October 17, 2019

Screen printing on T-shirts, sweat shirts, hoodies and other popular garments is a reliable and profitable market sector that has demonstrated the potential for continued growth in the 21st century. Despite competing technologies — such as direct-to-garment (DTG) printing and sublimation dyeing — being introduced, screen printing still is widely used in the garment-printing industry. This is primarily due to the technology’s accessibility and stability, as well as the color saturation and durability of screen-printed images.

Textile screen printing is preferred for short-run, artisan designs where pigmentation and image detail are paramount. Unlike the four-color, CMYK palette used in digital imaging, screen printing uses inks of various formulations and viscosities, depending on the specific application. Thicker and repeated coats of ink are applied directly to the substrate, with more pigments resulting in greater color and hue vibrancy, as well as overall superior color saturation.

At the same time, screen printing is a cost-effective and versatile technology for high-volume garment production, and these advantages ensure its viability for the foreseeable future, while offering opportunities for development and further expansion.

For startups and smaller print shops, transitioning to high-output production to leverage the intrinsic advantages of screen printing for the garment-decorating industry can present significant challenges that may be daunting — even prohibitive. In this context, it’s important to understand that each step screen printers take to standardize and automate their operations increases production efficiency and consistency, giving them greater control and the ability to serve more customers.

Screen printers seeking to expand their operations may find that one or multiple new, automatic multicolor presses are too expensive or simply too large for their current spaces. In such cases, incremental automation of prepress functions and ancillary processes can be a cost-effective way to increase productivity, improve consistency and gain access to potentially lucrative new markets.

Automatic Stretching & Exposure

As screen-printing shops begin to expand, the most common first steps typically involve bringing various ancillary operations in house, eliminating the need to contract the work to outside vendors. Screen making, exposing and cleaning are three areas in which printers often realize significant savings, ultimately exercising more control over their operations. In each of these areas, opportunities exist to achieve even greater efficiencies through the judicious use of technology and specialized equipment.

Making your own screens saves time and money, and most printers quickly develop the capacity to handle this operation themselves. This allows them to take advantage of better mesh pricing, tension screens for specific jobs and reduce turnaround times.

Although various manual systems can yield acceptable results, using one of the pneumatic mesh-stretching systems available on the market today is preferred to achieve maximum efficiency and consistency. Such systems deliver mesh that is accurately tensioned across the screen’s entire surface for crisper images and superior repetition. Uniform tension facilitates higher production rates, more precise registration and consistent ink deposits.

Screen exposure may be accomplished with a broad range of setups — you even can use the sun as your light source — but the procedure is similar in all instances. For faster and more accurate exposures, printers use commercially available exposure units, which typically include vacuum holddown for the image positive and a rubber blanket to draw the screen down tightly to a photographic-quality glass plate. Often, these exposure units include a timer for consistency and to help avoid under- and overexposure.

Exposure units use a variety of light sources, including fluorescent, light-emitting diode (LED), metal halide and high-output UV lamps. Operational parameters dictate which unit style, features, options and light sources are the most efficient and cost effective for specific applications. As with screen making, the advantages of automating this operation are not limited to increased production speeds. Specialized equipment can increase the consistency and uniformity of your procedures, ultimately improving output quality.

Many manual textile screen-printing operations include a screen-cleaning area with a washout booth and hand tools for cleaning and reclaiming screens between jobs, but these processes can be time-consuming and tedious, yielding uneven results. Emulsion removal can be particularly challenging without specialized equipment, and there are important safety considerations when employees are handling ink, emulsion and screen-
cleaning solvents.

Fortunately, there is a wide range of semi- and fully automatic products available to screen printers that streamline and speed up ink and emulsion removal while delivering more consistent results than manual procedures. Ideally, these systems are fully enclosed for improved employee safety and include a pump or power washer for more effective screen cleaning. Advanced automatic systems typically include separate solvent application and rinse cycles, and may include touchscreen controls to program and store various cycle parameters. Larger automatic screen-cleaning units may process several screens simultaneously, and these units may be paired with heated screen-drying cabinets for even more operational efficiencies.

Curing Inefficiencies & Squeegee Sharpening

Although screen making, exposing and cleaning/reclaiming are the three areas where textile printers can realize the most significant efficiency and consistency improvements, a number of products are available that can increase production speeds and deliver more professional results. These include automatic flash-cure units, squeegee-sharpening machines, drying and storage racks, and screen-drying cabinets.

If you are printing multicolor images on garments, you probably already have drying and flash-curing equipment, as they are essential to the process. A way to increase production is to incorporate an automatic sliding or swiveling flash cure into your operation, ideally at an unused station. These units move into position over the garment for curing and then retract while the screen-printing press’ print heads rotate. In such units, an automatic timer controls the curing interval, which also helps to prevent scorching.

Once screen making is done in house and you observe the higher-quality results that are possible, you may consider a squeegee sharpening-and-shaping machine for convenience and more precise edges. Each component in the screen-printing process makes an integral contribution to the final printed image’s quality, and a clean, sharp squeegee blade is important.

Considerations that often are overlooked include safe and secure storage and transportation of screens in the workshop. Drying and storage racks generally have casters for mobility; may have fixed or individually adjustable shelves; and can accommodate screens of different thicknesses. Fully enclosed, heated drying cabinets also are available to facilitate faster drying, eliminate pinhole formation and protect screens in production environments.

Automating Ancillary Processes

Making the transition from manual textile screen printing to a fully automated, multicolor press is a major commitment for smaller screen printers, involving both cost considerations and space requirements. But the twin benefits of automation — speed and consistency — can be realized incrementally even before you purchase your first automatic press by upgrading and automating prepress and ancillary processes throughout your facility.

Each of these incremental improvements can contribute to better overall operational efficiency and product quality, and most can be implemented at surprisingly reasonable price points. In this way, even small print shops that can’t immediately make the move to automatic production can reap many of the benefits of automation, even as they lay the groundwork for more significant equipment upgrades and acquisitions in the future.

Michael Hurley is a staff writer for The A.W.T. World Trade Group. He resides in Chicago. For more information or to comment on this article, email sales@awtworldtrade.com.

Article updated Oct. 30, 2023