Injection printing: additive molding via shell material extrusion and filling

Kazmer, David O.; Colon, Austin R.

doi:10.1016/j.addma.2020.101469

Cited by 6 publications

(6 citation statements)

References 19 publications

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“…Important factors for adhesion between polymers are entanglement and dissipation [22]. The adhesion between layers produced within a body of a single material produced by MEX can be influenced by various process parameters [23,24], as well as the geometry of the toolpaths [25][26][27]. The adhesion by which two bodies of different MEX printed materials stick together can be influences by a wide spectrum of pre-treatment methods, process parameters and material properties [21,28].…”

Section: Related Workmentioning

confidence: 99%

ITIL: Interlaced Topologically Interlocking Lattice for continuous dual-material extrusion

Kuipers

et al. 2022

Additive Manufacturing

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Extrusion (MEX) systems with dual-material capability can unlock interesting applications where flexible and rigid materials are combined. When chemically incompatible materials are concerned the adhesion between the two might be insufficient. Therefore researchers typically rely on dovetail type interlocking geometries in order to affix two bodies mechanically. However, dovetail type interlocking introduces extrusion discontinuities and relies on the material's resistance to deformation, which is difficult to model.We propose a simple and effective 3D lattice consisting of interlaced horizontal beams in vertically alternating directions which interlock topologically: the interlaced topologically interlocking lattice (ITIL). It ensures continuous extrusion and ensures an interlock even for highly flexible materials. We develop analytical models for optimizing the ultimate tensile strength of the ITIL lattice in two different orientations relative to the interface: straight and diagonal. The analytical models are applied to polypropylene (PP) and polylactic acid (PLA) and verified by finite elements method (FEM) simulations and physical tensile experiments. In the diagonal orientation ITIL can obtain 82% of the theoretical upper bound of 8.6 MPa. ITIL seems to perform comparably to dovetail interlocking designs, while it lends itself to application to non-vertical interfaces. Optimizing the lattice for non-vertical interfaces, however, remains future work.

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Section: Related Workmentioning

confidence: 99%

ITIL: Interlaced Topologically Interlocking Lattice for continuous dual-material extrusion

Kuipers

et al. 2022

Additive Manufacturing

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“…The bonding strength between the printed and overmolded parts can be improved by modifying the surface roughness because “rough” surfaces have a greater area for bonding [ 16 , 17 , 18 , 19 ]. Another method is to create protruding ridges or a deeply pitted surface, which will have a comparatively larger contact area.…”

Section: Experimental Planmentioning

confidence: 99%

“…In 2017, the Markforged company patented a similar concept, in which a preform is created from continuous CFs; then, this preform is overmolded with a thermoplastic matrix [ 18 ]. Another original hybrid manufacturing concept under the name “injection printing” was recently proposed by Kazmer and Colon [ 19 ]. The idea of injection printing involves manufacturing a 3D-printed shell and injecting a large volume of polymer into the shell’s cavities.…”

Section: Introductionmentioning

confidence: 99%

Personalized Mass Production by Hybridization of Additive Manufacturing and Injection Molding

2021

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The new trend in the composites industry, as dictated by Industry 4.0, is the personalization of mass production to match every customer’s individual needs. Such synergy can be achieved when several traditional manufacturing techniques are combined within the production of a single part. One of the most promising combinations is additive manufacturing (AM) with injection molding. AM offers higher production freedom in comparison with traditional techniques. As a result, even very sophisticated geometries can be manufactured by AM at a reasonable price. The bottleneck of AM is the production rate, which is several orders of magnitude slower than that of traditional plastic mass production technologies. On the other hand, injection molding is a manufacturing technique for high-volume production with little possibility of customization. The customization of injection-molded parts is usually very expensive and time-consuming. In this research, we offered a solution for the individualization of mass production, which includes 3D printing a baseplate with the subsequent overmolding of a rib element on it. We examined the bonding between the additive-manufactured component and the injection-molded component. As bonding strength between the coupled elements is significantly lower than the strength of the material, we proposed five strategies to improve bonding strength. The strategies are optimizing the printing parameters to obtain high surface roughness, creating an infill density in fused filament fabrication (FFF) parts, creating local infill density, creating microstructures, and incorporating fibers into the bonding area. We observed that the two most effective methods to increase bonding strength are the creation of local infill density and the creation of a microstructure at the contact area of FFF-printed and injection-molded elements. This increase was attributed to the porous structures that both methods created. The melt during injection molding flowed into these pores and formed micro-mechanical interlocking.

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“…Similarly, Zhang et al reported no obvious interfacial fracture in tensile testing of polylactic acid (PLA) 28 . Kazmer and Colon also observed fractures crossing multiple layer interfaces and near isotropic part strength with a hybrid injection printing technique 29 …”

Section: Introductionmentioning

confidence: 99%

“…28 Kazmer and Colon also observed fractures crossing multiple layer interfaces and near isotropic part strength with a hybrid injection printing technique. 29 In this work, we investigate the tensile behavior of a model polycarbonate system to explore what leads to different tensile properties. We use a one factor at a time (OFAT) design of experiments (DOE), print single road width boxes, and perform tensile test on specimens from these boxes.…”

Section: Introductionmentioning

confidence: 99%

Interrelationships between process parameters, cross‐sectional geometry, fracture behavior, and mechanical properties in material extrusion additive manufacturing

Adisa,

Colon,

Kazmer

et al. 2023

Polymer Engineering & Sci

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Additive manufacturing offers reduced lead time between design and manufacturing. Fused filament fabrication, the most common form of material extrusion additive manufacturing, enables the production of custom‐made parts with complex geometry. Despite the numerous advantages of additive manufacturing, reliability, reproducibility, and achievement of isotropic bulk properties in part remains challenging. We investigated the tensile behavior of a model polycarbonate system to explore what leads to different tensile properties, including sources of ductile versus brittle fracture. We utilized a one factor at a time (OFAT) design of experiments (DOE), printed single road‐width boxes, and performed tensile tests on specimens from these boxes. Additionally, we characterized the cross‐sections of parts printed under different conditions and their subsequent fracture behavior. The results demonstrate that isotropic bulk properties are achievable by printing at high speeds, and provide mechanisms to explain why.Highlights Printing at high speeds leads to improved mechanical properties. Printed samples undergo a mix of ductile and brittle failure. Jagged fracture path is associated with superior adhesion. High layer times lead to worse interfacial bonding.

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Injection printing: additive molding via shell material extrusion and filling

Cited by 6 publications

References 19 publications

ITIL: Interlaced Topologically Interlocking Lattice for continuous dual-material extrusion

ITIL: Interlaced Topologically Interlocking Lattice for continuous dual-material extrusion

Personalized Mass Production by Hybridization of Additive Manufacturing and Injection Molding

Interrelationships between process parameters, cross‐sectional geometry, fracture behavior, and mechanical properties in material extrusion additive manufacturing

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