scholarly journals Investigation of Product and Process Fingerprints for Fast Quality Assurance in Injection Molding of Micro-Structured Components

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 661 ◽  
Author(s):  
Nikolaos Giannekas ◽  
Per Kristiansen ◽  
Yang Zhang ◽  
Guido Tosello
Keyword(s):  
Quality Control ◽  
Injection Molding ◽  
Quality Data ◽  
Efficient Production ◽  
Short Cycle ◽  
Part Quality ◽  
Molded Parts ◽  
Micro Features ◽  
Product And Process

Injection molding is increasingly gaining favor in the manufacturing of polymer components since it can ensure a cost-efficient production with short cycle times. To ensure the quality of the finished parts and the stability of the process, it is essential to perform frequent metrological inspections. In contrast to the short cycle time of injection molding itself, a metrological quality control can require a significant amount of time and the late detection of a problem may then result in increased wastage. This paper presents an alternative approach to process monitoring and the quality control of injection molded parts with the concept of “Product and Process Fingerprints” that use direct and indirect quality indicators extracted from part quality data in-mold and machine processed data. The proposed approach is based on the concept of product and process fingerprints in the form of calculated indices that are correlated to the quality of the molded parts. A statistically designed set of experiments was undertaken to map the experimental space and quantify the replication of micro-features depending on their position and on combinations of processing parameters with their main effects to discover to what extent the effects of process variation were dependent on feature shape, size, and position. The results show that a number of product and process fingerprints correlate well with the quality of the micro features of the manufactured part depending on their geometry and location and can be used as indirect indicators of part quality. The concept can, thus, support the creation of a rapid quality monitoring system that has the potential to decrease the use of off-line, time-consuming, and detailed metrology for part approval and can thus act as an early warning system during manufacturing.

scholarly journals Investigation on Product and Process Fingerprints for Integrated Quality Assurance in Injection Molding of Microstructured Biochips

2018 ◽  
Vol 2 (4) ◽  
pp. 79
Author(s):  
Nikolaos Giannekas ◽  
Yang Zhang ◽  
Guido Tosello
Keyword(s):  
Injection Molding ◽  
Quality Monitoring ◽  
Efficient Production ◽  
Replication Fidelity ◽  
Part Quality ◽  
Replication Quality ◽  
Micro Features ◽  
Product And Process ◽  
Plastic Parts

Injection molding has been increasing for decades its share in the production of polymer components, in comparison to other manufacturing processes, as it can assure a cost-efficient production while maintaining short cycle times. In any production line, the stability of the process and the quality of the produced components is ensured by frequently performed metrological controls, which require a significant amount of effort and resources. To avoid the expensive effect of an out of tolerance production, an alternative method to intensive metrology efforts to process stability and part quality monitoring is presented in this article. The proposed method is based on the extraction of process and product fingerprints from the process regulating signals and the replication quality of dedicated features positioned on the injection molded component, respectively. The features used for this purpose are placed on the runner of the moldings and are similar or equal to those actually in the part, in order to assess the quality of the produced plastic parts. For the purpose of studying the method’s viability, a study case based on the production of polymer microfluidic systems for bio-analytics medical applications was selected. A statistically designed experiment was utilized in order to assess the sensitivity of the polymer biochip’s micro features (μ-pillars) replication fidelity with respect to the experimental treatments. The main effects of the process parameters revealed that the effects of process variation were dependent on the position of the μ-pillars. Results showed that a number of process fingerprints follow the same trends as the replication fidelity of the on-part μ-pillars. Instead, only one of the two on-runner μ-pillar position measurands can effectively serve as product fingerprints. Thus, the method can be the foundation for the development of a fast part quality monitoring system with the potential to decrease the use of off-line, time-consuming detailed metrology for part and tool approval, provided that the fingerprints are specifically designed and selected.

Filling-to-Packing Switchover Mode Based on Cavity Pressure for Injection Molding

2012 ◽  
Vol 501 ◽  
pp. 168-173 ◽  
Author(s):  
Jian Wang
Keyword(s):  
Injection Molding ◽  
Crucial Role ◽  
Mold Temperature ◽  
The Other ◽  
Injection Time ◽  
Cavity Pressure ◽  
Part Quality ◽  
Molded Parts ◽  
Screw Position

Filling-to-packing switchover control during injection molding plays a crucial role in ensuring the quality of the molded parts. In this study, a filling-to-packing switchover mode based on cavity pressure was presented, and it was compared with other two switchover modes by injection time and screw position. The objective of this study was to validate the accuracy of the switchover mode based on cavity pressure, and examine its consistency. Weight of the molded parts served as the main measure to probe the process capabilities. In this study, the change in mold temperature was monitored; variation of mold temperature affecting the process was examined. The results of the verification experiments revealed that the switchover mode based on cavity pressure could yield a better part quality and consistent part weight compared with the other two traditional switchover modes. It was proved that the switchover mode by cavity pressure can be used to improve the precision of the injection molding. However, a suitable switchover pressure must be used for achieving such high process capability, and the position to get the pressure signal and mold temperature should also be considered.

Direct Sinter Bonding of Metal Injection-Molded Parts to Solid Substrate Through Use of Deformable Surface Microfeatures

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Thomas Martens ◽  
M. Laine Mears
Keyword(s):  
Injection Molding ◽  
Solid Substrate ◽  
Metal Injection Molding ◽  
Full Density ◽  
Metal Powders ◽  
Molded Parts ◽  
Primary Obstacle ◽  
Injection Molded ◽  
Sinter Bonding ◽  
Micro Features

In the metal injection molding (MIM) process, fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density. Though able to create high-density parts of excellent dimensional control and surface finish, the MIM process is restricted in the size of part that can be produced, due to gravitational deformation during high-temperature sintering and maximum thickness requirements to remove the binding agents in the green state. Larger parts could be made by bonding the green parts to a substrate during sintering; however, a primary obstacle to this approach lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. In this work, we present a structure of micro features molded onto the surface of the MIM part, which bonds, deforms, and allows for shrinkage while bonding to the substrate. The micro features tolerate plastic deformation to permit the shrinkage without causing cracks after the initial bonds are established. In a first series of tests, bond strengths of up to 80% of that of resistance welds have been achieved. This paper describes how the authors developed their proposed method of sinter bonding and how they accomplished effective sinter bonds between MIM parts and solid substrates.

Study of the Structural Characteristics of Mold for Precise Injection Molding

2011 ◽  
Vol 291-294 ◽  
pp. 610-613
Author(s):  
Hong Lin Li ◽  
Zhi Xin Jia
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Structural Characteristics ◽  
Injection Mold ◽  
Industrial Products ◽  
Balance System ◽  
Molded Parts ◽  
Manufacturing Accuracy ◽  
Injection Molded

With the improvement of accuracy requirements for industrial products, the precise injection molding is replacing the traditional injection molding quickly and widely. Many factors influence the quality of injection-molded parts greatly, such as the property of the plastics, mold structure and the manufacturing accuracy, injecting machine and the injecting process parameters. In this paper, the work is emphasized for the influence of mold structure on the quality of injection-molded parts. Eight portions of injection mold are analyzed, including the cavities and cores, the guide components, the runner system, the ejection system, the side-core pulling mechanism, the temperature balance system, the venting system and the supporting parts. The structural characteristics of the above eight portions are presented.

Comparative study of rapid and conventional tooling for plastics injection molding

2017 ◽  
Vol 23 (2) ◽  
pp. 344-352 ◽  
Author(s):  
Gabriel Antonio Mendible ◽  
Jack A. Rulander ◽  
Stephen P. Johnston
Keyword(s):  
Injection Molding ◽  
Lower Cost ◽  
Rapid Tooling ◽  
Content Type ◽  
Part Quality ◽  
Molded Part ◽  
Molded Parts ◽  
Plastics Injection Molding ◽  
Rate Of Cooling ◽  
Manufacturing Techniques

Purpose This study aims to evaluate the performance of injection molding inserts produced via rapid and conventional manufacturing techniques considering the mechanical and thermal performance of the tools as well as the resulting molded part quality. Design/methodology/approach Three insert materials and manufacturing techniques were evaluated, jetted photopolymer (PolyJet) 3D printing using digital ABS, direct metal laser sintering (DMLS) using bronze and machining using stainless steel. Molding trials were performed, and the insert surface temperature, longevity and part properties were evaluated. Complementary information was acquired using computer simulation. Findings Similar behavior and part quality were observed in machined and DMLS inserts. The latter were used for 500 cycles without any signs of failure. PolyJet inserts had increased cycle time and slower rate of cooling which increased shrinkage and crystallinity in the molded parts. PolyJet inserts could be produced quickly at a lower cost than machined or DMLS inserts. Research limitations/implications Cooling within the insert was not studied; inserts were cooled indirectly by the mold plates behind them. Subsequent studies will incorporate cooling lines directly into the inserts. Originality/value Little research has been done to understand the thermal behavior of inserts manufactured via rapid tooling techniques. This study provides a direct comparison between rapid tooling techniques, which is supported by simulation results and analysis of the actual molding properties.

scholarly journals A Data Quality Control Program for Computer-Assisted Personal Interviews

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Janet E. Squires ◽  
Alison M. Hutchinson ◽  
Anne-Marie Bostrom ◽  
Kelly Deis ◽  
Peter G. Norton ◽  
...  
Keyword(s):  
Quality Control ◽  
Data Quality ◽  
Control Program ◽  
Quality Data ◽  
Computer Assisted ◽  
Data Quality Control ◽  
Process Data ◽  
Quality Control Program ◽  
High Quality Data

Researchers strive to optimize data quality in order to ensure that study findings are valid and reliable. In this paper, we describe a data quality control program designed to maximize quality of survey data collected using computer-assisted personal interviews. The quality control program comprised three phases: (1) software development, (2) an interviewer quality control protocol, and (3) a data cleaning and processing protocol. To illustrate the value of the program, we assess its use in the Translating Research in Elder Care Study. We utilize data collected annually for two years from computer-assisted personal interviews with 3004 healthcare aides. Data quality was assessed using both survey and process data. Missing data and data errors were minimal. Mean and median values and standard deviations were within acceptable limits. Process data indicated that in only 3.4% and 4.0% of cases was the interviewer unable to conduct interviews in accordance with the details of the program. Interviewers’ perceptions of interview quality also significantly improved between Years 1 and 2. While this data quality control program was demanding in terms of time and resources, we found that the benefits clearly outweighed the effort required to achieve high-quality data.

The Deformation Analysis and Optimization of the Injection Molded Parts Based on the Moldflow and Minitab Software

2013 ◽  
Vol 753-755 ◽  
pp. 1180-1183 ◽  
Author(s):  
Na Li ◽  
Hong Bin Liu ◽  
Hai Tao Wu
Keyword(s):  
Injection Molding ◽  
Process Parameters ◽  
Optimization Design ◽  
Deformation Analysis ◽  
Molded Parts ◽  
Injection Molded ◽  
The Common ◽  
Plastic Parts ◽  
Cae Technology

The deformation seriously affects the quality of the products, which is one of the common defects of plastic parts in the injection molding. Factorial design and CAE technology was used to study the product's warping rate influence in this paper. The minimum warping rate was obtained through the Minitab software and the optimized process parameters are verified with the Moldflow software. Experimental results show that the optimization design is effective and the warpage of the product is reduced.

End-Point Control of Holding Phase Based on Cavity Pressure for Injection Molding

2011 ◽  
Vol 221 ◽  
pp. 333-337
Author(s):  
Jian Wang ◽  
Peng Cheng Xie ◽  
Wei Min Yang
Keyword(s):  
Injection Molding ◽  
Control Method ◽  
Holding Time ◽  
Control Mode ◽  
Cavity Pressure ◽  
End Point ◽  
Sensor Position ◽  
Molded Parts ◽  
Point Control

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.

scholarly journals Injection Molding Development of Ceramic Turbine Components

1989 ◽  
Author(s):  
R. W. Ohnsorg ◽  
M. O. Ten Eyck ◽  
W. D. Friedman ◽  
P. Engler ◽  
G. J. Havrilla ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Volume ◽  
Field Trials ◽  
Development Project ◽  
Inlet Temperature ◽  
Development Programs ◽  
Control Variables ◽  
Part Quality ◽  
Molded Parts ◽  
Near Net Shape

Ceramic fabrication development of large static components has been an integral part of the U.S. Government sponsored gas turbine development programs. Carborundum has produced sintered alpha silicon carbide transition ducts which have been successfully tested in Garrett’s AGT 101 engine having a turbine inlet temperature of 2500°F. Injection molding as opposed to isopressing/green machining was chosen for the development project because of its near net shape capability and high volume potential. Mold design is important to minimize internal flaws and provide uniform green density. Injection molding control variables also influence external surface quality as determined by knit lines and blisters. Statistically designed three level experiments were instrumental in isolating the control variables which influence part quality and to determine their optimum values. Flow modeling was used to verify field trials and optimize specific molding variables to minimize pressure, shear rate and shear stress gradients within the part as well as suggest gating options. Destructive and nondestructive evaluation was then used to evaluate the quality of ducts at various processing steps. Dual energy tomography and X-ray fluorescence are being developed as techniques for measuring the density and composition of molded parts.

Status Analysis of Quality Prediction for Automotive Injection Molded Parts

2014 ◽  
Vol 998-999 ◽  
pp. 534-537 ◽  
Author(s):  
Chun Neng Wang ◽  
Xi Ying Fan
Keyword(s):  
Injection Molding ◽  
Coupling Effect ◽  
Kriging Model ◽  
Development Trend ◽  
Quality Prediction ◽  
Molded Parts ◽  
Injection Molded ◽  
Status Analysis ◽  
The Development Trend

Injection molding is a very complex multi-factor coupling effect and a nonlinear dynamic process. Therefore, under the influence of nonlinear and multi-factor, injection molding goal is to effectively predict and guarantee the quality of injection molded parts. In this paper, the common methods used to predict the quality of injection molded parts are introduced, including: Taguchi method, artificial neural network, response surface method, radial basis function method and Kriging model method. Research progresses as well as application examples of forecasting methods at home and abroad is summarized. Besides, the development trend of the injection molding quality prediction is discussed.

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