Filling behavior of micro-ribs on injection molded parts depending on micro-structure orientation and processing parameters

Lucyshyn, Thomas; Burgsteiner, Martin; Graninger, Georg; Holzer, Clemens

doi:10.1063/1.4965460

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Because of the small part thickness, the process is subjected to filling difficulties caused by premature freezing of the polymer inside the cavity . Furthermore, high temperature and elevated injection speed are applied to reproduce small features in the conventional process to reduce melt viscosity . Consequently, the materials experience high stresses and shear rates.…”

Section: Introductionmentioning

confidence: 99%

Dynamic local temperature control in micro‐injection molding: Effects on poly(lactic acid) morphology

Meo

Santis

Pantani

2017

Polymer Engineering & Sci

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Microinjection molding is one of the most efficient processes for wide‐scale production of thermoplastic polymer microparts. The injection molding process with a cold mold suffers from drawbacks, that is, the premature solidification, caused by the small thickness and large temperature difference between the surface of the mold and the incoming polymer. In this work, an original and versatile system to dynamically control the local temperature of the cavity surfaces in microinjection molding was developed. The system was used to investigate the effects of rapid variations of the temperature of a 200 μm thick cavity on the reachable flow length and study the morphology of microinjection molded parts of poly(lactic acid). For the rapid mold temperature control, electrical resistive thin components are located very near the surface of the impression to change the temperature by some tens of degrees per second. This study also demonstrates that the system is able to influence the final morphology of the part with a semicrystalline thermoplastic material. Changing the annealing time and temperature, the effects on the morphology of the part, in the mold and immediately after the injection, were investigated by microscopy analysis and X‐ray diffraction. POLYM. ENG. SCI., 58:586–591, 2018. © 2017 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Dynamic local temperature control in micro‐injection molding: Effects on poly(lactic acid) morphology

Meo

Santis

Pantani

2017

Polymer Engineering & Sci

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“…36 For the molds, we used metal ceramic heating (MCH) elements because of their thin profiles and high wattage; they have also been previously described for variotherm heating. 83–86 The portions of both A and B plates behind the cavities were hollowed out to enable the variotherm process (Fig. 2C).…”

Section: Resultsmentioning

confidence: 99%

Rapid microfluidics prototyping through variotherm desktop injection molding for multiplex diagnostics

Suarez¹,

Bayer²,

Suarez³

et al. 2023

Lab Chip

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“…Form filling and adequate demolding, already challenging in the molding of microfeatures, become even more delicate when replicating features at the submicron level. While the filling of cavities is attributed to the melt injection temperature and mold temperature [ 9 , 10 , 11 ], these replication-enhancing parameters also affect the demolding forces [ 12 ]. Acting forces in injection molding are the thermal contraction force related to the polymer, friction forces, adhesive forces and stiction, as well as a deformation force during the ejection stage [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Direct Processing of PVD Hard Coatings via Focused Ion Beam Milling for Microinjection Molding

2023

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Hard coatings can be applied onto microstructured molds to influence wear, form filling and demolding behaviors in microinjection molding. As an alternative to this conventional manufacturing procedure, “direct processing” of physical-vapor-deposited (PVD) hard coatings was investigated in this study, by fabricating submicron features directly into the coatings for a subsequent replication via molding. Different diamondlike carbon (DLC) and chromium nitride (CrN) PVD coatings were investigated regarding their suitability for focused ion beam (FIB) milling and microinjection molding using microscope imaging and areal roughness measurements. Each coating type was deposited onto high-gloss polished mold inserts. A specific test pattern containing different submicron features was then FIB-milled into the coatings using varied FIB parameters. The milling results were found to be influenced by the coating morphology and grain microstructure. Using injection–compression molding, the submicron structures were molded onto polycarbonate (PC) and cyclic olefin polymer (COP). The molding results revealed contrasting molding performances for the studied coatings and polymers. For CrN and PC, a sufficient replication fidelity based on AFM measurements was achieved. In contrast, only an insufficient molding result could be obtained for the DLC. No abrasive wear or coating delamination could be found after molding.

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Filling behavior of micro-ribs on injection molded parts depending on micro-structure orientation and processing parameters

Cited by 5 publications

References 10 publications

Dynamic local temperature control in micro‐injection molding: Effects on poly(lactic acid) morphology

Dynamic local temperature control in micro‐injection molding: Effects on poly(lactic acid) morphology

Rapid microfluidics prototyping through variotherm desktop injection molding for multiplex diagnostics

Direct Processing of PVD Hard Coatings via Focused Ion Beam Milling for Microinjection Molding

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