The Artisanal Engineering of Joining: Industrial
Textiles – another name for flexible fabrics of interwoven fibers – are found in all corners of life, from clothing to semiconductor circuit boards and everywhere in between. One of the oldest and largest industries in the world, textile manufacturing is currently modernizing from its traditional artisan roots into a sophisticated industrial supply chain full of automated processes like textile welding.
As we explain in this blog post, textile welding is a fabrication technique that bonds separate fabrics together into cohesive, resilient products.
The Many Forms of Modern Textiles
With so many different uses, textile manufacturing is too broad to define in a single sentence, so we’ll use four:
- Any product that includes fiber-based materials such as fibers, yarns, filaments or threads can be considered a textile.
- Textiles can be either woven (produced by weaving or knitting) or non-woven (produced by the chemical bonding of non-interlaced fiber mats).
- Textiles can be made of synthetic or natural materials, or a combination of both.
- Textile products are equally important at all stages of a supply chain, whether as raw materials, intermediate products, consumable wear parts or finished products.
The textile manufacturing industry is comparable in size to goliaths such as the automotive and telecommunications industries, which is no surprise given how widespread fabrics are used around the globe. Western textile manufacturers tend to be highly automated whereas Eastern manufacturers still tend toward manual labor, but both do employ automated technologies in their own ways. Overall, textile welding processes are popular thanks to their simplicity and relatively low adoption costs.
Textile Welding Technologies in Industrial Manufacturing
In essence, textile welding follows the same principles as most other forms of welding: Using heat and force, separate materials are melted into each other to the point that their molecular structures fuse into a single continuous piece. Distinct from metal and solid plastic welding, there is an entirely separate array of welding methods designed specifically for textiles, including:
- Heated air welding: This method uses a directed high-temperature airstream to heat two materials to their melting point, after which the materials are forced together with clamps or rollers to a specific pressure and for a set amount of time needed to complete the weld.
- Heated wedge welding: Hot wedge welding is similar to the above hot air welding method, with the key difference being that heat is transferred into the materials via a wedge-shaped iron instead of through hot air. After heating, the materials are pressed together, held and cooled to form the weld.
- Impulse welding: Impulse textile welding utilizes two main components: a high-resistance heating element and a continuous welding bar. Separate materials are overlapped and clamped together by the heat bar. Electricity is then pulsed through the heating element, heating the bar’s surface and completing the weld.
- Ultrasonic welding: Some materials do not need to reach high temperatures to be welded, which allows for alternative welding methods that do not rely purely on heat. Ultrasonic welding is the most popular heatless alternative, which uses high-frequency acoustic vibrations to generate just enough friction that the materials’ molecular structures can commingle into a single welded piece.
- Radio frequency welding: Like ultrasonic welding, radio frequency (or RF) welding subjects the materials to targeted radio waves while pressed together by clamp bars. The waves cause the materials’ molecules to oscillate, rise in temperature and interlace together into a welded piece.
Industrial Textile Welding Applications
Though textile welding is found across a massive range of products and industries, we can boil its applications down to two broad forms: Textile welding is used to either make a seam or a multi-ply layer of separate materials. With these visuals in mind, let’s imagine how either form could be applied to these example applications:
- Automotive: interior fabrics, headliners, firewall liners, airbags, car covers and canopies, and spare tire covers.
- Medical: gowns, masks and face coverings, gloves, sterile bags, privacy drapes, and linens.
- Construction: roofing membranes, tarps and coverings, vapor barriers, heavy equipment upholstery, architectural fabrics, and personal protective equipment.
- Recreation: tents, hammocks, awnings, technical fabrics, waterproof gear, vehicle covers, equipment bags and inflatable products.
- Aerospace: electrical insulator linings, heat shields, wind foils, air and water recycler filters, cargo liners, and flexible poly containers.
- Apparel: waterproof outerwear, technical clothing, clothing liners, umbrellas, dry cleaning slips and garment bags.
- Consumer goods: home linens and fabrics, upholstery, flags, reusable bags, appliance liners and insulation, and hygienic products.
- OEM and MRO: filter cartridges, elastomeric seal kits, equipment screens and shrouds, warehouse curtains, exterior signage, safety banners, sealed packaging, and consumable equipment parts.
Despite the wide variety of application types listed above, most utilize textile welding because of something they have in common: their material types. Textile welding is predominantly used with thermoplastic polymers – that is, textiles that are either made entirely from, or coated with, a polymeric material that melts under heat and reforms into a stable structure once cooled.
Common material types include:
- Polypropylene (PP).
- Polyurethane (PU).
- Polyethylene (PE).
- Polyvinyl chloride (PVC).
- Thermoplastic olefin (TPO).
- Polyester.
Why Manufacturers Choose Textile Welding Solutions
Industrial manufacturers opt for textile weld joints for several key productivity and cost-benefit reasons, such as:
- Joining speed: Textile welds can be completed very quickly, often between 5 and 30 seconds. Automated welding systems with automatic temperature regulation and feed systems can operate even faster, offering joining speeds that beat practically all other textile bonding methods.
- Joint cost: Textile welds do not require any additional materials or consumables, and efficiently run on low electrical loads to generate just enough heat to produce the weld. This keeps per-weld costs at a minimum, especially compared to glued, sewn and taped joints.
- Seal integrity: Textile welding achieves much higher seal integrity (even up to air- and water-tight levels) than sewing, gluing, stitching, taping or chemical bonding due to the molecular inter-stitching achieved through welding.
- Bond lifespan: Because textile welds are composed of the same materials that make up the overall product, these welds generally last the entire life of the product material itself.
- Aesthetics: Textile welding leaves appealing seam finishes, especially when compared to messy glue joints and discolored tape strips. At a distance, weld joints are virtually undetectable.
Maximizing Performance With Industrial Textile Welding
So long as compatible thermoplastic materials are selected and weld dimensions are manageable, there is little else in the way of achieving highly repeatable, reliable textile welds at industrial scales. That is not to say that textile welding isn’t technically complex – the material science underlying each weld does require consistency and precise process control – but this complexity is easily managed when specifying welding equipment and application parameters upfront.
To this end, here are several suggestions on how to best define and deploy industrial textile welding solutions:
- Process selection: Buyers should start with inventorying their desired weld size, profile, pattern, aesthetic and other physical properties, followed by their desired material types. These factors will coagulate into a short list of suggested textile welding techniques, ruling out incompatible solutions straight away. Buyers should then check their required production rates per hour or day, which will identify the scale and size of solution needed.
- Tests and trials: Before purchasing any textile welding solution, buyers should request and evaluate trial welds. This can include evaluation of a weld’s structural integrity, pressure/vacuum rating, waterproofing, visual appearance, induced failure rate and any other important factors. Even if initial trials are successful on benchtop demo units, buyers are also encouraged to request production samples run on full-scale systems to ensure that demo test results can be successfully scaled.
- Quality control: To combat performance decay as well as to physically confirm high quality production results, buyers should develop a robust quality control process for their textile welding systems, especially for technical fabric products that require low- or no-leak seals. As an example, AMS’ LT-401 Leak Testing System is a novel solution for automatic quality control, as it performs all types of leak tests of textile welded seams including pressure decay, vacuum decay, mass spectrometry and bubble test methods.
- Automated textile welding: Once a manufacturer grows out of fully manual textile welding solutions, the next decision becomes whether to invest in semi-automated or fully automated technologies. For moderate volumes of widely varying product profiles, a semi-automated system is likely best to allow for easier switching between weld types while still reducing the operator’s burden. For higher volumes and standardized product profiles, a fully automated solution such as AMS’ PJ-601 Plastic Joining System can complete complex textile welds repeatable over long duty cycles with greatly reduced labor demands.
Wrapping Up
At industrial scales, textile welding is often the only viable solution as many products simply cannot be sewn, glued, stapled or taped at a reasonable cost and high level of reliability. This fact places textile welding in a unique position to serve industrial applications, especially when deployed in an automated fashion.
Advanced PLC controls, built-in data storage and reporting, poka yoke safety devices, vision inspection systems, and automatic load/unload features allow automated textile welding systems to achieve high production rates at low per-unit costs that help maintain a manufacturer’s edge within their market.
Overall, textile welding has matured into a landmark modern fabrication method that when diligently matched to the right applications, always exceeds manufacturers’ expectations. Contact us with your questions about textile welding. We’re happy to help.
