Beginners Guide to 3D Printing

3D printing, which many views as prototyping and limited production technology, is currently making a quick shift to production technology. The adoption of this has accelerated, as seen by the growing demand for 3D printing technology from industrial sectors. As technology advances, it has the potential to change almost all major sectors.

3D printing is used in many industries as it includes a wide range of technologies and materials. Industries are using 3D printing technology in a wide variety of applications today.

Let’s take a closer look at 3D printing.

What is 3D Printing?

3D printing is a computer numeric controlled additive manufacturing technique in which melted plastic filament or other materials depending on applications is extruded in thin layers from a print head. Each layer represents a 3D model slice and to form a 3D object, each layer connects to and builds on the preceding layer.

Now you may be wondering what is additive manufacturing. Let’s discuss this as well.

Additive vs Subtractive Manufacturing

Additive manufacturing, often known as 3D printing, is a process that adds successive layers of material to create an object.

Subtractive manufacturing on the other hand, rather than adding layers, involves machining or cutting away portions of a material. It can be done manually or using a method known as computer numeric control (CNC) machining, which is increasingly prevalent.

Both additive and subtractive manufacturing expedite the prototyping process. The main consideration is the volume and the type of material and the effect this will have on the speed of the fabrication.

A large object that has a high volume, a large metal gear, for example, lends itself more to subtractive manufacturing. A small plastic part, such as a bracket, might be more suited to 3D printing.

Rapid Prototyping 

Rapid prototyping is the fast fabrication of a physical part, model or assembly using 3D computer-aided design (CAD). The construction of the part, model or assembly is usually done using additive manufacturing, or commonly referred to as 3D printing.

Prototypes are an integral part of engineering product design and more importantly in an overall new product development process. Rapid prototyping can be used at any stage of the product development cycle or for any component or subcomponent and can be repeated numerous times along the new product design process.

Types of 3D Printing

There are different types of 3D printing machine that work using different technologies and materials. However, all 3D printers have something in common – they all build up an object layer by layer. Some popular 3D printing types are

Fused Deposition Modeling (FDM)

This is the most popular type of 3D printer that works by melting plastic filament and depositing it onto a print bed, where it solidifies. The additional layers are printed on top of each other until the model is complete. The plastics that are commonly used are PLA, ABS, PET, etc.

Stereolithography (SLA)

Source:re-fream.eu

It is the form of 3D printing technology which works by focusing an ultraviolet (UV) laser onto a vat of photopolymer resin. It is also commonly known as resing 3D printing. SLA 3D printers use light-reactive thermoset materials called “resin.”

When SLA resins are exposed to certain wavelengths of light, short molecular chains join together, polymerizing monomers and oligomers into solidified rigid or flexible geometries. SLA parts have the highest resolution and accuracy, the sharpest details, and the smoothest surface finishes of all 3D printing technologies.

Selective Laser Sintering (SLS)

Source: Kruth et.al., 2004, Material Science

The selective Laser Sintering process works on the sintering principle, which means heating the powder just below its melting temperature to fuse it. In SLS, a laser selectively sinters the particles of a polymer powder, fusing them together and building a part layer-by-layer.

The materials used in SLS are thermoplastic polymers that come in a granular form. SLS 3D Printing is used for both prototyping of functional polymer components and for small production runs, as it offers very high design freedom, high accuracy and produces parts with good and consistent mechanical properties, unlike FDM or SLA.

Applications

3D Printing technology has evolved rapidly over the past 20 years and has been adapted to a wide variety of applications. Some of these include;

Aerospace Industry

Automotive Industry

Medical Sector

Consumer Goods

Industrial Goods

Construction

Art and Jewellery

Materials for 3D Printing

Polyactic Acid (PLA)

PLA, or polylactic acid, is one of the most widely used materials in desktop 3D printing. Because it can be printed at low temperatures and does not require a heated bed, it is the default filament of choice for most extrusion-based 3D printers.

PLA is an excellent initial material to use when learning about 3D printing since it is simple to print, cheap, and produces components that can be utilized for a broad range of purposes. It’s also one of the most eco-friendly filaments on the market right now. PLA is a biodegradable material.

Acrylonitrile Butadiene Styrene (ABS)

This was one of the first materials utilized with industrial 3D printers. ABS is recognized for its hardness and impact resistance, allowing you to print long-lasting parts that can withstand heavy usage and wear.

ABS has a greater glass transition temperature, which implies it can endure significantly higher temperatures before deforming. This makes ABS an excellent choice for outdoor or high-temperature applications.

When printing with ABS, be sure you print in an open area with sufficient ventilation, as the material has a mild odour. ABS also contracts quite a bit as it cools, so regulating the temperature of your build volume and the item within may be quite beneficial.

Glycol Modified Polyethylene Terephthalate (PET)

PETG is a Glycol Modified Polyethylene Terephthalate (PET) that is frequently used in the production of water bottles. It is a semi-rigid material with high impact resistance, but its surface is significantly softer, making it prone to wear.

The material also has excellent thermal properties, allowing the plastic to cool effectively with practically no warpage. This material is available in various forms on the market, including PETG, PETE, and PETT.

Wood-based Filaments

Wood-based filaments are usually a combination of a PLA base material with wood dust, cork, and other powdered wood derivatives. The filament is typically composed of approximately 30% wood particles, however, the precise percentage varies according to the manufacturer.

Because of the existence of these particles, the 3D printed pieces have the appearance of genuine wood. Because wood particles are softer, this filament is less abrasive than other composite filaments such as carbon-fibre filled and metal filled. Some wood-like filaments on the market include simply wood colour and no genuine wood particles, so they have a totally distinct look and feel.

Polycarbonate (PC)

Polycarbonate (PC) is a high-strength material designed for use in harsh environments and technical applications. It has good heat deflection and impact resistance. Polycarbonate has a glass transition temperature of 150° Celsius as well.

This implies that it will retain structural integrity up to that temperature, making it ideal for use in high-temperature applications. It can also be bent without breaking and is frequently utilized in situations requiring modest flexibility.

Flexible Filaments

Thermoplastic Elastomers (TPE), a mix of hard plastic and rubber, are used to make flexible filaments. As the name implies, this material is elastic in nature, allowing it to be readily stretched and bent.

TPE comes in a variety of forms, the most popular of which being thermoplastic polyurethane (TPU), which is used in 3D printing filaments. The elasticity of the plastic is determined by the type of TPE utilized and the chemical formulation employed by the producer.

3D Printing Features and Parameters

Layers/Print Resolution – refers to the thickness of each layer printed. 0.1 mm to 0.4 mm typical. The higher the resolution (0.1 is higher resolution) the longer the print time but the more refined/smooth/detailed the print

Print Quality – modifies to the speed at which the printhead moves

Build volume – Maximum physical size you can print on your printer (UpBox – 255mm x205mmx205mm)

Shell – thickness of the outer surface of printed objects

Infill – material on the inside of the printed object. Can be solid but more often a structural matrix with a density that can be adjusted to modify strength, weight, support structure, material use, print time etc…. More infill  =  more print time!

Raft – a printed base, to keep printed objects stable and help them adhere to the build plate, especially those without a wide surface at the bottom

Brim – similar to a raft but doesn’t go under the print object, just goes around its perimeter

Overhangs – When parts of a print object don’t have anything below them. 45-degree overhangs and lower can usually print without support material.

Support Material – For overhangs over 45 degrees, interior cavities, nested geometries, complex objects. PVA is a support material used with a dual-head 3D printer. Single head printers use the same filament as the printer object but the material is used as a scaffold to keep the overhangs and other features from sagging during printing. Usually easy to separate from a printed object after printing is done.

3D Printing Files / Models

The most common file format for 3D printing is .stl

Downloading 3D Models for 3D Printing

Many 3D models for 3D printing are available online. You may download them and immediately import them into your 3D Printing Software. Among the resources are:

• Thingiverse
• Cults3D
• Yeggi
• GrabCAD

Creating 3D Models from Scratch

You can create 3D printing files from scratch using many different 3D modelling programs. Some of the software for 3D modelling are

• Solidworks
• Rhino
• TinkerCAD
• Fusion 360
• OpensCAD

3D printing software

3D printing machines use software called slicer which will slice your 3D model into layers. There are different slicer available today. Each manufacturer has its own slicer. For example, Prusa 3D printers use their own PrusaSlicer. Sindoh 3D printing machine uses its own slicer.

You will load your 3D model into these slicers and adjust the parameters to obtain the print as per the quality you desire.

Bipin Sharma

Bipin Sharma is an Energy Systems Engineer. He cherishes, sharing his knowledge with other people. For the latest updates from him, subscribe to AcadBuddy. Do not hesitate to drop a message.