Source of Nonwoven Bag Machine Technology Development:
Today, nonwoven bag-making machines have advanced to the point where ultrasonic bonding technology has emerged.
Non-woven bag-making machines utilize ultrasonic bonding technology. Initially introduced in the textile industry primarily for processing mattresses and bedspreads, ultrasonic technology has now been widely adopted across the non-woven fabric sector. Ultrasonic energy is a form of mechanical vibrational energy with frequencies exceeding 18,000 Hz—far beyond the range of human hearing. For further reading: Non-woven bag-making machines, circular looms, four-column hydraulic presses, rotogravure printing machines, slitting machines, and cooling fans all offer a broad spectrum of wavelength options. When applied to bonding thermoplastic materials, such as joining non-woven fabrics, the most commonly used frequency is 20,000 Hz.
Compared to traditional needle-based sewing, the fully automatic non-woven bag-making machine utilizes ultrasonic bonding, eliminating the need for needles and thread altogether. This innovative process removes the tedious step of thread changes and prevents common issues like thread breakage or messy stitching found in conventional methods. Additionally, it enables precise, clean local cutting and sealing of non-woven fabrics.
The machine operates at high speed, producing sealed edges that remain intact without cracking or damaging the fabric’s delicate edges—resulting in a flawless finish, free from fraying or curling. Importantly, ultrasonic bonding effectively avoids the drawbacks of heat-sealing, such as fiber degradation, alterations in material porosity caused by adhesive layers, and potential delamination when exposed to liquid impacts.
Ultrasound bonding equipment primarily consists of an ultrasonic generator and a roller assembly. The main components of the ultrasonic generator include the horn, power supply, and transformer. The horn, also known as the radiating head, focuses sound waves onto a single, flat surface. Meanwhile, the roller—referred to as the anvil—helps concentrate the heat generated by the ultrasonic generator’s horn.
The materials to be bonded are continuously fed between the ultrasonic generator’s "horn" and the roller, where they join together under minimal static pressure. A frequency converter first transforms electrical power into high-frequency energy, which is then converted into ultrasonic vibrations by the transducer. These vibrations are further amplified by an amplification system (booster) before being transmitted to the horn, ensuring direct contact with the materials to be bonded.
The resulting ultrasonic frequencies induce mechanical stress between the material molecules, generating localized heat that breaks the molecular bonds within the materials. This process melts the materials precisely at the bonding interface, allowing them to fuse securely under gentle mechanical pressure—effectively joining multiple layers of material into a durable, seamless bond.
