Digital Output looks at textile finishing for the wide format printing industry. Main article on sewing options for digital print providers; sidebar on welding and seaming options.
When would it be better to utilize welding or seaming, rather than a sewing machine—what scenarios or conditions would make these better alternatives?
Anytime you are working with a PVC or PU coated material (Vinyl Banner Material), welding will provide a higher quality and watertight seam rather than sewing. If you use RF welding (radio frequency), the molecules of the plastic fuse together, and do not affect the thread inside, so the end result is the highest quality, most reliable seam you can achieve. Ascetically, the seam is smooth, and virtually invisible, with limited or no puckering and shrinkage of the material. This process is also excellent for multiple layer welding. For example, reinforcement webbing with a top and bottom layer of vinyl can all be welded at once. In general, RF welding is less operator dependent than sewing, especially with traveling head machines that require the operator to simply line up the material on the table, and the machine does the rest of the work. Other applications for RF welding include: weldable hook and loop and weldable PVC (plastic) grommets. For example, JTE just introduced a high speed punch and weld RF grommet machine for this application. Plastic grommets on banners are stronger, weather durable, and only require one for reinforcement, so they can be completely hidden, or clear, and not interfere with the image. There is no puncturing of the material, as needed with metal grommets.
Hot air or hot wedge welding is good for repetitive seams, and can minimize operator dependence in the traveling head format. Since this is not a molecular fusion, the reliability depends a bit more on the settings and operator, and this type of weld cannot be re-welded for repairs. It does not work with more than two layers, unless you have a custom setup up.
Ultrasonic welding is an alternative to sewing polyester fabrics and most thermal plastic material used in tradeshow graphics, flags and banners that are non-PVC coated. JTE offers a sewing style version with a rotary horn, that can weld curves and shapes that normally would be sewn. Pure nylon material is not usually a good fit for ultrasonic, as it is too slippery and usually too thin. Automatic Rotary adhesive glue machines can also bond polyesters, acrylics and many other materials, without the need for seaming tape.
Please send responses to Lisa Guerriero, email@example.com, and contact 978-921-7850 x12 with any questions or concerns.