Ultrasonic Plastic Welding Transducer

Ultrasonic welding piezoelectric transducer is composed of central piezoelectric ceramic elements, front and rear metal cover plates, prestressed screws, electrode sheets and insulating tubes. Almost all ultrasonic equipment uses ultrasonic plastic welding transducer.

The composition of an ultrasonic welding machine mainly consists of the following 5 parts: control system: the control system consists of a time relay or an integrated circuit time timer.

1. By controlling the working time of the ultrasonic generator, this system automates the entire welding process. During operation, only the button is activated to generate a trigger pulse, which can automatically complete the entire welding process.

2. Control the operation of the pneumatic transmission system to open the pneumatic valve under timed control during welding, pressurize the cylinder to lower the welding head, and press the welded object with a certain pressure. After welding, maintain the pressure for a period of time, and then the control system will reverse the pneumatic valve to make the welding head rise and reset;

3. The sequence of the entire control system is as follows: when the power is activated, a control signal is triggered, and the pneumatic transmission system is activated. The cylinder pressurizes the welding head, lowers and presses the welding to trigger the ultrasonic generator to work. The ultrasonic is emitted and maintained for a certain welding time to remove the ultrasonic emission and continue to maintain a certain pressure time for pressure reduction. The welding head rises and the welding ends.

Pneumatic transmission system:

Including: clutch, pressure reducing valve, oil mist filter, commutator, throttle valve, cylinder, etc.

During operation, the stroke cylinder is first driven by the air compressor to drive the vibration system of the ultrasonic transducer to move up and down. The power air pressure is adjusted according to the welding needs in low-power ultrasonic welding.

Ultrasonic tool head:

There are two types of tool heads, one with amplitude amplification and the other without amplitude amplification. The acoustic system tool head used in plastic welding machines is usually made of aluminum alloy, with hard alloy plating on its end face. When the power is high, it is also made of titanium alloy material, which has a fatigue strength more than twice that of aluminum alloy.

Different tool heads are required for different welding objects, whether it is near field welding or transmission welding. Only a half wavelength tool head can achieve the maximum amplitude of the welding end face.

Ultrasonic generator:

1. The generator used in ultrasonic welding machines with a power of over 500W adopts a self-excited power oscillator, which has a certain frequency tracking ability.

2. For high-power ultrasonic welding machines, the generator signal adopts a phase-locked frequency automatic tracking circuit, so that the output frequency of the generator is basically consistent with the resonant frequency of the transducer.

Ultrasonic Plastic Welding Transducer:

The acoustic system used in ultrasonic plastic welding machines consists of three parts: the driving part, the fixed part, and the working part. Among the three components mentioned above, the driver is the core, and a bolt clamped longitudinal vibration transducer is generally used. The half wavelength longitudinal oscillator is connected to the quarter wavelength longitudinal oscillator, and the half wavelength longitudinal oscillator is connected to the half wavelength concentrator to form a full wavelength plastic welding transducer. The quarter wavelength longitudinal oscillator is connected to the quarter wavelength concentrator to form a half wavelength transducer.

FAQ

Q: What are some common problems in the use of ultrasonic plastic welding transducers?

In case of wafer cracking, ultrasonic weakness, overload, electrode spark, electrode cracking, serious heating, abnormal sound, leaky wave, wafer dislocation and other problems during use, we believe that the causes can be divided into three categories.

1. Assembly of ultrasonic generator and ultrasonic mould. In this case, we recommend that the customer actively find out the cause, or communicate with our technical personnel to improve as soon as possible.

2. There is a problem with the ultrasonic transducer and ultrasonic horn. This is highly unlikely to happen.

3. There is no problem with the products, but they do not match. This is the most common case. The customer has good driving power supply, good frequency converter and normal assembly, but the components do not match. The main parameters causing the mismatch are the frequency and capacitance of the sensor

Q: Why do ultrasonic welding machines often break down transducers?

There are only two reasons: There are quality issues with the ultrasonic welding machine;

During the use process (caused by the ultrasonic welding machine not adjusting the mold properly before use, long-term overload operation, or poor mold quality), the transducer experiences severe heating.

Q: How to replace piezoelectric ceramic plates of ultrasonic transducers?

1. Check the piezoelectric ceramic sheet and select a piezoelectric ceramic sheet with good appearance and no oxidation of the substrate and silver coating as a backup.

2. To add tin to the piezoelectric ceramic sheet, first add tin to the copper/steel substrate of the piezoelectric ceramic sheet. Due to the fast heat dissipation of the copper/steel substrate, no more tin can be added, but the welding time is extended. Generally, it takes more than 2.5 seconds for the tin points to reliably adhere to the copper/steel substrate. Add tin to the silver coating, requiring a small solder joint and a tin adding time of less than 1.5 seconds.

Q: The ultrasonic transducer is good, but the welding head is good. Why doesn't it vibrate?

Ultrasonic transducers and welding heads are key components of ultrasonic welding equipment, responsible for generating and transmitting ultrasonic vibrations. If there is no malfunction of the ultrasonic transducer and welding head, but no vibration occurs, there may be the following reasons:

1 Power supply issue: Check if the device's power supply is functioning properly to ensure that the power supply voltage and frequency are consistent with the device's requirements.

2. Configuration issue: Confirm whether the ultrasonic welding parameters are set correctly, including amplitude, welding pressure, welding time, etc.

3. Coupling problem: Check whether the coupling between the workpiece and the welding head is good and whether there is sufficient contact area.

4. Elastomer issue: Check whether the elastomer between the welding head and the ultrasonic transducer is aged or damaged, and it needs to be replaced in a timely manner.

5. Ultrasonic transmission path problem: Check whether the ultrasonic transmission path is smooth, whether there are blockages or impurities affecting it.

6. Equipment malfunction: If all the above reasons are eliminated, it may be due to a malfunction in the equipment itself, and professional maintenance personnel need to be consulted for maintenance.

For more details of Ultrasonic Plastic Welding Transducer, please feel free to contact us!