Thursday, March 26, 2015

Finished with two "Text Book" bones

I have finally finished preparing two bones that could be in a textbook if any was ever written about Bernie. One is the forth braincase - a great bone. It is 30% larger than the previous one, and in great shape. I prepared out the rock that is in the center of the bone as much as possible. This illustrates how that branch of the brain looked. I also prepared out two of the larger nerve passages (one on each side) though I don't know which nerve it would be. The Occipital Condyle (where the backbone attaches to the skull)  and the Foramen Magnum (here the spinal cord comes out of the skull) are very strange. The OC is round with a depression in the middle. It is like a ball-and-socket joint found in a lot of reptiles, but it's reversed! the socket is on the skull side, not the backbone side. Huh?  And the FM is very large and not round out all. Double Huh??

The second bone is a centrum with the attached neural arch. This is only the second bone pair we have found, as normally the neural arches separate from the centrums at the cartilage joint. This bone pair is not only complete, it has the bumps on the side where the ribs connect to the backbone [diapophysis and parapophysis] and the bumps where the neural arch connects to the ones before and behind [anterior and posterior zygapophyses]. Very nice bumps - I really need to know how to pronounce the names. Both of these bones will be scanned next at Century High school after spring break.
So here are some pictures, the result of six weeks of work, 3 days per week:
 First the forth braincase by itself:








Next, the third and forth braincases side-by-side






 Last of all the Centrum-Neural Arch pair:






Sunday, March 22, 2015

Little Big Bones - Baby makes Five???

While preparing the 4th braincase I have encountered several small bones that appear to be from an infant Thalattosaur. They are two centrums (one from last year), what could be a leg bone and what could be a pelvic girdle bone. Here are some pictures:

Here is a plain centrum recovered in 2013. It shows the 'hour glass' scar where the neural arch connects, but no neural arch was found. In most cases the arches separate from the centrums at the cartilage joint. Without the neural arch it wasn't clear if this was just a bone at the end of the tail (from a larger animal) or a bone from a very small animal.
 Here is the recently found centrum with a partial neural arch attached. With the neural arch it must be one of the body backbones (instead of the tail). Thus it must be from a  very small individual = our 5th  animal! I hope we can find the skull for this one.
 Here's a top view of the small one and a normal sized one.
 Here is a different bone. It may be part of the pelvic girdle, though I'm not sure. The bones have 'growth areas' in three sides and a smooth saddle-curved surface on the side furthest from the camera. However, the nerve holes in the two bones don't correspond, so they may not be the same bone.
 Sincerely, Greg Carr

Tuesday, March 10, 2015

3D Printing Bones on my Printer!

I finally have my 3D printer working! It is a home-designed and built unit. The printing head moves in the X-Y plane at the top of the unit, and the build platform drops down as the build progresses. Many printers are like this. like the Ultimaker (r). Mine has a build volume of 8"x 8"x 17" (200mm x 200mm x 425mm for those of you who think rationally). This will let me print out and of Bernie's bones full size, including the whole skull.

Since this blog is about Bernie (and Bernice and Bernard and Beatrice and...) some of the first items I've been printing are copies of Bernie's bones. I've got a couple of brain cases, palate, etc. I'm considering a full skull, but the printer is not reliable enough to print the 60+ hours it will take to do a full skull. In fact right now after about 40 hours of printing the extruder barrel is broken. That's because it is inherently a poor mechanical design. I'm improving it and I'm waiting for some parts to get it running again.

There is an interesting balance required to print out these 'organic' parts. They don't have nice flat planes or straight edges - they are all curves, holes, overhangs, swells and shrinks. To do an overhang you need to have cool extruding temperatures and quick cooking of the extruded plastic so that it doesn't sag; to get good adhesion between layers you need slow cooling and  hot extrude temperatures.  And it really is true that different colors of the plastic need different conditions - mostly because the fillers change the physical characteristics of the plastic. Black is particularly hard to work with. So I think I'll mostly work with white and clear.

So here's some pictures. Here's the printer itself with the control panel in front.
 Here it is printing out part of a Teratorn Humerous. The Teratorn is an extinct eagle with a 15 foot wing span. This bone was excavated at Woodburn (Oregon) high school. It was CAT scanned and translated into .stl files by the University of Oregon where the original is displayed. it is quite a challenge to get this printed - I haven't succeeded yet, but I'm close.
 Here it is printing out Bernie's Scapula
Here is a printed copy of the most complete brain case next to the original. Guess which is which!



Here's a hint - it is the one with the catalog number and the better underside (overhangs are difficult).
Here is a print with the raft (the flat base that goes on the printer bed) and the supports added to hold up the overhangs as they are being made.

 Here's the built-in control panel.

 Here's the base of the Teratorn bones, showing the intricate internal structure captured by the CAT scan. No other copying technique can reproduce this intricate texture.

 And here's the Distal end of the Humerus of the teratorn printed in white ABS. I'll be trying clear PLA so that the inside structure can be seen (somewhat) without slicing it open.

And here is how you do this process. Brown outlines are the traditional fossil prep steps. Green is the scanning steps. Blue are software steps. Red is finishing it up as desired. Lots of complicated steps to this process if you want to do it right!


Finally, here is a video of the printer in action:
video
Sincerely, Greg Carr