Research On The Thermodynamic Behavior Of Ultra Thick-wall Solid Product Injection Molding With Conformal Cooling

With the application of injection molding products in home appliances, automobiles,electrons, medical devices and other fields, in order to ensure the bearing and mechanical property of the product,thick-wall transparent injection molding products need to be solid. Due to large volume shrinkage,traditional injection molding is difficult to control the forming quality of the product,easy to appear shrinkage hole、shrinkage, deformation and insufficient filling defects. These defects seriously affect the appearance quality and mechanical properties of the transparent plastic products. With the development of mold processing and manufacturing technology, Because cooling channel changes with the injection mold cavity surface geometry and the mold cavity surface distance is always consistent,uniform cooling and high forming efficiency,conformal cooling has been widely applied.In this paper,we choose the thick-wall transparent entity television,respectively designed the three cooling forms of traditional straight cooling channel、nearly conformal cooling channel and conformal cooling channel, and establish the geometric model of die structure on these channels. The traditional straight cooling channel is linear;Nearly conformal cooling channel show line type circular pipe square loop;Conformal cooling channels are divided into two parts,the upper is parallel circular pipe structure, while the lower part of core is simple baffle flow board array form. Combination of traditional injection molding,heat transfer theory and conformal cooling technology,using ANSYS and Moldflow,study heating and cooling processes thermal response of injection mold、transient temperature field distribution and the forming quality of the products,get injection mold cavity and core surface temperature field of heating and cooling stage、product temperature、frozen layer percentage、shrink mark、volume shrinkage rate and deformation.The results show that conformal channel on heating stage has faster thermal response rate,higher temperature,more even of the cavity surface temperature field distribution,needing less time to be heated to the specified mold temperature. On cooling stage, Conformal cooling channel can control mold temperature more effectively,uniform cooling,consistent cavity and core surface temperature field. In addition,the overall temperature is lower than the other two channels. At the same time,conformal cooling channel has minimum volume shrinkage rate and shrink mark,the volume shrinkage rate by 12.34% of traditional straight cooling channel and 10.47% of nearly conformal cooling channels is reduced to 10.41% of conformal cooling channel. Shrink mark value reduces from 0.7802 mm in traditional straight cooling channel and 0.3736 mm in near conformal channel to 0.2681 mm in conformal channel. It needs a shorter time to form this product, has higher forming efficiency and less molding defects such as shrinkage mark,shrinkage,deformation and so on.