Application of ultrasonic welding in non-woven fabrics

Ultrasonic welding is a process used to join two plastic parts together to form a strong, finished assembly. The process relies on high-frequency (ultrasonic) vibrations being generated and applied to the parts via a horn. Welding occurs as the vibrations are absorbed in the interface between the two parts, generating friction and causing the plastic to melt. The ultrasonic vibrations are generated by a series of components, including the power supply, converter, booster and horn, which ultimately delivers the mechanical vibration to the parts.

Application of ultrasonic welding in non-woven fabrics principle

The role of the power supply is to convert the incoming line voltage (at 50 or 60Hz) into a new frequency. This electrical energy then is sent to the converter, which as the name implies, converts the electrical energy into mechanical vibrations. The converter consists of piezoelectric ceramic discs, which expand and contract at the rate of the supplied electrical energy. The magnitude of the vibrations is referred to as amplitude, a term that becomes very important when specifying an ultrasonic system for a given application. The vibrations then are transmitted through the booster, which typically increases the amplitude by a predetermined multiple, also known as gain. Finally, the booster’s output amplitude is transmitted through the horn, where it then can be delivered to the plastic parts.

About ultrasonic welding application and non-woven fabrics

Non-woven fabrics are textile structure whose importance is increasing day by day. From the perspective of clothing, using non-woven fabric for especially disposable clothing is of great importance especially in terms of cost. Non-woven fabrics, used in surgical gown, single use products, medical and hygienic products. Hold an important place in medical purposes. However, conventional stitch types create mechanical damage on non-woven fabrics and hampers mobility.So the ultrasonic welding application in non-woven fabrics is very important.

Therefore, ultrasonic welding application in non-woven fabrics is inevitable for sewing of nonwoven fabrics.Ultrasonic sewing is even more preferred than other conventional sewing types in the production of nonwoven based products. The main reason for this is that the structure of nonwoven fabrics is more suitable for ultrasonic sewing.

Ultrasonic welding application in non-woven fabrics

Ultrasonic sewing is the best way to assemble nonwoven fabrics for single use products. With the rapid development of economy, ultrasonic welding technology is more and more widely used,such as disposable facemasks, disposable protective clothing, surgical gown(operating coat ), diaper, non-woven pockets, gloves etc.

Application of ultrasonic welding in non-woven fabrics
Ultrasonic welding machine application

Ultrasonic welding machine composition

An ultrasonic generator (power supply)

hcsonic ultrasonic generator
hcsonic ultrasonic generator
The ultrasonic generator converts the 110VAC or 220VAC electrical supply current into a high frequency, high voltage electrical signal.

An ultrasonic converter (transducer)

The ultrasonic converter utilizes the high frequency electrical signal from the generator and converts it into linear, mechanical movement. This conversion ccurs through the use of piezo-electric ceramic disks that expand when a voltage is applied.
hcsonic ultrasonic transducer
hcsonic ultrasonic transducer

An ultrasonic booster

hcsonic ultrasonic booster and round flange
hcsonic ultrasonic booster and round flange
The ultrasonic booster is a tuned component that mechanically adjusts the amount of linear vibratory movement from the converter to the required level for the specific application to produce optimal welding performance. The booster also provides a safe, non-vibrating location to clamp onto the welding tools.

An ultrasonic welding tool (horn/sonotrode)

The ultrasonic welding horn is a custom made tool that is engineered to vibrate at a specific frequency. These tools are painstakingly designed using computer modelling technology for optimum performance and longevity.Ultrasonic tools must be tuned to match the frequency of the system. This tuning procedure requires consideration of the horn’s mass, length and geometry.Common tool head sizes are 150 * 40mm and 110 * 20mm.
hcsonic ultrasonic welding tool head
hcsonic ultrasonic welding tool head

Ultrasonic welding application for disposable facemasks

Materials: 

non-woven fabric and meltblown

Technological process:

Material preparation → Shaped cutting → Ultrasonic mask welding → Cutting → Earband welding → Packaging. Obviously, the ultrasonic welding is the core of masks production.

Recommended:

35K ultrasonic spot welding machine and 20k ultrasonic welding machine are essential for disposable facemasks. The 35k ultrasonic spot welding machine is used for weld earbands. And the 20k ultrasonic welding machine for sealing the edges of facemasks.

hcsonic welding machine recommend foe facemasks
hcsonic welding machine recommend foe facemasks
hcsonic welding machine for facemasks
hcsonic welding machine for facemasks

Advantages of ultrasonic welding

  • Does not need external heat source: The primary advantage of ultrasonic welding is that it doesn’t need an external heat source. The heat is self-generated between the materials.
  • Fast: Since the frequency of vibrations is very high, ultrasonic welding is one of the fastest welding methods available in the industry.
  • Possibility of automation: Ultrasonic welding being uncomplicated in many ways, it is easy to automate. The ultrasonic machine comes with sensors that constantly monitor the temperatures.
  • Clean and strong joint: The contact surfaces melt/fuse upon welding, and it produces a very clean and strong joint.
  • No security risks: Because no needle is used, it avoids the situation that the broken needle remains in the material during the sewing process, eliminates hidden safety hazards.
  • More beautiful surface: There is no broken joint of traditional thread stitching, clear embossing, the surface has a three-dimensional relief effect, and the product is more upscale and beautiful.
  • Convenient operation: Automatic control of frequency and speed regulation

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