Abstract: Provided by the present disclosure is an ultrasonic phased array-based in-situ imaging method for melt flow in injection molding. The ultrasonic phased array is used for the detection of an injection molding process for the first time, and an effective dynamic monitoring imaging method for a melt front position is developed. A melt flow process in a mold cavity is dynamically monitored by collecting an FMC (Full matrix capture) dataset online. A mapping relationship between an incident angle and a target pixel point is established to rapidly determine time delay of each point in a measurement target region, and a melt bottom image is acquired using TFM (Total focusing method) imaging conditions, from which the melt front can be localized. The provided method is high in measurement accuracy, short in imaging time, and capable of effectively improving imaging efficiency of online measurement.

Abstract: The present disclosure provides a high-precision ultrasonic imaging method for an internal defect of a complex-shaped component based on a search-vector imaging condition. Based on full waveform inversion, the search-vector imaging condition is constructed, and a first-order derivative vector is combined with an approximate Hessian matrix for correction so that a high-quality image of a defect in a complex sound velocity model can be obtained. The high-precision ultrasonic imaging method is suitable for defect testing on complex surface components. The imaging condition used for the imaging method of the present disclosure does not involve an assumption on a wave field and is stricter than a traditional imaging condition theory, thereby ensuring high precision of the inventive method. Moreover, the imaging method of the present disclosure can highlight a defect in an entire measurement area, which is very convenient for locating a defect in a large-size measurement structure.

Abstract: The present disclosure discloses an ultrasonic online nondestructive measurement method for a melt density in injection molding, which solves the problems of difficult installation, high cost, influence on product surface quality, and the like existing in an existing density measurement method. According to the present disclosure, an ultrasonic velocity is obtained from a time domain signal with reference to time domain and frequency domain signal analysis of ultrasonic echo signals, an acoustic impedance is calculated by full spectrum analysis of a frequency domain signal, and the melt density is calculated from a correlation of the ultrasonic velocity, the acoustic impedance, and the density. The method has the advantages of having high measurement accuracy and being nondestructive, online and low in cost, and has a great application value in the injection molding industry.

Abstract: The present invention discloses a model-free optimization method of process parameters of injection molding to solve the problems of frequent tests required and performing adaptive adjustment on different parameters in the existing optimization method. The method need not build a surrogate model between a product quality index and a process parameter to render the process parameter to converge nearby the optimal solution by an on-line iteration method. The present invention calculates the gradient direction of a current point by an iterative gradient estimation method, and uses adaptive moment estimation algorithm to allocate an adaptive step for each parameter. The method can significantly reduce the cost and time required in the process parameter, which greatly helps improving the optimization efficiency of process parameters of injection molding.

Abstract: The present disclosure discloses a method for on-line measurement of the polymer melt temperature, comprising: on-line measurement of ultrasonic sound velocity c of melt in an injection molding process, on-line measurement of melt pressure P in the injection molding process, and obtaining melt temperature T in the injection molding process by formula (1). The present disclosure also discloses an apparatus for on-line measurement of the polymer melt temperature. The method and the apparatus provided in the present disclosure may enable on-line and in-situ characterization of the melt density and further enable on-line quantitative measurement of the melt quality. Compared with infrared measurement methods, the method provided herein is significantly reduced in cost, which is of great significance to theoretical researches of crystallization process and shear heating.

Abstract: The present invention provides an efficient ultrasonic phased array phase shift migration imaging method for the defect in a multi-layer structure, including the following steps: (1) transforming full matrix capture data of a multi-layer structure to a frequency-wavenumber domain by means of three-dimensional fast Fourier transform; (2) for any non-traversed layer in the multi-layer structure, extrapolating a surface wave field of the multi-layer structure to an upper interface of the non-traversed layer, to obtain wave field information of the non-traversed layer; (3) according to the obtained wave field information, performing focus imaging on the non-traversed layer in the frequency-wavenumber domain; and (4) repeating the steps (2) and (3), until all layers are traversed, to obtain an imaging result of the multi-layer structure.

Abstract: The present invention discloses a model-free optimization method of process parameters of injection molding to solve the problems of frequent tests required and performing adaptive adjustment on different parameters in the existing optimization method. The method need not build a surrogate model between a product quality index and a process parameter to render the process parameter to converge nearby the optimal solution by an on-line iteration method. The present invention calculates the gradient direction of a current point by an iterative gradient estimation method, and uses adaptive moment estimation algorithm to allocate an adaptive step for each parameter. The method can significantly reduce the cost and time required in the process parameter, which greatly helps improving the optimization efficiency of process parameters of injection molding.

Abstract: The present disclosure discloses a method for on-line measurement of the polymer melt temperature, comprising: on-line measurement of ultrasonic sound velocity c of melt in an injection molding process, on-line measurement of melt pressure P in the injection molding process, and obtaining melt temperature T in the injection molding process by formula (1). The present disclosure also discloses an apparatus for on-line measurement of the polymer melt temperature. The method and the apparatus provided in the present disclosure may enable on-line and in-situ characterization of the melt density and further enable on-line quantitative measurement of the melt quality. Compared with infrared measurement methods, the method provided herein is significantly reduced in cost, which is of great significance to theoretical researches of crystallization process and shear heating.