Rosa Amalia Morales

The evaluation of the state of dispersion in immiscible blends where the minor phase exhibits fractionated crystallization

SummaryDifferential Scanning Calorimetry (DSC) can provide a qualitative measure of the state of dispersion of an immiscible blend if the minor phase exhibits fractionated crystallization when dispersed into fine particles. The technique is only sensitive to the volume of the dispersed particle and not to its shape and can only be used when the exotherms of interest do not overlap with other thermal transitions present in the multicomponent system. Selfnucleation is a valuable tool to ascertain the presence of fractionated crystallization. The morphology induced by fractionated crystallization in immiscible blends could lead to enhanced plastic deformation during yielding of the matrix.

Effect of the Finite Element Meshing for Designing Plastic Pieces

Abstract The objective of this work was to modify the simulation mesh model characteristics (critical areas evaluation, mesh density, and elements size) of a commercial compact disk (CD) case by using computer-aided design (CAD) and computer aided engineer (CAE) software. The designing process was carried out by studying the geometry and dimensions of the three pieces (cover, holder, and base) that form commercial and optimized CD cases.The mesh model was obtained using 3D (three dimensional) modeler software and the simulation results were obtained using a simulation program typically used for the injection-molding process. The exposed designs were evaluated and different mesh model characteristics were established. The filling time, cycle time, and residual stress concentration seemed to be influenced by the nodes number model. An analysis of the results of the simulations showed remarkable differences when a high number of nodes in the mesh model were used.

Influence of Geometrical Factors on Cavity Pressure During the Injection Molding Process

The influence of the geometrical factors of plastic parts (shape factor, thickness, length/thickness ratio, and section changes) on the behavior of the cavity pressure during the injection process was studied. The instrumentation of injection molds was proposed, placing pressure transducers in the more critical zones of the parts. The evaluation of the molds was made using solid modelator and simulator software of the injection process with different polymers. The geometric factors determine the processing conditions to be used, the behavior of the cavity pressure during filling and postfilling phases, the cooling, and the dimensional stability of the part.

Mold Design Optimization for Security Caps Used in the Pharmaceutical Industry

Abstract: The main purpose of this study was to design and evaluate an injection mold in order to make a security cap for pharmaceutical bottles using the tools found in the computer-aided design (CAD) and computer-aided engineer (CAE) software. The process design included studying the geometry and dimensions of the two pieces (internal and external) that constitute the security cap. Two mold designs were proposed: a four-cavity one with a type “x” distribution and removable core, and eight-cavity design with a type “x” family-mold distribution. They both were designed with the finality of modeling the internal and external pieces that form part of the security cap into one single mold. Two different cavity dispositions were evaluated for this design. Additionally, several cooling systems were evaluated using the injection process simulator program, C-MOLD. The most efficient cooling system was selected and it was used in simulations with a four-cavity mold to produce the internal and external pieces. Afterwards, another simulation was carried out using the same cooling system for the eight-cavity mold. The exposed designs were evaluated establishing different kinds of operative conditions until optimal process conditions were met. Finally, two injection molds were proposed: One with four cavities and a removable core, and another one with eight cavities that could allow the production of both pieces at the same time. Also, both molds were designed using the solid modeling Pro/ENGINEER software. The family molds showed more reliability, with an increase of 12% in the cycle time, compared to the molds with four cavities and a removable core.