3D Bioprinting: Comparing Lattice Scaffolds with Traditional Rectangular Sheets

Bioprinting is not a simple endeavor – if it were, we would likely be transplanting 3D printed organs by now. It’s a delicate process that requires a number of factors to be in place, including bioinks that are both printable and biocompatible, and proper scaffolds. In a paper entitled “A Comparative Study of a 3D Bioprinted Gelatin-Based Lattice and Rectangular-Sheet Structures,” a group of researchers compares scaffolds with lattice mesh geometries to more traditional flat rectangular sheets.

“We hypothesised that the experiments performed as a part of this study would help us to observe considerable differences between the two structures, i.e., lattice and rectangle, and also open up the possibility of significantly enhancing the design of a 3D bioprinted construct for engineering cardiac tissue-on-a-chip, using bioprinting,” the researchers state.

The researchers used furfuryl gelatin (f-gelatin) as a base for their bioink, which they seeded with mouse mesenchymal stem cells. They used an ALLEVI 2 bioprinter to print the ink into two different structures – a lattice and a rectangular sheet. Rheological characterization of the bioink was conducted, and the bioprinted structures were cultured in an incubator. A live/dead cytotoxicity assay was performed, and the texture of the lattice was analyzed by scanning electron microscopy.

“The SEM cross-sectional image of the gelatin lattice revealed a highly organized, striated, patterned, and networked structure in comparison to the loosely networked and largely porous rectangular-sheet cross-section SEM, as reported in our previous study,” the researchers explain. “Porosity and pore-size are crucial to ensure cell colonization of the scaffold, deposited using bioprinting. Likewise, SEM micrographs showed a homogeneous distribution of equal sized pores within the entire area scanned and imaged….The average apparent porosity of this lattice structure was estimated to be about 50% compared to 21% for the rectangular-sheet. The results led us to conclude that although the mean pore size was significantly reduced by printing in the form of a lattice, the inherent design of the lattice allowed pores to be of a similar size and to be homogenously distributed throughout the entire structure, compared with the rectangular-sheet.”

Swelling behavior of the gels was monitored to study the hydration dynamics of the crosslinked hydrogel structure. Cell proliferation was assessed and flow cytometry was analyzed.

Results of the testing showed that the lattice structure was more porous than the flat rectangular sheet. It also exhibited a lower degradation rate.

“Further, the lattice allowed cells to proliferate to a greater extent compared to the rectangular-sheet, which initially retained a lower number of cells,” the researchers state. “All of these results collectively affirmed that the lattice poses as a superior scaffold design for tissue engineering applications.”

A scaffold is literally a foundation to build upon in bioprinting, and having an effective scaffold is key in any bioprinting application. Cells rely on a strong scaffold in order to survive and proliferate. A printable, biocompatible ink is also crucial for cells to be able to grow into tissue. The researchers find in this study that lattice structures are superior to rectangular sheets, which could mean the difference between success and failure in future applications.

Authors of the paper include Shweta Anil Kumar, Nishat Tasnim, Erick Dominguez, Shane Allen, Laura J. Suggs, Yoshihiro Ito, and Binata Joddar.

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below. 

 

PostProcess Technologies Uses Hybrid DECI Duo Solution to Achieve Excellent Surface Finish for 3D Printed Shrouded Impellers

Exacting Surface Finishing of Complex 3D Printed Metal Geometries.

PostProcess Technologies, which expanded its channel partner coverage in North America this spring, is well known for its software and post-printing solutions. With its automated Hybrid DECI Duo solution, PostProcess helps its customers achieve excellent surface finish standards and replicable results for complex metal parts.

Recently, PostProcess demonstrated in a new case study how well its technology can help other companies. The subject was Ingersoll Rand, a $14 billion global industrial manufacturing company that specializes in compressed air technologies. The company uses 3D printing for its shrouded impellers, which improve the performance of a compressor package more than open impellers because there is no clearance between the stationary inlet and the impeller, so no slip losses occur as a result of compression gas recirculating in the space.

The design for shrouded impellers, which rotate 60,000 RPM, has very tight tolerances in order to meet aerodynamic testing. In addition, the blades need excellent surface finishing, and it takes months to build using conventional forms of manufacturing. So Ingersoll’s engineering team, needing to commercialize its shrouded impeller design, turned to 3D printing because of its complete design freedom; the technology also makes it possible to build the part as monolithic, so no welding is required. But, in order for 3D printed parts to meet performance thresholds, they do require outstanding surface finishes.

Ingersoll 3D prints its shrouded impellers out of titanium and nickel alloy, but they unfortunately come off the print bed at an Ra (roughness average) value that doesn’t meet the engineering team’s specifications. The team has tried everything from manual sanding and grinding tools to chemical etching, but the results were inconsistent and did not have the necessary, repeatable quality needed to produce end parts within the required specifications.

The company needed to find a replicable process that would provide them with the necessary surface finish for its shrouded impeller’s complex geometry, in order to, as PostProcess wrote in its case study, “drive a measurable increase in efficiency for its advanced air compressors.”

So, Ingersoll turned to PostProcess in hopes that the company could work with complex metal part geometries, like organic shapes and internal channels, and help achieve repeatable results and excellent surface finish standards for its shrouded impellers.

Automated DECI Duo for Post-Print Support Removal & Surface Finishing.

PostProcess delivered a “transformative outcome” for Ingersoll’s 3D printed titanium and nickel alloy parts, thanks to its patent-pending, automated Hybrid DECI Duo solution. The Hybrid DECI Duo – a single, multi-functioning, data-driven system – promises fast cycle times for even the most complex of parts Designed to optimize production floor space, the system also includes noise reducing features for a low dBa, an LED lighted chamber, and a manual mode for hands-on part finishing when needed.

The system also uses PostProcess’ proprietary AUTOMAT3D software, in order to optimize energy and exclusive chemistry, which includes detergents and suspended solids so the geometries maintain their fine-feature details while still receiving the desired surface finish.

“We have chosen the DECI Duo because of its repeatability, minimal setup, processing times, and cost of ownership. Photochemical machining, extrude honing, and micro polishing or micro machining all yield very good results when applied correctly, however extensive tooling and equipment costs, setup times, and required DOE’s prior to applying the surface finishing method to obtain a repeatable process have made the DECI Duo a better option,” said Ioannis Hatziprokopiou, Mechanical Engineer, New Product Development, Ingersoll Rand Compression Technologies and Services.

“In addition, some of aforementioned finishing techniques unevenly remove material inside the flow path of the impeller, whereas the DECI Duo uniformly treats the entire surface of the flow path. The final geometry of the flow path must remain as unaltered as possible after post-processing of any kind.”

3D printed shrouded impellers were
implemented on the last 3 stages of this 6 stage 6R3MSGEP+4/30 engineered air booster machine.

The PostProcess solution established operating settings that were in line with Ingersoll’s standards using benchmark parts. Then, the DECI Duo was able to consistently finish metal parts that were able to successfully pass exacting aerodynamic tests.

Ingersoll came to PostProcess with a need for high quality and requirements in consistency and repeatability. But, it’s also achieved additional advantages from working with the company, such as cost savings and ease of operation.

In addition, the DECI Duo also produced an average of 70-80% reduction in Ra for parts run for 20 minutes or less.

Discuss this story and other 3D printing topics at 3DPrintBoard.com or share your thoughts below. 

[Images: PostProcess Technologies]

How 3D Printing Changed The Way Artist Tim Belliveau Teaches His Students

In the art world, the debate around handmade and machine-made products is certainly a heated one. But after an extensive research project focusing on the different perspectives in glass making, artist and educator Tim Belliveau knew how efficient and beneficial 3D printing was to his art form.

“I wanted to see my training in glass from a different perspective and make some understanding of the 3D printers that I started to see popping up in glass studios around 2014,” Belliveau told Shapeways. “I was also inspired to use 3D printing in my research because I was traveling a lot and it was becoming difficult to store and travel with material things. It caused me to kind of ‘compress’ my practice down to the basic ideas and images I wanted and find ways for even glassblowing to be represented in 3D software as small, portable files and small tools rather than big, heavy materials and equipment.”

His first attempt at 3D printing

Prior to his teaching career, Belliveau received his Masters of Fine Arts at Concordia University in Montreal in Fibers and Material Practices. With the help of Shapeways’ EDU discount, he was able to explore an avenue of 3D printing that he’d never experienced before.

“I wanted to use 3D printed metal for my mold at a scale that was big enough to fit blown glass and thin enough to stay on budget. I also wanted to test out how an ancient craft like glass can interact with newer 3D printing tools. I teach with it as a skill-building tool, but also to instigate thinking around skill, technology, and art,” he said. “The EDU discount made my project possible and without it, I would likely have had to do the more common method of casting positives and negatives and hiring a foundry to produce what I needed.”

Tim Belliveau's glass-blowing mold in 3D renderings and 3D printed bronze

Tim Belliveau’s two-part mold for glass blowing, made from 3D printed bronze

Belliveau never expected to love 3D printing as much as he now does. After completing his research project and launching his teaching career, he began to incorporate 3D printing into every one of his classes.

“This project tested the skills and thinking needed to get from 3D modeling to glass forms. I use 3D printing for teaching almost every class now. Once students get through the interfaces of various software and can intuitively sketch with it, the possibilities really expand but at the beginning, its more about learning through accidents and working with mistakes rather than getting perfection. This project sent me on a path of asking more questions about this process and trying to find less deterministic ways to use technologies like this.”

Overcoming the obstacles of being a beginner 3D designer

Like Belliveau explained, learning how to use 3D printing comes with its fair share of challenges and obstacles. Overcoming these difficulties, however, is what taught him a great deal about the craft.

“It was challenging at first to blow into this 3D printed mold in part because the opening is narrow. A very hot bubble of glass has to be stretched through the neck of the mold and inflated perfectly into the chamber. That took a lot of practice. I spent a lot of time shaping and thinning the model in my software to guess at what the minimum thickness could be,” Belliveau said.

The final outcomes have been extraordinary

Among the many products he’s made using 3D printing, one of his favorites has to be the “monuments” he constructed during his residency at the European Ceramics Work Centre last year.

Original plaster horse and 3D scanned and printed version

Deconstructing 3D print processes: using the plaster horse (left), Tim Belliveau 3D scanned and printed a new one (right)

“I’ve been kind of deconstructing 3D print processes, using more labour and trying to make it harder. During my residency at The European Ceramics Work Centre last year, I modeled a polygon and used software to unfold that shape into faces, projected it onto cardboard, cut that out, traced it into clay panels and assembled those together making the original polygon form again. The finished artworks, called ‘Monuments,’ have a trace of computer design but mostly, hand-marks and textures that come from forming it. You might not guess it came from computer modeling by looking at it and they were very challenging to make but also very rewarding.”

Reflecting on his journey with 3D printing, now utilizing it in every class he teaches, Belliveau said, “I wish I knew how to do 3D printing sooner! As with most skills, it’s not as intimidating as it might seem as long as you’re interested enough to spend the time and learn. It’s very accessible and, in some cases, very cheap to do.”

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The post How 3D Printing Changed The Way Artist Tim Belliveau Teaches His Students appeared first on Shapeways Magazine.

3D Hangouts – 200th Episode, Making Bladesaw from Zelda BOTW

Ancient Bladesaw from Zelda BOTW
https://learn.adafruit.com/bladesaw

Adafruit Crickit for Circuit Playground Express – https://www.adafruit.com/product/3093
Circuit Playground Express – https://www.adafruit.com/product/3333
NeoPixel UV Strips – https://www.adafruit.com/product/3851
NeoPixel Side Strip – https://www.adafruit.com/product/3636
All-Metal DC Motor – https://www.adafruit.com/product/3802
Ultimaker 3 – https://www.adafruit.com/product/3300

New Parts Every Week! Adafruit Fusion 360 Parts on GitHub
https://github.com/adafruit/Adafruit_CAD_Parts

PiGRRL Advanced
https://www.thingiverse.com/thing:3082579

Timelapse Tuesday Spotlight:

Helm of Glencairn – Viking Helmet
https://www.thingiverse.com/thing:1243621
https://www.youtube.com/watch?v=KwGftzRkZ7A

Community Makes:

Pumpkin skull remix https://www.thingiverse.com/make:536795
LED sandtoy https://www.thingiverse.com/make:536846
Dodecahedron https://www.thingiverse.com/make:536880
Monthly Prints Series by Liz https://www.youtube.com/watch?v=32pG1cjcRaQ
BLE Feather Cam NeoRing https://www.thingiverse.com/thing:3092206
3D Printing Nerd Joel Telling – Daft Punk
https://www.youtube.com/watch?v=wAY4ADb5tr4


649-1
Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!

The Adafruit Learning System has dozens of great tools to get you well on your way to creating incredible works of engineering, interactive art, and design with your 3D printer! If you’ve made a cool project that combines 3D printing and electronics, be sure to let us know, and we’ll feature it here!

New Project: Bladesaw – Zelda Breath of the Wild #3DThursday #3DPrinting

3D Printed BladeSaw from Zelda BOTW with motorized chain and NeoPixels! Build your own BladeSaw from Zelda BOTW with 3D Printing and Electronics from Adafruit. We designed and 3D printed parts to build a real bladesaw with actual moving parts and NeoPixel LEDs.

Links to files and parts in learn guide:
https://learn.adafruit.com/bladesaw


649-1
Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!

The Adafruit Learning System has dozens of great tools to get you well on your way to creating incredible works of engineering, interactive art, and design with your 3D printer! If you’ve made a cool project that combines 3D printing and electronics, be sure to let us know, and we’ll feature it here!

3D Hubs Switches Service to B2B Model

If you’ve been in the 3D printing scene for even a short while, you’ve undoubtedly heard of 3D Hubs. The famed peer-to-peer network company that links up 3D printing services is a major player in the industry. The company got its start by catering to all sorts of hobbyists, professionals and enthusiasts alike. However, they’re […]

The post 3D Hubs Switches Service to B2B Model appeared first on 3D Printing.

SCRIM Concrete Printing Robots Build Lightweight Structures

Researchers have long been looking for lighter concrete printing tech, making transport and processing smoother. This is especially relevant for robot-based building processes due to the obvious issue of robotic motion and speed. However, a joint research project may have cracked the code on this with a novel new method. SCRIM (Sparse Concrete Reinforcement In […]

The post SCRIM Concrete Printing Robots Build Lightweight Structures appeared first on 3D Printing.

Zortrax enters vat polmerization market with Inkspire 3D printer

Polish 3D printer manufacturer Zortrax has released a new 3D printer: the Inkspire. Unlike Zortrax’s existing range of 3D printers, including the M200 Plus that was released earlier in 2018, the Inkspire uses vat polymerization technology rather than fused filament fabrication (FFF). With this, Zortrax is tapping into a whole new range of materials, and resolution […]

New 3D printing jobs at Verashape, Thales Group, RP Support, and Create it REAL

3D Printing Jobs is growing day-by-day, providing the freshest opportunities from top enterprises across the industry. Today, we highlight open positions for sales engineers, plant directors, and software engineers. Start looking for your additive manufacturing career and apply for vacancies here for free. Do you need new 3D printing specialists for your company? Create a […]