IR2110 IR2153 Ultrasonic Welding Machine Circuit

I don’t know about ultrasonic welding for plastic, but there are projects that can be useful for those who are interested. The appropriate ultrasonic with sufficient power in the application is 60W at 68kHz, disassembled from an ultrasonic cleaner. A lower frequency is more suitable.

PVC welding The ultrasonic transducer behaves approximately like a series LC cell.

Circuit Diagram of IR2153 Ultrasonic PVC Welding Machine

The plastic welding machine circuit is a half-bridge controlled by IR2153, blocked by T3 (2SC945) and provided with synchronization voltage from a current transformer. The converter has excellent quality as a resonant circuit. Outside the resonant frequency it has such a large input resistance that it draws almost no current, i.e. it does not transmit any power. The size of C3 against C11 can be used to select the bandwidth at which the circuit will find resonance.

Isolation and regulation transformer 0-250V 4A. (or variac) Its biggest advantage over other welding methods is that it is a clean and safe operation. Nothing gets hot, burns, scorch or sticks anywhere unless the polyvinyl sonotrode is pressed against its tip.

Welding with ultrasound and HF current (dielectric heating) causes heat loss within the material at the point where the welding is needed. On the other hand, the outer electrodes are cold, cooling them and thus preventing damage and thinning of the polyvinyl near the welding.

In addition to this project, I am also adding the files of the other Ultrasonic welding circuit that is a source of inspiration. The circuit is based on 74HC4046N, 7402N, IR2110 integrated circuits.

Power ultrasonic driver

The circuit described here (i.e., a voltage-fed inverter connected directly to an ultrasonic transducer) will probably be happy driving low-powered transducers, below about 100W. However, as I’ve read more about ultrasonic transducers and driving circuits, I’ve realised that there are problems using this circuit for higher powers.

The proper electrical model for an ultrasonic transducer is a capacitance in parallel with an LCR series resonant circuit. The fixed capacitance corresponds simply to the electrical capacitance of the transducer, neglecting mechanical oscillation effects. The LCR circuit corresponds to the resonant behaviour of the transducer. Therefore, if the transducer is connected directly to the output of a voltage-fed inverter, the bridge transistors will charge and discharge the fixed capacitance, resulting in large current spikes at the switching transitions. For small transducers, this isn’t really a problem because the transistors can handle the spikes, but it becoms a problem for larger transducers.

To get around this problem, you need to use a matching network to adapt the electrical properties of the transducer to something that the inverter is happy driving. Matching networks come in many different forms, but the most common are LC and LLCC. Do a Google search on them and you should find some useful results.

Introduction

On this page, I describe the construction of a power supply for a 70W ultrasonic tank transducer, and the machining & tuning of an aluminium horn. I originally started all this in order to do ultrasonic drilling, but could find no simple, cheap means of driving high-power transducers. “Proper” ultrasonic horns are usually made from titanium, and the power sources are usually fancy affairs with auto frequency tuning. However, I found that, for the power levels I’m interested in, an aluminium horn works perfectly well, and it is possible to drive the transducer with a manually-controlled oscillator and inverter. I won’t go into too much detail on the principles behind piezoelectricity and these kind of ultrasonic transducers – I assume you know a bit of background since you’re reading this.

source: arambajk.blogspot.com/2014/02/ultrazvukova-svarecka-mekceneho-pvc.html