Vertical injection molding machine is a mechanical device. It is usually composed of injection system, mold clamping system, hydraulic transmission system, electrical control system, lubrication system, heating and cooling system, safety monitoring system, etc.

Structure and function

After the injection is completed, the molten material injected into the mold cavity is kept in shape. Composition of injection system: The injection system consists of a plasticizing device and a power transmission device. The plasticizing device of a screw injection molding machine mainly consists of a feeding device, a barrel, a screw, and a nozzle. The power transmission device includes an injection cylinder, an injection seat moving cylinder, and a screw drive device (melt motor).

(1) Injection system The function of the injection system: The injection system is one of the most important components of an injection molding machine. Generally, there are three main forms: plunger type, screw type, and screw pre-plastic plunger injection type. The most widely used one at present is the screw type. Its function is to heat and plasticize a certain amount of plastic within a specified time in one cycle of the injection molding machine, and then inject the molten plastic into the mold cavity through the screw at a certain pressure and speed.

(2) Clamping system The function of the clamping system is to ensure the closing, opening and ejection of the mold. At the same time, after the mold is closed, it provides sufficient clamping force to resist the cavity pressure generated by the molten plastic entering the cavity, prevent the mold from opening, and cause the product to be in a bad state. Composition of the clamping system: The clamping system is mainly composed of a clamping device, a mold adjustment mechanism, an ejection mechanism, front and rear fixed templates, a mobile template, a clamping cylinder and a safety protection mechanism.

(3) Hydraulic system The function of the hydraulic transmission system is to provide power for the various actions required by the process of the injection molding machine and meet the pressure, speed, temperature and other requirements of each part of the injection molding machine. It is mainly composed of various hydraulic components and hydraulic auxiliary components, among which the oil pump and motor are the power sources of the injection molding machine. Various valves control the oil pressure and flow, thereby meeting the various requirements of the injection molding process.

(4) Electrical control system The electrical control system and the hydraulic system cooperate reasonably to realize the process requirements (pressure, temperature, speed, time) and various program actions of the injection molding machine. It is mainly composed of electrical appliances, electronic components, instruments, heaters, sensors, etc. There are generally four control modes: manual, semi-automatic, fully automatic, and adjustable.

(5) Heating/cooling system The heating system is used to heat the barrel and injection nozzle. The barrel of the injection molding machine generally uses an electric heating ring as a heating device, which is installed on the outside of the barrel and detected in sections with a thermocouple. The heat is conducted through the barrel wall to provide a heat source for the plasticization of the material; the cooling system is mainly used to cool the oil temperature. Excessive oil temperature will cause a variety of faults, so the oil temperature must be controlled. Another location that needs cooling is near the discharge port of the material pipe to prevent the raw material from melting at the discharge port, resulting in the failure of the raw material to be discharged normally.

(6) Lubrication system The lubrication system is a circuit that provides lubrication conditions for the relatively moving parts of the injection molding machine, such as the moving platen, mold adjustment device, connecting rod hinge, etc., in order to reduce energy consumption and increase the life of parts. Lubrication can be regular manual lubrication or automatic electric lubrication.

Classification

1. Vertical AC/DC injection molding machine series: This model is mainly used for the injection molding of connecting wires, various electronic and computer data cables, and power plug cables. The injection molding products do not require high precision standards. Generally, PVC, PE and other plastic materials are used as the main injection molding. The specific applicable machine model specifications for this product generally range from 15T to 35T. Because the specific mold capacity and configuration of each manufacturer's machine model are different, you must ask the manufacturer to come to the factory to determine the specific parameters and specifications of the model before purchasing.

2. C-type injection molding machine series: This machine has vertical clamping and horizontal injection. It has no guide pillars and is named because the clamping part forms the English letter "C". The machine has a complex structure and a large injection volume. Because it has no guide column and a wide working area, it is mainly suitable for various safety power plug injection molding, such as French plugs, American plugs, British plugs, etc.

Three, vertical single slide injection molding machine, double slide injection molding machine series: This machine is mainly for engineering plastics, products with strict precision requirements, precision or small embedded parts are injection molded together, and it is also one of the most optimized molding solutions for embedded parts injection molding. Because the machine has the function of upper mold fixing and lower mold sliding out. The double slide type has one upper mold and two lower molds, and the two molds work alternately, which is more suitable for embedding or removing precision hardware. Some two-color molds can also be used for double-slide injection molding. Generally, molded products, such as electronic precision connectors, mobile phone connectors, integrated circuit components, etc., have the disadvantages of double slides: two working positions, which increases labor costs.

Fourth, vertical disc injection molding machine, rotary series: vertical disc injection molding machine rotary series can be said to be the most optimized solution for precision parts embedded injection molding and two-color mold, because the machine can be designed with one upper mold and two lower molds or multiple lower molds, which is more suitable for complex embedding and labor saving

Five, vertical and horizontal injection molding machines. Vertical and horizontal injection molding machines can be used for hardware rubber-coated inserts with large glue volume and must be locked with vertical structure. Because the vertical structure is convenient for inserts and the horizontal structure has a large amount of glue, it is a product that the market needs to combine vertical and horizontal structures.

Operation procedures

Preparation

1.1. Check whether all parts of the machine and the electrical control box are in good condition.

1.2. Check the oil level of the hydraulic oil, whether the oil storage is sufficient, start the motor and observe whether the oil output of the axial piston valve is normal.

1.3. Open the cooling water valve to connect the cooling water.

Operation

2.1¡¢Mould installation: Push the mold transfer mechanism to the highest position, install the plastic mold on the mobile template, unscrew the fixed template, calibrate the upper mold and the fixed template of the plastic mold and tighten the screw, fasten the lower mold of the plastic mold to the mobile template, operate the mold transfer mechanism, and check whether the mold position is correct.

2.2¡¢Barrel heating: Turn on the electric heating switch of the electrical control box, add plastic into the barrel, and fully heat it to melt the plastic.

2.3¡¢Injection molding operation: Turn on the solenoid valve 8 to make the mold transfer mechanism rise and close the plastic mold, and turn on the solenoid valve 6 to press the injection plunger into the barrel for injection molding. After the injection molding is completed, turn on the solenoid valve 6 to press the injection plunger out of the barrel, turn on the solenoid valve 8 to make the mold transfer mechanism descend, and then the plastic mold can be opened and demolded.

Maintenance and maintenance

3.1¡¢Check whether the hydraulic oil storage is sufficient. If it is insufficient, it should be replenished in time, and the oil should always be kept clean.

3.2. Lubrication points should be lubricated regularly according to regulations, and the oil filter should be cleaned regularly. Keep the area around the machine clean and do not allow dirt to enter the oil tank.

3.3. After use, the dirt on the machine should be wiped clean, and the smooth surface should be oiled.

3.4. Regularly check the electrical parts, remove dirt, oil and dust, keep the electrical contacts clean, and frequently remove dirt and dust from the joints.

Injection molding machines have been repaired for a long time. In the maintenance work, we have accumulated rich experience. Common problems

Common fault problems

Mold locking part fault

(I): No mold locking treatment method:

1): Check the travel switch before the safety door and repair it.

2): Check the 24V5A power supply in the electrical box, replace the insurance and power box.

3): Check whether the valve core is stuck and clean the valve core.

4): Check whether the I/O board has output and whether the solenoid valve is energized.

5): Check whether the hydraulic safety switch is pressed and whether the mechanical lock rod baffle is open.

(II): How to deal with the noise of the mold opening and closing machine:

1): Check whether the lubricating oil pipe is disconnected. If so, the oil pipe must be reconnected.

2): The amount of lubricating oil is small. Increase the amount of lubricating oil. It is recommended to oil 50 molds once or add enough lubricating oil manually.

3): The clamping force is large. Check whether the mold needs a large clamping force and lower the clamping force.

4): The current of the enlarged plate is adjusted disorderly. Check whether the current parameters meet the acceptance criteria and readjust the current value.

5): The parallelism is out of tolerance. Use a dial indicator to check whether the parallelism of the first two plates is greater than the acceptance criteria; adjust the parallelism.

(III): Wait a few seconds before opening the mold. How to deal with it:

1): The starting speed is slow. Check whether the screw damping is too large and reduce the screw damping hole.

2): The middle hole of the damping screw is too large. Check whether the damping of the Y-hole screw is too large, and replace the damping screw with a thin center hole.

(IV): Treatment method for mold opening and locking creeping:

1): The two-plate guide rails and the Corinthian column are worn out. Check the two-plate guide rails and the Corinthian column, replace the two-plate copper sleeves, the Corinthian column, and add lubricating oil.

2): The mold opening and locking speed pressure is improperly adjusted. When the flow rate is set to 20 and the pressure is 99, the mold locking two plates should not creep. Adjust the flow proportional valve hole, or the pilot valve hole, and adjust the proportional valve linear current value.

3): There is air in the pipeline and the oil cylinder, exhaust.

(V): Treatment method for mold opening and not being able to open:

1): Increase the mold opening and locking speed. The pressure and flow are too small and not adjusted well. Check whether the mold opening and locking speed and pressure are appropriate. Increase the mold opening and locking pressure and speed.

2): The zero position of the mold locking electronic ruler changes. Check whether the mold locking straightening machine ends at the zero position after twisting, and readjust the zero position of the electronic ruler.

3): Check whether it is reversed.

(Six): The mold adjustment will become tighter or looser during automatic production. Treatment method:

1): The mold adjustment solenoid valve leaks internally. Check whether the solenoid valve is "O" type, replace the solenoid valve or whether the solenoid valve is powered by 24V when it is not working.

2): Whether there is mold adjustment action when other actions are manually played, and see if the valve is stuck.

(Seven): After the mold is locked, when other actions are working, the mold is opened slowly and automatically. Treatment method:

1): The oil plate leaks, check or replace the express mold locking valve, and replace the oil plate.

2): The mold opening valve leaks, start the oil pump and the mold locking ends, press the shooting table or the injection action, whether the two plates move back, and replace the mold opening oil valve. Normally, the mold opening and locking does not move.

(VIII): When the mold is locked, only the mold opening action is handled:

1): Wrong wire connection, check whether there is 24VDC to the valve, check the line and connect the wires.

2): The valve is stuck or the valve core is installed incorrectly, check whether the valve core is installed incorrectly or blocked, reinstall the valve core or clean it. Under normal circumstances, the mold opening and locking action is motionless.

(IX): The solution for poor mold locking:

1): Improper adjustment of A and B holes, set the system flow 20, pressure 99, observe whether the mold locking action is creeping, readjust or change the valve.

2): There is air in the oil circuit, listen for air sound in the oil circuit, check whether there are bubbles in the oil, and exhaust is required.

3): The amplifier board is improperly adjusted to rise and fall, observe whether the current value of the ammeter is proportional to the rise and fall changes or the speed, and adjust the amplifier board.

(Ten): The clamping mold cannot withstand high pressure, and the treatment method for exceeding the stroke is:

1): The limit switch exceeds the limit, check whether the mold adjustment is appropriate, adjust the appropriate mold thickness; check whether the motor is in normal state.

2): The hydraulic limit exceeds the stroke, whether the electronic ruler stroke position is appropriate, check whether the mold adjustment is appropriate, and adjust the mold forward appropriately.

(Eleven): Manual mold opening termination, semi-automatic mold opening termination treatment method:

1): The mold opening valve leaks, the manual shooting table moves after, observe whether the two plates retreat, and replace the mold opening valve.

2): Check the maximum stroke and pressure flow of the electronic ruler.

(Twelve): No ejector action treatment method:

1): The ejector limit switch is broken, use a multimeter to check whether the 24V proximity switch is on. Replace the ejector limit switch.

2): Stuck valve, use a hexagonal key to press the ejector valve core to see if it can move, clean the pressure valve

3): The ejector limit rod is broken, remove the limit rod by hand after stopping the machine, and replace the limit rod.

4): The ejector switch is short-circuited, use a multimeter to check that the ejector switch has 0 voltage to the ground, and replace the ejector switch.

5): Improper electronic ruler position setting.

(Thirteen): Treatment method for ejector out of control during semi-automatic operation:

1): The ejector plate is broken, check whether the circuit is normal, the normal voltage is DV24V. Repair the ejector plate.

2): The line is broken, fully check the switch connection line and the connection line on the I/O board. Check the line and rewire.

3): Check whether the mold has moved.

4): Whether the cylinder piston rod seal is damaged.

(XIV) Treatment of automatic ejector out of control:

1): Proportional linearity is poor, the opening and closing time position pressure flow is poorly adjusted, check the parameters of the ramp up and ramp down, and adjust the ramp up and ramp down in the parameters.

2): The clamping machine hinge is poorly lubricated, check the Collin column, the second plate slide foot, and the machine hinge lubrication, increase lubrication, and increase the number of oiling times.

3): The mold clamping force is too large, check the clamping force when the mold is stressed, and reduce the clamping force according to the user's product situation. Check whether the time and position are appropriate.

4): Parallelism deviation of the head and second plates, check the parallelism of the head and second plates. Adjust the parallel error of the second plate and the head plate.

5): The setting position of slow to fast mold opening is too small and the speed is too fast. Check whether the position of slow mold opening to fast mold opening is appropriate, and whether the slow mold opening speed is too fast. Lengthen the slow mold opening position and reduce the slow mold opening speed.

(Fifteen): Semi-automatic has two clamping actions. Treatment method:

1): The clamping valve core is not completely reset. Check whether the next action is too continuous after the clamping action is completed.

2): Increase the delay time of the next action.

Mold adjustment part failure

(I): Unable to adjust the mold. Treatment method:

1): Mechanical level and parallelism are out of tolerance. Check with a level ruler. Adjust the parallelism and level. (For large models, small models have little effect)

2): The gap between the pressure plate and the mold adjustment nut is too small. Measure with a feeler gauge. Adjust the gap between the pressure plate and the nut, and the gap between the mold adjustment nut and the pressure plate (gap ¡Ü0.05mm).

3): Burnt nut: Check whether the nut can rotate and heat up and whether there is iron powder coming out. Replace the nut.

4): Adjust the upper and lower support plates. Disassemble the support plate locking nut for inspection. Adjust the adjustment nut.

5): The I/O board is broken. Check whether there is a signal at the output point on the computer page. Repair the electronic board.

6): The mold adjustment valve core is stuck. Remove the valve for inspection. Clean the valve.

7): The mold adjustment motor is broken: Check the oil motor. Replace or repair the oil motor.

Injection part failure

(I): Treatment method for failure to inject glue:

1): The nozzle is blocked by foreign matter. Check whether the nozzle is blocked. Clean or replace the nozzle.

2): The dispensing nozzle is broken. Disassemble the flange to check whether the dispensing nozzle is broken. Replace the dispensing nozzle.

3): The injection directional valve is stuck. Check whether the directional valve has a 24V voltage and a coil resistance of 15-20 ohms. If normal, the valve is blocked. Clean the valve or replace the directional valve.

4): The injection piston rod is broken. Loosen the injection piston rod nut and check whether the piston rod is broken. Replace the piston rod.

5): The barrel temperature is too low. Check whether the actual temperature reaches the required melting point of the material. Reset the barrel temperature.

6): The injection piston oil seal is damaged. Check whether the piston oil seal is broken. Replace the oil seal.

(II): The injection start sound is loud. Treatment method:

1): The injection speed starts too fast. Observe the changes in the injection speed. Adjust the injection flow and speed.

2): There is air in the oil circuit. Observe whether there is vibration in each action.

(III): The sound is loud when the injection ends and turns to melt. Treatment method:

1): The action conversion speed is too fast during injection. Check whether the injection has increased the pressure. Increase the pressure, adjust the injection level, and add melt delay.

(IV): The injection amount is unstable. Treatment method:

1): The cylinder oil seal is worn. Observe the pressure maintenance of the pressure gauge. Replace the oil seal.

2): The glue nozzle and the glue ring are worn. Use the glue injection twice to check. Replace the glue nozzle three-piece set.

3): The barrel is worn. Use the nozzle twice to check, and remove the material tube to check the wear. Replace the melt barrel.

(V): Semi-automatic glue-free action processing method:

1): The shooting platform does not stop moving forward. Check whether the stroke switch before the shooting platform or the clamping mold is normal. Check the circuit and the stroke switch.

2): The line is broken. Check the circuit. Reconnect the wires.

3): The clamping mold is reset to zero. When the hinge is straightened, the position is 0. Re-adjust the zero position of the electronic ruler.

(VI): When semi-/fully automatic working, the barrel temperature gradually exceeds the set value. Treatment method:

1): The melt speed is too fast. Use a tachometer to test whether the screw speed is too fast. Reduce the melt speed.

2): The back pressure is too large. Observe the product and the back pressure gauge value, and reduce the back pressure as much as possible.

3): The screw and the barrel are rubbed. Remove the screw and the barrel and check the wear. Replace the barrel or the screw.

4): The temperature setting is improper. Check whether the actual temperature is too low. Reset the temperature.

5): The shear heat of the plastic is too large. Check the temperature rise of the front section and the middle section. Reduce the melt speed and back pressure.

(VII): The screw makes noise during melt. Treatment method:

1): The drive shaft is improperly installed. Separate the screw and turn to check if there is any sound. If there is, remove the plane bearing. Reassemble.

2): The plane bearing is broken. Separate the screw to check if there is a sound in the rotating part. Replace the plane bearing.

3): The screw is bent. Remove the screw to check. Replace the screw.

4): There are iron filings in the screw. Disassemble the screw to check. Clean the screw.

5): Use a dial indicator to check and adjust the coaxiality of the screw. A jump of about 0.05mm is normal.

(VIII): Treatment methods for failure to melt glue:

1): Burnt bearings or burst transmission shafts. Separate the screw and melt glue again and observe the sound. Replace the bearing.

2): There are iron filings in the screw. Separate the screw from the barrel and check if there are iron filings in the screw. Disassemble the screw to clean.

3): The melt valve is blocked. Use a hexagonal key to push the valve core to see if it moves. Clean the solenoid valve.

4): The melt motor is damaged. Separate the melt motor, and replace or repair the melt motor when the melt does not rotate.

5): The heating coil is burned out. Use a multimeter to check whether it is normal. Replace the heating coil.

6): The plug is loose. Check whether the melt oil plug has poor contact. Connect the plug tightly. And check whether there is a 24 power supply.

(IX): The back pressure cannot be adjusted during melt processing:

1): The back pressure valve is broken. Increase the back pressure when unloading. Check whether the screw is retreating. Clean the back pressure valve.

(X): The product has black spots. Processing method:

1): The screw has carbon deposits. Check and clean the screw and barrel.

2): The barrel has carbon deposits and the auxiliary machine is not clean. Check whether there is dust on the feeder. Polish the barrel and clean the auxiliary machine.

3): The glue nozzle assembly is corroded. Check the glue nozzle. Replace the glue nozzle assembly.

4): Carbon deposits on flange and nozzle. Clean and replace.

5): Raw materials are unclean, check raw materials. Replace raw materials.

6): Temperature is too high, and the back pressure of melt is too large. Check the temperature of each section. Reduce the temperature and reduce the back pressure.

(XI): Treatment method for poor screw color mixing:

1): Material problem. Check the quality of color powder. Replace materials.

2): Temperature is too low. Check the actual temperature and the temperature required by the material. Increase the temperature.

3): Back pressure is too low, check the back pressure. Increase the back pressure.

4): Mixing time is short. Increase the mixing time or replace with a mixing head.

5): Speed is too low. Check the screw speed. Increase the screw speed.

(XII): Treatment method for no glue extraction action:

1): High back pressure. Check the speed of the nozzle spraying glue during manual glue melting. Reduce the back pressure.

2): Broken wire. The glue extraction valve is broken.

3): The spool of the directional valve is not flexible. Use an Allen wrench to press the spool to check whether it moves freely. Clean the spool.

(XIII): When melting glue, the motor swings its tail. How to deal with it:

1): The bearing is broken. Observe whether there is any abnormal sound during melting glue. Replace the bearing.

2): The inclined ball bearing is improperly adjusted. Observe whether the drive shaft swings. Re-adjust the clearance.

3): The screw is deformed. Separate the screw and observe the rotation of the drive shaft. Replace the screw.

4): The copper sleeve of the rear plate of the shooting platform is worn, and the two guide rods are deformed or the fixing screws are loose. Observe whether the copper sleeve of the second plate is ground out of copper powder. Replace the copper sleeve.

(XIV): The glue injection action is twice

1): The nozzle aperture is too small, and the resistance is too large during glue injection.

2): The nozzle heating coil is broken, check the heating coil or replace it.

3): Check whether the pressure flow output is changed.

(Fifteen): Reasons for screw breakage

1): The injection and displacement are not synchronized, adjust the injection and displacement synchronization ¡À0.05

2): The injection cylinder is not synchronized, adjust the injection cylinder synchronization ¡À0.05

3): The raw materials and the injection molding machine screw performance are not compatible.

4): The temperature does not reach the melting point of the material used.

5): Wait until the temperature is just reached before turning the screw.

6): The heating tube is burned out and does not heat up, check whether there is an anti-cold function, and replace the heating tube.

Hydraulic part failure

(I): Hydraulic oil contamination:

1): Air is mixed in the oil. Mainly due to poor sealing of pipe joints, hydraulic pumps, hydraulic cylinders, etc. It is manifested as bubbles on the oil tank.

2): Water is mixed into the oil. The oil will turn milky white. The main reason is that the cooler leaks or the environment is humid.

3): Solid impurities are mixed into the oil. Mainly chips, welding slag, rust flakes and metal powder.

4): Gel-like substances are produced in the oil. The main reason is that the seal is corroded by the oil or the oil is deteriorated, which causes the oil to produce gel-like substances, which often clog the small holes.

(II): What is the effect of temperature on the viscosity of hydraulic oil:

The impact caused: 1): When the temperature rises, the viscosity of the oil decreases. The change in oil viscosity directly affects the performance and leakage of the hydraulic system. (The normal temperature is between 30 and 50¡æ)

(III): Creeping failure:

The cause: 1): Poor lubrication conditions. "Pause-slide-pause" occurs. Increase the amount of lubrication.

2): Air is immersed in the hydraulic system. Exhaust is required.

3): Mechanical rigidity reasons. Wear and deformation of parts cause friction changes and produce creeping. Replace parts.

(IV): After the machine is turned on for a period of time, the oil pump makes noises.

Handling methods: 1): The quality of the oil suction pipe is poor or the throat code is not tightened. Remove the filter screen to check whether it is deformed. Whether the oil suction pipe is layered. Replace the oil pipe and filter screen.

2): The filter screen is not clean. Are there too many impurities in the hydraulic oil? Clean the filter screen.

3): Oil pump wear: Check the wear of the oil pump distribution plate and the end face of the rotor. Replace the oil pump.

(V): After the motor is started, the pressure gauge has pressure but no flow.

Handling methods: 1): The DA board is broken, repair the DA board.

2): The overflow valve is stuck. Remove the overflow valve for inspection, clean the overflow valve or replace the pressure gauge for inspection.

(VI): No pressure flow

1): Check whether the direction of rotation of the motor oil pump is normal.

2): Check whether there is oil leakage.

3): Check whether there is current in the pressure flow valve.

4): Is there any pressure when the hexagon socket is against the pressure valve core? Replace or clean it.

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