Fig 2 - uploaded by Andreas Schilling
Content may be subject to copyright.
Source publication
In this work, a toolchain for the solidification and the shrinkage of cast salt cores used in high-pressure die casting is implemented in the open-source computational fluid dynamics (CFD) library FOAM-extend to evaluate the displacements resulting from residual stresses. The toolchain consists of three stages, which first calculate the phase chang...
Context in source publication
Context 1
... other geometry used is a closed ring structure, Fig. 2, with a combined sprue and feeder on top. The structure refers to the The dies used in gravity casting, Fig. 3, consist of hot-work steel 1.234. The dies are divided into two halves, for the ring structure in a horizontal and the rod in a vertical dividing plane. Furthermore, the die of the ring structure has a movable center pin, ...
Citations
... Casting of salt cores offers complex geometries and the possibility of functional integration in lightweight components. Core viability is a decisive issue for the future process-safe use of salt in addition to process design through simulation of the cores and the die casting process [6]. The level of core loading in the die casting process is mainly attributed to the flow velocity of the impinging melt [3,7]. ...
In this work, a simulations study on the impact on gravity cast salt cores was carried out for the different casting parameters in high pressure die casting as well as in rheocasting. To compare the simulation results, salt cores were created in test casts and characteristic values were determined by means of a three-point bending test. The calculated loads on the cores were determined and aligned with the bending strength. Salt cores in rheocasting showed reduced loads and tend to increase core viability compared to conventional hpdc.
In this work, the high-strength composite salt cores reinforced by corundum powder were successfully prepared using 30 mol% Na2SO4 +70 mol% NaCl as the matrix materials, which can be used to fabricate hollow aluminum alloy die castings with complex structures. The influences of the content and size of corundum powder on properties and microstructures of Na2SO4-NaCl composite salt cores were investigated, and the strengthening mechanisms of the salt cores were analyzed. The results show that the flexure strength of Na2SO4-NaCl composite salt cores increases first and then decreases with the increase of the corundum powder content, and appropriately reducing the corundum powder size is beneficial to improving the flexure strength. The maximum flexure strength of Na2SO4-NaCl composite salt cores reinforced by corundum powder with multi-size hybrid can reach 59.08 MPa, increasing by 219.3% compared with the unreinforced salt cores, and the linear shrinkage rate and water-solubility rate are 1.56% and 231.9 g/(min·m²), respectively. The microscopic analysis shows that the corundum powder can remarkably refine the NaCl primary phase, which completely changes from coarse dendrites to fine equiaxed crystals, improving the flexure strength. Meanwhile, the flexure strength enhancement is also attributed to prolonging the crack propagation path.
The quality control of plastic products is an essential aspect of the plastic injection molding (PIM) process. However, the warpage and shrinkage deformations continue to exist because the PIM process is easily interfered with by several related or independent process parameters. Thus, great efforts have been devoted to optimizing process parameters to minimize the warpage and shrinkage deformations of products during the last decades. In this review, we begin by introducing the manufacturing process in PIM and the cause of warpage and shrinkage deformations, followed by the mechanism about how process parameters, like mold temperature, melt temperature, injection rate, injection pressure, holding pressure, holding and cooling duration, affect those defects. Then, we summarize the recent progress of the design of experiments and four advanced methods (artificial neural networks, genetic algorithm, response surface methodology, and Kriging model) on optimizing process parameters to minimize the warpage and shrinkage deformations. In the end, future perspectives of quality control in injection molding machines are discussed.
