1. Basic structure and function of injection molding machine
The most common types of injection molding machine are plunger type and screw type. Screw type injection molding machine is commonly used in these two types. Screw type injection molding machine is composed of mold closing system, plasticizing system, heating and cooling system, hydraulic system, lubrication system, electric control system, safety protection and monitoring system, etc.
① Mold closing system:
The function of the die closing system is to fix the die and make the moving die move to open and close the die and lock the die.
② Plasticizing injection system:
The main function of the plasticizing injection system is to plasticize the material and inject the molten material into the closed mold with a certain amount of pressure.
③ Heating and cooling system:
The function of heating and cooling system is to make the temperature of barrel and nozzle reach the best melting temperature of processed materials. The cooling system of injection molding machine is used to cool hydraulic oil, while the cooling system of barrel generally adopts the method of fan cooling.
④ Hydraulic system:
The role of the hydraulic system is to provide pressure and speed in each actuator (hydraulic cylinder) of the injection molding machine, so that it can complete the specified action.
⑤ Lubrication system lubrication system:
The function of the lubrication system is to reduce friction and wear between the relative movements of the moving parts of the injection molding machine, to ensure the normal operation of the working parts and to extend the service life of the parts.
⑥ Electric control system:
The function of the electronic control system is to control all kinds of actions of the injection molding machine, and to realize the adjustment and control of time position, pressure, speed and rotation speed.
⑦ Safety protection system:
The main function of the safety protection device of injection molding machine is to protect the safety of injection molding equipment and the personal safety of operators.
2. Maintenance and general rules of injection molding machine
① Fault classification of injection molding machine
A. According to the state of fault occurrence, it can be divided into gradual fault and sudden fault.
Gradual failure: most of the failures of injection molding machine caused by the gradual reduction of the initial performance of injection molding machine belong to this kind of failures, such as wear, corrosion and fatigue of various functional parts such as machinery.
Sudden failure: it occurs under the condition of joint action of various adverse factors and accidental external influences. For example: foreign matters fall into the hopper, or operation error, illegal operation.
B. According to the nature of fault occurrence, it can be divided into intermittent fault and permanent fault
Intermittent fault: some components lose some functions, which can be recovered after simple repair and debugging without replacing components. Permanent failure: some components lose their functions and can only work after repair or replacement of parts.
C. According to the cause of the fault, it can be divided into wear fault and misuse fault
The wear failure is due to the normal wear of injection molding machine, which leads to the loss of function of some parts, leading to the loss of function of some parts. Misuse fault is caused by operator's fault and improper maintenance.
D. According to the danger of failure, it can be divided into dangerous failure and safety failure
Dangerous fault: it refers to the fault (such as safety device) that causes great danger to equipment or human body after some parts lose function. Safety fault: generally, it refers to the fault that does not have joint damage to equipment and does not cause danger to human body.
D. According to the occurrence and development rules of injection molding machine faults, it can be divided into random faults and regular faults
Random fault: there is no certain rule to find.
Regular faults: the events follow certain rules, and each fault has its own specific mode, with its main characteristics; the following are classified:
Abnormal vibration, mechanical wear, signal cannot be transmitted or processed, mechanical hydraulic components are broken
Linear maladjustment of proportional valve, hydraulic leakage, abnormal hydraulic pump, hydraulic noise, line aging, oil
Quality deterioration, abnormal pressure drop, out of control temperature and no output of the amplifier.
2、 Maintenance and regular maintenance of injection molding machine
The maintenance of injection molding machine is to change the sudden shutdown and failure into predictable and planned shutdown or overhaul, and to prevent the interlocking failure.
The maintenance of injection molding machine is divided into complete machine maintenance, plastic part maintenance, mold closing part maintenance, hydraulic system maintenance and electrical control system maintenance.
1. The whole machine maintenance can be divided into daily maintenance and regular maintenance
① Daily inspection and maintenance items of injection molding machine
A. Check whether the emergency stop button is normal
B. Check whether the triple interlocking safety protection device of electrical, mechanical and oil pressure is normal, operate the manual, semi-automatic and full-automatic mode locking actions respectively, and open the safety door for 30mm to test whether the mode locking action can stop.
C. Check whether the oil supply of each part of the central lubricating oil feeding device is sufficient.
D. Check whether the heating cylinder and temperature control are normal.
E. Check whether the working pressure of oil pressure system is too high.
F. Check whether the mold is firmly installed.
② Weekly inspection and maintenance
A. Check whether the screw of the stopper and contact is loose, and whether the screw of the mould and moving parts is fastened.
B. Check all parts of the fuselage for oil leakage, trace the cause of the oil leakage and replace the seals accordingly.
C. Inspection of cooler.
③ Monthly inspection and maintenance
A. Check whether the electrical components and wiring are loose
B. Check the working condition of heating ring, whether it is loose, whether there is resin and whether the skin is damaged.
C. Check whether the hydraulic oil is polluted or wet, and clean the oil screen.
D. Check the linear proportion of the pressure and flow of the electronic amplifier, and readjust it if necessary.
E. Clean and scrub the whole machine.
④ Check and maintain cleaning items every year
A. Check whether the hydraulic oil is clean and has bubble pollution, etc.: generally, the new machine is