塑膠產(chǎn)品注塑成型常見問題及改善對策（Plastic products injection molding common problems and improvement measures）

1、塑膠產(chǎn)品注塑成型常見問題及改善對策（Plastic products injection molding common problems and improvement measures）Cooling the parts in hot water.3, how to avoid product dents and pores?Product dents are usually due to insufficient force on the product, inadequate material filling and unreasonable design of the product.

2、 The dents often appear in the thick wall which is close to the thin wall. The porosity is caused by insufficient plastic in the mold cavity, and the outer ring plastic is cooled and solidified, and the internal plastic shrinks to form a vacuum. Most likely due to the fact that hygroscopic materials

3、 are not dry properly, and that residual monomers and other compounds are present in the material. Determine the cause of the pores, as long as the observation of plastic bubbles in the mold when the instantaneous appearance or cooling occurs. If the mold appears when it is instantaneous, it is most

4、ly the material problem. If it is cooled, it belongs to the mould or injection molding condition.(1) material problems:Drying materialAdd lubricantReduce the volatile matter in the material(2) injection molding conditionInsufficient injection;Increasing injection pressure;Increase injection time;Inc

5、rease the total pressure time;Increasing injection speed;The increase of the injection cycle;The reason causing abnormal operation of the injection cycle.(3) temperature problemToo much material causes excessive shrinkage;The material is too cold, resulting in insufficient compaction;The mold temper

6、ature is too high due to mold wall material can be quickly cured;The mold temperature is too low, resulting in insufficient mold filling;Mould has partial over hot spot;Changing the cooling scheme.(4) die problem;Gate enlargement;Enlarge distributary channel;Increase mainstream road;Increase nozzle

7、hole;Improved mold exhaust;The balance filling rate;The filling material flow to avoid interruption;The gate feeding arrangement of WIP thick wall parts;If it is possible to reduce the wall thickness difference;The mold caused by abnormal injection cycle.(5) equipment problem:Increasing the plastici

8、zing capacity of the injection press;Make the injection cycle normal;(6) cooling conditions:The parts are cooled too long in the mold to avoid contraction from the outside and shorten the cooling time of the mold;Cooling the parts in hot water.How to prevent the product line (joint) product line is

9、usually due to low temperature, the pressure caused by small joints.The problem of temperature:The barrel temperature is too low;The nozzle temperature is too low;The mold temperature is too low;The seams of mold temperature is too low;Uneven temperature of plastic melt.The problem of injection mold

10、ing:The injection pressure is too low:The injection speed is too slow.(3) die problem: seams venting;The component does not exhaust properly; diversion channel is too small; gate is too small;Inlet diameter of three runner is too small; nozzle hole is too small;The gate is too far away from the seam

11、s, can increase the auxiliary gate; products are too thin and cause premature curing; core offset resulting in single edge thin; mold offset resulting in unilateral thinningThe parts in the seams are too thin, thick; filling rate is unequal; die filling flow interruption.(4) equipment problem:The pl

12、asticizing capacity is too small;The pressure loss in the cylinder is too large (plunger type press).Such material:Material pollution;Material fluidity is too bad, add lubricant to improve flowability.5, how to prevent product embrittlement, brittle products often due to material degradation in the

13、injection process, or other reasons.The problem of injection molding: cylinder temperature is low, increase the barrel temperature; nozzle temperature is low, raise it; if the material is easily degraded, then the barrel nozzle temperature will be lowered; improves injection speed; improves injectio

14、n pressure; increases injection time; increases full pressure time; mold temperature is too low to raise it; internal stress, reduce internal stress; parts have joint lines, try to reduce or eliminate; screw speed is too high, and therefore degradation of materials.The mold problem:The product desig

15、n is too thin;Gate is too small;The diversion channel is too small;The products increased reinforcement, round.The material problem:Material pollution;Materials are not dry well;Volatiles in the material;Too much material returning or too much feed in material;Low material strength.The equipment pro

16、blem:The plasticizing capacity is too small;Second, there are obstacles in the barrel, which leads to the degradation of the material.6, how to prevent discoloration of plastic discoloration materials, usually due to burning or degradation, and other reasons.(1) material problems:Material pollution;

17、Material drying is not good;There are too many volatiles in the material;Material degradation;Decomposition of colorant;The additive decomposition.(2) equipment problem:The equipment is not clean;Material drying is not clean;The environment air is not clean, and the colorant is floated in the air an

18、d deposited on the hopper and other parts;Thermocouple failure;The temperature control system is out of order;The resistance heating ring (or far infrared heating device) damage;The cylinder obstacle to material degradation.(3) temperature problem:The barrel temperature is too high to lower it;The n

19、ozzle temperature is too high to lower it.(4) injection molding:Reduce screw speed;Reduce back pressure;Reduce the clamping force;Reduce injection pressure;Shorten injection pressure;Shortening the total pressure time;The slow injection speed;We shorten the injection cycle.(5) die problem:Consider m

20、old exhaust;Increasing gate size and decreasing shearing rate;Increase the dimension of nozzle hole, main channel and bypass channel;Remove the oil and lubricant in the mold;Changing oil moistening agent.(6) in addition, polystyrene and ABS with high impact strength, such as internal stresses of pro

21、ducts, will also change color due to stress.7, how to overcome the product with silver markings(1) material problems:Material pollution;Materials are not dry;Uneven particle size.(2) equipment problem:Check the material cylinder nozzle flow system with or without obstructions and burrs to influence

22、the material flow;The salivation, using the spring nozzle;Inadequate equipment capacity.(3) injection molding:Material degradation, reduce screw speed, reduce back pressure;Adjust injection speed;Increase injection pressure;Lengthen injection time;Extended full pressure time;The longer the injection

23、 cycle.(4) temperature problem:The cylinder temperature is too low or too high;The mold temperature is too low to improve it;Uneven mold temperature.The nozzle temperature is too high will reduce salivation, it.(5) die problem:Increasing cold material hole;Enlarge runner;Polishing main flow way, dis

24、tributary channel and gate;Increase gate size or fan gate;Improving exhaust gas;To improve the smoothness of the cavity;Clean the cavity;The excess lubricant, reducing it or change it;To remove the dew in the mold (mold cooling caused);The material flow through the recess and thickening section, mod

25、ify the product design; local heating gate trial.8, how to overcome the products at the gate turbidity, product door markings and turbidity, usually due to expansion into the model, resulting in melt broken caused.(1) injection molding:Raise the temperature of the barrel;Improving nozzle temperature

26、;Slow the injection speed;Increase injection pressure;Change injection time;The lubricant to reduce or replace the lubricant.(2) die problem:Increasing mold temperature;Increasing gate size;Change gate shape (fan-shaped gate);Increasing cold material hole;Enlarge the dimension of diversion channel;C

27、hanging the gate location;The improvement of exhaust.(3) material problems:Drying material;Removing pollutants from material.9, how to overcome warpage and shrinkage of products, warpage and excessive shrinkage of products are usually due to poor design of products, bad gate location and injection m

28、olding conditions. Orientation is also a factor at high stress.(1) injection molding:During extended injection week;Increase the injection pressure without excessive filling;Increase the injection time without excessive filling;Increase the full pressure time without excessive filling;Increase the a

29、mount of injection without excessive filling;Reduce material temperature to reduce warpage;Minimize mold filling to minimize warpage;Minimize the stress orientation to reduce warpage;Increase injection speed;Slow down ejection rate;Workpiece annealing;The part is cooled on the setting frame;Make the

30、 injection cycle normal.(2) die problem:Change gate size;Change gate position;Adding auxiliary gate;Increasing the ejection area;Keep ejection balance;We have enough exhaust;The increase of wall thickness of strengthening parts;The increase of reinforcement and fillet;To check the size.The warpage a

31、nd excessive shrinkage of the product are a contradiction to the temperature of the material and the mold. The material temperature is high, the product shrinkage is small, but the warpage is big, otherwise, the product contraction is big, the warpage is small, the mold temperature is high, the prod

32、uct contraction is small, but the warpage is big, otherwise, the product contraction is big, the warpage is small. Therefore, the main contradiction must be solved depending on the product structure.10, how to control product size, product size change is due to abnormal equipment control, injection

33、molding conditions are irrational, product design is not good and material performance has changed.(1) die problem:An unreasonable mold size; the deformation of the product when it is pushed out;Uneven material filling;Filling material flow interrupted;Unreasonable gate size;The runner size unreason

34、able;The mold caused by abnormal injection cycle.(2) equipment problem:The feeding system is abnormal (plunger type injection press);Screw stop action is not normal;Screw speed is not normal;Uneven regulation of back pressure;The hydraulic system check valve is not normal;The thermocouple failure;Th

35、e temperature control system is not normal;The resistance heating ring (or far infrared heating device) is not normal;9 plasticizing capacity;The equipment caused by the abnormal injection cycle.(3) injection molding condition:Uneven mold temperature;Injection pressure is low, improve it;Insufficien

36、t filling time, longer injection time and longer full pressure time;Fourth, the barrel temperature is too high, lower it;The nozzle temperature is too high to lower it;The operation caused by the abnormal injection cycle.(4) material problems:The performance of each batch of material varies;The size

37、 of material particles is irregular;Material not dry.11, how to prevent the product sticking mold in the mold, mainly because of poor molding, insufficient ejection, insufficient injection, and incorrect mold design. If the product is stuck inside the mold, the injection process cannot be normal.(1)

38、 die problem: if the plastic die is due to insufficient injection, do not use the ejection mechanism; remove the inverted notch (trap);Remove chisels, nicks, and other cuts;Improve the smoothness of the mold surface;The surface of the polishing die shall be in the same direction as the injection;Inc

39、rease slope;Increase effective ejection area;Change the ejection position;Check the operation of ejector;In deep drawing core molding, enhanced vacuum damage and pneumatic core pulling;During the molding process, check whether the mold cavity is deformed and the mold base is deformed; check whether

40、the mold is offset when opening the mold;Reduce gate size;Auxiliary gate;Rearranging the gate position (13) (14) (15) aims to reduce the die cavity pressure;Filling rate of balanced multimode groove;Injection prevention;If the parts are poorly designed, re designed;Overcome mould induced cycle abnor

41、malities.(2) injection molding:Increasing release agent or improving release agent;Adjust material supply;Reduce injection pressure;Shorten injection time;Reduce the total pressure time;The lower mould temperature;The increase of the injection cycle;The injection molding cycle to overcome the abnorm

42、al conditions caused.(3) material problems:Clean material pollution;Add lubricant to the material;Drying material.(4) equipment problem:Repair ejection mechanism;If the top stroke is insufficient, lengthen it;Verify that the template is parallel;Overcome the abnormal injection cycle caused by equipment.12, how to overcome plastic paste flow channel?The plastic bonded runner is due to the poor contact between the nozzle and nozzle, the sprue material is not released with the product and