frequency.

Our Kornit machines allow us to alter the electronic frequency which controls speed.  We run mostly at standard frequency, or 10,000 KHz. But we can set the machines as high as 15,000 KHz, which is 50% faster. When we combine frequency with resolution settings we can optimize speed quite efficiently. However, we can do this only with certain jobs such as left chest prints or single color otherwise we sacrifice quality. We never print at high speed for darks; we run slower to ensure a better-quality print.

There are pros and cons on the advantages of a dual-platen vs. a single-platen machine. Although some people disagree, I don’t think that the number of pallets on the machine matters. Using multiple single-pallet machines can be just as effective as a dual pallet. If you have two single-platen machines versus one dual platen, if a machine goes down, you can still produce orders as opposed to having production shut down for the day when your one machine goes down. Dual pallet machines will actually use less ink in the long term because the print heads are in constant motion and spitting and purging less. The yield on dual pallet machines is higher.


Part 2

Blue Heron is the nations most well regarded authority for direct-to-garment printing on black t-shirts. Kevin Kelly can be reached at 800-709-2380.

06/23/2011
Little Falls, New Jersey 07424