How many common problems of blow molding products?


Author: MULAN -Plastic Molding Manufacturer

Jinlian Blow Molding Machinery Co., Ltd. was established in 1999, covering an area of ​​20,000 square meters. Specializing in the production of various types and sizes of blow molding products, blow molds, one-stop service, the company currently has more than 30 blow molding machines. It can produce 50g, 100g, 500g, 1000g, 1500g, 3000g and other blow molding products. Strong technical force, quality assurance, reputation first, welcome to discuss cooperation! The company mainly produces HDPE, LDPE, EVA, HIPS, ABS, PP and other materials. The company can produce: all kinds of blow molding accessories, plastic toys, electronic accessories, hardware accessories, toy wheels, plastic containers, simulated animals and plants, spherical, Halloween and Christmas products. Blow molding mainly refers to hollow blow molding (also known as blow molding), which is a method of blowing a hot-melt parison closed in a mold to form a hollow product by means of gas pressure. It is a fast-growing plastic molding method. The mold used for blow molding only has a female mold (concave mold). Compared with injection molding, blow molding products have lower equipment cost, stronger adaptability, good formability (such as low stress), and complex undulation curves (shape ) products. 1. Uneven longitudinal wall thickness of blow molding products: cause: ①Serious sagging of parison due to its own weight ② The diameter of the two longitudinal cross-sections of the blow molded product is too different. Solutions: ① Reduce the temperature of the parison melt, increase the extrusion speed of the parison, replace the resin with a lower melt flow rate, and adjust the parison control device ② Appropriately change the product design and adopt the bottom blowing method to form Second, the horizontal wall thickness of blow molding products is uneven: cause: ①The extrusion of the parison is skewed ②The temperature difference between the mold sleeve and the mold core is relatively large ③ The shape of the product is asymmetric ④ The parison inflation ratio is too large solution: ①Adjust the gap width deviation of the die to make the wall thickness of the parison uniform; before closing the mold, straighten the mold ②Increase or reduce the heating temperature of the mold sleeve to improve the temperature deviation inside and outside the die ③Before closing the mold, pre-clamp and pre-expand the parison so that the parison is properly offset to the thin-walled direction ④ Reduce parison inflation ratio 3. Orange peel-like patterns or pitting appear on the surface of blow molding products: cause: ①Poor mold exhaust ②Water leakage from the mold or condensation in the mold cavity ③Poor plasticization of the parison, resulting in melt fracture of the parison ④Insufficient inflation air pressure ⑤ Inflation speed is slow ⑥ Inflation ratio is too small solution: ①The mold parison is sandblasted and vent holes are added ②Repair the mold and adjust the cooling temperature of the mold to"dew point"above ③Reduce the screw speed and increase the heating temperature of the extruder ④Increase inflation air pressure ⑤ Clean the compressed air channel and check whether the blowing rod is leaking ⑥Replace the mold sleeve and mold core to increase the parison inflation ratio.

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