Prediction of the maximum flow length of a thin injection molded part

Liparoti, Sara; Speranza, Vito; Meo, Annarita De; Santis, Felice De; Pantani, Roberto

doi:10.1515/polyeng-2019-0292

Cited by 7 publications

(5 citation statements)

References 22 publications

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“…This result is consistent with those reported in the literature about flow filling length in micro-injection molding. It was reported that, with a settled 40 MPa filling pressure (that is lower than the pressure adopted in this work), a 140 °C mold temperature is necessary to obtain about a 40 mm filling length; furthermore, filling length improves with the increase in filling pressure [21].…”

Section: Resultsmentioning

confidence: 88%

“…In a previous work [21], a simple equation was provided to predict the final length, L f , of a polymer flowing in a rectangular cavity of thickness H:…”

Section: Resultsmentioning

confidence: 99%

“…As the process proceeds, viscosity increases due to the reduction of temperature and shear rate. At d = 1, which corresponds to the cavity surface, viscosity is the highest (10 7 Pa s) since the no-flow temperature is suddenly reached in that position [21]. At further distances from the cavity surface, viscosity decreases due to the flow, according to the implemented Cross model [29].…”

Section: µIm Simulationsmentioning

confidence: 98%

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Analysis of Weld Lines in Micro-Injection Molding

Liparoti,

De Piano,

Salomone

et al. 2023

Materials

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Micro-injection molding (µIM) is a widespread process for the production of plastic parts with at least one dimension, or feature, in the microscale (conventionally below 500 µm). Despite injection molding being recognized as a robust process for obtaining parts with high geometry accuracy, one last occurrence remains a challenge in micro-injection molding, especially when junctions are present on the parts: the so-called weld lines. As weld lines are crucial in determining mechanical part performances, it is mandatory to clarify weld line position and characteristics, especially at the industrial scale during mold design, to limit failure causes. Many works deal with weld lines and their dependence on processing parameters for conventional injection molding, but only a few works focus on the weld line in µIM. This work examines the influence of mold temperature on the weld line position and strength by both experimental and simulation approaches in µIM. At mold temperatures below 100 °C, only short shots were obtained in the chosen cavity. At increased mold temperatures, weld lines show up to a 40% decrease in the whole length, and the overall tensile modulus doubles. This finding can be attributed to the reduction of the orientation at the weld line location favored by high mold temperatures. Moldflow simulations consistently reproduce the main features of the process, weld line position and length. The discrepancy between experimental and simulated results was attributed to the fact that crystallization in flow conditions was not accounted for in the model.

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Section: Resultsmentioning

confidence: 88%

“…In a previous work [21], a simple equation was provided to predict the final length, L f , of a polymer flowing in a rectangular cavity of thickness H:…”

Section: Resultsmentioning

confidence: 99%

Section: µIm Simulationsmentioning

confidence: 98%

See 1 more Smart Citation

Analysis of Weld Lines in Micro-Injection Molding

Liparoti,

De Piano,

Salomone

et al. 2023

Materials

Self Cite

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“…Data such as the speed of the piston with respect to the injection time, the pressure exerted on the injection polymers, the filling time of the mold cavity and the position of the closing tools are one of the most used [51]. Various systems have been developed in order to improve the efficiency of the injection molding processes.…”

Section: State Of the Artmentioning

confidence: 99%

Integration of CAE Modeling and Artificial Intelligence Systems to Support Manufacturing of Plastic Microparts

Rojas

Chaves

Bolivar

et al. 2019

2019 Congreso Internacional De Innovación Y Tendencias en Ingenieria (CONIITI )

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“…Furthermore, research papers [3][4][5][6] investigated the influence of other process parameters, specifically pressure and temperature, on final flow length. The influence of process parameters was also investigated in publications [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

The influence of tool’s surface topography on mechanical properties of injection moulded product

Ovsík

Staněk

Dockal

et al. 2022

Surf. Topogr.: Metrol. Prop.

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This publication deals with influence of tool topography (injection mould) on properties of a product. Surface of the mould was machined by various finishing technologies (milling, grinding, polishing and electrical discharge machining) which resulted in varying surface quality of the tool. The tested topography had an effect on the flow length of polymer and topographical and mechanical properties of the specimen. Examined properties (surface topography and mechanical properties) were measured in several places along the length of the product (starting at the gate and finishing at the end of the specimen). The results show that increase of the tool’s surface roughness leads to longer flow length. These findings disprove the necessity for polishing of each and every shaping part of the mould when manufacturing non-visual products. Thus, from economical and manufacturing perspective the milled or grinded tool surfaces are sufficient. Furthermore, replication of the tool’s topography is non-homogenous, which results in varying mechanical properties throughout the product. The discrepancy in mechanical properties along the length of the product is caused by differing cooling speeds in the mould. In practice, guided cooling can be used to achieve varying mechanical properties in desired places of the injected article. For example, highly stressed parts can be manufactured with the goal of having improved mechanical properties in specific places of the product. Future application of these findings poses a significant benefit for industrial practice, as it could lower the manufacturing cost of the injection mould in order of tens of percent.

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Prediction of the maximum flow length of a thin injection molded part

Cited by 7 publications

References 22 publications

Analysis of Weld Lines in Micro-Injection Molding

Analysis of Weld Lines in Micro-Injection Molding

Integration of CAE Modeling and Artificial Intelligence Systems to Support Manufacturing of Plastic Microparts

The influence of tool’s surface topography on mechanical properties of injection moulded product

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