(1) Is the finished product incomplete?
Why did it fail? job operation
Plastic temperature is too low? Is the temperature of the melting pot rising too low? Is it enough to increase the injection pressure and injection volume? Increase the amount of glue injected
Improper matching between sprue sleeve and nozzle, plastic overflow? Is it too short to readjust its coordination before shooting? Increasing the injection time is too slow? Improper adjustment of low pressure to speed up glue injection? Is it too low to readjust the mold temperature? Raise the mold temperature. Is the mold temperature uneven? Poor exhaust of readjusted mold water pipe mold? Is the nozzle temperature not low at a proper position of the exhaust hole? Improve nozzle temperature and uneven glue feeding? Is the runner or overflow at the overflow position of re-opening the mold too small? Is there enough lubricant in the plastic to increase the flow passage or overflow? Increasing lubricant backpressure is insufficient? Slightly increase back pressure
Wear of apron and glue melting screw? Disassembly, inspection and repair of insufficient glue injection? Is it too thin to replace the injection molding machine products with larger specifications? Spray glue with nitrogen?
(2) What is the cause of shrinkage failure? Treatment method: insufficient mold glue and insufficient melt glue? Is the injection pressure too low? High injection pressure and insufficient back pressure? High back pressure glue injection time is too short? Long glue injection time and slow glue injection speed? Fast emissivity
Unbalanced overflow? Chip overflow is too small or misplaced.
The nozzle hole is too thin, and the plastic solidifies in the runner bushing, which reduces the back pressure effect. ? Is the temperature of the material replaced by the whole mold or nozzle too high? Is the mold temperature inappropriate when the material temperature is low? Is there enough cooling time at the right temperature? Too many pressure storage sections with delayed cooling time? The glue injection end meets the front end.
Is the product itself or its rib column too thick? Review the finished product design
Too much glue? Replace the thinner injection molding machine with a rubber ring, and the glue melting screw is worn? Demolition and overhaul
What is the back pressure caused by the solidification loss of plastic when the gate is too small? Increase gate size?
(3) What is the reason for the failure of die bonding of finished products? job operation
Filler is too full? Reduce the injection pressure, time, speed and injection quantity. Is injection pressure too high? Reduce the injection pressure. Overinjection? Reduce the amount of glue injected. Is the injection time too long? Is the material temperature too high when shrinking the injection chamber? Reduce the feed temperature
Uneven feeding makes some of them full? Change the size or location of the overflow. Is the mold temperature too high or too low? Adjust the mold temperature and the relative temperature on both sides. Does the mold have a demoulding chamfer? Repair the die to remove the uneven surface of the chamfering die? Polishing die
Vacuum caused by demoulding? Is the mold opening or ejection slow, or the injection cycle of the mold and air intake equipment is too short? Insufficient release agent to strengthen cooling? Slightly increase the dosage of release agent.
(4) What is the reason why the runner (nozzle) sticks to the mold? Treatment: the injection pressure is too high? Reduce the injection pressure. Is the plastic temperature too high? Reduce the temperature of plastic. Is the runner too big? Modify the mold
Is the runner not cooled enough? Is it enough to extend the cooling time or reduce the cooling temperature? Modify the mold to increase the angle. Is the sprue sleeve and nozzle not matched correctly? Re-adjust the inner surface of the matching runner, not only or with demoulding chamfer? Is there any damage to the outer hole of the gate of the maintenance mold? Overhaul the mold without runner pin? Add lock pin
Filler is too full? Reduce the injection amount, time and speed. Insufficient release agent? Slightly increase the dosage of release agent?
(5) What are the causes of burr and flash failure? job operation
Plastic temperature is too high? Reduce the temperature of plastics and molds. Is the injection speed too high? Slow down the injection speed. Is injection pressure too high? Reduce the injection pressure. Is the filler too full? Reduce injection time, speed and dosage. Is the line clamping or the anastomosis surface not good? Overhaul mold
Insufficient clamping force? Increase the clamping pressure or replace the injection molding machine with higher mold pressure.
(6) Is the finished product broken during mold opening or ejection? Why did it fail? How to deal with it? Is the package too full? Reduce injection pressure, time, speed and injection volume. Is the mold temperature too low? Is the demoulding angle enough to increase the mold temperature? Does the maintenance mold have a demoulding chamfer? Overhaul mold
Can't the finished product be balanced when demoulding? Insufficient or inappropriate position of trimming thimble? Overhaul mold
Local vacuum phenomenon occurs during demoulding? Can the mold opening be ejected slowly, and the release agent of the air inlet equipment is insufficient? Slightly increase the dosage of release agent.
Poor mold design and excessive stress in finished products? Is the timing or position of the side slider inappropriate in the improved finished product design? Overhaul the mold?
(7) combination line?
Why did it fail? job operation
Poor melting of plastic? Increase plastic temperature, increase back pressure and speed up screw rotation. Is the mold temperature too low? Raise the mold temperature. Is the nozzle temperature too low? Increase the nozzle temperature too slowly to inject glue? Increase the injection speed and the injection pressure is too low? Increase the injection pressure. Is the plastic unclean or has it infiltrated into other materials? Check whether there is too much plastic demoulding oil? Use less mold oil or try not to use runner and overflow. Is it too big or too small? Is the joint of mold adjustment and glue melting too far from the gate? Adjusting mould
Can't the air in the mold be excluded? Add vent holes or check whether the original vent holes are blocked and the amount of glue melted is insufficient? Too much mold release agent for larger injection molding machines? Do not use or reduce release agent?
(8) Flow pattern?
Why did it fail? job operation
Poor melting of plastic? Is the mold temperature too low to improve the plastic temperature, back pressure and screw speed? Raise the mold temperature. Improper mold cooling? Re-adjust the mold water pipe
Is the injection speed too fast or too slow? Adjust the appropriate injection speed. Is injection pressure too high or too low? Adjust the appropriate injection pressure. Is the plastic unclean or has it infiltrated into other materials? Check whether the plastic spill is too small to produce radiation? Amplification overflow
Is there a big difference in section thickness of finished products? Change the finished product design or overflow position?
(9) What is the reason for the unqualified matte finish? Solution: Is the mold temperature too low? Raise the mold temperature
Insufficient plastic dose? Increase injection pressure, speed, time and dosage. Is there too much demoulding oil in the mold cavity? Is it appropriate to wipe clean plastic? Is there any water on the inner surface of the improved drying mold? Wipe to check whether there is water leakage. The inner surface of the mold is not smooth. Polishing the mold?
(10) What are the causes of crazing and bubbles? job operation
Does plastic contain water? The plastic is completely dried and the back pressure increases.
Plastic temperature is too high or plastic stays in the barrel for too long? Reduce the temperature of plastic, replace the injection molding machine with smaller injection volume, and reduce the temperature of nozzle and front section. Other additives in plastics, such as lubricants and dyes, will decompose? Reduce its usage or replace it with a substitute with higher high temperature resistance. Other additives in plastics are not evenly mixed? Stir thoroughly and evenly, and the glue injection speed is not fast? Slow down the injection speed. Is injection pressure too high? Reduce the injection pressure. Is the melting speed too slow? Is the mold temperature too low to improve the melting speed? Improve the speed of the mold. Is the thickness of plastic particles uneven? Using granular homogeneous raw materials
There's air in the melting pot? Is it wrong to reduce the temperature in the back section of melting cylinder, increase back pressure and reduce the length of compression section? Adjust the size and position of the overflow port to keep the average mold temperature and the average thickness of the finished product?
(1 1) What is the reason for the deformation failure of the finished product? job operation
Hasn't the finished product cooled on it yet? Reduce the mold temperature, prolong the cooling time and reduce the plastic temperature. Is the plastic temperature too low? Increase the temperature of plastics and molds.
Is the shape and thickness of the finished product asymmetrical? The mold temperature is controlled in different areas. After demoulding, it was fixed with a fixing frame, which changed the molding design. Too much filler? Reduce the injection pressure, speed, time and dosage. How much flash is uneven? Change the imbalance of overflow thimble system? Improve the uneven temperature of the mold in the ejection system? Adjust the mold temperature
Is the plastic near the overflow too loose or too tight? Increase or decrease the injection time. Bad pressure keeping? Increase the holding time?
(12) What is the reason for the porosity in the finished product? job operation
The amount of filler is not enough to prevent the finished product from shrinking excessively.
Is the finished section, rib or column too thick? Change the finished product design or overflow position. Is the injection pressure too low? Increase injection pressure
Insufficient glue injection amount and time? Increase the amount and time of glue injection. Is the overflow of the runner too small? Is it too fast to increase the injection speed of runner and overflow? Slow down the injection speed. Does plastic contain water? The plastic is completely dry.
Plastic is too hot to decompose? Reduce the temperature of plastic.
Uneven mold temperature? Adjust the mold temperature
Cooling time is too long? Reduce the cooling time in the mold, and use the water bath to cool the water bath too fast? Is it enough to reduce the water bath time or increase the back pressure of water bath temperature? Increase back pressure
Is the temperature of the glue melting cylinder not suitable? Is the plastic shrinkage too large by lowering the nozzle and front section temperature and raising the rear section temperature? Use other plastics that shrink less?
(13) Black stripes?
Why did it fail? Treatment method of plastic overheating
Plastic temperature is too high? Reduce the plastic temperature, melt the glue too fast? Reduce the injection speed
The screw is eccentric with the glue melting cylinder, resulting in great friction heat? Is the nozzle hole of overhaul machine too small or too hot? Re-adjust aperture or temperature. Too much glue? Replace the smaller injection molding machine
Is there a corner of the glue melting cylinder that makes the plastic overheat? Check the contact surface between the nozzle and the glue melting cylinder for cracks or corrosion.
(14) black spots?
Why did it fail? job operation
Is the overheated part of the plastic attached to the inner wall of the glue melting cylinder? Thoroughly air-dry, remove the melting hose and clean it, reduce the plastic temperature, shorten the heating time and strengthen the plastic drying treatment. Plastic is mixed with sundries, scraps of paper, etc. Check the plastic and shoot it completely empty.
Will it produce focal spots when injected into the mold? Reduce the injection pressure and speed, reduce the plastic temperature, strengthen the vent hole of the mold, close the molding service as appropriate, and change the overflow position. Is there an angle in the melting hose that makes the plastic overheat? Check whether the contact surface between the molten rubber cylinders of the nozzle has gaps or corrosion. ?
(15) unstable period
Most of the forming shortcomings listed above are related to the stability of the cycle. Proper plasticization of plastics in the furnace or temperature control of molds is the result of heat transfer balance. That is to say, in the whole injection cycle, the plastic in the glue melting cylinder receives the friction heat generated by the rotation of the screw and the heat generated by the electric heating coil. Heat energy is injected into the mold with the plastic, and the heat energy of the mold comes from the constant device of the plastic and the mold, which is lost when the finished product is demoulded, lost in the air or taken away by cooling water. Therefore, if we want to keep the temperature of the glue melting cylinder or mold constant, we must keep the balance of heat transfer in and out. To maintain the balance of heat transfer, it is necessary to maintain a certain stable injection cycle. If the injection cycle time is shorter and shorter, the heat energy in the glue melting cylinder is not enough to melt the plastic, and the heat energy in the mold is more than enough, so the temperature of the mold will continue to rise. On the contrary, it has the opposite result. Therefore, in any injection operation, especially manual operation, it is necessary to control the stable cycle time and try to avoid different speeds. If other conditions remain unchanged, the acceleration of the cycle will cause: insufficient injection, shrinkage and deformation of the finished product, and mold sticking. ?
The delay of the cycle will cause flash, burr, mold and finished product deformation, plastic overheating and even burning, and the coke left in the mold may cause mold damage. Overheated plastic in the furnace may corrode the furnace, and black spots and black lines may appear in the finished product.