Piccadilly Booksellers and Conservative Sociability

Fallon, David

doi:10.1017/9781107587779.004

Cited by 1 publication

(2 citation statements)

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“…Gas penetration in the postfilling stage is called secondary gas penetration . Compared with conventional injection molding (CIM), GAIM can substantially reduce operating expenses by reductions in material costs, lowered injection‐pressure and clamp‐tonnage requirements, and reductions in cycle times for thick‐walled parts 1–12. In addition, some of the molding issues encountered in CIM of large parts, such as sink marks, residual stresses, distortion, and warpage may also be greatly reduced when GAIM is used instead.…”

Section: Introductionmentioning

confidence: 99%

“…Computer simulation3, 7, 8 has become an important and required aid in part design, mold design, and process evaluation in recent years. However, fundamental studies concerning the effect of gas channel design and molding conditions on gas penetration5–8 and part properties10–19 are also required to build quantitative design and molding guidelines to assist in the application of GAIM. The design of gas channels guiding gas penetration to desired locations is the most critical issue.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of gas channel design on the molding window of gas‐assisted‐injection‐molded polystyrene parts

Chien¹,

Chen²,

Lin³

et al. 2003

J of Applied Polymer Sci

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Gas channel design plays a dominant role in determining the successful application of gas-assisted injection molding. Although empirical guidelines for gas channel design have been proposed by the various equipment suppliers, quantitative criteria based on well-designed experiments have not been reported yet. In this study, transparent polystyrene plates designed with semicircular gas channels of different radii and with rectangular gas channels of different width-to-height ratios were gas-assisted-injectionmolded to investigate the geometrical effects on gas penetration with various plate thicknesses. Plate parts designed with gas channels having four different types of cross sections but with the same section area were also examined. Molding windows and criteria for gas penetration were properly chosen so that the design rule could be defined quantitatively. The moldability index was also classified into five levels (excellent, good, fair, poor, and bad) based on the relative areas of the molding windows. From a plot of the moldability index versus the ratio of the equivalent gas channel radius to the plate thickness, we found that the ratio should be approximately greater than 2 for an appropriate molding window (fair moldability index) to be obtained. The dimensional ratio of the width to the height for rectangular gas channels also affected the moldability index under the same equivalent radius. Meanwhile, for four gas channel designs, both gas channel designs attached to the top rib provided better moldability than the other designs. This investigation offers part designers preliminary quantitative design and molding guidelines for choosing an effective gas channel design that allows the parts to be molded under an appropriate molding window so that the uncertainty in both simulation and process control can be overcame. Furthermore, this study provides a methodology for the establishment of quantitative gas channel design guidelines.

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Section: Introductionmentioning

confidence: 99%