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Dr. Mike

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Posts posted by Dr. Mike


  1. I remember seeing 3D printed skulls from CT scans many years ago at JPAC, the Joint POW MIA Accounting command based at Pearl Harbor in Hawaii. It was a pretty cool idea to study the 3D printed models so that the original remains could be buried, thus giving families closure, etc. I think there is great potential in anthropology for this type of technology.


  2. This is an interesting topic. I think that a cluster of smaller, cheaper FDM printers is much more efficient and cost effective than fewer larger printers. Also, they are more fault tolerant. If a print fails, you only need to reprint a small part, not a larger more expensive part. Essentially this is the concept behind server clusters or RAID hard drive arrays. Use many smaller cheaper units to do the work of more expensive ones.


  3. Dear Envision,

     

    Thanks for being a great member. The problem isn't with democratiz3D but rather the CT scan. Actually it isn't the CT scan really either, but the metal in the patient's back. You see, the x-rays cannot penetrate the metal implants at all, so the CT detector interprets this as a dense, star-like pattern that is called beam hardening artifact. It is a common artifact in CT scans where patients have metal implants. Although there are some experimental research algorithms that when run at the time of the scan can remove these artifacts, they need to be on the actual scanner. Most CT scanners do not have this type of artifact correction. My tutorial on how to choose a good CT scan for 3D printing has a section on this called Imaging Artifact. Take a look and you will see what I mean.

     

    When the scan with the artifact is plugged into democratiz3D, the artifact is reproduced as well. Democratiz3D doesn't know what is artifact and what is bone. Other than getting a scan without the artifact, the only other options are to manually edit the mesh and remove the artifact, or live with it and understand that it represents artifact and not real anatomy. I know this isn't ideal but it is the limit of the technology today.

     

    Hope this helps.

     

    Dr. Mike 


  4. I agree with the Prusa Mk3S for most reliable FDM printer. Currently you can get it assembled for $999 or as a kit for $749. Link here. The quality is great and so far it is very reliable. It has an Multi Material Unit which promises to allow multicolor prints and that is definitely LESS reliable as I am still struggling with that. But for single colors, it is very stable.

     

    Regarding the Ultimaker I did a review on it and had a lot of problems with complex organic shapes needed for medical 3D printing. I had some catastrophic failures, some of which almost destroyed the printer. See my video review on it below.

     

    For STL I agree that the Form 3 is the way to go. Good printer and software and a great material library. I just got a new Form 3B and so far it is great. The optical engine is totally sealed. The Form 2 (which I also have) had an unsealed engine and vapor would deposit on the mirrors after several months of heavy printing requiring a disassembly to clean the mirrors. The Form 3 doesn't have this problem. 

     

    FYI, if any member of the community is interested in purchasing a Form 3, you can use the code below to get $500 off. When you contact Formlabs sales give them the code to receive your discount. To go to the Form 3 website, click here

     

    Form 3 Discount code: FORM3-JB9CY0

     

    Hope this helps.

     

     


  5. What exactly are you looking for Candace? Bones? Organs? Vessels? Some structures are amenable to automated segmentation (like bones) but others are much harder and must be done manually (organs, brain, tumors). There are models that were both automatically and manually segmented in the library. In general, if the thumbnails have a blue background they are probably auto segmented. Hope this helps.

     

    Mike


  6. A user asked me the following question. I am posting the response to help others who may have the same question.

    "I went through the tutorial video, I just wanted to know whether the following software is compatible with 3d printers from ultimaker which utilise fdm application. Also please let me know which all 3d printers is it compatible with. "

     

    Answer: Yes, the output STL files should be compatible with all FDM printers. Bear in mind that some models are very large and may not fit within the build volume of a specific printer. These models can be scaled down or printed in parts and joined after printing.

    Hope this helps.

    Dr. Mike


  7. A user recently asked me this question. I am posting the response here so others can benefit from the answer:

    "However, I have a question:

    Please note that the images do not show the hyoid bone (this horse-shoe shaped bone should be visible just under the jaw/withing the jaw bone) and no parts of thyroid catrilage are visible either.   Would you be able to let me know if it is possible to show those.please."

    Answer: democratiz3D will remove small bones automatically from models. This prevents small calcifications, particularly vascular calcifications, from being erroneously included in the model. If a desired structure is being accidentally removed, you can increase the model quality (High/Ultra) or decrease the threshold level and the missing part will be more likely to be included. It may take some trial and error to achieve the perfect result.

     

    Hope this helps,

     

    Dr. Mike


  8. A user recently asked how it will be possible to 3D print a model generated on the democratiz3D cloud service if the output model is too big to order printed. Embodi3D has a 3D printing service, but typically we cannot print models that are greater than about 40 cm in maximum dimension. There are a few options.

     

    1. Print the model at half-size. You can order your model printed at half-size, and we will scale down your part so that it will fit within the maximum print volume of our printers.

     

    2. Crop the input scan prior to processing with democratiz3D. In this option you reduce the volume of the input scan, so the output model file will be cropped. By cropping around only the desired anatomy you can exclude unwanted structures and reduce the volume of your model so that it can be printed. Here is a tutorial on how to do this.

     

    3. Crop the model after it is been processed with democratiz3D. If you have a completed model but it is still too big to print, you can download the model and scale, cut, or otherwise edit it utilizing mesh editing software such as Meshmixer or Blender. If you have your own printer you can then print the file directly. If you want to use the embodi3D 3D print service, you will have to re-upload the modified file. Click the Analyze Model link (see picture) and your newly uploaded model will be analyzed for print ability. Once this process is complete you will be able to get a 3D printing price quote and order your 3D printed model.

    analyze model.JPG


  9. It may be helpful to crop out the air around the body in the scan. This is dead space but still takes of file space. You can often reduce the file size quite a bit by cropping this out. Zipping the file will reduce the size, but right now democratiz3D cannot accept that file type.

     

    Hope this helps.


  10. Thanks for the question Mike.

     

    If your model is in the system, it is automatically analyzed for printability, including a size check. If it is printable, you should see a button "3D print this file" next to the download button, as shown in the picture below. If the mode is too small (less than 3 cm) or too large (greater than 40 cm), or has other technical constraints, it may not be printable and the print button will not show.

     

    If you have a question about a specific model that is now showing a button, please contact embodi3D via the contact form and someone will be back to you.

     

    Hope this helps

     

    Dr. Mike

     

     

    Screen Shot 2019-12-10 at 12.46.12 PM.png

     

     

     

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