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5. 3D scanning and printing#

image to hero shot

Individual Assignment#

  • design and 3D print an object (small, few cm3, limited by printer time) that could not be made subtractively
  • 3D scan an object (and optionally print it)

0.preparation#

I created a project to have ChatGPT summarize the assignment. For those who don’t know, ChatGPT’s “project” function is a new function that allows you to centrally manage chats, files, and custom instructions related to specific topics or projects. It is very useful when similar instructions are repeated. If you have custom instructions prepared, you can simply pass the subtitle file to have it summarize the assignment.

Custom Instructions
Provide the provided files and lecture information. Describe the assignment requirements in detail. Summarize the assignment requirements in detail.
chatgpto4 response
## 0-1. Identifying Requirements
The following is a detailed summary of the 3D scanning and 3D printing assignment requirements explained in the lecture.
---
### 1. 3D Printing Assignment
**Objectives/Challenges**
- **Pursuit of Originality:**
  You are required to create a design that takes advantage of the unique characteristics of 3D printing and cannot be achieved with conventional subtractive manufacturing (such as milling). Specifically, it is necessary to incorporate elements that demonstrate the week05_v1 of 3D printing, such as nested parts or overhangs (shapes that require no or minimal support material).
**Application of Design Rules**
- **Supports and Bridges:**
  Design to ensure that unnecessary support materials are not generated during printing by using appropriate overhang angles (e.g., 30 degrees or more) and bridging techniques so that layers are firmly stacked.
- **Wall Thickness and Filament Flow:**
  Design that considers the printer's performance and constraints, such as filament thickness during printing, infill patterns, and interlayer adhesion, is important.
**File Submission**
- **Design Files:**
  Submit the original design files, such as CAD data or STL files. Note that if the STL file is very large, it is not always necessary to submit the entire file.
**Size Restrictions**
- **Consider Printing Time:**
  Design the object so that it is not too large. It is recommended to keep it at a realistic size in terms of printing time and material costs.
---
### 2. 3D Scanning Assignment
**Objective**
- **Object Scanning:**
  To experience the basics of 3D scanning, scan an arbitrary object and acquire its shape (and optionally texture) as digital data.
**Scanning Methods**
- **Various Techniques:**
  The lecture introduced various methods, such as acquiring point cloud data and generating triangular meshes, photogrammetry, laser scanning, structured light, and even scanning with smartphone apps.
- **Points to Note:**
  Scanning results are greatly affected by lighting conditions, background, and the object's surface characteristics, so holes may appear or data may be partially missing. This is also something to learn as part of the scanning process.
**Deliverables**
- **Minimum Submission:**
  Submit at least the digital data of "something you scanned."
- **Optional:**
  If possible, consider 3D printing the object based on the scanned data.
---
### 3. Common Points
- **Experimentation and Learning:**
  The purpose of both assignments is to experience the technical constraints and possibilities of 3D printing and scanning technologies and to deepen your understanding through practice.
- **Process Recording:**
  Recording the progress of your work, the tools and methods you used, the problems you encountered, and their solutions will be helpful for later reflection and evaluation.
---
In this way, the assignment is set up to learn a wide range of digital fabrication technologies from two aspects: creating designs using 3D printing and digitizing actual objects using 3D scanning.

0-2. Assembling the purchased 3D printer, but it cannot be used due to initial failure…#

For this day, I had previously purchased a Bambu lab x1 combo. The deciding factor was that it was a bit cheaper in the December Christmas sale.

I found time between work to complete the assembly of the Bambu lab x1 combo, but it had an initial failure where the PTFE tube coupler broke and the filament could not be fed out…

I have ordered a PTFE tube coupler, but the first start will be after the local session 😭

https://wiki.bambulab.com/en/filament-acc/acc/replacing-the-pneumatic-connector

Furthermore, when I removed it, it was fixed without replacement. Apparently, in the process of removing the PTFE tube coupler, the malfunction of the tube inlet was fixed.

Anyway, I can now do 3D printing at home.

01. Group work#

See here for details. or more information, see the Week 05: Group assignment page.

01-1: 3d printhing test#

Adding descriptions about 3D printing tests#

By conducting 3D printing tests, you can understand some rules and constraints in design and printing.

  • Necessity of support material and overhang design

    • We found that overhangs of a few millimeters can be printed without problems, but the appearance is affected.
    • Generally, there is a correlation between overhang and layer height. The thinner the layer height, the stronger the overhang can be printed properly. Therefore, one way to handle works with severe overhangs is to set the layer height finely.
    • However, layer height is positively correlated with printing time. The more layers, the longer the printing time.
    • If your slicer software or 3D printer has a variable layer height function, trying it may allow you to both shorten printing time and deal with more severe overhangs.

  • Clearance

    • Clearances (gaps) could be printed successfully if they were 0.2mm or more, but problems occurred at 0.1mm. Gap adjustment must be considered when printing.

  • Angle
    • Regarding angles, slopes up to 30° can be printed without problems, and angles of 20° or less also worked, but the appearance deteriorated. Therefore, if you want to succeed in 3D printing, you need to be careful when printing with steep angles.

  • Bridging

    • It could be printed without problems up to 20mm, but the inner surface was not smooth, and it was found that the appearance was affected. This may be greatly affected by the nozzle diameter (0.2mm in this case) and the filament material.

  • Surface finish

    • Regarding the surface finish, we found that the more horizontal surfaces there are, the more noticeable the layer marks become, which particularly affects the finish.

  • Wall thickness

    • A wall thickness of 0.4mm could be printed without problems, but thinner walls may be ignored by the slicer application. We also found that even the smallest 0.1mm slit holes are visible.

Regarding dimensional accuracy, it was surprisingly accurate, and although the outer and inner dimensions were slightly smaller, they were within the allowable range. Furthermore, we compared the same data with Bambu Lab P1S and Creality Ender 3 V2, but the difference was very small.

Strength

As a characteristic of FDM 3D printing, it was confirmed that the strength in the layer direction is low. Because an L-shaped object was printed and broken in the layer direction when bent, it was found that the layer direction is a weak point in FDM printing.

  • Infill
    • Regarding infill, we tested 0%, 15%, 50%, and 100% infill. We found that the strength of the print can be changed by adjusting the infill density in BambuStudio.
    • How to change: “Strength > Sparse infill > Density”

  • From the above, conducting tests is a very important process for understanding the characteristics and parameters of a 3D printer.
  • These accuracies may vary depending on the filament material, nozzle diameter, adjustment of layer pitch, layer orientation, and external environment such as humidity and temperature. Tests must also be performed when conditions change.

02. Individual Assignment#

02-1: Design & Print#

  1. Design with Fusion 360. This time, I was told to make something that would be difficult to do subtractively, so I designed a labyrinth. You can see that it would be difficult to do subtractively when you consider the path that the piece can pass through and the width of the window for operating it.
  2. Of course, it is designed parametrically.

1. Here is the printed version.

02-2: 3D Scan & 3D Print#

I used Creality CR-Scan Ferret Pro for 3D scanning. I took 3D scans of my classmates together with my classmates in Kannai.

Creality CR-Scan Ferret Pro#

The Creality CR-Scan Ferret Pro is very easy to use.

  1. Create a new project from new project.

    • You can create a new project when the scanner is connected to the PC.

  2. Set the settings for scanning.

    • The settings this time were as follows.
      • object: face
      • feature: geometry
      • accuracy : hi-quality
      • disable flat base : no

  3. Press Scan when the settings are complete.

  4. Once you have confirmed that scanning is possible, click the green play button-like mark on the right. Scanning can be started.

    • Green indicates the best scan. Maintain this condition.

  5. Scan 360 degrees. See the video for details.

  6. Click the red square stop mark-like button on the right at a good time.
    • The scanned data will be processed.
  7. When completed, color mapping is possible. You can download the obj format data by clicking the DL button in the lower right. You can download the scanned data from here.
    • The above is my classmate, Mr. Tokuyama. In the same way, I also took 3D scans of people like Mr. Hayashi and me.

Incorporating Lessons from Group Assignment Test Pieces#

In our group assignment, we printed various test pieces to understand the capabilities and limitations of 3D printing. I applied these insights directly to my labyrinth design:

  1. Bridge structures: Our test pieces showed that bridges longer than 10mm exhibited some sagging. I designed the labyrinth’s passages to be a maximum of 10mm wide, which allowed them to print cleanly without support material while maintaining acceptable levels of deflection.

  2. Overhangs: The test results demonstrated that overhangs exceeding 45° showed decreased quality. My labyrinth design avoids overhangs entirely, with all walls being completely vertical.

  3. Wall thickness: From our test pieces, we learned that walls thinner than 0.8mm became fragile. I designed all walls in my labyrinth to be at least 2mm thick to ensure structural integrity.

  4. Tolerances and clearances: Our test pieces revealed approximately ±0.2mm tolerance in our printer. To ensure the cube could move freely through the labyrinth, I incorporated a generous 2mm clearance between the moving piece and the walls.

By applying these lessons from our test prints, I was able to create a complex internal structure that would be impossible to manufacture subtractively, while ensuring it would print successfully without supports.

3D Printing Environment and Process#

My 3D Printer Setup#

I use a Bambu Lab X1-Carbon Combo. I selected this printer for several key reasons: - High-speed printing capabilities (up to 500mm/s) - Multi-material support (with AMS system) - Carbon fiber reinforced frame for stability - Built-in camera with time-lapse functionality

Slicer Software#

I use Bambu Studio as my slicer software, which offers: - Complete compatibility with Bambu Lab printers - Cloud printing capabilities - Detailed print setting options - AI-assisted support structure optimization

Nozzle and Print Settings#

I used a standard 0.4mm nozzle for this print. The detailed settings were as follows:

Layer Settings: - Layer height: 0.2mm - Initial layer height: 0.2mm

Line Width: - Default: 0.42mm - Initial layer: 0.5mm - Outer wall: 0.42mm - Inner wall: 0.45mm - Top surface: 0.42mm - Sparse infill: 0.45mm

Infill: - Sparse infill density: 15% - Pattern: Grid - Infill direction: 45°

Walls and Shells: - Top shell layers: 5 (1mm thickness) - Bottom shell layers: 3 - Top surface pattern: Monotonic lines - Wall generator: Classic - Order of walls: inner/outer

Seam Settings: - Seam position: Aligned - Smart scarf seam application: Enabled - Scarf application angle threshold: 155°

Support: - No supports were used for this print

3D Scan Data Processing and Printing Workflow#
  1. I opened the scanned OBJ file in Fusion 360
  2. Selected the body and used the repair function with default settings

  3. After repair, the holes in the model were filled. I exported this as an STL file

  4. Time-lapse setup in Bambu Studio:

  5. Prepared and formatted the SD card
  6. Enabled prime tower (necessary for nozzle movement during time-lapse shots)

  7. Set time-lapse mode to “smooth”

  8. The estimated print time was 1 hour and 13 minutes

  9. Here is the time-lapse of my face being printed:

  10. Post-processing:

  11. Light sanding with 600-grit sandpaper
  12. Verification of dimensional accuracy and surface quality

The final 3D print exceeded my expectations, particularly in how well it captured the facial details from the scan data. The Bambu Lab X1-Carbon’s precision and the optimized slicer settings contributed significantly to the quality of the final result.

4.appendix#

tips#

Create a snippet to easily compress videos with ffmpeg#

*   I realized that I wanted to compress videos individually each time, so I created a command snippet to make the work easier.
*   I use [Alfred](https://www.alfredapp.com/) as a snippet tool. Alfred is a macOS app to boost your efficiency with hotkeys, keywords, text expansion and more.
    *   Copy the file name (or file path) and use the snippet.
    ```plain
    ffmpeg -i {clipboard} -vf "scale=-2:720,fps=30" -c:v libx264 -preset slow -crf 28 -c:a aac -b:a 128k -an -movflags +faststart -fs 10M