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valchanov last won the day on November 11 2018

valchanov had the most liked content!

About valchanov

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  • Birthday 06/22/1980

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  1. valchanov

    Formlabs Fuse 1 SLS printer

    This is why I'm not doing Electron Microscopy and SLA 3D printing - they are too hazardous. Besides, you can convert a simple FDM to print with biologicals and cells, but you can't convert any SLA printer to do the same
  2. valchanov

    Formlabs Fuse 1 SLS printer

    There is a game changer on the SLA front - Josef Prusa made an open source SLA printer - Prusa SL1. You can buy two of those and one Prusa MK3 with the money for one Form 2. It prints down to 10 microns layer thickness (after some tweaking of the slicer). It is open source, which means that the wave of cheap prusa clones is coming. This will change the whole SLA sector because let's face it - with the money for one Form 2 you can buy a whole 3D printer farm with the best printer of Winter 2018 (Prusa MK3) or you can buy two printers of the same class, with the same parameters, which requires more tinkering and experienced staff. The bad side about the Prusa printers are the limited Wi Fi options...
  3. valchanov

    Project Fancy Skull

    I decided to give my Prusa MK3 printer a real challenge, so I cut my best skull model, I added some slots for neodymium magnets and I started to print the parts. I'm done with the half of them and I'll update my post when I'm done.
  4. The build was easy, there are no parts which requires soldering. The manual is really good and helpful, the Haribo candies also helps a lot. The cable assembly part is a tricky one, I asked a friend from the Tech university for some help, but at the end I assembled them by my own and my friend just ate my extra Haribo package (and also ordered a Prusa MK3 kit for himself). You have to be sure that you're building the printer at the flattest and most horizontal surface available - the belt assembly and calibration part are the most important steps and if you do them correctly, you won't have further problems with the printer. The software is very good - Slic3r Prusa Edition is a freeware and have a lot of advanced features, advanced support material management included. When I started to edit my layers manually, the quality of the prints was increased substantially and I made some impossible prints. The whole kit deal is really good one - you can't find printer with the same effectiveness at the same price, it's an out-of-the-box experience and requires a simple build, which will make you familiar enough with your new printer in order to maintain it properly. If you're living in USA, you can order the Seemecnc Rostock Max printer - it's an excellent delta printer with 32 bit controller for 1000$. The reason I got Prusa are the custom taxes - Rostock comes to Europe two times more expensive and Prusa is the better deal. I hope that after the Trump nonsense I'll be able to get one...
  5. The last three weeks was a busy time for me. I purchased the best 3D printer of Fall 2018 - Prusa I3 MK3. I ordered it as a kit, the build itself took me 8 hours - my obsession with the electronics payed off - and immediately after that the printer was ready for some action. Prusa I3 is the most common 3D printer in the world - 70% of all printers are Prusa clones. Prusa MK3 is manufactured by the designer of the printer itself, Josef Prusa and most of it's parts are made by other MK3's in the Prusa's 3D printer farm. The printer is robust, tough, with very useful automatic functions and can print with most types of termopolymers (Polycarbonate included) with minimum layer thickness of 0,05 mm. Now I'm preparing an enclosure with automatic temperature and humidity control, Hepa and carbon filter and Octoprint upgrade for WiFi control. I bought cheap secon-hand server rack for this purpose (Fig. 4) - if it can keep a constant environment for the servers, it can do it for my printer, right? y first print was the object on Fig. 1 (what is the name of the organ?) Then I had more than 300 hours of unstoppable 3D printing and the printer doesn't made A SINGLE bad print. The only issue was the printing surface after print #12 - the next print didn't adhesed properly, so I had to wipe the printing surface with isopropyl alcohol. I was printing with PLA, now I'm starting with the first roll of PETG. My next step was to contact my colleagues from the orthopedic surgery clinic and to show them my first prints. They was exited by the result, so they provided a 1 mm. slide thickness CT scan of a Pylon fracture. Then I used the following workflow: 1. Slicer 3D, Resample Scalar Vollume to resample the set to 0,5 mm. 2. CurvatureAnisotropicDiffusion with 3 iterations. 3. Editor module for segmentation, model maker for the conversion to stl. 4. Autodesk Meshmixer for remeshing, editing and sculpting, Blender for smoothing. I prefer Meshmixer than Zbrush because it's much simpler and user-friendly. I'm also pretty good with it 5. I sliced the final stl with Slic3r, Prusa Edition and sliced the model on 0,150 mm slices, with support from the building plate, with 15% Gyroid infill (it looks exactly as a spongy bone), with Natural White PLA (17 euro per kilogram, from a local supplier) with the Natural PLA preset on the slic3r. 6. The print took 14 hours, the support was easy for removal (Fig. 2). 7. The orthopedical surgeons did their magic, first on the model (Fig. 3), then on the patient. They claimed, that the operation was very successful, thanks to my model and their skill. The chief surgeon is Dr. Preslav Penev MD PHD. My second project was a Pilon fracture of the ankle with multiple fragments, which I made with the same workflow. The patient is in operation right now. I also have two more projects, for a congenital aplasia of the talus with pes varus and for luxatio of the Lisfranc joint, so I hired two medical students and I'll teach them how to model (I already sent them Dr. Mike's beginners tutorial) for my future projects. I'm the first physician in Bulgaria, who performs preoperative 3D printing, which is very good for my career development. My colleagues called me a "pioneer" and I'm thinking about a 3D printing lab. I already ordered the Multimaterial Upgrade, which means SOLUBLE SUPPORT MATERIAL (I have to wait till January, it's in production right now). Jo Prusa's STL printer looks quite appealing too. Those printers are ridiculously cheap, considering how efficient never-stopping beasts of burden they are. I guest I should hit the vascular surgeons next...
  6. valchanov

    Panoplosaurus skull

    Version 1.0.0


    Panoplosaurus, “completely armoured lizard”. Skull from CT scan. Link to Sketchfab. Owner of the CT scan is Ohio University.


  7. If you are a small scale operator (1-2 FDM printers) and you need cheap and reliable solution for your filaments, then you can check CNC Kitchen's Fiament dryer guide. You can easily use it directly or you can install it on any type of enclosure you're using. All you need is an Ikea plastic box, two bowden connectors,, a PVC tube, a teflon tube and some filament for the 3D printed parts. The cost is under 40 bucks.
  8. Version 1.0.0


    An infant with proximal fracture of the tibia and external fixation. Source - Nukki BlastInjuri 1.0.0. Link in Sketchfab. Osteology, orthopedy, orthopedic, fracture, tibia, fibula, leg, external fixation, osteosynthesis, bone, 3d, model, .stl, printable, lower, limb, femur, condyles, lateral, medial


  9. Version 1.0.0


    Talar fracture. Source - Hristo Hristov. Link in Sketchfab. Excellent model for orthopedic training - just print it in PLA and have some fun anatomy, orthopedic, orthopedy, bone, talus, calcanus, foot, training, osteology, naviculare, phalanx, cuboideum, cuneiform, tarsal, metatarsal, fracture, .stl, 3d, model, printable, lower, limb, ankle


  10. Version 1.0.0


    This is my version of the Phenix CT dataset from the Osirix Dicom Library - an infant with Treacher-Collins syndrome and aplasia of the left zygomatic bone and maxilla after a reconstruction surgery with an autograft. I wanted to preserve the small details of the maxilla and the nasal cavity, so I segmented them manually. It took me a week. The spine is not done yet - I'm redoing it and I'll reupload the whole set in the following week. The model is 3D printable, but you'll need a multi-material extruder with soluble support for this purpose - PLA/PVA will be best (PLA/PVA is much better than ABS/HIPS in my opinion). I hope you'll enjoy it skull, face, 3d, model, printable, skull, skeleton, bone, ct, scan, maxilla, malformation, reconstruction, surgery, autograft, zygomatic, arch, fracture, craniotomy, stl, temporal, frontal, parietal, occipital, mandible, nasal, orbit, cervical, spine, clavicle, ribs, thorax, 3d, model, printable


  11. If you manage to find a good Z-stack (confocal microscopy dataset), you can use the following workflow to make a 3D model: 1. Use Fiji (an open-source software, extended version of ImageJ for scientific analysis) to convert .tiff slide to binary (Process/Binary/Make Binary). Then use the Dilate function to reduce the size (Process/Binary/Dilate) and crop a region of interest (Image/Crop). Those datasets are ridiculously large - 10 Gb and above (this is why I didn't uploaded such dataset here), so if you don't have a workstation, be prepared for a LONG wait. Finally, save the stack as a .tiff 2. Use 3D Slicer, Fiji, Osirix, Mimix or whatever segmentation software you prefer to create volume (Volume Rendering), to convert it to a label map and to export it as .stl. The workflow is the same as in the Dr. Mike's basic tutorial. Just don't forget to use the Curvature Anisotropic Diffusion module of Slicer or a similar denoising tool in the software you prefer. It will make your life A LOT easier - the confocal Z-stacks have a lot of noise and still you want to keep the curves of the objects. It's possible to segment a Z-stack with the Region Grow module of Slicer, but I didn't made it myself yet. 3. Finally, use Blender or Meshmixer to remove the artifacts. It's normal to have a lot of them. This topic is related to my PhD project, on which I'm working right now - "Bioprinting and morphological analysis of a 3D matrix for biosynthetic implants", so I'll post my results after I manage to add a syringe pump to my 3D printer and make it work...
  12. valchanov

    Snow leopard skull

    Version 1.0.0

    1 download

    A 3D model of a snow leopard skull. I made it from a CT scan, which is uploaded by George vd W on the site. The nasal cavity is a mess, so I'll fix the conchae in the following days and I'll reupload the result.


  13. There is a histological staining technique for bone tissue, which can be used with confocal microscope for detailed dataset of the haversian model, the lacunae, the canaliculae, the perivascular spaces - every detail you can possibly imagine. Then the dataset can be segmented into a 3D model with the same workflow, which is used for the CT datasets. The problem is that this technique is very demanding, expensive and potentially letal because of the chemical, which are used in the process. I made several models of pyramidal neurons from confocal datasets (here is one on sketchfab, I have another on embodi3d with the dendrite spikes on it) and it's not that bad - after some deconvolution you can segment the dataset with the automatic threshold segmentator or even with the grayscale model maker and you'll get a good model. Sadly, my department didn't received the funding for this technique and I don't have such dataset...
  14. valchanov

    Hand CT scan - stl file processed

    Well, to be honest - you should work more on the carpal bones and especially on the joints between them. Right now they are a solid mass, which can't be used for demonstration purposes. My advice - use the region growing segmentation module on Slicer 3D. Whit it you can seed the parts of your model and the joints between them, which after some surface modeling results in high quality, anatomy department level model without all the artifacts you have. You can watch this tutorial to see how it's used. Happy modeling
  15. Version 1.0.0


    This is my latest version of my paranasal sinuses model with emphasis on the nasal cavity. Every cavity is connected and can be reached with endoscope as an otorhynolaryngological training model. The wall thickness is 0,6mm. For best results, use transparent material with water or oil soluble support. paranasal, sinuses, osteology, ethmoid, sinus, paranasal, septum, nasal, maxillary, turbinate, otorhynolaryngology, 3d, model, stl, frontal, sphenoid, facial