Investigation on the Achievable Flow Length in Injection Moulding of Polymeric Materials with Dynamic Mould Tempering

Meister, Steve; Drummer, Dietmar

doi:10.1155/2013/845916

Cited by 10 publications

(7 citation statements)

References 18 publications

(16 reference statements)

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“…Previous approaches have focused on reducing the viscosity of the melt through high melt temperatures or dynamic mold temperature control to such A second example in which unintentionally high-pressure gradients can occur, is micro injection molding. In the production of thin-walled structures in injection molding, flow path and cross-section-dependent pressure and temperature differences can often lead to difficult mold filling, especially during the injection phase [30]. Previous approaches have focused on reducing the viscosity of the melt through high melt temperatures or dynamic mold temperature control to such an extent that the cavity can still be completely filled [31,32].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Compression Induced Solidification

2020

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This study presents a method for the determination of the dynamic pressure-dependent solidification of polycarbonate (PC) during flow using high pressure capillary rheometer (HPC) measurements. In addition, the pressure-dependent solidification was determined by isothermal pressure-volume-temperature (pvT) measurements under static conditions without shear. Independent of the compression velocity, a linear increase of the solidification pressure with temperature could be determined. Furthermore, the results indicate that the relaxation time at a constant temperature and compression rate can increase to such an extent that the material can no longer follow within the time scale specified by the compression rate. Consequently, the flow through the capillary stops at a specific pressure, with higher compression rates resulting in lower solidification pressures. Consequently, in regard to HPC measurements, it could be shown that the evaluation of the pressure via a pressure hole can lead to measurement errors in the limit range. Since the filling process in injection molding usually takes place under such transient conditions, the results are likely to be relevant for modelling the flow processes of thin-walled and microstructures with high aspect ratios.

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Section: Introductionmentioning

confidence: 99%

Dynamic Compression Induced Solidification

2020

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“…Results showed that ATT optimized not only the rheological characteristics of the process but also the morphology, and hence the overall properties of the molded parts, without increasing the cycle time. Meister and Drummer investigated the influence of mold temperature of the flow length of a spiral shaped mold, for which the cross‐section of the spiral had a dimension of 0.3 × 1.5 mm. The variotherm temperature control system used water as the circulating fluid and had a heating and a cooling circuit‐switching device and allowed a fluid temperature of up to 200°C.…”

Section: Various Heating Methods For Variotherm Processmentioning

confidence: 99%

The use of variotherm systems for microinjection molding

Zhang

Gilchrist

2015

J of Applied Polymer Sci

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Microinjection molding (lIM) is a fast-developing technology which is used to produce polymeric microcomponents or components with micro/nanoscale features, such as are used in many fields including microfluidic diagnostics, microneedle drug delivery devices, microgears, and microswitches. The capabilities and performance of the microinjection molding process can be improved by incorporating a variotherm system. This leads to improved component quality, especially for high aspect ratio features. It can also help to increase the polymer flow path, improve feature replication, reduce residual stresses and molecular orientations, and also can eliminate weld lines. This article reviews the use of different variotherm systems in lIM, and describes how simulation of its use can provide insight when designing a mold cavity or a component with challenging microfeatures. The article highlights important problems, challenges and areas for further research. An increased understanding of these issues will provide opportunities to enhance further developments in the lIM process.

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“…The influence of process parameters was also investigated in publications [7][8][9]. And finally, following published papers [10][11][12] investigated various effects of process parameters, for example pressure and melt flow index, or the reason for the creation of flow marks.…”

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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Investigation on the Achievable Flow Length in Injection Moulding of Polymeric Materials with Dynamic Mould Tempering

Cited by 10 publications

References 18 publications

Dynamic Compression Induced Solidification

Dynamic Compression Induced Solidification

The use of variotherm systems for microinjection molding

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

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