Provided is an evaluation system including: an analog-to-digital converting section comprised of a programmable circuit and configured to convert an analog signal, the analog signal being acquired by a physical quantity acquiring section and indicative of a time-series change of at least one of (i) welding current, welding voltage, or load applied to pieces to be welded and (ii) a displacement, during welding, of a welding head; and an evaluating section configured to determine, based on a digital signal, whether or not the time-series change satisfies a predetermined condition, wherein configuration data for configuring the programmable circuit is arranged to be changeable by a user.

A spot welding monitoring method is configured to monitor a state of spot welding that holds a work including metal plates stacked on each other, between electrodes in a pair, and supplies electricity between electrodes. The spot welding monitoring method includes: by a converter disposed in a vicinity of a weld zone of the work, detecting a change in magnetic flux density of a magnetic field generated around the weld zone by the supplying of the electricity between electrodes, and converting the change in the magnetic flux density into a current; and calculating three-dimensional data on a melting zone of the work, based on a temporal change in a value of the current.

An example apparatus to monitor a welding-type system includes: a test signal generator configured to output a test signal to a monitored circuit; and a lock-in amplifier configured to: receive a reference signal based on the test signal; measure a leakage current in the monitored circuit based on the reference signal; and generate an output signal representative of the leakage current.

A spatter detection method is a method for detecting an occurrence of spatter at the time of joining a workpiece using a spot welding apparatus including a pair of electrode chips, a welding power circuit connected to the pair of electrode chips, and a current sensor configured to detect a current flowing through the pair of electrode chips. A spot welding method using the spot welding apparatus includes supplying a pulse-shaped welding current to the workpiece, the pulse-shaped welding current being generated when the welding power circuit alternately repeats power distribution control and a power distribution pause over a plurality of cycles while the workpiece is sandwiched and pressurized by the pair of electrode chips. The spatter detection method includes determining, based on a current detection value detected by the current sensor in a power distribution pause section for each cycle, whether or not the spatter occurs.

A spot welding method includes supplying a welding current having a pulse-shaped waveform to a workpiece by alternately executing a step of maintaining the welding current within a set peak current range and a step of decreasing the welding current from the peak current range toward a bottom current and then increasing the welding current toward the peak current range when an effective value of the welding current reaches a set target range for a plurality of cycles. The spatter detection method includes measuring a pulse width IW(1), IW(2), . . . in each cycle of the pulse-shaped waveform and detecting the occurrence of spatter when a pulse width difference D(M)=IW(M)−IW(M−1) between a pulse width IW(M) in a target cycle (M-th cycle) and a pulse width IW(M−1) in a cycle immediately before the target cycle exceeds a width threshold value Dth.

The present disclosure provides a system for printing a three-dimensional (3D) object. The system may comprise a source of at least one feedstock, a support for supporting at least a portion of the 3D object, a feeder for directing such feedstock from the source towards the support, and a power supply for supplying electrical current. The system may comprise a controller operatively coupled to the power supply. The controller may receive a computational representation of the 3D object. The controller may direct such feedstock through a feeder towards the support and may direct electrical current through such feedstock and into the support. The controller may subject such feedstock to heating such that at least a portion of such feedstock may deposit adjacent to the support. The controller may direct deposition of additional portions adjacent to the support and may direct an additional feedstock through such feeder and subject to heating.

Provided is a spot welding method capable of reliably welding a metal sheet laminate while suppressing occurrence of expulsion. In the spot welding method, a pulse current is applied in a first current application step and a second current application step by a DC chopping control method. In the DC chopping control method, a pulse waveform of the pulse current is generated by switching between current application and current application stop to a pair of electrodes 12 and 22 by a current switch 28, a peak current value of the pulse current in the first current application step is set to a value A1 equal to that of the pulse current in the second current application step, and a power of the pulse current in the first current application step is set to a value larger than that of the pulse current in the second current application step.

A resistance welding control system includes an electrode displacement detector, a temperature estimation information acquiring unit, and a temperature estimation unit. The electrode displacement detector detects a positional displacement between opposite electrodes while the electrodes are supplying electricity between the electrodes to perform resistance welding of welding members held between the electrodes. At least one of the electrodes is movable toward or apart from the other electrode. The temperature estimation information acquiring unit acquires at least an interelectrode voltage, a current density in the welding members, and a physical property value of the welding members as temperature estimation information to be used to estimate a temperature of a welding portion between the welding members. The temperature estimation unit estimates the temperature of the welding portion based on the temperature estimation information and the positional displacement while at least either one of the positional displacement and the interelectrode voltage is stabilized.

A method for resistance welding includes performing a plurality of resistance welding processes during which welding electrodes are pressed against respective welding spots of respective workpieces. The welding electrodes are energized with a respective welding current for each of the plurality of resistance welding processes, and for each of the plurality of resistance welding processes, a respective at least one characteristic value that characterizes a quality of the welding is determined. A statistical analysis of the determined at least one characteristic value for each of the plurality of resistance welding processes is performed, and based upon the analysis, an adaptation of the prescribed welding parameters is determined.

A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding, wherein in the test welding, 0.2≤Vtp/Vtm≤1.5 is satisfied where Vtm is an average value of a voltage between the electrodes in main current passage in the test welding and Vtp is an average value of a voltage between the electrodes in subsequent current passage in the test welding, and in each of main current passage and subsequent current passage in the actual welding, a time variation curve of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume that are stored in a corresponding one of the main current passage and the subsequent current passage in the test welding are set as a target, and adaptive control welding is performed to control a current passage amount according to the target.