What is 3D Printing?

Tutorial to additive manufacturing

3D printing (AM/Additive Manufacturing) is a process whereby a 3D design is turned into a real object. It builds 3D objects by adding layer-upon-layer of material to build products. Once a file is produced using a 3D modeling software or 3D scanner, the additive manufacturing machine (known as 3D printers) reads the file and lays down successive layers of material to create a 3D object.

Because each object is built up uniquely, and can be made in a variety of materials (from plastics to metals to even ceramic) 3D printing is suitable for unique and customized items or small series of objects. In contrast, other processes like injection molding are much cheaper and faster at mass production. FF3DM will always be ready to provide you the newest technology and material, with our best effort to make your idea real!

Molecular Cell

The Basics

How does 3D printing work?

Every 3D print starts as a digital 3D design file – like a blueprint – for a physical object. Trying to print without a design file is like trying to print a document on a sheet of paper without a text file. This design file is sliced into thin layers which is then sent to the 3D printer.

Workflow for Additional Manufacturing

A Brief History of 3D Printing

While the technology was first introduced in the early 1980’s, its first uses were focused on prototyping and as a way to visualize models in preproduction. Since then, additive manufacturing has evolved and is being used to create end-use products across almost all industries.

SLA-1, the first 3D printer invented by Chuck Hull in 1983SLA-1, the first 3D printer invented by Chuck Hull in 1983

Until 2009 3D printing was mostly limited to industrial uses, but then the patent for fused deposition modeling (FDM) – one of the most common 3D printing technologies – expired.

Through the RepRap project’s mission to build a self-replicating machine, the first desktop 3D printer was born. As more and more manufacturers followed, what once cost $200,000 suddenly became available for below $2000, and the consumer 3D printing market took off in 2009.

3D printer sales have been growing ever since, and as additive manufacturing patents continue to expire, more innovations can be expected in the years to come. There are now roughly 300,000 consumer 3D printers in the world – and this figure is doubling every year.

Carbon3D, one of the fastest 3D printing technologies currently under development

The Pros and Cons of 3D Printing

It’s crucial to understand that 3D printing is a rapidly developing technology, which comes with its set of inherent benefits, but also lags behind traditional manufacturing processes in some aspects. We collected examples from both sides to help you get a grasp of these factors and to see where the technology is headed in the near future.

PROS

Complexity

3D printing lets designers create complex shapes and parts – many of which cannot be produced by conventional manufacturing methods. By the natural laws of physics, manufacturing through additive methods means that complexity doesn’t have a price; elaborate product designs with complicated design features now cost just as much to produce as simple product designs that follow all the traditional rules of conventional manufacturing.

Customizability

Have you ever wondered why we purchase our clothing in standardized sizes? With traditional production methods, it’s simply cheaper to make and sell products at an affordable price to the consumer. Alternatively, 3D printing allows for easy customization; one only needs to change the design digitally to make changes with no additional tooling or other expensive manufacturing process required to produce the final product. The result? Each and every item can be customized to meet a user’s specific needs without additional manufacturing costs.

No tools or molds

When metal casting or injection molding, each part of each product requires a new mold – a factor that can balloon manufacturing costs very quickly. To recoup these upfront manufacturing costs, most companies rely on thousands of the same item being sold. Alternatively, since 3D printing is a “single tool” process there is no need to change any aspect of the process and no additional costs or lead times are required between making an object complex or simple. Ultimately, this leads to substantially lower fixed costs.

Rapid prototyoing, low cost & risk

Since there is no expensive tooling required to create objects through 3D printing, it is particularly a cost effective method for designers or entrepreneurs who are looking to do market testing or small production runs – or even launch their products through crowdfunding sites like Kickstarter. At this stage, it is also easy for design changes to be made without compromising more formal – and expensive – manufacturing orders. Thus, 3D printing offers a much less risky route to market for those who are looking into manufacturing a product idea.

Less waste

Many conventional manufacturing processes are subtractive: you start with a block of material, cut it, machine it, and mill it until it has been processed as your intended design. For many products – such as a bracket for an airplane – it’s normal to lose 90% of the raw material during this process.

Alternatively, 3D printing is an additive process; you create an object from the raw material layer by layer. Naturally, when an object is manufactured this way, it only uses as much material that is needed to create that particular object. Additionally, most of these materials can be recycled and repurposed into more 3D printed objects.

CONS

High cost for mass production

Despite all of the benefits of manufacturing through additive methods, 3D printing is not yet competitive with conventional manufacturing processes when it comes to large production runs. In most cases, this turning point is between 1,000 to 10,000 units, depending on the material and the design. As the price of printers and raw materials continue to decrease, however, the range of efficient production is expected to increase further.

Less material / colors / finishes

Despite there being more than six-hundred 3D printing materials available today – most of which are plastics and metals – the choices are still limited compared to conventional product materials, colors and finishes. However, this field is rapidly catching up, the number of new materials added to the 3D printing palette is growing rapidly every year including wood, metals, composites, ceramics, and even chocolate.

Limited strength and endurance

In some 3D printing technologies the part strength is not uniform due to the layer-by-layer fabrication process. As such, parts that have been 3D printed are often weaker than their traditionally manufactured counterparts. Repeatability is also in need of improvement as well; parts made on different machines might have slightly varying properties. However, as technical improvements continue to be made on new continuous 3D printing processes like Carbon3D, these limits will likely to vanish in the near future.

Lower precision

Although we may not be able to 3D print objects that have cutting edge tolerances like an iPhone, 3D printing is still a very capable method of creating objects at a precision of around 20-100 microns – or about the height of a single sheet of paper. For users who are creating objects with few tolerances and design details, 3D printing offers a great way for making products real. For objects requiring more working parts and finer details – such as the silent switch on the iPhone – it’s difficult to compete with the high precision capabilities of certain manufacturing processes.

Technologies

How many different processes are there in 3D printing?

All 3D printing technologies create physical objects from digital designs layer by layer, but each using its own proprietary method. To shed the confusion, we’ve created an infographic highlighting all the main technologies starting from the high level grouping, guiding through the printing process, exact technology titles, material options and ending with the key industry players.

Additive manufacturing technologies infographic (created by 3dhubs)

How do these technologies work exactly and what does their output look like? What are the benefits of each process and what are the flaws?

In the following section, we’ll be introducing the most common 3D printing technologies in detail.

FDM – Fused Deposition Modeling

additive-manufacturing-fused-deposition-modeling-enSchematic of FDM technology

Fused Deposition Modeling is used to build your design with this material. The principle is simple. You can compare it with a hot glue gun into which you put sticks of glue. The glue is heated up until it melts and is then pushed through a fine nozzle in the front of the glue gun.

Objects created through FDM are produced by extruding small strings of melted material, which harden immediately, to form layers. The machines have a plastic filament or metal wire that is unwound from a coil to supply material to the extrusion nozzle, and can turn the flow of material on and off. The nozzle is heated in order to melt the material, and can move in both horizontal and vertical directions to build from the bottom up.

Check the video below:

SLA/DLP – Stereolithography/Digital Light Processing

additive-manufacturing-stereolithography-enSchematic of SLA/DLP technology

Both Stereolithography (SLA) and Digital Light Processing (DLP) create 3D printed objects from a liquid (photopolymer) resin by using a light source to solidify the liquid material.

To create a 3D printed object, a build platform is submerged into a translucent tank filled with liquid resin. Once the build platform is submerged, a light located inside the machine maps each layer of the object through the bottom of the tank, thus solidifying the material. After the layer has been mapped and solidified by the light source, the platform lifts up and lets a new layer of resin flow beneath the object once again. This process is repeated layer by layer until the desired object has been completed. There are two common methods today differentiated by the light source: SLA uses a laser, whereas DLP employs a projector.

Check the video below:

SLS – Selective Laser Sintering

additive-manufacturing-laser-sintering-enSchematic of SLS technology

Selective Laser Sintering (SLS) uses a laser to melt and solidify layers of powdered material into finished objects.

These printers have two beds that are called the pistons. When the printing process begins, a laser maps the first layer of the object in the powder, which selectively melts – or sinters – the material. Once a layer has been solidified, the print bed moves down slightly as the other bed containing the powder moves up; and a roller spreads a new layer of powder atop the object. This process is repeated, and the laser melts successive layers one by one until the desired object has been completed.

Check the video below:

Polyjet/MJP – Material Jetting

additive-manufacturing-material-jetting-enSchematic of Polyjet/MJP technology

Polyjet(Stratasys)/MJP(3D systems) is a process that spray photopolymer materials onto a tray in very thin layers until the 3D object is built. Each layer is cured with a UV light after being extruded allowing models to be handled and used immediately. A support material that is built to support complicated designs can be removed by hand and water jetting after the object is complete.

The build process begins when the printer jets the liquid material onto the build tray. These jets are followed by UV light, which instantly cures the tiny droplets of liquid photopolymer. As the process is repeated, these thin layers accumulate on the build tray to create a precise object. Where overhangs or complex shapes require support, the printer jets a removable gel-like support material that is used temporarily, but can be removed after the print is completed.

Check the video below:

3DP – Binder Jetting

additive-manufacturing-binder-jetting-enSchematic of 3DP technology

This term explains a process in which layers of material are bonded by selectively depositing a liquid binding agent to join powdered material. This process of additive manufacturing is capable of printing a variety of materials, such as metals, sands and ceramics. While other additive techniques use a heat source to bind materials together, Binder Jetting does not employ any heat during the build process. This process provides the ability to print large parts and can be more cost effective than other methods.

The process starts with a nozzle spreading the binding agent across the first layer of the object and binding the powder together. Once the first layer has been fused with the binding agent, the printing bed moves down slightly and a thin layer of new powder is spread atop the object. This process repeats until the desired object has been fully formed. After it is removed from the print bed, the object is cleaned from excess powder and coated with an adhesive glue to give it strength and to make it resistant to discoloration.

Check the video below:

SLM & EBM – Metal Printing

additive-manufacturing-laser-melting-enSchematic of SLM technology

additive-manufacturing-electron-beam-melting-enSchematic of EBM technology

Selective Laser Melting and Electron Beam Melting (SLM and EBM) are two of the most common metal 3D printing technologies. Just like SLS, these processes create objects from thin layers of powdered material by selectively melting it using a heat source. Due to the higher melting point of metals they require much more power – a high power laser in the case of SLM or an electron beam for EBM.

During the printing process, the machine distributes a layer of metal powder onto a build platform, which is melted by a laser (SLM) or an electron beam (EBM). The build platform is then lowered, coated with new layer of metal powder on top and the process is repeated until the object is fully formed. Both SLM and EBM requires support structures, which anchors the object and overhanging structures to the build platform and enables heat transfer away from the melted powder. In addition, SLM takes place in a low oxygen environment and EBM in vacuum, in order to reduce thermal stresses and prevent warping.

Check the video below: