Papers by Author: Peng Cheng Xie

Abstract: Microfluidic chip injection photocuring is a new method for microfluidic chip fabrication. The accuracy of microfluidic chip photocuring has an important impact on the reliability of microfluidic chip. The reaction rate of photocuring system directly affects the final quality and efficiency of microfluidic chip. The rapid reaction rate of photocuring system will lead to poor feeding effect of the reaction system. The forming accuracy is affected, and the reaction rate is too slow, which will increase the forming time and affect the forming efficiency. In this paper, the conversion rate and reaction rate of different active monomers and oligomers used in the formulation system of microfluidic chips were measured on-line. The photocuring reaction kinetics of microfluidic chips was studied, and the influence of the formulation system on the photocuring reaction was explored, which laid a foundation for optimizing the formulation of microfluidic chips.

Abstract: A new concept of microinjection molding module was designed and presented. The module was designed as a multi microinjection module, which is matched with a vertical injection molding machine (IMM) and can be applied to usual IMMs. A planetary gear pump was integrated in this module to complete the multi microinjection molding(MμIMM)。The module is fixed between the stationary platen and the mold of IMM. The plasticizing unit of the IMM provides the melt and initial pressure for the multi microinjection molding module. With this module, a usual IMM could be upgraded to a precise microinjection machine and has the capability of precise metering for the microinjection molding.

Abstract: While the switchover from filling to packing is particularly crucial during injection molding, the transfers from holding to screw recovery also significantly affects the quality of molded parts. In this study, the end-point control of the holding phase based on cavity pressure was presented. It was compared with the traditional control method by holding time. The purpose of this study was to validate the feasibility of the end-point control of holding phase by cavity pressure, and to examine its consistency. The weight of the molded parts served as the main measure to probe the process’s capabilities. The results of the verification experiments revealed that the end-point control mode based on cavity pressure could yield better consistency of part weight than the traditional control method by holding time, however, the benefits were not significant. The trigger value of cavity pressure and sensor position should be considered for achieving such high process capabilities.

Abstract: The current work is a continuation of Part I. In this part, the simulation results showed that the free tire contour changed measurably after charging and installing it on a steel rim. A distinct stress concentration appeared on the tire shoulder part whenever the tire was charged, touching ground or rolling. When the rotational velocity of the free tire changed, the displacement of the tire crest remains stable while the tire shoulder changes considerably.

Abstract: Defects such as black spots and yellow surfaces appeared in the process of injection molding light guiding plate as a result of the failure surfaces of the screw and screw tip. To choose and optimize the solutions of different surface treatments of the special screw for light guiding plate, the stripping performance testing platform was established. The experimental results showed that TiN and TiAlN or similar coatings by physical vapor deposition could significantly reduce the adhesion force between polycarbonate (PC) and different coatings. Through surface topography analysis of diversified coatings with SEM and AFM, TiAlN coatings represented the excellent surface quality of its smoothness, continuum, and low surface wave. To enhance the bonding force between the molding screw and coatings, TiAlN/Cr and TiAlN/Ti multi-films was developed which owned much more firm bonding force than TiAlN and good surface quality to be suitable for the special screw for manufacturing light guiding plate.

Abstract: In this paper, self-designed electrospinning equipment was used to make a series of electrospinning experiments with materials of polypropylene. The influences of the receiver area, the upper plate area, and the overlapping area between the receiver and the upper plate, on the melt spinning electric field, the spinning efficiency, and the fiber diameter, were investigated respectively. The results showed that when the other parameters were kept unchanged, with the increase of the receiver’s diameter, the electric field strength and spinning efficiency increased, and the fiber diameter increased at first and then decreased; the bigger the overlapping area between the receiver and the upper plate, the more stable the vertical spinning path.

Abstract: An expert system of precise injection molding process optimization based on Moldflow software was set up in this paper. Expert system of precise injection molding process optimization based on Moldflow-MPI module consist of optimization of packing curve, analyzer of parallelism and coaxiality, analyzer of process optimization and integrative forecaster of weld line. The system can be used in the process optimization of precise injection molding, the forecast and control of product properties, and the flaw elimination of product molding.

Abstract: The light guide plate is an important element of the LCD backlight module which demands a certain degree of transparency and uniformity of gray. The defects such as black spots and yellow surface appeared when the light guide plate was processed by domestic equipments. The main problem was caused by the plasticization unit. The Influencing factors of performance for polycarbonate (PC) special screw were discussed in this paper. The conveyance capacity of melt in the metering zone of injection screws with different flight width and channel depth was analyzed by POLYFLOW software. In order to obtain high surface hardness, corrosion resistance and smoothness of PC special screw, surface coating processing was the key point for injection molding light guide plate. Moreover, the peel strength of PC with different coating processing metallic block was tested and measured. he experimental results of the analysis showed that the nickel-tungsten alloy plating and physical vapor deposition can significantly improve stripping properties, corrosion resistance and smoothness. The influencing factors of coating and PC materials’ stripping were analyzed. Through industrial testing, the defective rate of light guide plate had been greatly reduced with physical vapor deposition compared to the screw with hard chromium plating.

Abstract: While the transfer from filling to packing is particularly crucial during injection molding, the transfers from packing to holding and holding to screw recovery also significantly affect part quality. In this study, the control of the transfer from holding to screw recovery, that is the control of the end-point of the holding phase, was examined. The holding end-point control by time, cavity pressure and cavity temperature were presented. The purpose of this study was to validate the feasibility of the control methods of holding end-point by cavity pressure and cavity temperature. The qualities of injection-molded parts, weight, will serve as measures to probe their process capabilities. Recently found to be a good indicator of product quality, both cavity pressure and temperature profiles are applied here to obtain more precise control. Change of mold temperature was specially considered. After the experimental verification is conducted, the results reveal that the innovative holding end-point control by cavity temperature yields a more uniform product weight with mold temperature. It proved that the holding end-point control by cavity temperature can be used to obtain the optimum holding time and accommodate the product weight to the change of mold temperature, which is the other holding control methods cannot obtain.

Abstract: Pressure-Volume-Temperature (P-V-T) properties of two amorphous polymers (ABS and PS) were measured by an on-line testing measurement in the temperature ranges from 20 to 150 °C and pressures from 20 to 120 MPa. The on-line testing measurement is based on an injection molding machine (IMM), and it can be used to get P-V-T data of polymers directly with a special testing mold under normal processing conditions. The experimental P-V-T results of amorphous polymers under industrial processing conditions were presented. A new modified two-domain Spencer-Gilmore equation of state (EOS) was developed. The P-V-T properties were correlated by the modified Spencer-Gilmore EOS and a modified two-domain Tait EOS, showing a good agreement with measurements. The effects of sample forms were investigated. A sample with large length diameter ratio is the best one to be measured.