Use of Polymer Scaffolding and Electroplating to Create Porous Metal Structures

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Adam Mihalko ◽  
Jordan Felice ◽  
Allen Madura ◽  
Davide Piovesan

Additive manufacturing (AM) offers a fabrication process that provides numerous advantages when compared with traditional fabrication methods. Specifically, AM technology allows for the creation of porous media where porosity and permeability can be precisely controlled. When manufacturing metallic artifacts for biomedical use (e.g., bone implants), the investment in a laser sintering machine can be prohibitive for the budget-conscious enterprises limiting the study and use of this technology. Electroforming, electroplating, and electrotyping have been used for decades to replicate the complex shape of unique artifacts and can be viable techniques to create complex metallic shapes starting from a conductive mandrel. We investigated a fabrication technique that combines the stereolithographic additive manufacturing of a polymeric mandrel with electroforming, to obtain porous composites of polymers and metals. The fabrication method to electroform a porous artifact is presented, and an analytical model of the combined properties of the composite material is provided.

2021 ◽  
pp. 101925
Author(s):  
Henrik Andersson ◽  
Jonas Örtegren ◽  
Renyun Zhang ◽  
Markus Grauers ◽  
Håkan Olin

2015 ◽  
Vol 219 ◽  
pp. 10-16 ◽  
Author(s):  
Tatsuaki Furumoto ◽  
Ayato Koizumi ◽  
Mohd Rizal Alkahari ◽  
Rui Anayama ◽  
Akira Hosokawa ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Furkan Ulu ◽  
Ravi Pratap Singh Tomar ◽  
Ram Mohan

Purpose PolyJet technology allows printing complex multi-material composite configurations using Voxel digital designs' capability, thus allowing rapid prototyping of 3D printed structural parts. This paper aims to investigate the processing and mechanical characteristics of composite material configurations formed from soft and hard materials with different distributions and sizes via voxel digital print design. Design/methodology/approach Voxels are extruded representations of pixels and represent different material information similar to each pixel representing colors in digital images. Each geometric region of a digitally designed part represented by a voxel can be printed with a different material. Multi-material composite part configurations were formed and rapidly prototyped using a PolyJet printer Stratasys J750. A design of experiments composite part configuration of a soft material (Tango Plus) within a hard material matrix (Vero Black) was studied. Composite structures with different hard and soft material distributions, but at the same volume fractions of hard and soft materials, were rapidly prototyped via PolyJet printing through developed Voxel digital printing designs. The tensile behavior of these formed composite material configurations was studied. Findings Processing and mechanical behavior characteristics depend on materials in different regions and their distributions. Tensile characterization obtained the fracture energy, tensile strength, modulus and failure strength of different hard-soft composite systems. Mechanical properties and behavior of all different composite material systems are compared. Practical implications Tensile characteristics correlate to digital voxel designs that play a critical role in additive manufacturing, in addition to the formed material composition and distributions. Originality/value Results clearly indicate that multi-material composite systems with various tensile mechanical properties could be created using voxel printing by engineering the design of material distributions, and sizes. The important parameters such as inclusion size and distribution can easily be controlled within all slices via voxel digital designs in PolyJet printing. Therefore, engineers and designers can manipulate entire morphology and material at each voxel level, and different prototype morphologies can be created with the same voxel digital design. In addition, difficulties from AM process with voxel printing for such material designs is addressed, and effective digital solutions were used for successful prototypes. Some of these difficulties are extra support material or printing the part with different dimension than it designed to achieve the final part dimension fidelity. Present work addressed and resolved such issued and provided cyber based software solutions using CAD and voxel discretization. All these increase broad adaptability of PolyJet AM in industry for prototyping and end-use.


2020 ◽  
Vol 19 (01) ◽  
pp. 107-130 ◽  
Author(s):  
R. Borrelli ◽  
S. Franchitti ◽  
C. Pirozzi ◽  
L. Carrino ◽  
L. Nele ◽  
...  

Additive manufacturing (AM), applied to metal industry, is a family of processes that allows complex shape components to be realized from raw materials in the form of powders. Electron beam melting (EBM) is a relatively new additive manufacturing (AM) technology. Similar to electron-beam welding, EBM utilizes a high-energy electron beam as a moving heat source to melt metal powder, and 3D parts are produced in a layer-building fashion by rapid self-cooling. By EBM, it is possible to realize metallic complex shape components, e.g. fine network structures, internal cavities and channels, which are difficult to make by conventional manufacturing means. This feature is of particular interest in titanium industry in which numerous efforts are done to develop near net shape processes. In the field of mechanical engineering and, in particular, in the aerospace industry, it is crucial for quality certification purpose that components are produced through qualified and robust manufacturing processes ensuring high product repeatability. The contribution of the present work is to experimentally identify the EBM job parameters (sample orientation, location of the sample in the layer and height in the build chamber) that influence the dimensional accuracy and the surface roughness of the manufactured parts in Ti6Al4V. The repeatability of EBM is investigated too.


2017 ◽  
Vol 29 (17) ◽  
pp. 1604211 ◽  
Author(s):  
Luca Hirt ◽  
Alain Reiser ◽  
Ralph Spolenak ◽  
Tomaso Zambelli

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 811 ◽  
Author(s):  
Jørgen Blindheim ◽  
Torgeir Welo ◽  
Martin Steinert

Hybrid Metal Extrusion & Bonding Additive Manufacturing (HYB-AM) is a hybrid manufacturing technology for the deposition of layered metal structures. This new deposition process is a complex metal forming operation, yet there is significant lack of knowledge regarding the governing mechanisms. In this work, we have used finite element analysis (FEA) to study material flow in the extruder, as well as the conditions at the interfaces of the deposited extrudate and the substrate, aiming to identify and characterize the process parameters involved. Analysis of the material flow shows that the extrusion pressure is virtually independent of the deposition rate. Furthermore, from the simulations of the material deposition sequence, it is clearly visible how the contact pressure at the interface will drop below the bonding threshold if the feed speed is too high relative to the material flow through the die. The reduced pressure also leads to the formation of a ‘gas-pocket’ inside the die, thus further degrading the conditions for bonding. The analyses of the process have provided valuable insights for the further development and industrialization of the process.


1998 ◽  
Vol 521 ◽  
Author(s):  
J. Banhart ◽  
J. Baumeister

ABSTRACTThe possibilities for making metallic foams or similar porous metal structures are reviewed. The various processes are classified according to the state of the starting metal - liquid, powdered, ionised. Liquid metal can be foamed directly by injecting gas, gas-releasing foaming agents or by producing supersaturated metal-gas solutions. Indirect methods include investment casting and usage of filler materials. Metal powders can also be used as starting materials for metallic foams: mixtures of such powders with foaming agents are compacted to foamable precursor materials that can be foamed in a second step. Instead of foaming agents inert gas can be directly entrapped in the precursor. Metal foams can also be made from metal powder slurries or by using polymer/powder mixtures. Finally, galvanic electro-deposition also allows to make highly porous metallic structures with open pores.


Author(s):  
W. Polini ◽  
L. Sorrentino

When the roving is winding on the die, the tension value may move away the nominal one that has been optimized by considering the quality and the mechanical properties of the wound composite parts. The variance of the tension value during winding from the nominal one strongly depends on the deposition head trajectory. The present work focuses on the planning of the winding trajectory for winding complex shape parts in composite material by a robotized cell. The planning of the winding trajectory should be based on the structural constraints of the robotized cell and on the technological requirements of the process. In particular, this work aims to study the conditions by which the value of the roving tension verges on the nominal one during winding. The developed planning logics and implemented by a CAD/CAM software have been validated by experimental tests. This work represents the first step towards the optimization of the winding trajectory.


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