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3D Printing & 3D Scanning - Tips & Tricks#

Rico Kanthatham February 26, 2020

Some random but hopefully helpful thoughts on 3D Printing (3DP) and 3D Scanning…#

3D Printing (3DP)#

Additive vs Subtractive Fabrication#

Additive Fabrication: Simplistically…”Additive” means starting with nothing, then adding material little by little until the final object is done. In the context of digital fabrication, an “Additive” process allows the building of exterior and interior structures of an object…simultaneously (i.e. Nested Structures). 3D printing is an “Additive” fabrication process.

A good imagery is a builder who makes a brick house by laying one brick at a time, building layer by layer.

Subtractive Fabrication: Simplistically…”Subtractive” means to start with something, then removing bit by bit of the starting material until the final object is revealed. Unlike “Additive” processes, “Subtractive” processes must reveal the exterior structures, before revealing, with big limitations due to obstruction by the exterior structures, the interior structures. CNC milling is a “Subtractive” process.

A good imagery is a sculptor who chisels away marble to get to the final sculpture artwork.

A better, more detailed explanation of the difference between “Additive” and “Subtractive” fabrication can be found at Manufacturing Lounge here…

3D Printing Characterization Group Assignment#

Basic Assignment Objective:

  • Investigate the capabilities and limitations of different 3D Printers
  • Learn how calibrate the 3D printer and make adjustments in the 3DP process to get the best results

Basic 3D Printer Characterization Parameters:

There are actually many, many, many things that can be used to characterize 3D printers…but 3D printing a “Test Model” should help to understand 3DP capability/limitations resonably well.

Some Testing Factors:

  • Clearance - What is the narrowest hole/space between printed areas can be achieved?
  • Minimum Print Width/Print Resolution - What is the thinnest wall/point that can be printed?
  • Overhang - How far can a horizontal extension be printed (without supports) before failing?
  • Bridging - How wide is the gap can be jumped by the printer extruder and still lay down filament material (…will be different for different material too)?
  • Surface Finish - How smooth is the surface of the finish print, especially on curved surfaces?

Some examples of “Test Models” are described in this video here…

And a super-detailed explanation of the different characterization of 3D printing can be watched in this video here

3DP Workflow Overview#

  • 3D Model - The 3D printing process requires an STL file of the print object as the initial input.
  • Slicer Software - Slicer software is used to specify print quality and other print settings for the 3D object…and finally output a Gcode file to drive the 3D printer.
  • 3D Printing - To make a good print, the 3D printer needs printing specific calibration and print settings (see the next section below) which will be used with the Gcode information from the slicer software to print.
  • Post Processing - After printing, the 3D printed object may need additional “clean up” work…such removal of rafts and supports…to make the object more beautiful.

Basic 3D Printer Settings Overview#

Successful 3D printing requires proper calibration and settings for each printer. Some important settings include…

  • Bed Leveling - A flat print bed surface is critical to a good print.
  • Bed and Nozzle Temperature Control - Each filament material has a specific print bed and extruder nozzle temperature that produces the best prints.
  • Layer Height - Changing the print layer height for each pass affects print quality and print time…better quality = longer print time.
  • Infill % - Changing the infill percentage will affect the rigidity/strength of the printed object and affect print time…higher % = sronger and longer print time.
  • Extruder Movement Speed - Generally, the default extruder movement speed will result in the best prints. But a more advance technique is fine-tuning of movement speed for different aspects of printing…wall, bridges, corners, overhangs…can be used to improve print quality and save print time.

3D Printing Tips & Tricks#

3DP Time Awareness - 3D printing takes a lot more time than you think…to print a moderate size, moderate complexity, reasonably good quality print. Factor for this in SSTM.

Changing various settings can be used to adjust the length of print time…Print quality, infill, support/raft settings, extruder head speed, etc.

Rafts & Supports…can be used to help ensure the success of the printing of more complicated objects (…with many overhangs and bridges).

3DP Filament Types#

There are many many different types of filaments that a 3D printer can use to print objects. PLA and ABS are the most common, but there are many others that have different and unique characteristics to these well-known options.

A great overview of the many different types of 3D printing filaments is available in this video here…

3DP Plastic Waste/Recycling Awareness#

3D printing generates environmentally polluting plastic waste. As a FabLab, we should aim to be good to the environment and practice “Circular Economy” methods.

  • Try to make only necessary prints.
  • Recycle failed prints and 3D printing waste. Most 3DP filaments are made of thermoplastics and can be re-melted and re-used.
  • Try using environmental friendly filaments.

3D Scanning (3DS)#

3D Scanning using inexpensive equipment is a very imprecise and difficult to control process.

3DS Objective#

3DS is a process to use specialized imaging to produce a 3D model, which can possibly be used for 3D printing or 3D animation, etc.

Different 3DS Technologies#

There are many 3DS technologies/methods today, each with advantages and disadvantages. Some of the methods include…

  • LASER triangulation 3D scanning technology
  • Structured light 3D scanning technology
  • Photogrammetry
  • Contact-based 3D scanning technology
  • LASER pulse-based 3D scanning technology

A detailed explanation of the different types can be read here…

The 3D Sense Scanner uses a regular cameras and an IR camera to capture 3D scans. A PDF User Manual (English) for the scanner can be found here…

3DS Workflow#

Getting a good 3D scan with the 3D Sense…is more of an art than a science. Trial and error will generate the best results.

A an efficient way to understand the process and technique of 3DS with the 3D sense machine is to watch this good instructional video here…

3D Sense Scanner Tips & Tricks#

Based on my own observation and learning, some tips and tricks to generate a successful 3D scan as follows…
- Scan in a well lit room
- Try to have good contrast between the object to be scanned and the background (black Asian hair requires a light colored background)