In-line rheological testing of thermoplastics and a monitored device for an injection moulding machine: Application to raw and recycled polypropylene

Fernández, Jesús J.; Muniesa, Manuel; Javierre, Carlos

doi:10.1016/j.polymertesting.2013.11.008

Cited by 36 publications

(19 citation statements)

References 20 publications

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“…The injection molding process is affected by rheological behavior, especially at the filling stage [24,25]. However, it is not the only process affected by the replacement of raw materials with recycled ones.…”

Section: Introductionmentioning

confidence: 99%

Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

et al. 2019

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The usage of recycled polymers for industrial purposes arises as one of the most promising methods of reducing environmental impact and costs associated with scrapping parts. This paper presents a systematic study of the dimensional stability of a raw and 100% recycled polypropylene subjected to realistic environmental conditions occurring along its working life. The component studied is an internal part of an induction hob assembly. Industrial samples manufactured with both materials, in the same mold, and in the same injection machine, are subjected to ejection conditions, storage conditions (50 °C), and extreme performance conditions (80 °C). Induced dimensional changes are registered and analyzed using a coordinate measuring machine, and a tactile sensing probe. To verify the process capability of the samples manufacturing, Cp and Cpk values are calculated to evaluate the suitability of the recycled material as an alternative. Results conclude that, although the use of recycled material implies slight differences in terms of dimensional stability due to the changes induced in the polymer structure, these differences are not significant enough to affect the injection process capability. Therefore, recycling arises as one effective method to reduce both overruns associated with the consumption of raw polypropylene material and its environmental impact.

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Section: Introductionmentioning

confidence: 99%

Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

et al. 2019

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“…There are several original solutions that allow rheological measurements under actual injection molding conditions. One of them is placing temperature and pressure sensors between the injection molding plasticizing unit and the segment nozzle . Lewandowski and co‐workers used a rheological head built into the injection mold .…”

Section: Introductionmentioning

confidence: 99%

The Influence of Processing Conditions on the Polypropylene Apparent Viscosity Measured Directly in the Mold Cavity

Sykutera

Wajer

Kościuszko

et al. 2018

Macromolecular Symposia

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Measurements of rheological properties of polymeric materials play an increasingly important role in the polymer plastics industry. Knowledge about the plasticized material flow behavior is essential at the injection molds design stage. The polymeric viscosity curves usually are determined by a capillary rheometer tests. Nevertheless, the rheological properties determined this way differ from those observed during actual processing conditions. This paper presents a comparison of apparent viscosity measurements of polypropylene conducted by three methods. The first one was plastometer measurements made at different masses of test load. The second method evaluated the viscosity in the injection mold cavity equipped with pressure and temperature sensors. Capillary rheometer was used as the third method. It was observed that polypropylene viscosity curves, determined by different methods have a similar pattern. Comparing changes in apparent viscosity values obtained with the capillary rheometer and directly in the mold cavity, the largest differences were found for the shear rate below 1000 s −1. This proves the non‐isothermal measurement in the injection mold cavity. In the range of shear rate above 1000 s−1, the apparent viscosity determined directly in the injection mold was about 40 Pa · s greater than that measured by the rheometer, regardless of the test temperature. The results recorded by the plastometer reflect the real polypropylene viscosity curve at low shear rate values in a better way.

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“…In the research of energy consumption and green rheomolding, Fernandez et al [12] developed a methodology for the rheological testing of polymers during the injection molding process, this method has been designed to consider the nonconventional features of the plastication phase that result from the injection of recycled thermoplastics. VeraSorroche et al [13] showed that polymer rheology had a significant effect on process energy consumption and thermal homogeneity of the melt.…”

Section: Introductionmentioning

confidence: 99%

Energy-Efficient Enhancement for Viscoelastic Injection Rheomolding Using Hierarchy Orthogonal Optimization

Wang

Zhang

2018

Mathematical Problems in Engineering

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The viscoelastic injection molding involves multidisciplinary thermoplastic rheomolding parameters which is a complex mathematical problem. Particularly for rheomolding of complex parts with thin-walled structure, boss, and grooves, the increasing higher requirements on energy efficiency and rheomolding quality are put forward. Therefore, an energy-efficient enhancement method for viscoelastic injection molding using hierarchy orthogonal optimization (HOO) is proposed. Based on the thermoplastic rheomolding theory and considering the viscoelastic effects in injection molding, a set of partial differential equations (PDE) describing the physical coupling behavior of the mold-melt-injection molding machine is established. The fuzzy sliding mode control (FSMC) is used to reduce the energy consumption in the control system of the injection molding machine's clamping force. Then, the HOO model of viscoelastic injection rheomolding is built in terms of thermoplastic rheomolding parameters and injection machine parameters. In initial hierarchy, through Taguchi orthogonal experiment and Analysis of Variance (ANOVA), the amount of gate, melt temperature, mold temperature, and packing pressure are extracted as the significant influence parameters. In periodical hierarchy, the multiobjective optimization model takes the forming time, warping deformation, and energy consumption of injection molding as the multiple objectives. The NSGA-II (Nondominated Sorting Genetic Algorithm II) optimization is employed to obtain the optimal solution through the global Pareto front. In ultimate hierarchy, three candidate schemes are compared on multiple objectives to determine the final energy-efficient enhancement scheme. A typical temperature controller part is analyzed and the energy consumption of injection molding is reduced by 41.85%. Through the physical experiment of injection process, the proposed method is further verified.

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In-line rheological testing of thermoplastics and a monitored device for an injection moulding machine: Application to raw and recycled polypropylene

Cited by 36 publications

References 20 publications

Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

The Influence of Processing Conditions on the Polypropylene Apparent Viscosity Measured Directly in the Mold Cavity

Energy-Efficient Enhancement for Viscoelastic Injection Rheomolding Using Hierarchy Orthogonal Optimization

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