Prediction method of gas penetration in gas-assisted injection molding based on finite volume method

Abstract

The invention discloses a prediction method of gas-assisted injection molding gas penetration based on a finite volume method. The method includes the following steps that (1) a three-dimensional node control body is constructed by cavity entity grids to serve as a finite volume; (2) forming process parameters are set; (3) material parameters are set; (4) the flow velocity, pressure and the temperature of plastic melt are calculated; (5) the flow leading edge of the plastic melt is updated, and the time step length is determined; (6) whether the filler content of the plastic melt reaches an appointed volume or not is judged; (7) the flow velocity, pressure and the temperature of the plastic melt and the flow velocity, pressure and the temperature of gas are calculated; (8) the flow leading edge of the plastic melt and the penetration leading edge of gas are updated, and time steps are determined; (9) whether a cavity is filled or not is judged. The method is based on the three-dimensional finite volume method, a traditional finite volume method is improved, coupled flowing of the plastic melt and gas is calculated, consideration is given to strong nonlinearity among viscosity, the velocity, pressure and the temperature, and distribution of the gas-assisted injection molding gas penetration leading edge and various physical quantity fields can be accurately predicted.

Description

Technical field [0001] The invention belongs to a computer numerical simulation method, and particularly relates to a gas penetration prediction method for gas-assisted injection molding based on a finite volume method, which is used for gas-assisted injection molding. Background technique [0002] Gas-assisted injection molding (GAIM) is based on traditional injection molding. Gas is injected into the plastic melt through a gas needle. The gas pressure pushes the plastic melt to continue to flow and fill the mold cavity. In the process of penetration, a cavity inside the plastic melt is formed, thereby obtaining an advanced injection molding process for hollow plastic products. GAIM process has many advantages, such as saving raw materials, reducing clamping force, shortening cooling time, preventing product sink marks, reducing product internal stress, reducing or eliminating product warpage, improving product surface performance, improving production efficiency, reducing produ...

AI Technical Summary

Problems solved by technology

Based on the mid-plane, surface model and two-dimensional numerical simulation method, a simplified model is introduced to describe the gas penetration front, which cannot simulate the complex gas penetration front in the thickness direction, especially at the thicker part of the product, the thickness change part, and the structure intersection.

Images