Investigation of Plastic Freeformed, Open-Pored Structures with Regard to Producibility, Reproducibility and Liquid Permeability

Hirsch, André; Dalmer, Christian; Moritzer, Elmar

doi:10.1007/978-3-030-54334-1_9

Cited by 5 publications

(11 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides those effects, no significant patterns could be observed. However, it must be highlighted that the highest mechanical performance for both methods was reached at an infill angle of 45 • and with two contour lines, which was also concluded by Hirsch et al [14]. These fabrication strategies correspond with the recommended setting for 3D printing, at least for MEX methods.…”

Section: Tensile Propertiessupporting

confidence: 77%

“…Regardless of the chamber temperature, the stress and strain at break for the specimens printed vertically (Z-orientation) were significantly lower than those printed horizontally (XY-orientation), as other researchers observed [14,52,53]. The results of samples printed at a 80 °C chamber temperature are way below the stresses and strains observed in the previous samples.…”

Section: Tensile Propertiesmentioning

confidence: 50%

“…Further optimization can be performed by optimizing the printing speed of the APF method, increasing the heating time, and reducing the acceleration forces acting on the printed samples. Interlayer diffusion can be enhanced at longer diffusion times or Regardless of the chamber temperature, the stress and strain at break for the specimens printed vertically (Z-orientation) were significantly lower than those printed horizontally (XY-orientation), as other researchers observed [14,52,53].…”

Section: Tensile Propertiesmentioning

confidence: 74%

“…The part formation occurs in a heated chamber and hence in a controlled environment, as a further difference to most MEX machines. Consequently, a controlled print envelope temperature can strongly influence material properties, especially for semi-crystalline polymers [12][13][14][15]. A schematic display is given in Figure 1b.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of the Print Envelope Temperature on the Morphology and Tensile Properties of Thermoplastic Polyolefins Fabricated by Material Extrusion and Material Jetting Additive Manufacturing

Hentschel,

Petersmann,

Kynast

et al. 2023

Polymers

View full text Add to dashboard Cite

Additive manufacturing (AM) nowadays has become a supportive method of traditional manufacturing. In particular, the medical and healthcare industry can profit from these developments in terms of personalized design and batches ranging from one to five specimens overall. In terms of polymers, polyolefins are always an interesting topic due to their low prices, inert chemistry, and crystalline structure resulting in preferable mechanical properties. Their semi-crystalline nature has some advantages but are challenging for AM due to their shrinkage and warping, resulting in geometrical inaccuracies or even layer detaching during the process. To tackle these issues, process parameter optimization is vital, with one important parameter to be studied more in detail, the print envelope temperature. It is well known that higher print envelope temperatures lead to better layer adhesion overall, but this investigation focuses on the mechanical properties and resulting morphology of a semi-crystalline thermoplastic polyolefin. Further, two different AM technologies, namely material jetting (ARBURG plastic freeforming—APF) and filament-based material extrusion, were studied and compared in detail. It was shown that higher print envelope temperatures lead to more isotropic behavior based on an evenly distributed morphology but results in geometrical inaccuracies since the material is kept in a molten state during printing. This phenomenon especially could be seen in the stress and strain values at break at high elongations. Furthermore, a different crystal structure can be achieved by setting a specific temperature and printing time, also resulting in peak values of certain mechanical properties. In comparison, better results could be archived by the APF technology in terms of mechanical properties and homogeneous morphology. Nevertheless, real isotropic part behavior could not be managed which was shown by the specimen printed vertically. Hence, a sweet spot between geometrical and mechanical properties still has to be found.

show abstract

Section: Tensile Propertiessupporting

confidence: 77%

Section: Tensile Propertiesmentioning

confidence: 50%

Section: Tensile Propertiesmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of the Print Envelope Temperature on the Morphology and Tensile Properties of Thermoplastic Polyolefins Fabricated by Material Extrusion and Material Jetting Additive Manufacturing

Hentschel,

Petersmann,

Kynast

et al. 2023

Polymers

View full text Add to dashboard Cite

show abstract

“…For characterisation of mechanical properties, ten dog-bone specimens were manufactured for each LT-DAR combination with the selected DR from Table 2 according to DIN EN ISO 527 Type 1B. Due to the high number of specimens and since Hirsch et al have shown that the manufacturing of multiple specimens per building job has no influence on the geometry of the voids, the entire build plate was used [ 16 ]. Accordingly, seven dog-bone specimens could be manufactured at the same time.…”

Section: Methodsmentioning

confidence: 99%

Can Different Parameter Sets Lead to Equivalent Optima between Geometric Accuracy and Mechanical Properties in Arburg Plastic Freeforming?

et al. 2023

View full text Add to dashboard Cite

Technological advances have led to the increased use of plastic-based additive manufacturing processes for the production of consumer goods and spare parts. For this reason, the need for the best possible mechanical properties while maintaining geometric accuracy is becoming increasingly important. One of these additive manufacturing processes is the Arburg Plastic Freeforming process, which differs from the widely used Fused Filament Fabrication process in the way that droplets are discharged along a track instead of continuous extruded tracks. As with all other plastic-based additive manufacturing processes, due to the round shape of the tracks, voids occur between the individual tracks during manufacturing, which effects mechanical properties. In contrast to previous work, which mainly focused on how the mechanical properties change with a change in a single printing parameter, this work focused more closely on the interaction of three relevant printing parameters considered as a parameter set. Their influence on the mechanical properties was investigated by tensile tests, the influence on the residual porosity by density measurements and the influence on the geometric accuracy by surface roughness measurements. It was shown that by considering the parameters as a parameter set, states of high density and therefore high mechanical properties while reaching minimal surface roughness can be achieved for significantly more combinations than previously assumed. However, for these states the residual porosity was slightly different. This difference was explained by a parameter-dependent deformation factor of the droplets, which influences the maximal possible degree of filling during manufacturing. For the optimization of arbitrary parameter sets, an analytical model was derived.

show abstract

Numerical and experimental investigation of a 3D-printed PCU patient-specific cranial implant

et al. 2023

View full text Add to dashboard Cite

Arburg plastic freeforming (APF) technology allows for fabricating patient-specific implants (PSIs) in a hospital environment using medical-grade thermoplastic polymers. Among these materials, poly(carbonate-urethane) (PCU) is of great relevance since it is characterised by excellent biocompatibility. This study explores the opportunity to realise a patient-specific cranial plate via APF. First, a Finite Element model (FEM) of the implant under compressive loads is developed and validated using a quasi-isotropic material. Then, this model is used for Finite Element Analysis (FEA) considering Technical Datasheet (TDS) material properties and those measured on 3D-printed specimens, by Three-Point Bending (TPB) tests. Finally, a PCU PSI is fabricated through APF and tested under static loads to validate the consistency of the numerical results. Considering TDS properties, the FEA results indicate that PCU can be used for the manufacturing of this device. Nonetheless, the TPB tests show that the material suffers from a loss of mechanical properties. Using these properties, the displacements calculated via FEA exceed the admissible values for the application. A further decrease in stiffness is observed in the manufactured plate. Overall, findings suggest that PCU can be a viable material to be printed by APF technology for fabricating craniofacial PSIs, with the advantage of minor stress concentration in critical points of the implant if compared with polyetheretheretherketone (PEEK). However, further studies are necessary to effectively represent the effects of 3D printing in the FEMs used for structural validation and design optimisation.

show abstract

Investigation of Plastic Freeformed, Open-Pored Structures with Regard to Producibility, Reproducibility and Liquid Permeability

Cited by 5 publications

References 8 publications

Influence of the Print Envelope Temperature on the Morphology and Tensile Properties of Thermoplastic Polyolefins Fabricated by Material Extrusion and Material Jetting Additive Manufacturing

Influence of the Print Envelope Temperature on the Morphology and Tensile Properties of Thermoplastic Polyolefins Fabricated by Material Extrusion and Material Jetting Additive Manufacturing

Can Different Parameter Sets Lead to Equivalent Optima between Geometric Accuracy and Mechanical Properties in Arburg Plastic Freeforming?

Numerical and experimental investigation of a 3D-printed PCU patient-specific cranial implant

Contact Info

Product

Resources

About