Refrigerator door handle - ZY-6006

Name:Refrigerator door handle

The brief introduction of gas assistance injection molding technique

First,introduction

The gas assistance injection molding is a kind of new method in plastic production process.The 80's starts in production line physically, at present it has been applied extensively in Europe and North Americas,Japan and Korea are also already successive applied, some factories also already have applied this new technique in home.

The gas assistance injection molding compared to the traditional injection molding more than 1 gas injection stage, the mold cavity is filled with plastic by the gas impetus.Therefore while using the assistance injection molding technique to design mold and product forming must provide the explicit gas channel to guide the gas.The gas channel geometry size,the shape of section and the position arrangement all will affect the gas penetration and the interference on moving of fused mass,thus it will affects the products quality finally.

According to the different of the melted plastic volume.The gas assistance injection molding craft can be divided into 2 ways:

a,Hollow molding,namely inject the melted plastic when the mould cavity fills with cavity volume up to 60-70%,then stop melted plastic injection,and starts to inject the gas until guarantees pressure and cooling to molding.This craft is mainly used in the handles and thickness plastic products,the application effect is very ideal.

b,short injection,namely inject the melted plastic when the mould cavity fills with cavity volume up to 90-98%,then starts to inject the gas,because of gas full of the volume contraction,the product warp will be reduced greatly.Its craft control is very complex. That method mainly used for the thin wall of the bigger flat surface product or side wall series.

Second,the gas assistance injection craft theory

First stage:Plastic injection..Melted plastic enters into cavity,when it meets the low temperature mold wall,it can form a thin coagulation layer.

Second stage:Gas incidence..when the inert gas enters the melted plastic,it impels the central of unfixed plastic to enter the place which the plastic has not filled with.

Third stage:Gas incidence conclusion..The gas continues to impel the melted plastic to flow until full filling with the entire cavity.

Forth stage:The gas guarantees pressure conclusion..Under the condition of guarantees pressure,the gas compress melted plastic in the gas channel,carries on making up the material to guarantee the appearance of product.

Third,the gas assistance injection molding craft merit

Eliminates contractive marks which stay in the surface of products,improves the surface quality of products,reduces the warp and distortion,reduces the flowed streak,reduces the inner stress of products,increase the intension of products,saves the material of plastic,lightens the weight of products(generally reduce 20-40%),improves the distributing of material,improves the rigidity of products,reduces the power of lock mold,the power of inject plastic and the injection molding machine power consumption,cuts the time of molding,enhances the production efficiency,lengthens the mold service life,reduces the mold production cost.