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Defects and solutions of blow molding products

2020-06-29  Visits:323

1、 The vertical wall thickness of blow molded products is uneven;            

      The causes are as follows: 1. The weight of parison is loose seriously; 2. The diameters of two vertical sections of blow molded products differ too much           

      The countermeasures are as follows: 1. Reduce the temperature of the mold body, increase the extrusion rate of the mold body, remove and replace the epoxy resin with low flow rate of the mold body, and adjust the control equipment of the mold body; 2. Moderately change the design concept of the crafts and select the bottom blowing method for forming

2、 The wall thickness of blow molding products is uneven;            

      Causes: 1. Extrusion inclination of parison 2. Large temperature difference between the top block and the inside and outside of the core 3. Different appearance design of handicrafts 4. Too large parison inflation ratio            

      Treatment measures: 1. Adjust the total width error of the die gap to make the wall thickness of the blank symmetrical; straighten the mold before closing; 2. Raise or reduce the heating temperature of the top block to improve the temperature error inside and outside the die opening; 3. Carry out pre clamping and pre expansion of the blank before closing the mold to make the blank moderately deviate to the thick wall direction; 4. Reduce the blow expansion ratio of the blank

3、 The surface of blow molding products has orange peel like lines or black spots;            

      Causes: 1. The exhaust pipe of the mold is not good; 2. The mold has water seepage or the mold cavity has cold doubt; 3. The mold billet has poor melting and the mold billet causes solution cracking; 4. The standard air pressure for blowing out is not enough; 5. The blowing out speed is relatively slow; 6. The blowing out ratio is very small  

      Treatment measures: 1. Sand blasting process shall be carried out for the mould blank, and exhaust air holes shall be added. 2. Maintain the mould, and adjust the cooling temperature of the mould to the 'leakage point'. 3. Reduce the screw speed ratio of the extruder, and increase the heating temperature of the extruder. 4. Improve the standard air pressure of the inflation. 5. Clear the air compression safety channel, and check whether the air blowing check rod leaks. 6. Remove the top block, mould core, and increase the inflation ratio of the mould blank

4、 The capacity of blow molding products is reduced;            

      Causes: 1. The wall thickness of the blank is enlarged, resulting in the wall thickness of the artwork. 2. The shrinkage of the artwork is increased, resulting in the specification of the artwork. 3. The inflation standard air pressure is small, and the artwork is not inflated to the design conception specification of the die  

      Countermeasures: 1. Adjust the system control equipment to reduce the parison wall thickness; increase the parison solution temperature and reduce the bloom ratio from the mold; 2. Replace the epoxy resin with small shrinkage, increase the blowing inspection time and reduce the cooling temperature of the mold; 3. Moderately increase the working pressure of air compression

5、 The profile or drawing of blow molded products are not clear;            

       Causes: 1. The exhaust pipe of the die is not good; 2. The inflation pressure is low; 3. The solution temperature of the die is slightly low, and the melting of the raw materials is not good; 4. The cooling temperature of the die is slightly low, and the die has a "cold doubt" condition            

       Treatment measures: 1. Maintain the mold, sand blasting process of female mold or add exhaust pipe slot; 2. Increase the standard air pressure of inflation; 3. Moderately increase the temperature of extruder and engine; add appropriate plastic filler masterbatch if necessary; 4. Increase the temperature of mold to the temperature above the leakage point

6、 Too much and too thick burr of blow molding products;            

       Causes: 1. Die expanding and die locking working pressure is not enough; 2. Die wound is damaged and locating pin is displaced; 3. Die body inclines when blowing; 4. The escape groove at the cut of clip body is shallow or the depth of the wound is shallow; 5. Die body is inflated and started too early            

       Treatment measures: 1. Improve the working pressure of mold locking and properly reduce the inflation standard air pressure; 2. Repair the mold wound, correct or replace the mold locating pin; 3. The management center of the mold blank and the air blowing inspection rod; 3. Repair the mold and increase the depth of the chute or knife; 4. Adjust the air filling time of the mold blank

7、 Too deep vertical pattern appears;            

       Causes: 1. The mold mouth is dirty; 2. There is burr or vacancy on the top block and core edge; 3. The color masterbatch or epoxy resin dissolves and causes dark brown pattern; 4. The filter screen is perforated, and the raw material infiltrates into the residue and accumulates in the mold mouth           

       Treatment measures: 1. Use copper knife to clean the die opening 2. Repair the die opening 3. Reduce the temperature moderately, and remove and replace the color masterbatch with good permeability 4. Remove and replace the filter screen plate, and use the leftover material with stained edges and corners

8、 During the formation, the type of embryo was blown out;            

       Causes: 1. The die cut is too sharp; 2. There are residues or bubbles in the blank; 3. The blow out ratio is too large; 4. The compressive strength of the solution of the blank is low; 5. The length of the blank is not enough; 5. The wall of the blank is too thin or the thickness of the blank is not even; 6. The vessel cracks when it comes out of the mold (the blow out time is not enough); 7. The treatment measures for the insufficient mold locking force:            

        Treatment measures: 1. Moderately increase the total width and visual angle of the wound; 2. Apply dry and cold raw materials, and apply them after air drying, Clean up the raw materials; clear the die opening; 3. Remove and replace the top block and die core to reduce the blow out ratio of mold failure; 4. Remove and replace the appropriate raw materials to moderately reduce the temperature of the solution; 5. Check the operation equipment of the extruder or the discharge cylinder engine to reduce the change of the main parameters of the processing technology and improve the length of the mold; 6. Remove and replace the top block or die core to thicken the mold wall; check the operation equipment of the mold; Adjust the die gap 7. Adjust the air release time or delay time. 8. Increase the working pressure of mold locking or reduce the standard air pressure of inflation

9、 Blow molding products are difficult to mold;            

       Causes: 1. The blow out cooling time of handicraft is too long, and the cooling temperature of mould is low. 2. The design idea of mould is not good, and there is burr on the surface of die. 3. When opening the mould, the moving speed of front and rear left and right mould plates is unbalanced. 4. The mould installation is not correct          

       Treatment measures: 1. Moderately shorten the mold Expanding time and raise the mold temperature; 2. Repair the mold; reduce the depth of the concave groove and the inclination of the convex rib to 1:50 or 1:100; apply the film remover; 3. Repair the mold locking equipment to make the moving speed of the front and rear left and right templates consistent; 4. Reassemble the mold to correct the installation position of the two modules

10、 The quality of blow molding products fluctuates greatly;            

       The reasons are as follows: 1. The wall thickness of parison changes suddenly; 2. The edge recycled material mixed with people is uneven; 3. The feeding section is blocked, resulting in the feeding fluctuation of extruder; 4. The heating temperature is unbalanced            

        Treatment countermeasures: 1. Maintain the parison control equipment; 2. Select the proper material error equipment to increase the time of material error; 3. Reduce the amount of edge recycled material when necessary; 3. Remove the agglomerates at the material outlet; 4. Reduce the temperature at the material outlet; 5. Replace the electric heater cabinet

        Blow molding machine in the process of operation will inevitably produce many defective products, combined with the plastic bottle visual inspection machine let your products from the root to eliminate defective products, quality improvement is the survival of the enterprise.


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