Ultrasonic Spot Welding Equipment WW2803L

Ultrasonic spot welding joins two thermoplastic parts at localized points without a preformed hole or energy director. It produces a strong structural weld, and is especially suitable for large parts or parts with complicated geometry or hard-to-reach joining surfaces.  In spot welding, the horn has a pilot tip, which melts through the top part and into the bottom part to a predetermined depth, when ultrasonic vibrations are applied. When vibrations cease, the melt from both parts flow together, forming a weld with the top side having a raised ring produced by the welding tip. The bottom layer of a spot welding joint has a smooth appearance. Spot welding can be performed with hand-held guns, single- or double-headed bench welders.

Ultrasonic welding machine principleThe 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.

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.
Ultrasonic transducer
Ultrasonic transducer

An ultrasonic booster

Ultrasonic booster and round flange
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 diameter is 10mm.
ultrasonic welding tool head
welding tool head

Longer service life

Transducer prestress

All piezoelectric transducers for ultrasonic welding are of the Langevin type — i.e., one or more piezoceramics that are mechanically compressed (prestressed) between a front driver and a back
driver.

Transducer cross section
Transducer cross section
Transducer Relative axial amplitudes
Transducer Relative axial amplitudes

Because piezoceramics are weak in tension, a static compressive prestress must be applied to prevent the piezoceramics from ever experiencing tensile stresses when the transducer vibrates ultrasonically. In addition, the prestress assures that the piezoceramic interfaces make good contact so that the acoustic waves transmitt well with minimum loss. We use the most convenient center screw design.

A specific prestress can be obtained by tightening the transducer center screw to tighten the transducer. The traditional method is to use a torque wrench for tightening, but this parameter is
affected by many factors and often has deviations.

Prestress vs torque Langevin type transducers
Prestress vs torque Langevin type transducers

When the tightening of the ultrasonic transducer is insufficient, its impedance is large, which will cause serious heat generation; when the tightening is excessive, it is easy to cause problems such as damage to the ceramic sheet (crystal crack) and durability. Transducer is the most important part of ultrasonic welding equipment. So it is very important to accurately tighten the transducer and obtain the best prestress.

Get the best prestress of the transducer
Get the best prestress of the transducer

Piezoelectric ceramic sheet

Piezoceramics are typically classified as “soft” or “hard”. Hard piezoceramics are used for power applications. Among hard piezoceramics there are two basic types, generally designated as PZT4 and PZT8 (PZT stands for lead-zirconate-titanate of which the piezoceramics are composed). Different manufacturers may have their own designations for these types but the general performance is similar. Our device uses PZT8 piezoelectric ceramics, which has better relative performance.

Nominal piezoceramic properties at low electric field conditions
Nominal piezoceramic properties at low electric field conditions

Advantages of ultrasonic spot 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.

Ultrasonic welding has many advantages when compared to traditional welding technologies. Many industries use ultrasonic welding due to these specific combinations of merits.

Application of ultrasonic spot welding

Ultrasonic welding is an eco-friendly process that takes seconds, consumes very little energy and reduces costs while maintaining a high degree of quality. The equipment fuses contact points on cell phones and other consumer electronics that are generally inaccessible with other welding methods. These techniques can be adapted to a wide range of commercial and industrial applications. In the food industry, the ultrasonic welding process is used to create a hermetic seal. It can fasten blister packs and facilitate the manufacturing of a variety of products, including toys, disposable lighters , pipettes and intravenous catheters.

Ultrasonic welding is commonly used in the plastics, aerospace and automotive industries to join similar materials. It is particularly useful in the production of medical products. Since the process does not introduce exhaust or other contaminants and the welds do not degrade, the manufacturing equipment can be used in a clean-room environment.

Ultrasonic spot welding tips

Ultrasonic welding is very effective at sealing or welding plastics. However, you cannot weld all types of plastics.ike metals, plastics also have different types. And it is very important to ensure that the plastics to be welded are chemically compatible.If you try welding polyethylene and polypropylene, it may melt together, but there will be no chemical bond. A chemical bond is important for creating strong weld joints.Another factor to keep in mind while welding any material through ultrasonic welding is maintaining a uniform contact area.
Attributes Parameter Attributes Parameter
Brand HCSONIC Item Model WW2803L
Maximum Power output 300W Frequency 28KHZ
Maximum Amplitude 3µm Working model Continuous, intermittent
Weldable materials Thermoplastic materials Welding Head Material Al,Steel
Welding Head diameter 10mm  Driven Type Electric
Technical Support Video, mail, phone Warranty One year, except horn
Full Set Weight 4.5KG Place of Origin China
hcsonic ultrasonic equipment naming rules
hcsonic ultrasonic equipment naming rules
Production time: within 15 days or according to customer requirements.
Shipping method: DHL, FedEx, UPS, TNT, sea or air.

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