CN104002017A - Efficient electric spark cladding machine - Google Patents

Abstract

The invention discloses a high-efficiency electric spark cladding machine. After the alternating current is stepped down, rectified and filtered, it charges an energy storage capacitor through a current-limiting resistor, and at this time, the IGBT is in a cut-off state. When the charging amount of the capacitor reaches a given value, the comparison amplifier outputs a pulse signal, and the IGBT is turned on through the trigger, and the energy storage capacitor is quickly discharged through the discharge circuit composed of the IGBT, the electrode and the workpiece. During the capacitive discharge, the electrode stops rotating to ensure that the capacitive discharge can be concentrated on a certain point at the end of the electrode. When the remaining power of the capacitor discharge reaches another given value, the comparison amplifier outputs a pulse signal, and the IGBT is cut off through the trigger, and the electrode starts to rotate. At this time, the energy storage capacitor returns to the charging state again, and the electric spark cladding machine into the next working cycle.

Description

Efficient EDM cladding machine

technical field

The invention relates to a device for improving the efficiency of electric spark cladding, which belongs to the field of metal material surface modification treatment technology.

Background technique

EDM cladding technology is an important part of the surface modification technology of metal materials, which is applied to the surface strengthening treatment of tools and molds and the surface repair of metal parts. Compared with other cladding technologies, EDM cladding has the advantages of small heat-affected zone, no influence on the mechanical properties of the base material, and no deformation of the processed parts.

EDM cladding is through the rapid discharge of the energy storage capacitor, which generates spark discharge between the electrode and the metal material to be processed. The instantaneous high temperature melts the end of the electrode and the surface of the substrate, and part of the electrode material transfers to the surface of the substrate to form a cladding layer.

The early electric spark cladding machine used mechanical vibration to make the electrodes contact frequently on the surface of the substrate: the capacitor was discharged when it was in contact, and the capacitor was charged when it was disconnected. Later, people used the fast switching function of the new power semiconductor device "insulated gate bipolar transistor (IGBT)" to realize the charging and discharging of the capacitor: the capacitor is charged when the IGBT is off; the capacitor is discharged when the IGBT is on. The switching frequency of the IGBT is adjusted by the operator through the switching frequency adjustment knob on the panel. During the EDM cladding process, the IGBT charges and discharges the capacitor at a fixed frequency. This charging and discharging mode makes it difficult for the EDM cladding machine to have the maximum power output. For example, when the switching frequency of the IGBT is high, the IGBT is turned on before the capacitor is fully charged, and the discharge energy at this time is relatively low; when the switching frequency of the IGBT is relatively low, the fully charged capacitor still has to wait until the IGBT is turned on to start discharging , At this time, the efficiency of the EDM cladding machine cannot reach the maximum value.

In addition, the electrode of the EDM cladding machine rotates at a constant speed when it is working, and the speed is adjusted by the operator. During the discharge of the capacitor, since the electrode is always rotating, the electric energy released by the capacitor cannot be concentrated and discharged at a fixed part of the electrode end, which affects the melting rate of the electrode.

Contents of the invention

The purpose of the present invention is to provide a device that can improve the efficiency of electric spark cladding, through which the cut-off and conduction of the IGBT, the charging and discharging of the capacitor, and the rotation and stop of the electrode are kept synchronized to ensure energy storage. The capacitor starts to discharge when it is charged close to the maximum value each time, and stops discharging when the capacitor is discharged to a certain minimum value, that is to say, the switching frequency of the IGBT is determined by the charge and discharge frequency of the capacitor. In addition, the electrode stops rotating during the discharge of the capacitor, so that the electric energy released by the capacitor is concentrated at a certain point at the end of the electrode.

In order to achieve the above object, the present invention adopts the following technical solutions:

After the alternating current is stepped down, rectified and filtered, it charges the energy storage capacitor through the current limiting resistor, and the IGBT is in the cut-off state at this time. When the energy storage capacitor is charged to a given value, the comparison amplifier outputs a pulse signal to turn on the IGBT through the trigger and stop the rotation of the electrode. The energy storage capacitor discharges rapidly through the discharge circuit formed by the IGBT, the electrode and the workpiece. When the remaining power of the discharged energy storage capacitor reaches another given value, the comparison amplifier outputs a pulse signal, and the IGBT is cut off through the trigger, and the electrode starts to rotate. At this time, the capacitor enters the charging state again, and the spark cladding enters next work cycle.

The beneficial effects of the present invention are:

In the process of EDM cladding, the discharge starts only when the energy storage capacitor is charged to a state close to full charge; when the capacitor discharges to the point where the remaining power has little effect on the cladding effect, the discharge is stopped. This charging and discharging mode can ensure The EDM cladding machine is always running at the highest cladding efficiency state. In addition, the electrode rotates or stops synchronously according to the charging and discharging of the capacitance, which can ensure that the capacitance discharge is concentrated on a certain point at the end of the electrode, so as to further improve the efficiency of electric spark cladding.

Description of drawings

Accompanying drawing 1 is the structural representation of the device of the present invention.

Detailed ways

Example: As shown in the figure, the 220V AC is stepped down, rectified and filtered to obtain a 100V smooth DC, which is charged to a 100 microfarad energy storage capacitor through a 10-ohm current-limiting resistor. When the energy storage capacitor is charged to 95%, the logic circuit of the comparison amplifier controls the trigger to output a pulse signal to turn on the IGBT and stop the rotation of the electrode. At this time, the energy storage capacitor discharges to the workpiece through the IGBT and the electrode, forming a a cladding point. When the energy storage capacitor has 10% remaining power, the logic circuit of the comparison amplifier controls the trigger to output a pulse signal to turn off the IGBT, the electrodes start to rotate, the capacitor starts charging again, and the spark welding device enters the next working cycle. Compared with the traditional electric spark cladding device, the invention can improve the cladding efficiency by more than 30%.

Claims (2)

1. an electric spark cladding machine, comprise decompression rectifier filter circuit, current-limiting resistance, storage capacitor, IGBT switching device, comparison amplifying circuit, circuits for triggering, rotation electrode, electric capacity is to control charging and discharging by IGBT, it is characterized in that in the time that the charge volume of electric capacity reaches a certain set-point, IGBT conducting, electric capacity starts electric discharge; In the time that capacitor discharge dump energy reaches another set-point, IGBT cut-off, electric capacity charges again.

2. device according to claim 1, is characterized in that electrode stops operating in the IGBT conducting period; Close the period at IGBT, electrode starts rotation.