09 - 3D printing basics

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3D printing, also known as additive manufacturing, is a process of creating three-dimensional objects layer by layer from a digital 3D model. It involves depositing or solidifying material (like plastic, resin, metal, or ceramics) in precise layers to build the desired shape.

Key Steps in 3D Printing:

1. Design: A 3D model is created using CAD (Computer-aided design) software or downloaded from online repositories. You can skip this part if someone has already uploaded the design to Thingiverse.
2. Slicing: The model is sliced into thin layers, and G-code instructions are generated for the printer.
3. Printing: The printer follows the G-code to deposit material layer by layer.
4. Post-Processing: The final print may require cleaning, sanding, or other finishing touches.

Different motion systems

1. Orthogonal (Cartesian): Uses a 3-axis system (X, Y, Z) with straight-line movement along Cartesian coordinates. Each axis is controlled independently.

   • Most common motion type for 3D printers.

   • Easy to calibrate and control.

   • Highly accurate for rectangular or cubic designs.

   • CoreXY is a variation of the classic orthogonal. It combines X and Y axis movement using belts in a lightweight setup for faster, more stable printing.
2. Delta (Triangular): Uses three arms connected to carriages that move along vertical columns. The print head is suspended and controlled by these arms. They require precise calibration. Useful for tall cylindrical objects.
3. Polar: Uses a rotating base (circular motion for one axis) combined with radial (in and out) movement for the second axis. Z-axis moves vertically.

Printing materials

Materials like PLA (Polylactic acid), ABS (Acrylonitrile Butadiene Styrene), or PETG (polyethylene terephthalate glycol) are common, depending on the application and strength requirements. Each one requires different temperatures for:

• Bed.
• Extruder (nozzle *boquilla).

Printing materials are sold in filament spools (*carretes):

The chassis: t-slot

T-slot se traduce como “perfil estructurado”

T-slots are aluminum extrusion profiles. They are often used as the building bricks of 3D printers and many, MANY other things. You can sketch T-slot models in the website Craftyamigo. I read somewhere that t-slots are like LEGO for grown-ups.

Nuts and bolts slide into the slots to secure other components. There are many accessories:

The extruder

This is the piece that “prints” the material. It produces a tiny stream of plastic (0.2 mm typically):

Snapmaker prints in 3 resolutions: 0.08, 0.16 and 0.24 mm.

One student created an extruder that recycles plastic bottle PET. It cuts it to create long ribbons and then melts it to create the filament.

Slicer

A slicer software is a program used in 3D printing to convert a 3D model (usually in STL, OBJ, or 3MF format) into instructions that a 3D printer can understand, typically in the form of G-code. These instructions tell the printer how to build the object layer by layer.

Slicer:

• Orca slicer
• Ultimaker Cura
• Snapmaker Luban

The G-code is the plan (the steps) that the printer follows.

G-code (geometry code)

• CAD: computer aided design. Any software for 2D or 3D design/drawing. I.e: Inkscape, AutoCAD, TinkerCAD.
• CAM: computer-aided manufacturing. It is the use of software to control machine tools in the manufacturing of work pieces. Octoprint.
• CNC: computer numerical control: Any automated machine that performs manufacturing (=fabricación). I.e: mill (=torno), 3D printer, laser cutter…

Ojo, “mill” significa “molino”, pero también “torno” (de fabricación mecánica)

Excerpt from wikipedia:

G-code (also RS-274) is the most widely used computer numerical control (CNC) and 3D printing programming language. It is used mainly in computer-aided manufacturing (CAM) to control automated machine tools, as well as for 3D-printer slicer applications. The G stands for geometry. G-code has many variants.

Other machine tools and functionalities

• Infrared laser engraver 1600 mW (it does NOT cut)
• CNC (Computer Numerical Control) drill.

Xunta gave us a different machine for laser cutting:

Beam = rayo

Bean = haba

LOTS of information on YouTube

Scott Yu-Jan is an English-speaking youtuber that has lots of information about printing and also does a lot of mods in his Ender-3, one of the cheapest 3D printers available (~200€)

Scott’s not happy with his laptop but he wants his computer on-the-go:

Problem solved.

Enterprises in the area

itfab. Impresión 3D Galicia: https://www.itfabricacion.com/

Writing - ask your teacher to print something

Write an informal e-mail (<100 words) to your teacher asking him to print a piece from Thingiverse. Explain him why you need that thing printed (what are you going to do with it).

Thingie = cosita (es un diminutivo)

It is an informal letter, but don’t forget the basics: greet, farewell… You don’t need a signature since this time you are not pretending to be a worker, but you have to state which one is your class.

pretend = fingir (=fake)

Write a post scriptum clarifying whether you really want the piece printed or not.

post scriptum = postdata

Yes, you can

You can ask teachers to print you things. We can’t afford to spend a lot, but we can print some things for your personal enjoyment.

We can even design simple things for you! Just remember the magic words: “please” and “thank you”.

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