How to use spot welder
1. When welding, the position of the electrode rod should be adjusted first, so that the electrode arms are kept parallel to each other when the electrode is just pressed to the weldment.
2. The number of current adjustment switch stages can be selected according to the thickness and material of the weldment. After the power is turned on, the power indicator should be on. The pressure of the electrode can be adjusted by adjusting the spring pressure nut and changing its compression degree.
3. After completing the above adjustments, you can turn on the cooling water before turning on the power to prepare for welding. The procedure of the welding process: the welding piece is placed between the two electrodes, and the foot pedal is depressed, and the upper electrode is brought into contact with the welding piece and pressurized. When the foot pedal is further depressed, the power contact switch is turned on, so the transformer starts to work. The circuit is energized to heat the weldment. When the pedal is released after welding for a certain period of time, the electrode rises. The power of the spring is used to cut off the power and then return to the original state. The single-point welding process is over.
4. Weldment preparation and assembly: Before welding the steel weldment, all dirt, oil, scale and rust must be removed. For hot-rolled steel, the weld must be pickled, sandblasted, or removed with an abrasive wheel. Although uncleaned weldments can be spot welded, the service life of the electrodes is severely reduced, while the production efficiency and quality of spot welding are reduced. Welding can be directly applied to medium and low carbon steel with thin coating.
Installation and maintenance of spot welders
The spot welder must be properly grounded before use to ensure personal safety. Before using the welding machine, use a 500V megohmmeter to test that the insulation resistance between the high voltage side of the welding machine and the casing is not less than 2.5 megohms before applying power. Before maintenance, cut off the power before opening the box for inspection.
The spot welding machine is first applied with water and then welded. It is strictly prohibited to work without water. The cooling water should be guaranteed to supply industrial water at 5--30 ℃ under the inlet pressure of 0.15--0.2MPa. After the welding machine is finished working in winter, compressed air should be used to blow the water out of the pipeline to avoid freezing the water pipe.
The lead of the welding machine should not be too thin or too long. The voltage drop during welding must not be greater than 5% of the initial voltage, and the initial voltage must not deviate from the power supply voltage by ± 10%.
When operating the spot welder, gloves, apron and protective glasses should be worn to prevent burns from flying out from Mars. The sliding part should be kept well lubricated and the metal splash should be removed after use.
After the new spot welder is used for 24 hours, the screws of each part should be tightened once. Pay particular attention to the fastening screws between the copper soft coupler and the electrode. After use, you should always clear the Oxides to ensure good contact.
If the spot welding machine is found to be inaccurate when the AC contactor is in use, it means that the grid voltage is too low. The user should first solve the power supply problem. The power supply can be used only after it is normal. The wearing parts of this machine have moving contacts and static contacts of upper and lower electrodes (see the attached picture for details).
Spot welding machine failure phenomenon and troubleshooting
1. The stepping pedal welding machine does not work, and the power indicator is off:
a Check whether the power supply voltage is normal; check whether the control system is normal.
b Check the foot switch contacts, AC contactor contacts, and split-shift switch for good contact or burnout.
2. The power indicator is on, and the workpiece is not pressed and welded:
a Check if the foot pedal travel is in place and the foot switch is in good contact.
b Check that the pressure lever spring screws are properly adjusted.
3. Unexpected splashing occurs during welding:
a Check if the electrode tip is heavily oxidized.
b Check whether the welding workpiece is severely rusted and has poor contact.
c Check if the switch position is too high.
d Check if the electrode pressure is too low and the welding procedure is correct.
4. Welding indentation is serious and there is extrudate:
a Check for excessive current.
b Check whether the welding workpiece is uneven.
c Check whether the electrode pressure is too high, and the electrode tip shape and cross section are appropriate.
5. Weak workpiece strength:
a Check if the electrode pressure is too low, and check if the electrode rod is fastened.
b. Check whether the welding energy is too low, and whether the welding workpiece is severely rusted, making the solder joints poorly contacted.
c Check if there is too much oxide between the electrode tip and electrode rod, electrode rod and electrode arm.
d Check if the electrode tip cross section is increased due to wear and tear resulting in reduced welding energy.
e Check whether the electrode and copper soft coupling and bonding surface are severely oxidized.
6. The AC contactor sounds abnormally during welding:
a Check whether the incoming voltage of the AC contactor is lower than its own release voltage by 300 volts during welding.
b Check whether the power lead is too thin or too long, causing too much voltage drop in the line.
c Check if the network voltage is too low to work properly.
d Check if the main transformer is short-circuited, causing too much current.
7, the welding machine has overheated:
a Check if the insulation resistance between the electrode holder and the body is not good, causing a local short circuit.
b Check whether the inlet water pressure, water flow, and water supply temperature are appropriate, and check whether the water system is blocked by dirt, which may cause the electrode arm, electrode rod, and electrode tip to overheat due to poor cooling.
c Check the copper soft coupling and the electrode arm, whether the contact surface of the electrode rod and the electrode head is seriously oxidized, which causes the contact resistance to increase and generate serious heat.
d Check whether the cross section of the electrode tip is excessively increased due to wear, which causes the welder to overload and generate heat.
e Check whether the welding thickness and load continuity rate exceed the standard, which will overload the welding machine and generate heat.