Modelling and verification of ejection forces in thermoplastic injection moulding

Bhagavatula, Narayan; Michalski, D.; Lilly, Blaine; Glozer, G.

doi:10.1088/0965-0393/12/3/s12

Cited by 8 publications

(5 citation statements)

References 15 publications

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“…Bhagavatula et al [15] compared results from the Menges and Mohren model [1], an ANSYS simulation and experimental results. A cylindrical canister with a height of 49.5, thickness of 0.5 and inner-radius of 15mm was moulded.…”

Section: Injection Mouldingmentioning

confidence: 99%

Demoulding Force Prediction for Micro Polymer Replication: A Review of Relevant Literature

Delaney¹,

Bissacco²,

Kennedy³

2010

Proceedings of the 7th International Conference on Multi-Material Micro Manufacture

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Demoulding components without damage to either the components or tool is critical to successful replication processes. During tooling development designers strive to optimize replication tools to minimize demoulding force and resultant stress on replicated parts. A critical element of this process is an accurate demoulding force prediction model. Various models have been proposed to predict demoulding forces, each showing limitations in its applicability. This paper reviews existing demoulding force models and parameters affecting demoulding force for micro polymer replication.

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Section: Injection Mouldingmentioning

confidence: 99%

Demoulding Force Prediction for Micro Polymer Replication: A Review of Relevant Literature

Delaney¹,

Bissacco²,

Kennedy³

2010

Proceedings of the 7th International Conference on Multi-Material Micro Manufacture

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“…This work aims to investigate the effect of glass fibers and nanoclays on the shrinkage and ejection forces in the injection molding process [22][23][24] being this a critical issue when using this processing technique since the force required to eject the part from the mold is a fundamental design variable that defines the project of the ejection system [2,16,25].…”

Section: Introductionmentioning

confidence: 99%

Experimental study of shrinkage and ejection forces of reinforced polypropylene based on nanoclays and short glass fibers

Garcia

Netto

Pontes

2017

Polymer Engineering & Sci

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This study presents the influence of nanoclays and glass fibers on the shrinkage and ejection forces of polypropylene-based composites for tubular parts produced by injection molding. An instrumented mold was used to measure cavity pressure, surface temperature and ejection forces in the tubular parts during the injection cycle. The materials used for the study were polypropylene homopolymer Domolen 1100L, nanoclays for polyolefin nanocomposites (P-802 nanoMax, used in percentages of 2%, 6%, and 10%) and reinforced polypropylene homopolymer with a content of 10% and 30% glass fiber (Domolen P1-013-V10-N and Domolen P1-102-V30-N, respectively). Part shrinkage was measured 48 h after production. The results show that the incorporation of nanoclays reduces shrinkage and ejection forces while glass fibers decrease shrinkage and increase ejection forces due to an increase in elastic modulus. Nanoclays decrease the ejection forces when compared to glass fibers and pure PP. The effects of nanoclays are less pronounced than those of glass fibers. Moldings produced with different materials were also analyzed to assess the effect of mold temperature on the ejection forces. Shrinkage rises slightly by increasing the mold temperature while the ejection force decreases. POLYM. ENG. SCI.,[58][59][60][61][62]

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“…The surfaces of injection parts would become scarred when the contact stress between the ejector pin and the surface of the component is too high. For many applications, the surfaces of the plastic injection parts should be flawless or exhibit precise profiles [1][2][3]. A pinless ejection mechanism is required to prevent scars and is the objective of this research.…”

Section: Introductionmentioning

confidence: 99%

A smart pinless ejection mechanism using dual-resonance excitation Langevin piezoelectric transducers

Wang

2015

Smart Mater. Struct.

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This study investigated a smart pinless ejection mechanism comprising two dual-resonance excitation Langevin piezoelectric transducers (DRELPTs) for keeping the injection parts intact and protecting their top and bottom surfaces from scarring during plastic injection molding. The dimensions of each DRELPT were determined using longitudinal vibration models, and an optimization method was used to set the frequency ratio of the first to the second longitudinal mode to 1:2. This concept enables the driving of DRELPT in its two longitudinal modes consistent with the ejection direction in resonant-type smooth impact drive mechanisms. During the ejection process, DRELPT provides an ejection force, which is applied on the sidewalls of the injection parts to protect their top and bottom surfaces from scarring. Considering individual differences in the resonance frequencies of DRELPTs, a resonance frequency tracking circuit based on a phase-locked loop was designed to keep DRELPT actuating in resonance. The ejection velocity of the injection part was estimated using the kinetic models derived from the dynamic behavior of the mold cavity and injection parameters. A characteristic number S was defined to evaluate the average velocity of the injection part during ejection. Proof-of-concept experimental results of the pinless ejection mechanism are presented. The ejection time, that is, the time from triggering the composite wave to the full departure of the injection part from the mold cavity, was 72 ms.

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Modelling and verification of ejection forces in thermoplastic injection moulding

Cited by 8 publications

References 15 publications

Demoulding Force Prediction for Micro Polymer Replication: A Review of Relevant Literature

Demoulding Force Prediction for Micro Polymer Replication: A Review of Relevant Literature

Experimental study of shrinkage and ejection forces of reinforced polypropylene based on nanoclays and short glass fibers

A smart pinless ejection mechanism using dual-resonance excitation Langevin piezoelectric transducers

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