Surface analysis of injection molded TV components

Skands, Ulrik; Wahlberg, Pia; Christensen, Leif Højslet; Palfelt, B.; Borregaard, Louise M.; Alexandersen, N.B.; Johansen, Tonni Franke; Rønning, A.; Russ, John C.

doi:10.1016/s0890-6955(97)00092-8

Cited by 4 publications

(2 citation statements)

References 1 publication

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“…could be solved [1][2][3][4][5][6][7] , and considerably the subsequent coating process which is harmful to the environment could be left out [8] . In addition, injection speed, injection pressure and residual stress of the polymer part could be changed better relatively.…”

Section: Introductionmentioning

confidence: 99%

Research on a New Variotherm Injection Molding Technology and its Application on the Molding of a Large LCD Panel

Wang

Zhao

et al. 2009

Polymer-Plastics Technology and Engineering

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The polymer injection products produced by using the current injection molding method usually have many defects, such as short shot, jetting, sink mark, flow mark, weld mark, and floating fibers. These defects have to be eliminated by using post-processing processes such as spraying and coating, which will cause environment pollution and waste in time, materials, energy and labor. These problems can be solved effectively by using a new injection method, named as variotherm injection molding or rapid heat cycle molding (RHCM). In this paper, a new type of dynamic mold temperature control system using steam as heating medium and cooling water as coolant was developed for variotherm injection molding. The injection mold is heated to a temperature higher than the glass transition temperature of the resin, and keeps this temperature in the polymer melt filling stage. To evaluate the efficiency of steam heating and coolant cooling, the mold surface temperature response during the heating stage and the polymer melt temperature response during the cooling stage were investigated by numerical thermal analysis. During heating, the mold surface temperature can be raised up rapidly with an average heating speed of 5.4 C/s and finally reaches an equilibrium temperature after an effective heating time of 40 s. It takes about 34.5 s to cool down the shaped polymer melt to the ejection temperature for demolding. The effect of main parameters such as mold structure, material of mold insert on heating/cooling efficiency and surface temperature uniformity were also discussed based on simulation results. Finally, a variotherm injection production line for 46-inch LCD panel was constructed. The test production results demonstrate that the mold temperature control system developed in this study can dynamically and efficiently control mold surface temperature without increasing molding cycle time. With this new variotherm injection molding technology, the defects on LCD panel surface occurring in conventional injection molding process, such as short shot, jetting, sink mark, flow mark, weld mark, and floating fibers were eliminated effectively. The surface gloss of the panel was improved and the secondary operations, such as sanding and coating, are not needed anymore.

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Section: Introductionmentioning

confidence: 99%

Research on a New Variotherm Injection Molding Technology and its Application on the Molding of a Large LCD Panel

Wang

Zhao

et al. 2009

Polymer-Plastics Technology and Engineering

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“…Choosing which of these various roughness parameters is the most relevant to describe a surface topography of a specific application remains a difficult task of paramount importance [23][24][25][26][27]. Most often, practitioners retain a restrictive set of roughness parameters [28,29]. In an industrial environment, practitioners often decide to select normalized roughness parameters that are widely recognized by the profession [30].…”

Section: Limitations Of Conventional Analysesmentioning

confidence: 99%

Multiscale morphology of high-precision turning process surfaces

Bigerelle

Gorp

Gautier

et al. 2007

Proceedings of the Institution of Mechanical Engineers, Part B:

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The characterization of functional surfaces is done mainly by roughness which can be quantified by many parameters. In order to select relevant roughness parameters, a multiscale discriminant method is proposed and applied to characterize high-precision turned surfaces. First, surfaces are characterized by a single roughness parameter and secondly by a pair of roughness parameters. In all cases, the most relevant evaluation length is also determined for each parameter. The results obtained on four different samples show that the most relevant roughness parameter is Rk estimated on a 10μm evaluation length. The best pair of parameters is Δa and Ri, estimated respectively on 20μm and 100μm evaluation lengths. Rk well characterizes the microroughness, which seems to be mainly representative of the roughness of high-precision machined surfaces. However, only multiscale analyses with a pair of roughness parameters can characterize both the macroscopic and microscopic morphologies of machined surfaces.

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Surface microstructure replication in injection molding

Theilade

Hansen

2006

Int J Adv Manuf Technol

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Surface analysis of injection molded TV components

Cited by 4 publications

References 1 publication

Research on a New Variotherm Injection Molding Technology and its Application on the Molding of a Large LCD Panel

Research on a New Variotherm Injection Molding Technology and its Application on the Molding of a Large LCD Panel

Multiscale morphology of high-precision turning process surfaces

Surface microstructure replication in injection molding

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