Core deflection in injection molding

Giacomin, A. Jeffrey; Hade, Aaron J.; Johnson, L. M.; Mix, A. W.; Chen, Yi‐Chang; Liao, Hui-Chen; Tseng, Shi‐Chang

doi:10.1016/j.jnnfm.2011.04.005

Cited by 19 publications

(32 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our apparatus is robust, and its tempered glass window can be reused without breaking. We find qualitative agreement with the Newtonian analysis of Giacomin and Hade [1] , though we have discovered an inflection in core deflection near the origin. Our apparatus also precisely records the curious phenomenon of core recoil that happens just before the core comes to rest.…”

Section: Resultssupporting

confidence: 85%

“…Figure 9 also records an inflection, from concave up to down, just after the core begins to deflect. This inflection differs from the analysis of Giacomin and Hade [1] . Figure 9 also shows the slight and rapid core recoil beginning at about 89% and completing before 94%.…”

Section: Resultscontrasting

confidence: 83%

“…Interestingly, our flow analysis neglects normal stress difference effects that are known to enhance core deflection [4] . The shapes of the curves in Figure 9, concave down, are a good qualitative match for the fifth-order ordinary differential equation for core deflection of Giacomin and Hade [1] . Figure 9 also records an inflection, from concave up to down, just after the core begins to deflect.…”

Section: Resultsmentioning

confidence: 62%

“…Giacomin and Hade [1] have used dimensional analysis to obtain a fifth order ordinary differential equation for core deflection. They applied a 1-D flow analysis applied to a flat rectangular core in a flat rectangular cavity.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Core Deflection in Plastics Injection Molding: Direct Measurement, Flow Visualization and 3D Simulation

Chen

Liao

Tseng

et al. 2011

Polymer-Plastics Technology and Engineering

Self Cite

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 85%

Section: Resultscontrasting

confidence: 83%

Section: Resultsmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Core Deflection in Plastics Injection Molding: Direct Measurement, Flow Visualization and 3D Simulation

Chen

Liao

Tseng

et al. 2011

Polymer-Plastics Technology and Engineering

Self Cite

View full text Add to dashboard Cite

“…Process parameters could be one cause 4 as well as an asymmetric part or inlet design or an unbalanced venting. 5 Already in 1981, Bangert 6 presented an approach to calculate the core shift. The notion that the core shift results from pressure differences on the core surface in the process is essential.…”

Section: Basicsmentioning

confidence: 99%

Measuring mechanical stresses on inserts during injection molding

Heinle

Drummer

2015

Advances in Mechanical Engineering

View full text Add to dashboard Cite

Assembly molding presents an interesting approach to innovative product solutions. Here, individual components can be simultaneously positioned, affixed, and provided with a casing. However, while overmolding elements in the mold cavity with hot polymer melt, high mechanical loads occur on, in some cases, very sensitive components such as electronic devices. For the design of such systems, it is important to know these stresses, the influences on their quantities, and mathematical options for their prediction. In this article, a new measurement method for determining the forces acting on a small element in the cavity during the injection molding process in three dimensions is presented. Therefore, a new installation method for a force sensor was developed. The results in this article concentrate on force changes during one molding cycle. Our research shows that there are different mechanical load spectra in the different phases of the molding process. For example, the force component in flow direction on an element in the cavity is positive in the direction of the flow during filling. However, after the filling step, the force becomes negative due to the contraction of the injected material and results in a continuously increasing permanent force.

show abstract

Exact Analytical Solution for Large‐Amplitude Oscillatory Shear Flow

Saengow

Giacomin

Kolitawong

2015

Macro Theory & Simulations

View full text Add to dashboard Cite

When polymeric liquids undergo large‐amplitude shearing oscillations, the shear stress responds as a Fourier series, the higher harmonics of which are caused by fluid nonlinearity. Previous work on large‐amplitude oscillatory shear flow has produced analytical solutions for the first few harmonics of a Fourier series for the shear stress response (none beyond the fifth) or for the normal stress difference responses (none beyond the fourth) [JNNFM, 166, 1081 (2011)], but this growing subdiscipline of macromolecular physics has yet to produce an exact solution. Here, we derive what we believe to be the first exact analytical solution for the response of the extra stress tensor in large‐amplitude oscillatory shear flow. Our solution, unique and in closed form, includes both the normal stress differences and the shear stress for both startup and alternance. We solve the corotational Maxwell model as a pair of nonlinear‐coupled ordinary differential equations, simultaneously. We choose the corotational Maxwell model because this two‐parameter model (η0 and λ) is the simplest constitutive model relevant to large‐amplitude oscillatory shear flow, and because it has previously been found to be accurate for molten plastics (when multiple relaxation times are used). By relevant we mean that the model predicts higher harmonics. We find good agreement between the first few harmonics of our exact solution, and of our previous approximate expressions (obtained using the Goddard integral transform). Our exact solution agrees closely with the measured behavior for molten plastics, not only at alternance, but also in startup.

show abstract

Core deflection in injection molding

Cited by 19 publications

References 3 publications

Core Deflection in Plastics Injection Molding: Direct Measurement, Flow Visualization and 3D Simulation

Core Deflection in Plastics Injection Molding: Direct Measurement, Flow Visualization and 3D Simulation

Measuring mechanical stresses on inserts during injection molding

Exact Analytical Solution for Large‐Amplitude Oscillatory Shear Flow

Contact Info

Product

Resources

About