By Melissa Donovan
Welding is an alternative to sewing for finishing digitally printed fabrics. For those not familiar with how to operate an industrial sewing machine, the option of welding is available. It is often used to finish vinyl banners, so many manufacturing businesses or print shops may already have experience using such a device.
The decision to weld versus alternative methods is based on the application, end use, and user. There are different types of welding processes as well—although certain methods are more ideal for fabric over others. As digital printing to fabric gains popularity, welding devices change and adapt to the newest trends.
Above: Fabric finished with Matic Ares welders, which are available in the U.S. through Media One.
A welding device is used to finish fabric for many reasons. While sewing machines or seamers are ideal finishing solutions, a welder offers both durability and less material waste, all while providing a clean and polished end product.
According to Christina Lefebvre, area sales manager, NA, Matic S.A., welded fabric is aesthetically pleasing, especially compared to sewing. “There is no stitching running through the print. No matter what the printed image is, there is no way that the weld will interfere with the message. It is invisible. Welding creates a flat, uniform bond between two layers of fabric. In addition, when the fabric is hung, there are no ruffles, therefore the printed image is not disrupted by creases.”
“When welding, operators no longer have to try to thread match or worry about thread rotting when hung outdoors. Welding provides a high-quality seam that can be used in outdoor environments. Some of the largest billboards in the world are welded,” shares Jeannette Hendrickson, marketing manager, Miller Weldmaster.
Traci Evling, managing director, JTE Machine Systems, Inc., lists benefits including lower cost of labor, no weakening—puncturing—of material at the seam, and reduced cost of materials—no thread needed. “In many cases, the amount of fabric used can be reduced, as a sewn seam usually requires a folded hem and a welded seam does not necessarily,” she continues.
Compared to other technologies related to finishing fabric, a welder is not as dependent on a user’s experience level, suggest Rod Butler, business unit manager, Sani USA and Pascal Smeets, sales engineer, Asco BV.
It’s important to note that certain fabric types are more weldable than others. “Most polyester fabric, nonwovens, and some Tyvek-type material can be ultrasonically welded. All PVC/PU unsupported and coated materials can be radio frequency (RF) welded. Non-coated acrylics and nylon material are not easily weldable. True silicone or non-PVC silicone edge graphics are not weldable. Cottons are not weldable without a tape,” recommends Evling.
Different welding technologies include ultrasonic, hot air or wedge, and impulse.
Hendrickson says that each has its benefits depending on the application. “From our experience, ultrasonic is typically used for lighter textiles and delicate fabrics. Impulse is a static bar that goes up and down, however, as the bar touches the outside surface; it can leave a sheen on the image and does not always produce the most desired look. Hot air or hot wedge welding both use a technology that puts the heat in between the seams leaving the outside print untouched and providing the best looking seams for banners,” she suggests.
Lefebvre argues that there is no possible injury or harm that can come from using an impulse welder. “The electrodes do not stay hot to touch once the weld is completed and the machine does not emit anything harmful.”
“Impulse welding offers accurate temperature and positioning of where the heat is applied. It is also less noisy and inexpensive,” agree Butler and Smeets.
Ultrasonic technology is best for polyester fabrics typically used in digital printing, advises Evling. “With the right settings and tooling, ultrasonic welding can be very fast and easy, without the need for seaming tape or special materials. In an ultrasonic weld, the melt is created within the material itself, as a result of the high frequency vibrating the metal surfaces above and below the material, causing the thermoplastic to melt, and fuse together within a few seconds,” she continues.
Ideal for Fabric
While a number of welding technologies are available, some are more suitable for banner material than fabric. Here are some of the best devices designed for welding digitally printable fabric.
DAP America, Inc. distributes Pfaff Industrial welders in North America. The Pfaff 8320 is programmed as a hot wedge or hot air welding machine. An interchangeable swivel allows it to transform from hot air to hot wedge and back. All parameters are controlled electronically, with one integrated control board monitoring heat sealing temperature, air flow, roller pressure, and two motors for the top and bottom roller.
The Fiab 900 is Fiab’s standard high-frequency device, designed to work with a variety of materials. Features include lasers to make handling fabrics easy, a vacuum table system, weld joint tape application, remote control, and side platforms. There are five versions of the Fiab 900, all with different output powers and welding surfaces.
Forsstrom High Frequency AB offers the TX 200-500 high frequency welding machine. It can be used as a standalone device or complementing a larger system of welders. The machine offers three side access for optimized material handling.
The JTE Sonic Bar Welder welds digital graphic fabrics in short, straight seams in seconds. It uses ultrasonic frequency to weld fabrics without any puckering including recyclable fabrics to non-coated polyesters and acrylics.
Kabar Manufacturing Corporation’s 20 KW standard track and trolley RF welder is ideal for finishing digitally printed fabric. It features impulse sealing capability. Common applications completed include awnings, billboards, and banners.
Leister Technologies LLC offers the Seamtek 900 AT. A multi-arm system guarantees flexibility between multiple applications. It produces lap welds, hems, open hems, piping welds, and tape welds. A test mode allows for quick parameter determination. Guides allow for even the inexperienced user to utilize the Seamtek 900 AT easily.
Media One distributes the Matic Ares and Ares Plus welders. Both are equipped with cooling parameters that allow the electrodes to stay in contact with the fabric after the welding period. According to Lefebvre, this acts as ironing and prevents the fabric from buckling and creasing. All of the welders are fully programmable, meaning the operator can set specific controls just for fabric.
Miller Weldmaster’s Digitran is ideal for finishing digitally printed fabrics. It is an all-in-one sewing and welding solution. A transport system synced with the sewing machine provides precise material handling. The device utilizes a robust high lead sewing machine for maximum uptime with easy-to-use touch controls. It is configured for multiple seam finishes and a driven roller for accommodating any size job.
Sani USA distributes Asco welders in the U.S. The company has manufactured impulse welders as large as 24 feet. Its models include automatic pocket folding and welding, automatic seaming of panels, invisible welding, and data logging and ERP software integration.
Supply55, Inc. offers the BannerPRO banner welding system, which hems for grommets, pole pockets, and pocked sign fabrication. The heavy-duty, all-steel construction is hands free with foot pedal operation. A solid state electronic timer ensures consistent welds every time.
Trends in this segment of the market affect the newest iterations of welding machines. With digitally printed fabric becoming increasingly popular, finishing hardware is poised to handle an influx of job requests at a rapid response rate.
For example, models like the Matic Ares Plus include a Turbo Device to give an extra boost, cutting the welding time in half versus regular electrodes. “Printers are now so fast that finishing is the bottleneck,” adds Lefebvre.
Hendrickson agrees, citing large customers who have thousands of banners to finish and want solutions that eliminate all of their finishing bottlenecks. “As such, they seek automation, which is able to finish the sides of the banners including grommets and cutting banners to size,” she says.
Application introductions affect welder usage. Evling gives silicone edge graphics systems as one such factor. “Now their edges are typically made from PVC material and are excellent candidates for welding,” she shares.
“We are experiencing a wider range of digital textiles and fabrics that can be printed on because of UV technologies. As an example, most of the billboards are now all polyethylene. Polyethylene is well suited for hot air welding,” explains Hendrickson.
Welding is an ideal alternative to sewing for finishing digitally printed fabric. It not familiar or not ready to invest in a sewing machine, a welder is a good option. Not only does it offer durability, but can save on labor and material costs. A number of welders are available to work with digitally printed fabric, be sure to conduct due diligence prior to purchasing as some are designed for banner and more rugged vinyl materials.
Nov2017, Industrial Print Magazine