How to make a welding semi-automatic machine with an

The automatic welding machine can be bought ready-made, but there are always people who are trying to make it with their own hands. This is not easy to do, but those who really want to assemble a semiautomatic device with their own hands will have to prepare in advance all the necessary components.

The device is a semi-automatic welding.

For the manufacture of semi-automatic welding machine from the inverter you will need tools and materials:

• an inverter that is capable of producing a current of approximately 150 A;
• feeder;
• burner;
• flexible hose;
• wire reel, with some changes in the design;
• welding inverter;
• Control block.

The power scheme of the welding machine.

The feeding mechanism in this case deserves special attention: it is used to feed the electrode wire through a flexible hose to the point of welding. Ideally, the wire feed speed should match the melting rate of the consumable. The electrode wire feed speed is very important for the welding process: the quality of the weld depends on it. It is necessary to provide the possibility of controlling the speeds in order to be able to work with electrode wires of different sizes from different materials. The most commonly used wire of the following diameters: 0.8 mm, 1 mm, 1.2 mm, 1.6 mm. It is wound onto coils and charged with a welding inverter. Fully automatic wire feed to the welding torch significantly reduces the time spent on work.

The control unit of the welding machine has a control channel that stabilizes the current. The action of the current controls the microcontroller in pulse-width mode. The voltage across the capacitor directly depends on the filling of the pulse-width mode. It is this voltage that affects the strength of the welding current.

Subtleties of the transformer

Winding scheme of the welding transformer.

There are small subtleties in the preparation of the transformer. The transformer must be wound with a copper strip (width - 40 mm, thickness - 30). Pre-strip must be wrapped with thermal paper (suitable from the cash register). Winding a simple thick wire in this case is excluded, since it will warm up.

The secondary winding should consist of three layers of tin. Isolate the layers from each other need fluoroplastic tape. At the output it is necessary to solder the contact ends of the secondary winding. This is done in order to increase the conductivity of currents. It is imperative to provide a fan in the case of the inverter.

How to set up an inverter?

If you decide to make a semiautomatic device with your own hands, you must first de-energize the power unit. By the way, for the input and input rectifiers, as well as for power switches (previously soldered to copper substrates) of the power section, good radiators should be provided. In the case of the most heated radiator, it is necessary to position the thermal sensor. Now the power part is connected to the control unit and is included in the network. When the indicator lights up, you need to turn on the oscilloscope Out1, Out2. Now find bipolar pulses, the frequency of which should be 40-50 kHz. The time between them is corrected by changing the input voltage. The time should be 1.5 µs.

Scheme of the device welding inverter.

Oscilloscope pulses should be rectangular with fronts no more than 500 ns. After checking the inverter connect it to the network. The semi-automatic welding indicator should show 120 A, if this inscription on the indicator does not light up, then it is necessary to search and eliminate the cause of the low voltage in the welding wires. This situation happens if the voltage is less than 100 V. Then you need to test the welding inverter by changing the current (with constant monitoring of the voltage on the capacitor). Then you can check the temperature.

After the welding inverter is tested, it is necessary to check how it behaves in a loaded state. To this end, a 0.5-ohm load resistor is included in the welding wires, which must withstand a current of more than 60 A. In this state, the current is monitored with a voltmeter.

If there are discrepancies between the specified current value and its monitored value, it is necessary to select the resistance until a match is achieved.

Welding Inverter Rules

The main modes of welding semiautomatic.

By default, when you start the inverter, the controller will automatically set the size of the current. If all the actions mentioned earlier are executed correctly, then the welding current will be equal to 120 A. If it suddenly turns out that the figure eight shows on the indicator, this will indicate a malfunction. Such faults occur in the case when the voltage in the welding wires does not rise more than 100 V. If this happens, you will have to look for and fix the fault.

When everything is done correctly, in the place of the eights there should be a number indicating the value of the specified current. Using the buttons, this value can be changed, depending on what amount of welding current is required in each specific case. The interval in which it is possible to change the amount of current varies from 20 A to 160 A.

The work of the welding machine.

It is possible to control the temperature of the inverter during the entire process. To do this, you must simultaneously press both buttons. After that, it will be possible to observe the temperature change of the radiator, the data of which will be displayed on the indicator. Normally, the temperature of the radiator should not exceed 75 ° C. If the temperature has increased by more than 75 ° C, it will immediately appear on the indicator and the inverter will start to emit a sound signal of an intermittent type. If this happens, the set current will automatically decrease to 20 A. Despite the fact that the current will be drastically reduced, the inverter will continue to work. This sound signal will be issued until the display temperature returns to normal.

The indicator may give an error code Ert: this will happen in the event of a breakdown or closure of the temperature sensor.

In this case, exactly the same set current will be reduced to 20 A.

The use of automatic welding machine

Semiautomatic welding of an inverter is used for precision welding of steels, as well as it is used for welding thin metal, for example, the car body.

The welding inverter, of course, can be purchased in the store, but many prefer to assemble a semi-automatic machine with their own hands.