MakerBots - 3D Printing: Session 1

Overview of 3D printers in Library Innovation Lab

In this lesson, we'll take a look at the basic process of 3D printing, and introduce you to some terminology you will need to know to understand the process. We'll teach you the basic parts of the SKETCH and REPLICATOR MakerBots we have available for your use at the Earl K. Long Library. We'll show you how to load and unload filament, the size and type of filament that these machines use, and interact with the machines to show you how they work in real life.  

3D printing is a way to turn a three-dimensional digital model into a physical object. In the simplest terms, a 3D printer heats a roll of plastic material until it melts, then squeezes the melted plastic out into the exact shape and size of the digital model. 

3D Printing Terminology for MakerBots

Material Extrusion:  A category of 3D printers. A plastic that gets soft when heated (thermoplastic filament) is heated by a 3D printer and extruded layer by layer onto a build plate to create parts. FDM is a type of material extrusion.

FDM: Fused Deposition Modeling is the 3D printing technology used by 3D printers like our MakerBots.

Slicing: Turning a 3D model into 2D layers used for 3D printing.

Filament: Plastic material used to create 3D printed parts.

Extruder: The "hot glue gun" of your 3D printer; it melts the filament to build the layers of 3D printed parts.

Build Plate/Platform: A flat surface inside a 3D printer on which 3D prints are built.

Gantry: A group of motors, belts, and gears that moves the carriage around the inside of a 3D printer.

Carriage: Holds the extruder.

Essential Parts of a 3D Printer

• Material Hub on the Sketch, Filament Drawer on the Z18
• Guide Tube
• Extruder 
• Extruder Nozzle
• Build Plate/Platform
• Build Plate Latch

SKETCH and REPLICATOR parts diagrams.

Introductory Video on the MakerBot Sketch

Both the SKETCH and REPLICATOR printers are compatible with the same basic type of material, which is known as PLA.

• PLA - Poly(lactic acid) Acid - PLA is a very common plastic produced from fermented vegetable matter, and is ideal for 3D printing applications since it is easy to work with. It can be recycled, or even composted in an industrial composter. 
• PLA TOUGH - PLA Tough is a more durable version of PLA that requires a special "TOUGH extruder+" We don't have this type of material for use in our 3D printers.

Activity - Load and Unload Filament

• Load - spools are loaded in a clockwise manner (with the free end of the filament near the front of the machine).
• Unload - Take care to carefully wind excess filament neatly back onto the spool to prevent tanging. 

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Almost all 3D printers generally work in a similar series of steps:  

• The user places a spool of filament into the printer, then starts the filament loading process. The machine uses a tiny set of gears to pull filament through the guide tube until the end of the filament reaches the extruder.
• The extruder heats the filament and squeezes a thin line of melted filament out through a metal nozzle on the bottom of the extruder. The extruder moves back and forth along the x and y plane (side to side and backwards and forwards) to make a single layer about 1/10th of a millimeter thick.
• As each layer of filament cools and hardens, it is able to support the next layer of filament. Once a layer is complete, the extruder moves away from the build platform approximately 1/10th of a millimeter before starting the next layer.
• The layers fuse together as they cool, and the process continues until the final shape is completed.

The three-axis movement of 3D printers. 

Typically, lateral movement (i.e. left, right, front, back) is usually assigned to the X- and Y-axes, while the Z-axis corresponds to vertical motion.

• X-Axis, left and right direction
• Y-axis, forward and back direction
• Z-axis, up and down direction

It's important to note that while the Sketch and Replicator printers both move in the Z-axis, they do it in different ways. On the Sketches, the extruder lifts up along the Z-axis after finishing each layer.  On the Replicator Z18, the build platform drops down along the Z-axis after finishing each layer. Both methods accomplish the goal of giving the extruder enough room to lay a fresh layer of filament on top of the previous layer.

A small object to start printing will be completed by the end of this training session.

The easiest and quickest way to get started with 3D printing is to find a model that someone else has already created. There are a number of websites where users can upload and share their 3D models. Two of the most popular are Thingiverse.com and Printables.com. Using sites like these you can search for 3D models, get suggestions for successful prints, and even upload your own designs.  Some sites also offer 3D models for a fee.

file downloaded from Thingiverse.

Activity

Create account in TinkerCad.com

(Instruction note) The class moves back to room 320-C to see the completed object removed from the printing platform. 

Each student in class will practice how to load and unload filament.