Overview
A die casting machine is a machine used for pressure casting. It includes two types of presses, hot press chamber and cold press chamber. The latter are further divided into two types: straight and horizontal. Die-casting machine under pressure to molten metal hydraulic injection into the mold cooling molding, open the mold can get solid metal castings, initially used for die-casting lead.
With the progress of science and technology and industrial production, especially with the development of automobile, motorcycle and household appliances and other industries, die-casting technology has obtained extremely rapid development.
Working Principle
Pressure casting is a process in which molten metal is filled into the mold at high pressure and high speed, and crystallized and solidified under high pressure to form a casting. The commonly used pressure is tens of MPa, the filling speed (inner gate speed) is about 16~80 m/s, and the time for the metal liquid to fill the mold cavity is extremely short, about 0.01~0.2 seconds.
Applications
Die-casting process is mainly used in automobile, tractor, electrical instrument,telecommunication equipment, aerospace, medical equipment and light industrial daily hardware industry.
Classification
Die-casting machine classification methods, according to the use of the scope of general die-casting machine and special die-casting machine; according to the size of the clamping force is divided into small machine (≤ 4 000 kN), medium-sized machine (4 000 kN ~ 10 000 kN) and large machine (≥ 10 000 kN); usually, mainly according to the machine structure and the location of the injection chamber (hereinafter referred to as the pressure chamber) and its working conditions are classified.
Generally divided into two kinds of hot press room and cold press room, according to its press room structure and layout and divided into horizontal, vertical two forms.
Selection Guide
Die-casting machine selection principles:
(1) understand the type of die-casting machine and its characteristics;
(2) Consider the type of alloy of the die casting and the related requirements;
(3) The selected die-casting machine should meet the conditions of use and technical requirements of die castings;
(4) The selected die-casting machine should have certain margins in terms of performance, parameters, efficiency and safety to ensure satisfactory yield, productivity and safety;
(5) In order to ensure the premise of point 4, should also consider the reliability and stability of the machine, according to this to choose a reasonable cost-effective die-casting machine;
(6) For the production scale of die-casting machine with many varieties and small production volume, under the premise of guaranteeing point 4, the specifications that can be compatible should be selected scientifically, so that both the due varieties can be covered and the number of die-casting machines can be reduced;
(7) In the die-casting machine of the technical indicators and performance parameters, the primary attention should be paid to the pressure injection performance, in the same specifications or similar specifications, priority selection of pressure injection performance parameters of a wide range of models;
(8) Under possible conditions, try to be equipped with mechanized or automated devices, for product quality, production efficiency, safe production, enterprise management and cost accounting are beneficial;
(9) Evaluate the effectiveness of the selected die-casting machine, including: yield, productivity, failure rate, maintenance frequency and its workload, stability of performance, reliability of operation, and safety, etc.
Maintenance
In order to ensure the normal operation of the die-casting machine, should be in the correct use at the same time, should also carry out scientific maintenance work. Therefore, according to the requirements of the manual and the relevant regulations, the operating procedures and maintenance management system of the machine must be formulated, especially the safety procedures, a person responsible for the implementation, and strictly prohibit the violation of regulations.
Cautions
1、Before starting the motor, first put the pressure relief valve handle in the pressure relief position, and then release the pressure relief valve handle after the motor is running normally.
2、Before operation, check whether (a) opening the safety door (b) pressing the emergency stop button can terminate the clamping action during manual/semi-automatic/automatic operation. Pressing the emergency stop button can cut off the power supply to the oil pump motor to terminate the mold locking.
3、Protective shields should be used at the mold parting surface contact and sprue, and the operator must wear protective glasses. The operator should not stand on the opposite side of the parting surface contact. In order to prevent the metal liquid spray injury.
4、Check whether the position of the button mast system is properly adjusted and whether the time of the button mast is sufficient.
5、Check whether the oil pressure system is higher than the selected pressure when operating at the highest pressure? If higher than this pressure, the working life of alloy die-casting machine will be greatly shortened, should check the total pressure relief valve, immediately notify the maintenance personnel maintenance check.
6, the machine in the installation of die-casting die, should use manual slow speed state to adjust the work.
7、Avoid putting the alloy material containing water and oil in the furnace.
8、Avoid to take out the material from the mold by hand, should be supplemented with appropriate tools to take out.
9、Disassemble any hydraulic parts or other maintenance, should shut down the oil pump motor to remove the high pressure oil circuit pressure oil (unload back to the oil tank).
10、The machine needs to stop for a long time, should shut down the oil pump and three-phase power switch.
11、When the machine is in operation, make sure that the front and rear safety doors are closed to prevent the metal liquid from splashing out of the mold parting surface and burning the staff.
Troubleshooting
1, die-casting machine in the course of work once the aura of failure, the operator should pay great attention to, and calmly observe, determine the parts of the failure and the possible causes, to determine the feasible repair method. A, the oil pump can not start
Inspection and analysis: press the oil pump start button, observe whether the motor relay suction.
1、If the relay does not absorb, then check
(1) whether the motor thermal relay action or damage.
(2) whether the power circuit is normal (check with a multimeter).
(3) whether the start and stop button contacts are normal, and whether the control line is broken.
(4) whether the relay coil is damaged (check with a multimeter).
2、If the oil pump starts after the relay has suction then check
(1) whether the oil pump is damaged jammed.
(2) whether the line from the relay to the motor is normal.
(3) whether the oil pump is damaged or assembled too tight. The coupling should be easy to move by hand, and the axial moving coupling should have a clearance of about 3~5mm as appropriate.
2, two, according to the oil pump start button, the thermal relay tripped
Inspection and analysis: press the oil pump start button, the thermal relay tripped. This is related to the current, load and three-phase resistance value symmetry.
(1) The motor thermal relay is damaged or the rectification current is too small.
(2) the voltage is too low resulting in an increase in current or three-phase voltage imbalance.
(3) motor three-phase winding resistance unbalance.
(4) the total pressure or double pump pressure adjustment is too high, resulting in the machine overload operation and tripping.
(5) oil pump damage or assembly is too tight, so that the motor overload operation and tripping.
3、 No total pressure
(1) three-phase power supply is out of phase, the motor can not start or oil pump, motor, shaft damage
Elimination: system no total pressure, if the oil pump does not work, should first check the three-phase power supply, and then check, repair and replace the oil pump, motor or shaft coupling.
(2) electromagnetic proportional valve without electricity to, starting pressure conditions are destroyed
Exclusion: Check whether the circuit has signal output? Is the wiring loose? Is the valve spool stuck or damaged?
(3) the oil tank oil level is too low or oil filter blockage
Exclusion: Add hydraulic oil or clean and replace the screen.
(4) the entire hydraulic system circuit in the hydraulic valve is stuck by foreign objects or solenoid damage and can not be reset
Exclusion: Check and clean the oil circuit or oil valve, replace the damaged hydraulic valve
Inspection and analysis: after the pump starts, press the start button, first observe the pressure and flow indication current meter to determine the proportional pressure valve (proportional relief valve) solenoid coil current, distinguish between electrical or hydraulic failure.
1、If there is current output, then check
(1) whether the oil pump is reversed (human face pump shaft direction, clockwise rotation for positive rotation).
(2) Check the relief valve to see if it is not properly adjusted or jammed.
(3) Check whether the shut-off valve is closed.
(4) Whether the throttle valve of the proportional relief valve is lost or loose.
2、If there is no current output, check
(1) whether the rectifier board is normal and whether the pressure proportional amplifier board is improperly adjusted or damaged.
(2) observe whether the computer is working normally, press the start button by hand to see whether there is input at the corresponding point on the computer and whether there is output at the total pressure point, if there is no input, check whether the line between the start button and the computer is normal, if there is input and no output at the total pressure point, the computer is faulty or the back door is not closed and other conditions are not met.
(3) Check whether the line between the output of the electric proportional board and the oil valve is normal, and whether the electric proportional coil is normal.
(4) Check whether the pressure dial code is normal.
4、No automatic
If the manual action are normal, but no automatic action, you should check whether the safety door limit switch is normal, the action is back to the original point (according to the requirements of the machine manual). For example, for Likin horizontal cold chamber die-casting machine, the following conditions should be met before automatic action: safety door input signal is lit; automatic input signal is lit; mold lock input signal is lit; ejector pin back to the limit input signal is lit, back to the hammer in place is lit.
If the manual action is not normal, it should be checked and excluded first.
5、Can not adjust the mold
The mold adjustment should be carried out in the no-load state (i.e. open mold state), the possible causes of mold adjustment failure are
(1) the mold opening is not terminated, mold conditions are destroyed
Troubleshooting: Refer to the troubleshooting method of not opening the mold to eliminate the related problems
(2) The electric eye counting failure
Exclusion: a. Check whether the electric eye has signal output or is damaged and failed? b. Check whether the installation of the corresponding mechanical parts of the electric eye is loose, induction distance improperly adjusted, etc. caused by the inductive failure of the electric eye, inaccurate counting?
(3) overload the mold motor
Exclusion: a. Check whether the relevant mechanical parts are damaged or jammed and caused by over-current protection? If yes, then replace the relevant parts or repair. b. Check whether the three-phase power supply is out of phase or voltage instability and caused by over-current protection relay tripping?
(4) Mechanical failure
Exclusion: Check the sprocket, chain drive system for jamming or parts damage, to be excluded
Inspection and analysis: select the mode of operation of the mold adjustment, the machine can not achieve the mold movement, should check the following:
(1) whether the conditions of mold movement are met. (2) Whether the setting of mold pressure is too low. 3) Whether the manual operation mode is correct.(4）If there is no problem with the above content check, then check the following content:①Whether the mold adjusting hydraulic motor is stuck or whether the mold adjusting motor is damaged.②Whether the hydraulic valve spool is stuck.
(3) Whether the transmission vice of the mold adjusting mechanism is worn or stuck.
6, The whole machine no action
Inspection and analysis: after starting the oil pump, the whole machine manual, automatic are no action, hand press the pressure button (pressure, flow has been set parameters) to see if there is pressure.
1、If there is no pressure, then check
(1) whether the rectifier board is damaged or fuse burned out. (2) P01 board input and output is normal.
(3) Check whether the proportional relief valve is properly adjusted or damaged or stuck. (4) Whether the computer is working normally. (5) whether the pressure dial code is damaged, whether the line is normal, or whether the pressure flow setting is too small.
2、If there is pressure, check
(1) whether the fourteen-way amplifier board is normal.
(2) whether all oil valve line 0V wiring is normal.
7、Not lock the mold
Check and analysis: Close the safety door, press the lock button (if the mold is equipped, choose slow speed to avoid crashing the mold), observe whether the lock indicator on the electrical box panel is on or whether the main computer has a lock signal output.
1、If there is no signal output, check
(1) whether there is signal input, no signal input, then check the external circuit.
(2）Whether the ejector pin is back, the ejector pin can not be locked if it is not back.
(3）Lock the mold in place to confirm whether the limit switch (Ji system) is damaged.
(4) If the locking conditions are met and there is no locking signal output, the computer is damaged.
2、The computer has signal output, but still does not lock the mold, then check
(1) whether the clamping pressure is normal (press the clamping button to observe the pressure value on the pressure gauge).(2) whether the 14-way amplifier board is normal (the input and output lights are on at the same time when working).(3) Whether the normal slow speed valve is properly adjusted or damaged, and whether the open clamping valve is improperly adjusted or damaged. (4) Check whether the line connection from the electric box clamping output to the oil valve is normal, and whether the clamping solenoid valve coil is normal.(5) whether the clamping cylinder is damaged.
8、No low pressure mold locking
Inspection and analysis: Observe whether the low-pressure mold lock indicator on the electrical box panel is on.
(1）If the light is not on, check the low-pressure mold locking induction switch to see if it can be sensed or has been damaged.(2) If the light is on, check whether the low-voltage dial code is well adjusted or damaged.
9、No high pressure clamping
Inspection and analysis: If there is no high pressure when the clamping movement to the high pressure induction switch, check whether the high pressure induction switch is damaged or sensed, the total pressure setting is too low and there is no high pressure clamping.
10. No constant speed clamping mold
Inspection and analysis: observe the computer with or without constant speed input and output.
(1) The computer does not have constant speed input, then check whether the line from the external constant speed selection knob to the computer is normal.(2) If the computer has input and no output, the computer is faulty.(3) If the computer has input and output, check: whether the 14-way amplifier board works normally; whether the line from the 14-way amplifier board to the oil valve is normal; whether the oil valve coil is damaged.(4) The normal speed hydraulic valve spool is stuck by a foreign body or the normal speed flow is too smal