For many, 3D printing is no less than a technology right out of Star Trek or some parallel universe. Also known as additive manufacturing, or desktop fabrication. it is a process in which a real, physical object is created based on a 3D design blueprint. 3D printing is an emerging technology that first was introduced in the year 1986; however, it wasn’t until the 1990s that it began to draw serious attention from all corners of the technology world.
How It Works
Contrary to traditional subtractive manufacturing processes that rely on methods of cutting and drilling to carve out objects, an additive manufacturing process like 3D printing works by ‘fusing together’ layers of powdered material to build an object.
This task is performed by a machine called a 3D printer which, under computer control, can carry out this process with unmatched precision and superior accuracy.
FDM (Fusion Deposition Modelling) Decoded
In reality, there are many different 3D printing technologies, but FDM, on which this article is focused, is the most common one.
Fused deposition modelling (FDM) is a 3D printing technology that prints parts using thermoplastic filament, which is basically a cord of material capable of being melted, selectively deposited, and cooled. Parts are built by adding up layers on top of each other.This process was created because its creators wanted a way to rapidly prototype parts. Even today, rapid prototype production is one of the biggest benefits of FDM and 3D printing in general.
Currently Srishtaara employs an FDM printer, although we are also in the process of getting an SLA printer added to our stocks soon. While an FDM printer uses some type of filament, an SLA printer or stereolithography apparatus uses resin. The SLA printing process however remains similar.
Anatomy of a 3D Printer
The easiest way to understand how FDM works is to first learn the parts of an FDM 3D printer. It is here worth mentioning that conventional FDM 3D printers can perform movements in three axes, named X, Y, and Z. The X- and Y-axes are responsible for left, right, forward, and backward movements, while the Z-axis handles vertical movement.Following is an image of Ender, the 3D printer used by Srishtaara Makerspace and the corresponding parts labelled and explained:
· Build Platform: The build platform is essentially the surface on which the parts are made. Build platforms are usually heated to help with the adhesion of a part, but more on that later.
· Extruder(s): The extruder is the component responsible for melting and gradually depositing the filament to build the model.
- In truth, an extruder is made of two subcomponents: The hot end and the cold end. The hot end contains a heater and a nozzle which actually deposits the molten filament, while the cold end consists of a motor, drive gears, and other small components, which push the filament into the hot end to be melted.
- Between the hot end and the cold end lies a heatsink and fan because it’s imperative that the cold end stays cool to avoid jamming.
- In addition to the heatsink fan, there is usually at least one other fan meant for cooling the molten filament after it exits the extruder – this is usually called the part cooling fan.
· Print Head: The print head has one or more extruders on it, and on the top of the print head, there’s a tube which feeds the filament into the print head.
· Control Interface: Some modern 3D printers have a touch screen which is used for controlling the 3D printer. On older printers, a simple LCD display with a physical scroll and click wheel may be present instead of a touch interface. Depending on the model, an SD card slot and a USB port might also be present.
The Designing Process: Acquiring and Designing 3D Models
The entire process basically consists of four parts: - Ideation, Model Design, Conversion to STL and lastly slicing.
3D printers allow designers to go straight from concept ideas and designs to physical models. In order to do so, the object needs to be designed on a computer using some sort of 3D design software. There are many different CAD (Computer Aided Design) programs out there to design 3D models for a variety of purposes. Design programs like TinkerCad or Autodesk 123D are free and great for beginners interested in 3D design and 3D printing, while programs like SolidWorks, Autodesk Inventor, Autodesk Fusion 360 and Blender are used by professional engineers to design parts and assemblies for production.
Several sites have emerged as repositories for 3D models. This way, anyone can get their hands on a model if they don’t possess modelling skills.
Here are some of the most popular ones:
3D models need to be prepared for 3D printing using a special kind of software that translates the model into machine instructions. This is done using slicing software, also referred to as slicers. Slicing is dividing a 3D model into hundreds or thousands of horizontal layers and is done with slicing software.3D models are imported into a slicer, which then virtually “slices” the model into layers. The resulting files consist of G-code, which is essentially a long list of instructions followed by the 3D printer to build the model.
G-code is the “language” of 3D printers and CNC machines. These files contain important parameters required to produce a model, such as printing speed and temperature, wall thickness, infill percentage, layer height, and many others. In other words, 3D printing is impossible without G-code files!
CURA, an open source slicing application, is our preferred software for the purpose at Srishtaara.
Some Additional Tips:
A couple of things always need to be done on a 3D printer before it’s ready to print:
1. Bed Levelling: In order for the printer to deposit filament and build the object successfully, the build platform must be level. Depending on the machine, levelling can be either manual or automatic. If the print bed is too far away from the nozzle, the first and the most important layer won’t stick to the bed, causing the print to automatically fail.
2. Loading Filament: The extruder needs to be ready to extrude filament before printing begins. The loading process begins by heating the hot end to the filament’s molten temperature