Getting started with 3D printing can be daunting and intimidating. As with any new industry, there’s a whole new set of language that comes with it and learning how to speak 3D can be difficult. This glossary should serve as a guide to help you gain a better understanding of the the technology behind 3D printing. By knowing your options and choices, you can create a clear idea in your mind about the viability of any 3D printing project.
In the post, we will cover acronyms that relate to:
3D Printing Technologies
File types
3D Printing Materials
Let’s get started with the most basic acronym that you may have already come across.
CAD - COMPUTER AIDED DESIGN
This acronym is used as a general term to talk about software that is used by 2D and 3D designers, engineers, and artists. CAD does not have to be 3D but any software used to generate qualitative models suitable for 3D printing is called CAD.
3D Printing Technologies
As mentioned previously, there are a lot of different technologies that are used for 3D printing. In this section, we will cover some of the most important parts of the industry to help you better understand what is possible.
SLS - SELECTIVE LASER SINTERING
SLS is a powder bed fusion technology which uses powdered polymer material and a high-power laser to fuse it. The laser draws the 2D layer onto the powder to selectively melt an area, leaving the remaining powder untouched. It lays more layers and repeats this action to build parts. This is great for rugged material properties and volume production.
FDM - FUSED DEPOSITION MODELLING (AKA FFF)
This is the method that most people think of when they hear the word 3D printing. Using heat to melt a thermoplastic filament, this process deposits material on a surface layer by layer, eventually generating the 3D item, much like a glorified glue gun on a cartesian robot.
SLA - STEREOLITHOGRAPHY (APPARATUS)
SLA is a 3D printing technology that uses chemical monomers and light to create a 3D item, layer by layer. The light causes the photo-reactive liquid resin to solidify and fuse to create stable polymers. This technology is mostly used to create prototypes for the medical, technology and jewellery industries. By nature, SLA is a very fast and effective process for 3D printing, but it is also more expensive than other processes. It is considered the first and original 3D printing model, drawing its roots from a patent published by Charles Hull in 1986.
DLP - DIGITAL LIGHT PROCESSING
Similar to SLA, but rather than a laser, this method uses a projector to cure photo-reactive acrylic resins to build parts. The wider surface area of a projector’s light results in faster completion of the 3D printing process but lower quality parts.
DMLS - DIRECT METAL LASER SINTERING
Direct Metal Laser Sintering is a 3D printing process that creates metal parts directly - like SLS but not for polymers. It uses powdered metal to create 3D parts with the help of a high-temperature laser according to the specifications made in the 3D files you’ve provided.
CJP - COLOUR JET PRINTING
A powder bed technology similar to SLS fuses gypsum using a binding agent (glue) rather than fusing a polymer with high temperatures. In addition, in every layer, an inkjet prints a colour image around the object's surface, eventually creating a full CMYK (cyan, magenta, yellow, black) part. Material properties greatly suffer as a result of the gypsum material.
MJF - MULTI JET FUSION
Multi Jet Fusion is a technology that uses agents and heat to fuse polymer powder. A 2D printer-style inkjet head prints the layer using detail and fusing agents, and then a heat process binds those areas together to form a layer. This produces similar parts to SLS, but its natural colour is grey/black.
CFF - CONTINUOUS FIBRE FABRICATION
A Markforged technology that is in addition to an FDM process. After printing a layer by FDM, a separate print-head lays a continuous fibre of carbon fibre into the part to add strength and stiffness. This creates the best strength-to-weight ratio in the 3D printing world.
File TYPES
Just like there is a wide array of hardware technologies put to use for 3D printing, there are also a lot of software solutions that you will use to create these files. Here we will talk more about what these files are, how they are used, and which one is the most suitable one for 3D printing.
.STL - 'STEREOLITHOGRAPHY' FILE FORMAT
The golden child of the 3D printing industry, .STL files by design work in a similar way to how most of the current 3D printers handle the printing process, i.e. layer by layer. Because of this, .STL files are the best solution for 3D printers. They’re easily created with any 3D CAD program, though an additional plugin may be required. Capable of using both ASCII (American Standard Code for Information Interchange) and Binary, the file can support the recording of additional data beyond geometry (i.e. colour information), making it a valuable tool in the 3D printers arsenal.
The file was initially created by a company called 3Dsystems in 1987. Since then, with the increasing availability of 3D printers to the general public, it has slowly but surely gathered enough support to position itself as the industry’s standard.
At 3D People, we encourage clients to use this file format in millimetres for the best possible final product.
.3DM (RHINO)
Created by the “Rhinoceros” 3D CAD software developed by Robert McNeel & Associates, this file is not directly suitable for 3D printing. However, some plugins can enable the software to become compatible with most 3D printers. In addition to this, the software has the native capability of exporting its data to .OBJ and .STL file types, both of which are compatible with most 3D printers and accepted by most 3D printing services.
.DXF - DRAWING EXCHANGE FORMAT FILE (AUTOCAD)
This acronym represents CAD data typically generated in AutoCAD. Initially created by Autodesk to improve the interoperability (exchange and use of information) of their software, this file type is now recognised by a significant number of 3D software solutions across all platforms.
While useful for transferring 3D CAD data from one software to another, it does not have any direct compatibility with 3D printers.
.OBJ - OBJECT FILE, WAVEFRONT/ALIAS OBJ
Developed by Wavefront Technologies in the mid-1980s, this file type contains an ASCII representation of 3D geometrical data. It only stores the shapes, i.e. polygons, lines, curves, and surfaces. The file type cannot store additional data, such as colour, material, texture, but they can be applied separately with the help of UV maps. To do this, you would need to provide a .MTL file and a texture file in .jpg, .bmp, or .png formats.
.SKP - SKETCH UP FILE
SKP files are created by SketchUp, a 3D CAD software developed by Trimble. It contains data about 3D models created in the software, as well as other components that you have used to create your 3D environment.
While it is sometimes accepted by 3D printing services, your best bet is to export your data in an .STL file, which is the industry’s standard .
.SLDPRT- SOLIDWORKS PART FILE
This file extension represents an image file that is created by the Solidworks CAD software, developed by Dassault Systèmes. It contains a 3D item that is combined with other items to create a complete assembly file. SLDPRT files are not directly usable for 3D printing but need to be converted to an STL file type.
.STEP - STANDARD FOR THE EXCHANGE OF PRODUCT DATA (AKA .STP/ISO 10303)
Sharing graphical data between different software solutions, created by geographically separated teams of developers is a major challenge for the CAD community. STEP was created as a potential solution that will increase interoperability, enabling teams around the world to access 3D files, regardless of the software that they are using.
A STEP file is a CAD file format, usually used to share 3D models between users with different CAD systems. STEP files need to be converted to STL before being usable for 3D printing purposes.
3D Printing Materials
In this last section, we will cover some of the most notable materials that are used in 3D printing, as well as their applications. This should help ensure that your final product will have the expected qualities.
ABS - ACRYLONITRILE BUTADIENE STYRENE
ABS is a very common, affordable, resistant, and light plastic that is commonly used in 3D printing. One downside is that it loses surface colour and consistency when exposed to the elements. It is used in both professional and hobby 3D printing, mainly due to its availability and low price.
It melts at 200°C (392°F) which is considered safe, however, this plastic has become a concern after it was discovered that the material immediately releases toxic fumes when it reaches its melting point. Using this type of material for your printing should only be done in enclosed printers, with ventilation to follow-up the printing process. This will minimize the risk of breathing in toxic fumes
ASA - ACRYLONITRILE STYRENE ACRYLATE
Known in the industry as the “better ABS”, this plastic is considered to be an engineering plastic due to its high resistance qualities. Unlike ABS, it does not warp under the weather or lose colour, and can stay consistent for a long time.
As such, it is in high demand for a variety of different product types. Machinery, packaging, prototypes and everyday items are all created using ASA regularly.
PET - POLYETHYLENE TEREPHTHALATE, P RIC LEVEL 1 ♳
Invented during WW2 in England, this material is used in a wide selection of products today. The plastic is completely recyclable. It is most commonly used in single use water bottles.
In 3D printing, the material is used as a filament and its melting point is 250°C, making it suitable for both novice and professional printers. The material is commonly used & affordable, and finished products are strong and durable.
PETG - POLYETHYLENE TEREPHTHALATE GLYCOL
PETG is a copolymer of PET, created by combining the material with cyclohexane dimethanol. It has slightly different properties to its precursor, including a lower melting point, making it a better choice for 3D printers. This material is also stronger, more impact-resistant and retains transparency even if higher temperatures are applied. Compared to PET, it is more common for 3D printers to use this material
PLA - POLYLACTIDE; POLYLACTIC ACID, RIC LEVEL 7 ♹
PLA is a polyester created from biomass. It is 100% degradable, usually created from corn, beetroots, or sugarcane. As well as 3D printing, PLA is used in a wide array of industries. PLA is often used in the disposable cutlery industry as it’s compostable properties make it a great fit for throw away items. As it’s completely non-toxic, it is considered the safest material for 3D printing and is regularly used for medical applications.
TPU - THERMOPLASTIC POLYURETHANE (TPE)
TPU is a flexible and abrasion-resistant thermoplastic which is used in a variety of consumer and industrial implementations. There are two blends created with TPU; one with polyether and the other with polyester. Both have different characteristics, but in general they are flexible, impact and chemical resistant, soft, and stable in ambient environments.
TPU has a very high level of elasticity, so fast printing typically ruins models. It’s often used for flexible parts that need to stretch and return to their original form. In addition to its flexible properties, it also has great electro insulating properties. It is capable of enduring heavy workloads and resisting tearing, abrasions, and impacts. It is stable at ambient environments between -30 and 140°C, making it suitable for a variety of applications
PA - POLYAMIDES (Nylon, PA12, PA2200)
Most polyamides are nylons (i.e. semi-crystalline plastic). Versatile, strong, and flexible materials such as polyamides are very appealing for 3D printers and artists. The most common variants of these nylons are called PA12, PA6 and PA11 (which is biodegradable.) This material gives an impressive amount of freedom to the designers as it can be used to make objects for many different functionalities. The result can be a rigid or flexible 3D item, in a variety of colours. To print with polyamides, the SLS process is used, where items are generated by melting thin layers of powdered polyamides until they become the shape you want them to be.
Our Materials Index should help to provide more insight on the best material to use for your 3D printing needs.
Conclusion
3D printing may seem extremely complicated to beginners, and rightly so. It requires a mix of practice, experience, and knowledge to get 3D printing to work correctly. While we have created this article to share some of our understanding, we want to grow alongside you.
If you have any questions, feel free to reach out to us at print@3dpeople.uk and we will gladly answer any questions you might have.