SU789257A1 - Method of stabilizing the energy of welding pulses - Google Patents

Description

one

The invention relates to the field of welding technology and can be used in control systems of the sealing mode of integrated circuits by seam contact welding using frequency pulses of an industrial network.

There is a method of regulating the welding process by resistance between electrodes, measured in between the welding pulses.

The disadvantage of this method is that the inertia of the regulation is large, which is explained by the time separation of the measurement and control points.

There is also known a method of stabilizing the energy of welding pulses according to a generalized parameter of controlling and adjusting the resistance welding mode between electrodes, at which the voltage amplitude is measured, compared to the reference voltage, and by the result of the comparison, the energy is adjusted by changing

the moment of switching on the controlled power valves 2.

The disadvantage of this method is the overheating of the sealing elements, as well as the splash and burn-through of the connected parts as a result of the high steepness of the leading front of the welding pulse.

The closest to the technical solution of this invention is 10 with a method of stabilizing the energy of welding pulses, in which the measured voltage of the welding pulses is compared with this and controls the duration of the thyristors on.

15

Claims (1)

The disadvantage of this method is the impossibility of controlling the energy of the welding pulse directly in the measured pulse. The speed of the control system using this method is not less than the period of the industrial network frequency, which is insufficient for such a fast-flowing process as sealing the case with resistance seam welding, which is done by gradual creation of overlapping overlapping points from each current pulse. The purpose of the invention is to improve the accuracy of the dosing of welding energy, which is directly related to the quality of the welded joint. This goal is achieved by controlling the duration of the turning on of the thyristors in each welding pulse by varying the steepness of the rise of the pulse front. The method of stabilization of the energy of welding pulses realizes the dependence of the change in the steepness of the rising front of the voltage on the variation of the voltage amplitude in each welding pulse under the action of disturbing factors (change in the voltage of the network, change in resistance between the electrodes, resistance instability in the welding contacts). FIG. Figure 1 shows a time frame for the measurement of the steepness of the growth front of a welding pulse; FIG. 2 is a block diagram of a device implementing the method. When the sinusoidal voltage of the network is crossed through zero, the welding pulse is turned on, while the steepness of the rising edge Sd of the rising pulse V JHOK / is measured - the voltage at which the front of the welding pulse is measured; - front duration of a welded pulse. The duration of the welding pulse is determined as follows: The pulse duration is g, o (and the specific for a given type of enclosure size is set. The pulse duration starts from the intersection of the varying sinusoidal voltage with the nominal voltage. With increasing voltage on the winding of the welding transformer to increasing from the rising edge steepness., the duration of the rising front f increases automatically, reducing the intensity of the welding pulse If the pressure on the windings of the welding transformer decreases to the value U, the steepness of the rising front Vf decreases, the duration of the rising front increases, the duration of the cooking pulse t also increases, and the energy of the welding pulse automatically stabilizes. measurement of the rising edge steepness allows predicting the quality of the welded joint and automatically finding the optimal sealing mode. The block diagram of the device implementing the method contains a thyristor switch 1, a block 2 measuring the steepness of the pulse rise front, a setting 3 for the duration of the welding pulses, a block 4 for controlling the thyristors, a welding transformer 5. The device operates as follows. The unit 3 of the duration of the welding pulses is set to the optimum welding mode corresponding to a specific frame size. When the sinusoidal voltage of the network passes through zero, the thyristor switch 1 is turned on. Simultaneously, the pulse growth rate measurement unit 2 receives a signal from the welding transformer 5, and when the voltage reaches the value, a pulse duration of the welding pulse 3 is output. f back thyristor key 1 is turned off by the signal of the thyristor control unit 4. This method makes it possible to determine the required energy of a welding pulse directly in the process of forming each welding pulse before the end time of the welding pulse. Such a control of the energy of the welding pulse makes it possible to eliminate spud and incomplete fusion during the welding process. Formula from. gaining The method of stabilizing the energy of welding pulses, mainly for sealing integrated circuits by seam welding using frequency pulses of an industrial network,