Common misunderstandings of ultrasonic welding equipment
Most ultrasonic welding equipment follows one of two design concepts: ①Modular system, ②Integrated system.
In a modular system, the control device and power supply are separated from the transmission device. When a high level of control is required and the original equipment manufacturer requires convenient packaging, a modular system is usually used. The integrated system is less expensive, but less controllable.
1. Misunderstanding of welding principle
There are quite a few people who have been engaged in ultrasonic welding for many years. There is a misunderstanding about the transmission of ultrasonic energy, thinking that sound waves are welding on the contact surface. In fact, this is a misunderstanding. The real ultrasonic welding principle is: the transducer converts electrical energy into After the machine, it is conducted through the material molecules of the workpiece, and the acoustic resistance of the sound wave in the solid is much smaller than the acoustic resistance in the air. When the sound wave passes through the joint of the workpiece, the acoustic resistance in the gap is large, and the thermal energy generated is quite large. First, the capacity point of the workpiece is reached, and a certain pressure is added to make the seam welded. The other parts of the workpiece will not be welded due to the small thermal resistance and low temperature. The principle is similar to Ohm's law in electrical engineering.
2. Misunderstanding of workpiece material:
Ultrasonic welding machines also have requirements for the material of the workpiece to be welded. Not all materials can be welded. Some people understand that any material can be welded. This is a big misunderstanding. Some materials can be welded better. , Some are basically fused, and some are not fused. The melting point of the same material is the same, and it can be welded in principle, but when the melting point of the workpiece to be welded is greater than 350 ℃, it is not suitable for ultrasonic welding. .Because ultrasound melts the molecules of the workpiece instantly, the judgment basis is that within 3 seconds, if the welding cannot be performed well, other welding processes should be selected, such as hot plate welding.
3. Process misunderstanding of ultrasonic welding workpiece
Ultrasonic energy bursts in an instant, the welding point should be a point or line, and the distance of transmission must be in line with the ultrasonic welding method. Some people think that as long as it is a plastic material, no matter how the joint surface can be welded well, this is also a misunderstanding. When instantaneous energy is generated, the larger the joint area, the more severe the energy dispersion, the worse the welding effect, and the worse the welding effect. In addition, the ultrasonic wave is longitudinally transmitted, and the energy loss is proportional to the distance. Long-distance welding should be controlled within 6 cm. The welding line should be controlled between 30 and 80 wires, and the arm thickness of the workpiece should not be less than 2 mm, otherwise it will not be well welded, especially for products that require airtightness.
4. Misunderstanding of ultrasonic output power
The size of the ultrasonic output power is determined by the diameter and thickness of the piezoelectric ceramic sheet, the material, and the design process. Once the transducer is finalized, the power is finalized. Measuring the size of the output energy is a complicated process, not a transducer. The larger the device, the more power tubes used in the circuit, and the greater the output energy. It requires a very complicated amplitude measuring instrument to accurately measure its amplitude. Because most users know too much about ultrasound, and some sales staff Misleading, give consumers a misunderstanding. The amount of electrical energy consumed does not reflect the size of the output excess power. For example, the vertical energy generated is low, and the current consumption is large, which can only indicate the low efficiency of the equipment. The reactive power is large.
5. Misunderstanding of ultrasonic welding machine selection
How much output power to use, the oscillation frequency, and the amplitude range should be considered according to factors such as the material of the workpiece, the area of the welding wire, whether there are electronic components in the workpiece, and whether it is airtight or not. Misunderstood that the greater the power, the better. This is also a misunderstanding.
