3D Imaging and Printing
Alexa Gaffaney, Jenny Haynes, Juhi Patel, Ginny Moses
Tech Talk
What is 3D Printing?
Founder
Terminology
How it Works
Process Overview
Create a Model →
Catch Errors in Model →
Transfer Model to G-Code (Slicing) →
Send to Printer →
Printer interprets G-Code and prints by layer
Modeling
There are two main ways to create a model that will be sent to the printer:
-Creating a model through a 3D modeling program
-Creating a model manually, then scanning it in to the computer
Error Catching
Before a file can be printed, the STL file needs to be checked for errors so the print will perform correctly.
Some common errors:
-Holes/Boundary Edges
-Intersecting Faces
-Shared Edges
-Wall Thickness
Slicing
After the STL is correctly repaired from errors and is ready to be printed, a slicer breaks down layers into g-code. Most 3D printers work by printing the object in layers.
G-Code Basics
Breaking down G-Code
What do the Codes Mean?
Alpha numeric codes are used for programming as they are a simple way to:
Miscellaneous Commands
The line of a program might also include m-codes, which are generally codes that tell a machine how to perform an action. While not guaranteed to be the same across machines, some common, standard m-codes are:
Example
G01 X1 Y1 F20 T01 M03 S500
G is the motion/function command.
X and Y are Cartesian coordinates for horizontal and vertical position, and Z represents the depth of the machine
F determines the feed rate (for feed moves or circular moves)
T is used to select a tool
M will shut a certain tool on or off -- here turning a spindle on clockwise whose speed is determined by S
Modality
G-code functions are active until deactivated by another code. In other words, only one function can be active at any given time. To deactivate a function, just select a new function.
Example: A code begins with a linear rapid move at X1 Y1 (G00 X1 Y1).
-If the next function is a linear rapid move, don’t need to write G00 again, just the new position (modal condition = same)
-To change function to a linear feed (G01), program G01 on the next line deactivates the linear rapid move and activates the linear feed.
Printing
Printer Movements
Every g-code tells the machine which variation of these basic motions to perform, and how to perform it.
Printing
The printer uses fused depositional modeling (FDM) which is when the printer builds up a 3D model one layer at a time, from the bottom upward, by repeatedly printing over the same area.
The printer creates a model over a period of hours.
The printer turns a 3D model into many two-dimensional, cross-sectional layers (basically 2D prints) that sit on top of each other.
The print can be completed using a variety of materials, but the most common is plastic, in which the nozzle of the printer will use melted plastic (which will dry and harden quickly) and move horizontally and vertically through each layer of the model.
Layers are fused together with adhesive or ultraviolet light.
Getting Started
If you have access to a 3D printer, there’s a lot of software for beginners.
Example
Tactile campus map puzzle for the visually impaired - created for Maze Day 2017
Models were created using TinkerCAD and printed on a Lulzbot 3D printer in the UNC Kenan Science makerspace
Cost and Pricing
-A Lulzbot 3D Printer will cost typically between the range of $1,250 - $2,500, depending on the size of the printer
-Industrial printers will cost upwards of $5,000, typically for advanced designs in high volume for large companies
-Printer filament prices vary between $32.99 - $199.99 depending on the weight of the filament (One, 1kg spool of filament yields 392 chess pieces)
-filament can be customized based on size(3mm or 1.75 mm), weight, and color
Uses for 3D Printing
Common Uses for 3D Printing
3D printing can have a large amount of applications. Some examples of objects that can be created through 3D printing:
-Medical Models
-Prosthetics
-Tools
-Clothing
-Furniture
-Pottery/Ceramics
-Cars
-Toys
Examples of Usages in Recent News
3D Printed Skin for Burn Victims
-Research in Spain has been conducted in regards to creating 3D printed human skin for burn victims, as they have slim options for healing their disfigured skin
-Using a biological ink, with plasma from humans and various materials from skin biopsies, are able to print around 100 square cm of human skin in half an hour
Pharmacology with Taking Multiple Medications
-3D printing a capsule that will include all of the various medications a patient takes into one pill, so patients don’t have to take multiple pills in the morning/afternoon/evening