Search results for "Injection molding"

Compression and injection molding of recycled polyethylene for greenhouses in presence of the natural fibres

2003

Compression and injection molding of recycled polyethylene for greenhouses in presence of the natural fibers

2003

Automated Uncertainty Quantification Through Information Fusion in Manufacturing Processes

2017

International audience; Evaluation of key performance indicators (KPIs) such as energy consumption is essential for decision-making during the design and operation of smart manufacturing systems. The measurements of KPIs are strongly affected by several uncertainty sources such as input material uncertainty, the inherent variability in the manufacturing process, model uncertainty, and the uncertainty in the sensor measurements of operational data. A comprehensive understanding of the uncertainty sources and their effect on the KPIs is required to make the manufacturing processes more efficient. Towards this objective, this paper proposed an automated methodology to generate a hierarchical B…

The continuous cooling transformation (CCT) as a flexible tool to investigate polymer crystallization under processing conditions

2009

An experimental route for investigating polymer crystallization over a wide range of cooling rates (from 0.01 to 1000◦C/s) and pressures (from 0.1 to 40 MPa) is illustrated, using a method that recalls the approach adopted in metallurgy for studying structure development in metals. Two types of experimental setup were used, namely an apparatus for fast cooling of thin films (100–200 μm thick) at various cooling rates under atmospheric pressure and a device (based on a on-purpose modified injection molding machine) for quenching massive samples (about 1–2 cm3) under hydrostatic pressure fields. In both cases, ex situ characterization experiments were carried out to probe the resulting struct…

The role of crystalline, mobile amorphous and rigid amorphous fractions in the performance of recycled poly (ethylene terephthalate) (PET)

2012

[EN] The action of thermo-mechanical degradation induced by mechanical recycling of poly(ethylene terephthalate) was simulated by successive injection moulding cycles. Degradation reactions provoked chain scissions and a reduction in molar mass mainly driven by the reduction of diethyleneglycol to ethylene glycol units in the flexible domain of the PET backbone, and the formation of -OH terminated species with shorter chain length. The consequent microstructural changes were quantified taking into account a three-fraction model involving crystalline, mobile amorphous (MAF) and rigid amorphous fractions (RAF). A remarkable increase of RAF, to a detriment of MAF was observed, while the percen…

Indentation test as a tool for monitoring the solidification process during injection molding

2003

An inline method for monitoring the solidi-fication process during the injection molding of semicrystalline polymers is demonstrated. The method has been applied to various poly(ethylene terephthalate) (PET) and poly(buthylene terephthalate) (PBT) samples. The technique is based on a simple device by which an additional ejector pin is pushed onto the injection-molded part with a fixed force at different times during the solidification phase while the mold remains closed. The residual deformation (the so-called indentation depth) due to the applied load is measured offline after ejection. By the performance of indentation at different times during the cooling phase, an indentation depth prof…

Injection Molding and Mechanical Properties of Bio-Based Polymer Nanocomposites

2018

The use of biodegradable/bio-based polymers is of great importance in addressing several issues related to environmental protection, public health, and new, stricter legislation. Yet some applications require improved properties (such as barrier or mechanical properties), suggesting the use of nanosized fillers in order to obtain bio-based polymer nanocomposites. In this work, bionanocomposites based on two different biodegradable polymers (coming from the Bioflex and MaterBi families) and two different nanosized fillers (organo-modified clay and hydrophobic-coated precipitated calcium carbonate) were prepared and compared with traditional nanocomposites with high-density polyethylene (HDPE…

Redesign of the Geometry of Parts Produced from PBT Composite to Improve Their Operational Behavior

2021

Parts produced from PBT-GF30 (70% polybutylene terephthalate +30% fiberglass) are very often used in car construction, due to the properties of this material. The current trend is to make parts with a shape designed to be as complex as possible, to take over many functions in operation. During the research, a part that is a component of the structure of car safety systems, and that must be completely reliable in operation, was analyzed. This piece has a complex shape that involves the intersection of several walls. Thus, the research aimed at establishing the optimal radius of connection between the walls (R), the ratio between the thickness of the intersecting walls (K) and the angle of in…

El futuro de los plásticos o los plásticos del futuro

2020

espanolEn los ultimos tiempos politicos, activistas ambientales, periodistas y otros lideres de opinion han dirigido sus armas contra los plasticos. Este mal concepto nace como resultado de los cambios en el entorno como consecuencia de la utilizacion de nuevas fuentes de energia, tanto nuclear como la de combustibles fosiles y el desarrollo de la industria petroquimica en especial la de los plasticos que se da a partir del descubrimiento del petroleo. Sin embargo y a pesar de las consideraciones ambientales el plastico ha construido nuestro mundo hasta el punto en que hoy es dificil imaginar nuestra vida sin el. Muchos disenadores han sostenido desde mediados del siglo XX, que los articulo…

A study via simulation of solidification during injection molding

2011

The final properties of an injection-molded part are strictly dependent on the solidification dynamics occurring during the processing. The experimental derivation of information about polymer solidification throughout the injection molding cycle is still an open challenge. To overcome the practical issues, the process simulation is proposed as a mean to derive useful data, and especially for identifying the most influencing parameters. The no-flow temperature (NFT) is a parameter used in most of injection molding simulation packages as a mean to determine whether the polymer flows or it is solid. With this simple parameter it is possible to take into account the rheological solidification …