Today was spent researching all the manipulations involved in getting a CT scan into printable form and I managed to get a print out of it. The process starts with DeVide where the dicom data from the CT scan is processed using a dual threshold, decimation filter, and stl writer. The stl file contains a lot of unwanted stuff, in this case, soft tissues inside my head that add triangles but won’t be seen in the print, so those are removed by applying ambient occlusion followed by selecting and deleting vertices by “quality” (which will be very low values for vertices on the interior of the object). This process invariably blows small holes in the desired surface, so you apply a “close holes” filter to fix that (which closed up the nostrils very nicely). Next you open the stl file in netfabb and rotate and clip unwanted external stuff and apply repairs as necessary. Finally, drag it into slicer and scale it. slice and print.
While investigating software to extract bone data from CT scans and turn it into 3D printable STL files, I played with a CT scan of my own head that was used to treatment plan orthodontics. I have been using DeVide to process the data and finding it is not only easy to use, but a lot of fun!
The animated gif was made by sweeping the lower threshold of a dual threshold module from -800 to 900 in steps of 100 with the upper threshold fixed at 1400. The effect is to strip away the lower density tissues leaving only dense bone at the end of the sweep. I saved the result of each run as a png file then converted to an animated gif using an on-line service.
I recently acquired a B&L Balplan biological microscope (about $200 on ebay) to look at really small critters and decided it would be nice to be able to record some of their antics. After a few measurements with a caliper and about 30 minutes with Sketchup, the design was ready to print on MegaMax. Initial test results, seen below, look pretty good! The camera is a Logitech Quickcam Pro for Notebooks (seriously, when are they just going to start using model numbers?) that can capture video at 960×720 and 15 fps. The camera is not a current product at Logitech but can be picked up for $10-20 on ebay. The still and video were captured using quvcview running on my laptop (ubuntu 13.04). Logitech’s software works great on Windows. The image below shows “horns” on the head of a pinhead sized bug that was crawling around in my work room. Magnification is 640X!
The adapter design and .stl files will appear on Thingiverse soon.
See the vase being described at the end of the Hack-a-day video posted below.
After a year’s work designing, building, scrapping, redesigning, building, and working through software and firmware issues, the MegaMax 3D printer is now functional. It has some common 3D printing issues like printed objects peeling up off the glass printbed. Tweaked settings in Slic3r, ABS “juice”, and Aquanet hairspray have all been tested with moderate success in attempts to improve adhesion to the printbed. Finally, have_blue gave me a block of foam out of the Stratasys printer to try out and it seems to work better than the other methods and doesn’t require heating the bed! Further experiments to be conducted post-haste.
More info on this project can be found here: http://wiki.milwaukeemakerspace.org/projects/megamax_3d_printer
The video shows the last few layers of the calibration cube “printing” at 414% speed (according to my LCD display).
The Bucketworks 3D printing meet-up on 8/12 paid off big-time! Gary Kramlich helped me debug a problem that was preventing me from flashing the firmware on the controller board for the MegaMax 3D printer. After a few tweaks I was able to get it moving.
This gallery contains 5 photos.
Jerry Malek drove his son’s Fisker Karma to the space yesterday. It is a sweet ride! Here are a few photos to give you a taste of how the other half lives… Yes, I asked, but for some reason he wouldn’t let anyone take it apart to see how it works or see if we […]
This is my on-going project at the Milwaukee Makerspace. It is a 3D extruded plastic printer with about 1 cuft build envelope. I want to print life-size human skulls (among other things) from CT scan data. The printer is made mostly from salvaged parts and materials so the cost has been very low. When it’s finished it will have a heated 12″x12″ bed (13″x13″ if I can find an aluminum plate that big) and dual extruder so it can print in two colors.
I have learned a lot on this project- some things that work and others that don’t work so well, and how to use a milling machine to drill holes precisely and square the ends of the 8020 extrusion pieces used to build up the frame of the machine.
I could not have done any of this without access to the people, materials, and tools at Milwaukee Makerspace. Every time I go there to do some work on this project someone says something that gives me new ideas for improvements to the design. I frequently find materials and parts left for me on the machine’s cart by other members who know what I’m trying to do. If you have a project idea find your local Makerspace and get busy- there is nothing that will get your creative juices flowing like being around a bunch of people with similar interests and different skills and experience!