3DPrinting Body Organs >

Circulatory System

Circulatory System (Photo credit: kevin813)

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ARTICLE SPECIALIST KNOWLEDGE LEVEL > > > > >5

The goal of building lab-grown bodily organs out of a patient’s own cells is something that Bio-engineers have been advancing toward, but a few major challenges remain – one of them is making vasculature, the blood vessel plumbing system that delivers nutrients and removes waste from the cells on the inside of a mass of tissue.

Without these blood vessels, interior cells suffocate and die.

Growing thin layers of cells is already possible, so one proposed solution is to “print” the cells layer by layer, leaving openings for blood vessels as necessary. The downside is that this method leaves seams in the printed output: when blood is pumped through the vessels, the seams are pushed apart.

The University of Pennsylvania’s Bio-engineers have turned the problem inside out by utilising a RepRap 3DPrinter called to manufacture templates of blood vessel networks out of sugar. Once the networks are encased in a block of cells, the sugar can be dissolved, leaving a functional vascular network behind.

“I got the first hint of this solution when I visited a Body Worlds exhibit, where you can see plastic casts of free-standing, whole organ vasculature,” says Bioengineering postdoc Jordan Miller.

Miller, along with Christopher Chen, the Skirkanich Professor of Innovation in the Department of Bioengineering, other members of Chen’s lab, and colleagues from MIT, set out to show that this method of developing sugar vascular networks helps keep interior cells alive and functioning.

After the researchers design the network architecture on a computer, they feed the design to the RepRap. The printer begins building the walls of a stabilizing mold. Then it then draws filaments across the mold, pulling the sugar at different speeds to achieve the desired thickness of what will become the blood vessels.

“I got the first hint of this solution when I visited a Body Worlds exhibit, where you can see plastic casts of free-standing, whole organ vasculature,” says Bioengineering postdoc Jordan Miller.

When the sugar becomes hardened, the researchers add liver cells, suspended in a gel, to the mold. The gel surrounds the filaments, encasing the blood vessel template.

After the gel sets it can be removed from the mold with the template still inside. The block of gel is then washed in water, dissolving the remaining sugar inside – the liquid sugar then empties from the vessels it has created without harming the growing cells.

“This new technology, from the cell’s perspective, makes tissue formation a gentle and quick journey,” says Chen.

The researchers have successfully pumped nutrient-rich media, even blood, through these gels blocks’ vascular systems. They also have experimentally shown that more of the liver cells survive and produce more metabolites in gels that have these networks.

The RepRap makes testing new vascular architectures quick and inexpensive, and the sugar is stable enough to ship the finished networks to labs that don’t have 3DPrinters of their own. The researchers hope to eventually use this method to make implantable organs for animal studies.

 Video by Kurtis Sensenig

Materials: Wood Filament > > > 
The End of Opensource? > > >
3 Colour Home 3DPrinting > > > 

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REVIEW: LulzBot TK-0

SPECIALIST KNOWLEDGE LEVEL  > > > >4 >

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Aleph Objects’ LulzBot TK-0 3D Printer  announced a huge 300mm x 300mm x 225mm build volume…

The high end specifications continue with a 250mm/sec printing speed at 100 microns.

Just as amazingly it is designed to be assembled and calibrated in 2.5 hours.

^This somewhat amazing fold-up design could make the TK-0 one to watch…

 

For the more technically minded reader, here is an in-depth of those all important specifications.

 

Main specs:

  • RAMBo electronics.
  • Fully enclosed electronics case with fan and strain relief.
  • Panucatt Heatbed.
  • LM8EUU bearings.
  • Marlin firmware.
  • Pronterface printer control.
  • Comes with 0.50mm, 0.35mm, 0.25mm nozzles.
  • No belt slippage or stretching.
  • Folds up into a small box, for easier and less expensive shipping.
  • Weight: 11kg including power supply.
  • Size: 585mm x 525mm x 525mm.
  • Size of unit when folded: 585mm x 525mm x 190mm.
  • Enclosed UL certified power supply (will be 24V).
  • Wade’s Reloaded extruder.
  • All extrusion lengths the same–very easily scalable up or down.
  • All rod lengths the same.
  • All belt lengths the same.
  • Colored LEDs to indicate heat and cooling.
  • Materials: ABS or PLA.

Water Cooled RepRap > > >

Adrian Bowyer, inventor of the world’s most popular home 3DPrinter genus, the RepRap, has been experimenting with a water-cooled print head.

Whilst the fan-cooled heads are a highly successful design, having a very short melt zone and high-power to respond to changes in load, the fan is often deemed relatively bulky.

The application of water cooling, which has emerged as a subtle but growing trend in the home computing world, has an outcome much lighter and more compact.

Best of all the cooling is more efficient.

A brass block that replaces the normal aluminium cooling block that attaches to the fan.  The brass has water channels drilled in it, and some soft silicone tubing connecting it to a small 12V gear pump.  The inflow and outflow temperatures are only a fraction of a degree different, meaning that multiple heads could be chained in series and all cooled by the same flow.

Here is a video from the inventor’s labs to whet your intrigue…

<p><a href=”http://vimeo.com/45756426″>RepRap water-cooled head</a> from <a href=”http://vimeo.com/user403878″>Adrian Bowyer</a> on <a href=”http://vimeo.com”>Vimeo</a&gt;.</p>

More: http://reprappro.com/Special_Blog?cmd=post&id=6

Visualising Data Using a 3DPrinter > > >

SPECIALIST KNOWLEDGE LEVEL > > > > >5/5

‘Some time ago, I had some data that lent themselves to a 3D surface plot. The problem was, the plot was quite asymmetrical, and finding the right viewing angle to see it effectively on a computer screen was extremely difficult. I spent ages tweaking angles and every possible view seemed to involve an unacceptable compromise.

Of course, displaying fundamentally 3D items in two dimensions is an ancient problem, as any cartographer will tell you. That night, as I lay thinking in bed, a solution presented itself… I had recently been reading about the work of a fellow University of Bath researcher, Adrian Bowyer, and his RepRap project, to produce an open-source 3DPrinter.

The solution was obvious: I had to find a way to print R data on one of these printers!

I managed to meet up with Adrian back in May 2012, and he explained to me the structure of the STL (stereolithography) files commonly used for three-dimensional printing. These describe an object as a large series of triangles. I decided I’d have a go at writing R code to produce valid STL files.

I’m normally a terrible hacker when it comes to programming; I usually storm in and try to make things work as quickly as possible then fix all the mistakes later. This time, I was much more methodical. As a little lesson to us all, the methodical approach worked: I had the core code producing valid STL files in under 3 hours.

Unfortunately, it then took until September 2012 before I could get hold of somebody with a 3DPrinter who’d let me test my code. A few days ago the first prototype was produced:

3dfunctionr.jpg

So now I’d like to share the code under a Creative Commons BY-NC-SA licence, in case anybody else finds it useful. You can download the code here, in a file called r2stl.r.

One day, when I learn how, I might try to make this a library, but for now you can just call this code with R’s source()command. All that is in the file is the function r2stl(), and having once called the file withsource(), you can then use the r2stl function to generate your STL files. The command is:

r2stl(x, y, z, filename='3d-R-object.stl', object.name='r2stl-object', z.expand=FALSE, min.height=0.008, show.persp=FALSE, strict.stl=FALSE)

    • xy and z should be vectors of numbers, exactly as with R’s normal persp() plot. x and y represent a flat grid and z represents heights above this grid.
    • filename is  self-explanitory.
    • object.name The STL file format requires the object that is being described to have a name specified inside the file. It’s unlikely anybody will ever see this, so there’s probably no point changing it from the default.
    • z.expand By default, r2stl() normalizes each axis so it runs from 0 to 1 (this is an attempt to give you an object that is agnostic with regard to how large it will eventually be printed). Normally, the code then rescales the z axis back down so its proportions relative to x and y are what they were originally. If, for some reason, you want your 3D plot to touch all six faces of the imaginary cube that surrounds it, set this parameter to TRUE.
    • min.height Your printed model would fall apart if some parts of it had z values of zero, as this would mean zero material is laid down in those parts of the plot. This parameter therefore provides a minimum height for the printed material. The default of 0.008 ensures that, when printed, no part of your object is thinner than around 0.5 mm, assuming that it is printed inside a 60 mm x 60 mm x 60 mm cube. Recall that the z axis gets scaled from 0 to 1. If you are printing a 60mm-tall object then a z-value of 1 represents 60mm. The formula is min.height=min.mm/overall.mm, so if we want a minimum printed thickness of 0.5mm and the overall height of your object will be 60mm, 0.5/60 = 0.008, which is the default. If you want the same minimum printed thickness of 0.5mm but want to print your object to 100mm, this parameter would be set to 0.5/100 = 0.005
    • show.persp Do you want to see a persp() plot of this object on your screen as the STL is being generated? Default is FALSE.
    • strict.stl To make files smaller, this code cheats and simply describes the entire rectangular base of your object as two huge triangles. This seems to work fine for printing, but isn’t strictly proper STL format. Set this to TRUE if you want the base of your object described as a large number of triangles and don’t mind larger files.

To view and test your STL files before you print them, you can use various programs. I have had good experiences with the free, opensource Meshlab.

Even if all you ever do is show people your 3D plots using Meshlab, I believe r2stl() still offers a useful service, as it makes viewing data far more interactive than static persp() plots.

Demo

source('r2stl.r')

# Let’s do the classic persp() demo plot, as shown in the photograph above

x <- seq(-10, 10, length= 100)

y <- x

f <- function(x,y) { r <- sqrt(x^2+y^2); 10 * sin(r)/r }

z <- outer(x, y, f)

z[is.na(z)] <- 1

r2stl(x, y, z, filename=”lovelyfunction.stl”, show.persp=TRUE)

# Now let’s look at R’s Volcano data

z <- volcano

x <- 1:dim(volcano)[1]

y <- 1:dim(volcano)[2]

r2stl(x, y, z, filename=”volcano.stl”, show.persp=TRUE)

I hope you might find this code useful. ‘

– Ian Walker, Department of Psychology, University of Bath.

http://psychologicalstatistics.blogspot.co.uk/2012/09/guest-post-visualizing-data-using-3d.html

Materials: Wood Filament > > >

Advertised as looking and even smelling like wood after printing, this 3DPrinter wood filament can be grinded and painted as per conventionally formed wood commodities. By alternating 3DPrint temperatures it’s even possible to produce tree rings. 

This is a big step forward for the home 3DPrinting sector, particularly as one of the major limitations that has been cited over the last year of rapid hype expansion for additive manufacturing has been the low breadth of materials available for the cheaper varieties of printer that are more likely to find themselves on the desk tops of the masses.

That which widens applications widens appeal, that which widens appeal widens potential market, that which widens potential market widens the window of opportunity for 3DPrinting to fulfill it’s publicised, now almost prophetically projected, rise into a revolutionary technology.

TECH SPECS:  The wood is 3mm Diameter, comes as bundle of 500g as per the featured the picture. The material is especially designed for RepRap and similar 3DPrinters. No heated bed is necessary. Recommended extruder temperatures 185°-230°C.

Largest 3DPrinter [video] >

The largest single part printed by a custom designed, open-source, RepRap based, home-built 3DPrinter.

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Three Colour Three Dimensional Printing > > >

The inevitable progress of home 3DPrinting to full colour has taken another step forward thanks to RichRap.RepRap hobbiest RichRap has taken a leap for mankind by developing a 3-way extruder (material depositing mechanism, picture a print-head on a conventional printer) for opensource RepRap 3DPrinters.__________________________________________________________________

RichRap says:
‘…In June I …added three feeder tubes. I had initially intended these to be separately driven Cyan, Magenta and Yellow feed, but after some testing realised that all sorts of blends could be made by running single or multiple extruder’s at intervals separately or together.’
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The outcome of a single extruder capable of accepting up to three separate filament inputs produces beautifully colourful objects.What is more, as this is a free opensource project, RichRap has made the plans for this extruder available on the 3DPrintable object online catalogue Thingiverse.com for all to use.As 3DPrinters can produce everything from a vase to 3D Van Gogh the possibilities are simply endless.
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