Practical 3D Printing: Fundamental Knowledge

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Fundamental Knowledge

05.08

00:00	This course is divided into four main sections, each dedicated to the four main forms of Additive Manufacturing.
00:06	These are then followed by the practical skills involved with using each technology.
00:11	To be clear from the beginning, we'll be using the terms 3D printing and Additive Manufacturing interchangeably.
00:17	Additive Manufacturing is the term used for a manufacturing process where the product is made by adding material rather than removing it.
00:25	And so 3D printing is an example of this.
00:28	It makes sense that we start with the most common, most accessible and arguably the most useful type of 3D printing for our work, Fused Deposition Moulding or FDM for short.
00:39	Keep in mind that some of what we'll cover in this section on FDM also applies to the other methods.
00:45	So, we'll be spending some more time covering these topics now, so we don't have to repeat them further into the course.
00:51	Despite the slight differences mostly concerning patents, this form of 3D printing can also be called Fused Filament Fabrication or FFF for short.
01:01	The main parts of an FDM printer are the extruder, nozzle and build plate or print bed.
01:07	The material used for printing is a polymer or put more simply FDM prints plastics.
01:13	More specifically thermoplastic polymers which can be melted and recured as opposed to the thermoset polymers which can't be remoulded or recycled like this.
01:23	Many different materials are available.
01:25	Some even reinforced with carbon fibre.
01:27	But we're going to be diving deeper into this in a coming module.
01:31	While thermoplastics are by far the most common materials used for FDM, it's also worth noting that using metals with FDM is possible.
01:40	Although metal additive manufacturing is usually done with the SLM technology which stands for Selective Laser Melting.
01:47	Something that we'll be covering later in the course.
01:50	Usually, the thermoplastic material is in the filament form and wound onto a spool.
01:54	However, there are alternative forms of the material.
01:57	Like pellets which are more typically used for larger scale industrial printers.
02:02	The print head or hot end is an assembly that includes the nozzle, heating element, temperature sensors and cooling fans to help solidify the printed material.
02:12	The hot end also sometimes incorporates the extruder although this can also be remotely mounted.
02:17	The extruder draws in the filament and feeds it through a heated nozzle which melts it and prints it onto the heated build plate.
02:25	Then builds the part up layer by layer.
02:27	The melted filament cures shortly after leaving the nozzle aided by a cooling fan.
02:32	And as it cures it adheres to itself and hardens.
02:35	The first layer also sticks to the build plate to some degree.
02:39	Although the bond here isn't as strong as between the layers.
02:42	Depending on the geometry of the part we're printing and its orientation on the build plate there could be overhangs.
02:48	In this case a support structure may also need to be printed.
02:52	How the system moves in 2D to print each layer and build up the 3D object is to 2D.
02:57	This is determined by what's known as the kinematics.
03:00	This varies between different printers.
03:02	Some will move the print head in all three axes.
03:05	While other printers might just move the print head in a horizontal plane and then move the print bed vertically.
03:11	There are many different combinations of kinematics in use across the market.
03:16	It's all just slightly different movement methods being used to essentially achieve the same thing.
03:21	Side note here the vertical axis that builds up the layers is referred to as the Z axis.
03:26	As is the convention for most CNC machining where this axis is perpendicular to the bed and the other two axes are X and Y.
03:36	Other auxiliary elements also vary between different FDM printers and this is usually a result of how they function.
03:42	For example there's a lot of variety in the frame designs due to the different kinematics.
03:48	Some printers will have an enclosure that might also have temperature control or build plate adjusters for leveling and many other features.
03:55	Past this the CNC printing machine will naturally have a range of electrical components like the main board and power supply.
04:03	For those who aren't familiar with the term, CNC stands for Computer Numerical Control.
04:09	Essentially the printer is given a set of instructions in the form of a toolpath and can use these to automate the manufacturing process just like a CNC mill.
04:19	However, the detailed technicalities of how the printer works are not the focus of this course.
04:24	We aren't learning how to make your own printer.
04:27	We just need to know what's necessary to get the best results from our projects.
04:31	So, let's summarise our first look at FDM 3D printing.
04:35	This is the most widely used, accessible and arguably the easiest of the printing technologies that we'll cover.
04:42	The basic process involves the extruder feeding the thermoplastic filament into the heated nozzle where it's melted and printed onto the build plate building up layer by layer to create the 3D part.
04:53	There are many variations in the 3D printing machines in terms of kinematics, which is how the motion is achieved, as well as auxiliary features which we'll discuss further in the next module.