Theoretical Calculation of Thermal Transmittance

The article is focused on the theoretical calculation of thermal transmittance for new plastic window frame. Constant making the thermos-technical requirements stricter lays higher demands on improvement of window frames which the weakest element from the point of heat engineering. One important part of the window, which is needed to be improved, is a frame profile. Assessment of newly proposed window profile system is realised based on currently effective technical norms and regulations. The main aim of the theoretical assessment and computer simulation is to define the coefficient of passage of heat of the frame construction of a new plastic profile system.

Optimization Design in Cooling Channels of Calibrator for Plastic Profile Extrusion Based on Numerical Simulation

Hot plastic profile produced by extrusion die is cooled down and calibrated by calibrator. Therefore, the cooling and calibrating ability of the calibrator directly influence the quality and output of the profile. The key is to design the distribution of cooling channels in calibrator. By analyzing the heat transfer process during cooling in calibrator, the cooling process of plastic profile in calibrator is simulated. Based on the finite element analysis results, the optimization objective is established to obtain the cooling efficiency and uniformity of each node in the profile cross sections of the calibrators exit and finish the optimization design of the cooling channels positions.

Research on the Numerical Simulation of Cooling Process for Plastic Profile in Calibrator

The calibrator is an important part of extrusion die. Its cooling and calibrating ability directly influence the quality and output of the profile. Based on the analysis of the heat transfer process during cooling in calibrator, the initial and boundary conditions of cooling numerical simulation are further analyzed and calculated. Then the cooling process of plastic profile in calibrator is simulated. The calculation rationality of the initial and boundary conditions and the accuracy of numerical simulation are verified by measuring the surface temperature of profile in production.

Optimization approach for processing design in the extrusion process of plastic profile with metal insert

The extrusion process of plastic profile with metal insert is a kind of novel and advanced plastic processing method which requires rigorous control on processing conditions to ensure the quality and performance of final products. However, it is still difficult to achieve an optimal processing design by using traditional “trial and error” method. An optimization approach for the processing design in the extrusion process of plastic profile with metal insert is proposed based on finite element simulation, back propagation neural network and genetic algorithm in the study. The finite element simulation is conducted to predict polymer melts flow in the extrusion process. The simulated results are extracted for the establishment of neural network. The genetic algorithm is performed for the search of globally optimal design variable with its objective function evaluated by using the established neural network model. The proposed approach is adopted for the optimization of processing conditions in the extrusion process of plastic profile with metal insert. According to the flow balance principle, the uniformity of outlet flow distribution is taken as the optimization objective with a constraint condition on the maximum shear stress. The optimization of two processing parameters including the volume flow rate and the metal insert moving velocity is conducted in the extrusion process of plastic profile with metal insert and the optimization objective is successfully achieved.