Today we will discuss the issue of blow molding chairs and injection molding chairs.
The blow-molded chair uses the principle of gas pressure to inflate the hot blank tire stored in the mold into a chair-shaped product. Extrusion blow molding is to use the extrusion method to first make the plastic into a bottomed parison, and then move the parison to a blow mold to blow into a hollow product. Except for the injection machine and extruder, the blow molding equipment is mainly the mold for blow molding. Blow moulds are usually composed of two parts, which are equipped with coolant channels, and small holes on the parting surface can be inserted into the pressurized air blowpipe.
The injection molding chair is a method in which the thermoplastic or thermosetting plastic raw materials are heated in a heating barrel and uniformly plasticized, and then pushed into a closed mold by a plunger or a moving screw to form a chair. Almost all thermoplastics can be used in injection-molded chairs. Injection-molded chairs have also successfully used certain thermoset plastics. The molding cycle of the injection-molded chair is short, from a few seconds to a few minutes. The molded chair is from large to small, and the weight can range from several grams to tens of kilograms. It can form complex shapes, precise dimensions, and plastics with metal or non-metal inserts. Finished product.
Compared with chairs produced by injection molding, chairs made by extrusion blow molding have the following advantages:
1. The cost of blow molding machinery, especially blow molds, is low. When molding similar products, the cost of blow molding machinery is about 1/3 of that of injection machinery, and the production cost of products is also low.
2. In the process of blow-molding the chair, the chair parison is used to form a plastic chair under lower pressure through the machine head, and inflated under low pressure. The product has small residual stress, resistance to stretching, impact, and environmental protection. The performance of various strains is higher, and it has better performance. When the injection molding chair is injection molded, the melt must pass through the mold runner and gate under high pressure, which will cause uneven stress distribution.
3. The relative molecular mass of blow molding grade plastic raw materials is much higher than that of injection grade plastics. Therefore, the chair made by blow molding has a high impact toughness and high environmental stress crack resistance.
4. Since the blow mold is only composed of a female mold, the wall thickness of the product can be changed by simply adjusting the gap between the die orifice of the die or the extrusion conditions, which is very beneficial for products that cannot accurately calculate the required wall thickness in advance. The cost of changing the wall thickness of the product for injection molding is much higher.
5. The blow-molded chair can produce a complex, irregular, and monolithic chair. When using injection molding, after producing two or more products, they should be combined with snap fitting, solvent bonding, or ultrasonic welding.
The accuracy of blow-molded chairs is generally not as high as that of injection molded products; the appearance of injection-molded chairs is often rough, which is determined by their different processes. As for the question of which one is better, blow-molded chair, or injection-molded chair, I think it depends on specific needs.
Yankang Plastic Machine is a manufacturer specializing in the production of large-scale hollow blow molding machines. It can produce blow molding chairs of various models and colors. Welcome to buy.