Plastic Molding Machine

Plastic molding machine is a kind of machine for plastic product. The molten plastic is injected into the plastic product mold by pressure, cooled and molded to obtain all kinds of plastic parts. There is a special mechanical plastic molding machine for injection molding. At present, the most commonly used plastics are polyethylene, ABS, PA, etc.

What are the common faults in the injection part of plastic molding machine?

1. ZOWEITE® Plastic molding machine cannot spray glue

●The nozzle is blocked by foreign matters. Check whether the nozzle is blocked, clean or replace the nozzle

●The dispensing nozzle is broken. Disassemble the flange, check whether the rubber separating nozzle is broken, and replace the rubber separating nozzle.

●The glue injection direction valve is stuck. Check whether the directional valve has 24V voltage and the coil resistance is 15-20 ohms. If it is normal, the valve is blocked. Clean the valve or replace the directional valve.

●The rubber injection piston rod is broken. Loosen the nut of the injection piston rod and check whether the piston rod is broken. Replace the piston rod.

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

●The rubber injection piston oil seal is damaged. Check whether the piston oil seal is damaged and replace the oil seal.

2. The sound of plastic molding machine is loud

●The glue injection speed starts too fast. Observe the change of starting speed of glue injection. Adjust the glue injection flow and speed.

●If there is air in the oil circuit, observe whether there is vibration in each action.

3. The sound is loud when the plastic molding machine stops the sol transfer.

●The action switching speed is too fast during glue injection. Check whether the nozzle increases the pressure holding, increase the pressure holding, adjust the glue injection stage, and add sol delay.

4. The injection quantity of plastic injection molding machine is unstable

●The oil cylinder oil seal is worn, and observe the pressure holding condition of the pressure gauge. Replace the oil seal.

●The rubber separating nozzle and rubber ring are worn. Use the nozzle twice to detect and replace the glue melting cylinder

5. Semi automatic non injection action of plastic molding machine

●The forward of the shooting platform is not terminated. Check whether the front of the shooting platform or the mode locking travel switch is normal. Check the circuit and travel switch.

●Break the line. Check the wiring. Rewire.

●Mode locking zeroing. When the machine hinge is straightened, the position is 0. Readjust the zero position of the electronic ruler.

6. When the plastic molding machine works semi / fully automatically, the barrel temperature gradually exceeds the set value.

●The speed of glue melting is too fast. Use a tachometer to test whether the screw speed is too fast. Reduce the melt speed.

●Excessive back pressure. Observe the table value of the back pressure of the product and reduce the back pressure as much as possible

●Friction between screw and barrel. Remove the screw and barrel and check the wear. Replace the barrel or screw.

●Improper temperature setting. Check whether the actual temperature is too low. Reset the temperature.

●Plastic is subjected to excessive shear heat. Check the temperature rise of the front and middle sections. Reduce melt speed and back pressure.

7. Screw ring when plastic molding machine melts glue.

●Improper installation of drive shaft. Separate the screw and check whether there is sound. If so, remove the plane bearing. Reassemble

●The plane bearing is broken. Separate the screw and check the rotating part for noise. Replace the plain bearing.

●The screw is bent. Remove the screw for inspection. Replace the screw.

●The screw has iron filings. Disassemble the screw for inspection. Clean the screw.

●Check the coaxiality of the adjusting screw with a dial indicator. The runout around 0.05mm is normal.

8.ZOWEITE®  Plastic molding machine cannot melt glue

●Burn shaft or drive shaft burst. Separate the screw rod, re melt the glue and observe the sound. Replace the bearing.

●The screw has iron filings. Separate the screw from the barrel and check whether there are iron filings on the screw. Remove the screw and clean it.

●The melt valve is blocked. Top the valve core with a hexagonal key to see if it moves. Clean the solenoid valve.

●Glue motor damage: separate the glue motor when the glue does not rotate. Replace or repair the sol motor.

●Burn out the heating ring. Check whether it is normal with a multimeter. Replace the heating ring.

●The plug is loose. Check whether the glue oil plug has poor contact. Tighten the plug. And check whether there is 24 power supply.

9. Plastic injection molding machine back pressure cannot be adjusted during sol

●The back pressure valve is broken. Increase the back pressure during blanking. Check whether the screw retreats. Clean the back pressure valve

10. The product has black spots

●The screw has carbon deposit. Check and clean the screw and barrel.

●There is carbon deposit in the barrel and the auxiliary machine is not clean. Check the feeder for dust. Polishing barrel and cleaning auxiliary machine.

●Corrosion of rubber separating nozzle assembly. Check the dispensing nozzle. Replace the dispensing nozzle assembly.

●Carbon deposit on flange and nozzle. Clean and replace.

●Raw materials are dirty, check the raw materials and replace the raw materials.

●The temperature is too high and the melt back pressure is too high. Check the temperature of each section. Reduce temperature and back pressure.