Welding requirements of ultrasonic welding machine
With the popularity of ultrasonic welding equipment, more and more plastic parts are switched from the old technology to ultrasonic welding. So what kind of product is suitable for ultrasonic welding
1. The thermal resistance must reach the melting point of the workpiece
After the ultrasonic transducer converts electrical energy into mechanical energy, it conducts through the material molecules of the workpiece. The acoustic resistance of ultrasonic waves in solids is smaller than that in air. When sound waves pass through the joint of the workpiece, the acoustic resistance in the gap is large. , The heat generated is great. The temperature first reaches the melting point of the workpiece, and then is applied to the welded joint to form a certain pressure. The other parts of the workpiece will not be welded due to low thermal resistance.
2. The two workpieces must be weldable
Some different materials can be welded well, some can basically be fused, and some cannot. In principle, the melting point of the same material can be welded, but when the melting point of the workpiece to be welded is higher than 350°C, ultrasonic welding is not suitable. Since ultrasonic waves will instantly melt the molecules of the workpiece, the basis of judgment is that they cannot be welded well within 3 seconds, so other welding processes should be selected. Such as hot plate welding. Generally speaking, ABS materials are easy to weld, while nylon or PP materials are difficult to weld.
3. There are certain requirements for the joint area
When instantaneous energy is generated, the larger the joining area, the more serious the energy diffusion, the worse the welding effect, and the worse the welding. In addition, ultrasonic waves are transmitted in the longitudinal direction, 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 30-80 welding wires, and the wall thickness of the workpiece should not be less than 2 mm, otherwise it will not be able to weld well, especially for products that require air tightness.
4. The output power must be constant
In the design process, the output power of the ultrasonic welding machine depends on the diameter, thickness, material and piezoelectric ceramic sheet. Once the ultrasonic transducer is completed, the high power is complete. Measuring output energy is a complicated process. This is not to say that the larger the ultrasonic transducer and multiple ultrasonic power tubes used in the circuit, the greater the output energy. It requires a very complex amplitude measuring instrument to accurately measure its amplitude.
Handheld ultrasonic welding machine
5. Misunderstood the ultrasonic welding machine
How much output power to use, the oscillation frequency and amplitude range should be based on materials such as the workpiece, considering the area of the welding wire, whether there are electronic components in the workpiece and whether there is airtightness.
6. Need strict inspection
Traditional ultrasonic mold manufacturers have strict inspection procedures for incoming materials, and the processing dimensions are processed after computer software simulation and verification. Quality assurance. These processes cannot be completed in a normal workshop. If the mold design is incorrect, the reaction problem will not be obvious when welding small workpieces, and various shortcomings will appear at high power. In severe cases, the power components will be directly damaged.