Quality control using a multivariate injection molding sensor

Quality control is a crucial issue in the injection molding process with target of obtaining a high yield rate and reducing production cost. Consequently, effective methods for monitoring the injection conditions (e.g., pressure, velocity, and temperature) in real-time and adjusting these conditions adaptively as required to ensure a consistent part quality are essential. This study proposes a quality index based on the clamping force increment during the injection cycle, as determined by four strain gauges attached to the tie bars of the injection molding machine. Also, various quality indexes for online quality monitoring and prediction purposes based on the pressure, viscosity, and energy features extracted from the pressure profiles obtained at the load cell, nozzle, and molding cavity, respectively, are compared. The feasibility of the proposed quality indexes is investigated experimentally for various settings of the barrel temperature, back pressure, and rotational speed of the plasticizing screw. It is shown that all of the quality indexes are correlated with the injection-molded quality and hence provide a feasible basis for the realization of an on-line quality monitoring and control system. Particularly, the tie-bar elongation quality index requires no modification or invasion of the injection molding system or cavity and hence provides a particularly attractive solution for monitoring and controlling the part quality.

Section: Literature Reviewmentioning

confidence: 99%

Quality Indexes Design for Online Monitoring Polymer Injection Molding

Chen

Tseng²,

Huang³

2019

“…In order to reveal more online process information during injection molding, the comprehensive use of various sensors has become a commonly used research approach. Gao et al [30,31] obtained online melt viscosity and speed through the combined use of a variety of sensors (thermocouples, infrared temperature sensors, pressure sensors, and multitemperature and pressure sensors, cf. Figure 3).…”

Section: Temperature Measurementmentioning

confidence: 99%

Intelligent Injection Molding on Sensing, Optimization, and Control

Zhao

Zhang

Dong

et al. 2020

Injection molding is one of the most significant material processing methods for mass production of plastic products. It is widely used in various industry sectors, and its products are ubiquitous in our daily life. The settings and optimization of the injection molding process dictate the geometric precision and mechanical properties of the final products. Therefore, sensing, optimization, and control of the injection molding process have a crucial influence on product quality and have become an active research field with abundant literature. This paper defines the concept of intelligent injection molding as the integral application of these three procedures—sensing, optimization, and control. This paper reviews recent studies on methods for the detection of relevant physical variables, optimization of process parameters, and control strategies of machine variables in the molding process. Finally, conclusions are drawn to discuss future research directions and technologies, as well as algorithms worthy of being explored and developed.

“…The precision injection machine is lower than 0.5%, and the highest international level is less than 0.15% at present [16]. The improvement of the repetition precision of injection weight depends on the accuracy of mold processing and the rationality of the structure design, the performance of the raw materials, the rationality of the process parameters, and the control performance of the machine [17,18]. Therefore, it is instructive for improving the repetition accuracy of injection weight to study the process parameters affecting the injection weight and the algorithm of repetition accuracy of injection weight which conforms to the characteristics of injection molding.…”

Section: Introductionmentioning

confidence: 99%

Effect of Process Parameters on Repeatability Precision of Weight for Microinjection Molding Products

Wang

Yang

et al. 2019

The repeatability precision of weight for injection molded products is important technical parameter to measure the quality and accuracy of injection molded products and evaluate the performance of injection molding machine. The influence of mold temperature, melt temperature, packing pressure, and packing time on the weight of microinjection molding products was studied by Taguchi orthogonal experiment. The influence of peak cavity pressure on the weight of products also was analysed. The experimental results show that the packing pressure is the most important process parameter affecting both the weight of the tensile and the impact specimens. With the increase of the packing pressure, the weight of the tensile and the impact specimens increases. When the peak cavity pressure reaches a certain value, the pressure value of the tensile specimen is 65 MPa, and the pressure value of the impact specimen is 68 MPa, the weight of the product increases quickly. The packing pressure increased from 85 MPa to 100 MPa, the weight of the tensile specimen increased from 0.544g to 0.559g, an increase of 2.7%, and the weight of the impact specimen increased from 0.418g to 0.425g, an increase of 1.7%.