Transient Heat Conduction in a Thin Layer Between Semi-Infinite Media in Polymer Shaping

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Leendert van der Tempel ◽  
Willem Potze ◽  
Jeroen H. Lammers
Keyword(s):  
Heat Conduction ◽  
Thin Layer ◽  
Surface Heat Flux ◽  
Fused Deposition Modeling ◽  
Transient Heat Conduction ◽  
Surface Heat ◽  
Test Cases ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Infinite Media

A series expansion and an approximation have been derived for the temperature in the general case of transient heat conduction in a thin layer with a surface heat flux between two semi-infinite media at different uniform initial temperatures. Their temperature accuracy has been evaluated for two test cases in the field of thermoplastic shaping of polymers. The series enables quick yet fairly accurate thermal analysis of compression molding (CM) and injection molding (IM) and its vitrification rate and of fused deposition modeling™ (FDM) and its bead welding and vitrification rate.

Development of a Low-Cost Parallel Kinematic Machine for Multidirectional Additive Manufacturing

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Xuan Song ◽  
Yayue Pan ◽  
Yong Chen
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Low Cost ◽  
Work Piece ◽  
Test Cases ◽  
Constraint Checking ◽  
Fused Deposition ◽  
System A ◽  
Deposition Modeling ◽  
Tool Motion

Most additive manufacturing (AM) processes are layer-based with three linear motions in the X, Y, and Z axes. However, there are drawbacks associated with such limited motions, e.g., nonconformal material properties, stair-stepping effect, and limitations on building-around-inserts. Such drawbacks will limit AM to be used in more general applications. To enable 6-axis motions between a tool and a work piece, we investigated a Stewart mechanism and the feasibility of developing a low-cost 3D printer for the multidirectional fused deposition modeling (FDM) process. The technical challenges in developing such an AM system are discussed including the hardware design, motion planning and modeling, platform constraint checking, tool motion simulation, and platform calibration. Several test cases are performed to illustrate the capability of the developed multidirectional AM system. A discussion of future development on multidirectional AM systems is also given.

Effect of Implicitly Derived Infill Patterns on Mechanical Properties

2017 ◽  
Author(s):  
Davis W. Adams ◽  
Cameron J. Turner
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Tool Path ◽  
Stress And Strain ◽  
Test Cases ◽  
Fused Deposition ◽  
Thin Walls ◽  
Strain Data ◽  
Deposition Modeling ◽  
Slicing Method

One of the most important steps in the preprocessing stage of fused deposition modeling is the generation of a set of instructions that control every movement of the tool head, known as GCode, which is created by a slicer software. The tool path is dependent on various user defined inputs including infill pattern, infill density, layer height, and feed rate. All current slicers generate the path explicitly and do not consider certain geometries that will create critical voids such as thin walls and small corners. This work replicates a new implicit slicing method in which functionally derived infill patterns are overlaid onto each layer of a part reducing the possibility of voids and flaws. Further research investigating the effects of varying implicit infill patterns have on mechanical properties is also included. Stress and strain data is gathered for three different test cases, and the resulting mechanical properties for each case are compared.

Biodegradable 3D Printed Polymer Microneedles for Transdermal Drug Delivery

2018 ◽  
Author(s):  
Michael A. Luzuriaga ◽  
Danielle R. Berry ◽  
John C. Reagan ◽  
Ronald A. Smaldone ◽  
Jeremiah J. Gassensmith
Keyword(s):  
Drug Delivery ◽  
3D Printing ◽  
Transdermal Drug Delivery ◽  
Fused Deposition Modeling ◽  
Fused Deposition ◽  
Modeling Software ◽  
Deposition Modeling ◽  
3D Printed ◽  
Microfabrication Technique ◽  
Mechanical Strengths

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1 – 55 µm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.

An Update on the Use of Alginate in Additive Biofabrication Techniques

2019 ◽  
Vol 25 (11) ◽  
pp. 1249-1264 ◽  
Author(s):  
Amoljit Singh Gill ◽  
Parneet Kaur Deol ◽  
Indu Pal Kaur
Keyword(s):  
Fused Deposition Modeling ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Layer By Layer ◽  
Three Dimension ◽  
Anionic Polymer ◽  
Fused Deposition ◽  
The Status ◽  
Deposition Modeling ◽  
Extrusion Printing

Background: Solid free forming (SFF) technique also called additive manufacturing process is immensely popular for biofabrication owing to its high accuracy, precision and reproducibility. Method: SFF techniques like stereolithography, selective laser sintering, fused deposition modeling, extrusion printing, and inkjet printing create three dimension (3D) structures by layer by layer processing of the material. To achieve desirable results, selection of the appropriate technique is an important aspect and it is based on the nature of biomaterial or bioink to be processed. Result & Conclusion: Alginate is a commonly employed bioink in biofabrication process, attributable to its nontoxic, biodegradable and biocompatible nature; low cost; and tendency to form hydrogel under mild conditions. Furthermore, control on its rheological properties like viscosity and shear thinning, makes this natural anionic polymer an appropriate candidate for many of the SFF techniques. It is endeavoured in the present review to highlight the status of alginate as bioink in various SFF techniques.

Recent Advance on Fused Deposition Modeling

2014 ◽  
Vol 7 (2) ◽  
pp. 122-130 ◽  
Author(s):  
Zhe Shi ◽  
Yonggang Peng ◽  
Wei Wei
Keyword(s):  
Fused Deposition Modeling ◽  
Fused Deposition ◽  
Deposition Modeling
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