Nucleation and impact modification of polypropylene laser sintered parts

Kleijnen, Rob G.; Schmid, Manfred; Wegener, Konrad

doi:10.1063/1.4965572

Cited by 9 publications

(14 citation statements)

References 12 publications

(14 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[ 12,15 ] However, the use of nanoparticles can negatively affect the processability of the polymer powders, as they can also act as heterogeneous nuclei for polymer crystals, thus accelerating the crystallization kinetics [ 16 ] and narrowing the thermal process window. [ 17 ] Hence, only small amounts of flowing agents in the range of 0.1 wt% are typically used. [ 12,18 ]…”

Section: Introductionmentioning

confidence: 99%

Improvement of polymer properties for powder bed fusion by combining in situ PECVD nanoparticle synthesis and dry coating

Bonilla

Düsenberg

Lanyi

et al. 2021

Plasma Processes & Polymers

View full text Add to dashboard Cite

Polypropylene (PP) powders are coated with silica nanoparticles in a fluidized bed to improve the flow behavior of the powders and the processability in powder bed fusion. The nanoparticles are produced in situ via dusty plasma‐enhanced chemical vapor deposition (PECVD) in an atmospheric‐pressure Ar/O2 plasma jet fixed at the distributor plate of the fluidized bed. Hexamethyldisiloxane is used as a precursor of the nanoparticles. The influence of the oxygen concentration in the plasma gas and the number of treatment cycles on the chemical composition of the nanoparticles, the amount of nanoparticles deposited, and the flow properties of the coated PP powders is investigated. The chemical composition of the formed silica particles is determined by X‐ray photon spectroscopy and infrared spectroscopy. The results reveal that the composition of the nanoparticles is SiOxCy, that is, the portion of organic residues introduced by the precursor can be controlled by changing the oxygen concentration in the plasma gas. The mass of nanoparticles deposited on the polymer powder's surface, as determined by inductively coupled optical emission spectroscopy, shows a linear dependence of the number of cycles and the oxygen concentration in the plasma gas. A considerable improvement of the flow behavior of the PP powders is observed after PECVD treatment.

show abstract

Section: Introductionmentioning

confidence: 99%

Improvement of polymer properties for powder bed fusion by combining in situ PECVD nanoparticle synthesis and dry coating

Bonilla

Düsenberg

Lanyi

et al. 2021

Plasma Processes & Polymers

View full text Add to dashboard Cite

show abstract

“…* The values were not provided directly, and they have been interpreted from experimental data. [24,25,31,32,34]. …”

Section: Figurementioning

confidence: 99%

Additive Manufacturing of Polypropylene: A Screening Design of Experiment Using Laser-Based Powder Bed Fusion

2018

View full text Add to dashboard Cite

The use of commodity polymers such as polypropylene (PP) is key to open new market segments and applications for the additive manufacturing industry. Technologies such as powder-bed fusion (PBF) can process PP powder; however, much is still to learn concerning process parameters for reliable manufacturing. This study focusses in the process–property relationships of PP using laser-based PBF. The research presents an overview of the intrinsic and the extrinsic characteristic of a commercial PP powder as well as fabrication of tensile specimens with varying process parameters to characterize tensile, elongation at break, and porosity properties. The impact of key process parameters, such as power and scanning speed, are systematically modified in a controlled design of experiment. The results were compared to the existing body of knowledge; the outcome is to present a process window and optimal process parameters for industrial use of PP. The computer tomography data revealed a highly porous structure inside specimens ranging between 8.46% and 10.08%, with porosity concentrated in the interlayer planes in the build direction. The results of the design of experiment for this commercial material show a narrow window of 0.122 ≥ Ev ≥ 0.138 J/mm3 led to increased mechanical properties while maintaining geometrical stability.

show abstract

“…PP is already widely used in FMCGs on account of its low cost, good chemical resistance, and reasonably robust mechanical properties. Furthermore, PP has already been shown to useful in LS, with several studies reporting the manufacture of good quality PP parts by LS (Wegner, 2016;Drummer et al, 2010;Zhu et al, 2015;Kleijnen et al, 2016;Ituarte et al, 2018), although the exact part properties are dependent on the specific grade of PP powder used. For example, early research by Drummer et al demonstrated that while they could produce PP parts by LS, the mechanical properties obtained were significantly lower than both comparable PA12 parts, and benchmark values for injection molded PP (Drummer et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

The effect of powder age in high speed sintering of poly(propylene)

Williams

Fox

Majewski

2021

RPJ

View full text Add to dashboard Cite

Purpose This study aims to demonstrate for the first time that the cheap, commodity polymer, poly(propylene), can be successfully processed using high speed sintering, and that it can be recycled several times through the process, with little to no detriment to either the polymer itself or the parts obtained. This is significant as a step towards the realisation of high speed sintering as a technology for high-volume manufacturing. Design/methodology/approach A poly(propylene) powder designed for laser sintering was used to build parts on a high speed sintering machine. The unsintered powder was then collected and reused. Repeating this process allowed creation of seven generations of aged powder. A variety of characterisation techniques were then used to measure polymer, powder and part properties for each generation to discern any effects arising from ageing in the machine. Findings It was found that poly(propylene) could be used successfully in high speed sintering, albeit with a low build success rate. Increased powder age was found to correlate to an increase in the build success rate, changes in microscopic and bulk powder properties and improvement to the dimensional accuracy of the parts obtained. By contrast, no discernible correlations were seen between powder age and polymer molecular weight, or between powder age and the tensile properties of parts. Originality/value This is the first report of the use of poly(propylene) in high speed sintering. It is also first study regarding powder recyclability in high speed sintering, both in general and using poly(propylene) specifically.

show abstract

Nucleation and impact modification of polypropylene laser sintered parts

Cited by 9 publications

References 12 publications

Improvement of polymer properties for powder bed fusion by combining in situ PECVD nanoparticle synthesis and dry coating

Improvement of polymer properties for powder bed fusion by combining in situ PECVD nanoparticle synthesis and dry coating

Additive Manufacturing of Polypropylene: A Screening Design of Experiment Using Laser-Based Powder Bed Fusion

The effect of powder age in high speed sintering of poly(propylene)

Contact Info

Product

Resources

About