Runner Optimization for In-Mold Assembly of Multi-Material Compliant Mechanisms

Author(s):  
Wojciech Bejgerowski ◽  
Satyandra K. Gupta

The runner system in injection molding process is used to supply the polymer melt from injection nozzle to the gates of final part cavities. Realizing complex multi-material mechanisms by in-mold assembly process requires special runner layout design considerations due to the existence of the first stage components. This paper presents the development of an optimization approach for runner systems in the in-mold assembly of multi-material compliant mechanisms. First, the issues specific to the in-mold assembly process are identified and analyzed. Second, the general optimization problem is formulated by identification of all parameters, design variables, objective functions and constraints. Third, the implementation of the optimization problem in Matlab® environment is described based on a case study of a runner system for an in-mold assembly of a MAV drive mechanism. This multi-material compliant mechanism consists of seven rigid links interconnected by six compliant hinges. Finally, several optimization approaches are analyzed to study their performance in solving the formulated problem. The most appropriate optimization approach is selected. The case study showed the applicability of the developed optimization approach to runner systems for complex in-mold assembled multi-material mechanism designs.

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 369-376 ◽  
Author(s):  
Małgorzata Chwał ◽  
Aleksander Muc

AbstractA simplified procedure has been developed to optimize the molding processes of thermosetting resins. The proposed methodology involves the classical finite element commercial package (NISA II v. 17). Here, the theoretical background and numerical implementation of the procedure are described. Various design variables that can describe the RIM are discussed. The solved example represents the influence of the heating regime on the curing process. The results are compared with the results obtained with the use of full analysis conducted with the aid of the finite volume analysis (filling and curing stages). They demonstrate the evident advantages of using the simplified optimization approach.


2021 ◽  
Author(s):  
Hugo Miguel Silva ◽  
João Tiago Noversa ◽  
Leandro Fernandes ◽  
Hugo Luís Rodrigues ◽  
António José Pontes

Abstract Fabricating conformal cooling channels (CCCs) has become easier and more cost-effective because to recent advances in additive manufacturing. CCCs provide better cooling performance in the injection molding process than regular (straight drilled) channels. The main reason for this is that CCCs can follow the molded geometry's paths, but regular machining methods cannot. Thermal stresses and warpage can be reduced by using CCCs, which also improve cycle time and provide a more uniform temperature distribution. Traditional channels, on the other hand, have a more involved design technique than CCC. Computer-aided engineering (CAE) simulations are essential for establishing an effective and cost-effective design. The sensitivity analysis of design variables is the emphasis of this research, with the goal of establishing a design optimization approach in the future. The ultimate goal is to optimize the location of Cooling Channels (CCs) in order to reduce ejection time and increase temperature uniformity. It can be concluded that the parametrization performed in ANSYS Parametric Design Language (APDL), as well as the design variables used, can be applied in practice and could be relevant in future optimization approaches.


2017 ◽  
Vol 52 (14) ◽  
pp. 1971-1986 ◽  
Author(s):  
T Vo-Duy ◽  
T Truong-Thi ◽  
V Ho-Huu ◽  
T Nguyen-Thoi

The paper presents an efficient numerical optimization approach to deal with the optimization problem for maximizing the fundamental frequency of laminated functionally graded carbon nanotube-reinforced composite quadrilateral plates. The proposed approach is a combination of the cell-based smoothed discrete shear gap method (CS-DSG3) for analyzing the first natural frequency of the functionally graded carbon nanotube reinforced composite plates and a global optimization algorithm, namely adaptive elitist differential evolution algorithm (aeDE), for solving the optimization problem. The design variables are the carbon nanotube orientation in the layers and constrained in the range of integer numbers belonging to [−900 900]. Several numerical examples are presented to investigate optimum design of quadrilateral laminated functionally graded carbon nanotube reinforced composite plates with various parameters such as carbon nanotube distribution, carbon nanotube volume fraction, boundary condition and number of layers.


2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Hong Zhou

The hybrid discretization model for topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. Each design cell is further subdivided into triangular analysis cells. This hybrid discretization model allows any two contiguous design cells to be connected by four triangular analysis cells whether they are in the horizontal, vertical, or diagonal direction. Topological anomalies such as checkerboard patterns, diagonal element chains, and de facto hinges are completely eliminated. In the proposed topology optimization method, design variables are all binary, and every analysis cell is either solid or void to prevent the gray cell problem that is usually caused by intermediate material states. Stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum and to avoid the need to choose the initial guess solution and conduct sensitivity analysis. The obtained topology solutions have no point connection, unsmooth boundary, and zigzag member. No post-processing is needed for topology uncertainty caused by point connection or a gray cell. The introduced hybrid discretization model and the proposed topology optimization procedure are illustrated by two classical synthesis examples of compliant mechanisms.


Author(s):  
Charles B. Theurer ◽  
Li Zhang ◽  
David Kazmer ◽  
Robert X. Gao

This paper presents the design, analysis, and validation of a self-energized piezoelectric pressure sensor that extracts energy from the pressure differential of the polymer melt during the injection molding process. To enable a self-energized sensor design, an analytical study has been conducted to establish a quantitative relationship between the polymer melt pressure and the energy that can be extracted through a piezoelectric converter. Temperature and pressure are monitored during an injection molding cycle and the performance of the piezoelectric element is evaluated with respect to a mechanically static, electrically transient model. In addition to corroboration of the proposed model, valuable statistical information about the working temperature in the prototype sensor will prove very useful in the package design of molding cavity sensors. A linear model examining the energy conversion mechanism due to interactions between the mechanical strain and the electric field developed within the piezoelectric device is established. This model is compared to the functional prototype design to evaluate the relevance of the assumptions and accuracy. The presented design enables a new generation of self-energized sensors that can be employed for the condition monitoring of a wide range of high-energy manufacturing processes.


Author(s):  
Juan C. Blanco ◽  
Luis E. Muñoz

The vehicle optimal design is a multi-objective multi-domain optimization problem. Each design aspect must be analyzed by taking into account the interactions present with other design aspects. Given the size and complexity of the problem, the application of global optimization methodologies is not suitable; hierarchical problem decomposition is beneficial for the problem analysis. This paper studies the handling dynamics optimization problem as a sub-problem of the vehicle optimal design. This sub-problem is an important part of the overall vehicle design decomposition. It is proposed that the embodiment design stage can be performed in an optimal viewpoint with the application of the analytical target cascading (ATC) optimization strategy. It is also proposed that the design variables should have sufficient physical significance, but also give the overall design enough design degrees of freedom. In this way, other optimization sub-problems can be managed with a reduced variable redundancy and sub-problem couplings. Given that the ATC strategy is an objective-driven methodology, it is proposed that the objectives of the handling dynamics, which is a sub-problem in the general ATC problem, can be defined from a Pareto optimal set at a higher optimization level. This optimal generation of objectives would lead to an optimal solution as seen at the upper-level hierarchy. The use of a lumped mass handling dynamics model is proposed in order to manage an efficient optimization process based in handling dynamics simulations. This model contains detailed information of the tire properties modeled by the Pacejka tire model, as well as linear characteristics of the suspension system. The performance of this model is verified with a complete multi-body simulation program such as ADAMS/car. The handling optimization problem is presented including the proposed design variables, the handling dynamics simulation model and a case study in which a double wishbone suspension system of an off-road vehicle is analyzed. In the case study, the handling optimization problem is solved by taking into account couplings with the suspension kinematics optimization problem. The solution of this coupled problem leads to the partial geometry definition of the suspension system mechanism.


Author(s):  
Zhaoyan Fan ◽  
M. Haris Hamid ◽  
Robert X. Gao ◽  
Stephen Johnston ◽  
David Kazmer

This paper presents the design and optimization of a temperature-pressure sensing module that is structurally integrated into an injection mold. The sensor extracts energy from the polymer melt pressure differential during the injection molding process and uses ultrasonic pulses as the wireless information transmission carrier. The dimension of the piezo ceramic rings that scavenge energy from the mold pressure change is optimized to minimize the volume of the sensor while maintaining the minimum Signal-to-Noise Ratio (SNR) required for reliable signal reception. An analytical expression of the optimal dimension is presented. Based on the optimized design, the sensor module package, together with the injection mold steel and the polymer melt that flows over the sensor into the mold cavity, was modeled using the finite element method. To quantify the behavior of polymer melt and its effect on sensors output, a coupled fluid-structure interaction analysis was performed to examine the mold-melt interface, by using the solution-looping and mesh-morphing techniques. A case study of the sensor design for a 40 mm thick injection mold was investigated by using the presented optimization method and FEA model. Results show that the volume of the piezo stack can be reduced to 0.7 cm3 while meeting the minimum SNR requirement. The minimum insulator thickness of 1 mm is presented by the FEA model to maintain the thermal induced error below 0.5%.


2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Hong Zhou ◽  
Pranjal P. Killekar

The modified quadrilateral discretization model for the topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. There is a certain location shift between two neighboring rows of quadrilateral design cells. This modified quadrilateral discretization model allows any two contiguous design cells to share an edge whether they are in the horizontal, vertical, or diagonal direction. Point connection is completely eliminated. In the proposed topology optimization method, design variables are all binary, and every design cell is either solid or void to prevent gray cell problem that is usually caused by intermediate material states. Local stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum. No postprocessing is required for topology uncertainty caused by either point connection or gray cell. The presented modified quadrilateral discretization model and the proposed topology optimization procedure are demonstrated by two synthesis examples of compliant mechanisms.


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