Die-casting machines may have various faults during use. Understanding common faults and their causes, and mastering the corresponding maintenance methods are essential to ensure the normal operation of the die-casting machine.
Common faults of die-casting machines:
Insufficient feed
The reasons may be multifaceted. During the conveying process, if the material channel is blocked, such as impurities and residues accumulated in the material pipe, it will hinder the normal conveying of the material, resulting in insufficient feed. Insufficient raw materials are also one of the common reasons. If the amount of raw materials in the hopper is too small to meet the die-casting requirements, insufficient feed will occur. In addition, the structure or state of the mold may also affect the feed. For example, the gate size of the mold is too small, the runner is not smooth, or there are blockages inside the mold, which will hinder the feed.
The oil pump cannot start
After pressing the oil pump start button, if it is observed that the motor relay is not attracted, it may be that the motor thermal relay is activated or damaged, causing the circuit to fail to conduct normally. Incorrect power supply circuit, such as line break, short circuit or wiring error, can also prevent the oil pump from starting. In addition, abnormal contact of the start and stop buttons, open circuit of the control circuit, or damage of the relay coil will affect the start of the oil pump. If the relay is energized after pressing the oil pump start button, but the oil pump still cannot start, it may be that the oil pump itself is damaged and stuck, or the line from the relay to the motor is abnormal, or the oil pump is assembled too tightly, it is not easy to turn the coupling by hand, or the axial movement of the coupling gap is not appropriate (normal should be about 3-5mm).
Press the oil pump start button, the thermal relay trips
This is related to factors such as current, load and whether the three-phase resistance is symmetrical. If the motor thermal relay is damaged or the set current is too small, the thermal relay will trip easily. When the voltage is too low, the current will increase or the three-phase voltage will be unbalanced, causing the thermal relay to trip. Unbalanced resistance of the motor's three-phase winding will also cause similar problems. In addition, the total pressure or double pump pressure adjustment is too high, causing the machine to overload, or the oil pump is damaged or assembled too tightly, causing the motor to overload, which will cause the thermal relay to trip.
No total pressure
After the oil pump starts, press the pressure start button, first observe whether the pressure and flow indicating ammeters have indications to determine whether the electromagnetic coil of the proportional pressure valve (proportional relief valve) has current, so as to distinguish whether it is an electrical or hydraulic fault. If there is current output, it may be due to the oil pump reversal (people face the direction of the oil pump shaft, clockwise rotation is positive rotation), or the relief valve is improperly adjusted or stuck, the stop valve is closed, the throttle valve of the proportional relief valve is lost or loose, etc. If there is no current output, it may be due to abnormal rectifier board, improper adjustment or damage of pressure proportional amplifier board, abnormal computer operation, abnormal line between pressure start button and computer, abnormal line between electric proportional board output and oil valve, abnormal electric proportional coil, abnormal pressure dial code, etc.
No automatic action
Check whether the safety door limit switch is normal and whether the relevant action returns to the origin. For example, for the Lijin horizontal cold chamber die casting machine, before automatic action is performed, the safety door input signal, automatic input signal, clamping input signal, ejector return limit input signal, and return hammer arrival position should be satisfied. If the manual action is abnormal, the manual action fault should be checked and eliminated first.
Unable to adjust the mold
When the mold adjustment mode is selected for operation and the machine cannot achieve mold adjustment movement, first check whether the conditions for mold adjustment movement are met, whether the mold adjustment pressure value is set too low, and whether the manual operation mode is correct. If there are no problems with these contents, check whether the mold adjustment hydraulic motor is stuck or the mold adjustment motor is damaged, whether the mold adjustment hydraulic valve core is stuck, and whether the transmission pairs of the mold adjustment mechanism are worn or stuck.
