Study On Diffusion Bonding Process Of Conformal Cooling Channel For Injection Mold

The newly developed conformal cooling technology can effectively improve the cooling uniformity and improve the cooling efficiency,which can avoid warpage and other defects caused by uneven shrinkage of plastic parts.However,the existing manufacturing technology of conformal cooling channel is difficult to ensure the accuracy of die manufacturing,and its application in large and medium-sized die manufacturing is greatly limited.In this paper,a new manufacturing technology of hollow structure——diffusion bonding technology,is introduced through innovative thinking to realize precise manufacturing of conformal cooling channel die.At present,diffusion bonding technology is still in the experimental stage in die manufacturing.The research on diffusion bonding technology of conformal cooling channel is of great significance for its application and development.In this paper,P20 die steel is used as the research material,and the diffusion bonding technology of conformal cooling channel die is systematically studied with experimental method and theoretical analysis.The conformal cooling channel die which meets the design requirements is successfully manufactured.The main contents and conclusions of this paper are as follows:In order to optimize the diffusion bonding process of P20 die steel,different process parameters were selected to carry out diffusion bonding experiments of P20 die steel,observe the microstructure of diffusion bonding interface,and analyze the diffusion bonding quality,interface hole size and deformation rate of P20 die steel under different parameters.The optimized process parameters were obtained by comprehensive comparison.In order to predict the bonding rate of diffusion bonding interface of P20 die steel,the closure process of diffusion bonding interface voids was studied based on HILL interface void geometry model.According to the mechanism of interface void closure in diffusion bonding,a mathematical model of interface void closure in diffusion bonding of P20 die steel was established.The curves of interface void height,width and interface bonding rate with bonding time were obtained.Compared with the data of interface bonding rate obtained from diffusion bonding experiment,the maximum error of bonding rate was less than 4%.The validity of optimizing process parameters and reliability of the hole closure model of P20 die steel were verified.According to the shape dimension,diffusion bonding rate and pressure resistance design requirements of the conformal cooling water channel,the design and manufacture of the conformal cooling water channel die were completed,and the diffusion bonding of the conformal cooling water channel die was carried out by using the optimized process parameters.Waterway deformation measurement,microstructure observation of welding interface,C scan of welding interface and pressure test of the welded die were carried out.The results show that the non-waterway interface of the die has been fully welded,and the maximum deformation of cooling water channel is less than 2.5%.Finally,the electronic shell plastic parts were formed by testing qualified conformal cooling water channel mould.The maximum surface roughness of the product is Ra0.018 mm,and the maximum thickness error is 2%,which all meet the design requirements.The results show that the diffusion bonding process can be successfully applied to the manufacturing of conformal cooling channel of injection mold.The conformal cooling channel mold designed and manufactured in this paper fully meets the requirements and can produce qualified plastic parts,which provides a new process for the manufacturing of conformal cooling channel of injection mold.