The 3D Printing Process

Table of Contents

How does 3D Printing Work?

3D printing is a new type of manufacturing and processing technology. Visually speaking, ordinary printers print graphics and text on 2D paper with ink, while 3D printers convert raw materials (such as metals, ceramics, plastics, etc.) into thin layers by heating, light, laser, etc. Then, like building a house, the layers are added up to form an entity in the space. Mainstream 3D printing technologies are FFF, SLA, SLM, etc. The FFF is the most common technology, which will be focused on in this article.

FFF (Fused Filament Fabrication)

FFF (Fused Filament Fabrication) is a 3D printing technology using PLA, ABS and other thermoplastic filaments, which will be heated and extruded by an extrusion head, and then stacked layer by layer under the control of a computer to finally construct a shaped three-dimensional model. It is the most common and widely used 3D printing technology, with higher precision and lower cost.

Credit: Create it Real

The 3D Printer

At present, there are various brands and printers on the market, you can choose the most suitable 3D printer according to your needs. At Moose 3D we operate a farm of Creatlity 6 SE printers as these are self efficient and straightforward to operate!

The Ender 3 V2 features a Bowden setup, in which the hot and cold ends are separate (Source: All3DP)

The easiest way to understand how FDM works is to first learn the parts of an FDM 3D printer. Before we talk about specific parts, though, it’s worth mentioning that most 3D printers use three axes: 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.

Now, let’s look at the main components of a 3D printer:

Build platform: The build platform (also called a print bed) is essentially the surface on which the parts are made. Build platforms usually include heated beds to make it easier for parts to stick to them, but more on that later.
Extruder: The extruder is the component responsible for pulling and pushing the filament through the printhead. Depending on the extruder setup (direct or Bowden), the extruder and the printhead are sometimes considered to be the same thing (i.e. the block that moves along the gantry or gantries). This is often the case when considering or discussing entire extruder and hot end assemblies. From this perspective, the extruder consists of two sub-components:
The cold end is the mechanical portion that consists of a motor, drive gears, and other small components that push and pull the filament. Regardless of naming conventions, the extruder always consists of at least the cold end.
The hot end contains a heater and a nozzle, where the former heats up the filament so that it can be extruded out of the latter. In the case of a Bowden setup, the hot end is never considered to be part of the extruder.
Printhead(s): There can be one or more printheads on a printer, though most printers only have one.
On the printhead, between the hot end and the cold end, is a heatsink and fan, which are imperative for keeping the cold end cool to prevent jamming.
In addition to the heatsink fan, there’s usually at least one other fan for cooling the molten filament after it exits the hot end. This is usually called the part cooling fan.
Control interface: Some modern 3D printers have a touchscreen that’s 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.

3D Printing a Model

Unlike traditional processes, 3D printing requires very few steps, allowing you to print more easily. Generally speaking, to print a model through 3D printing, it needs to go through the following four steps: modeling, slicing, printing, and post-processing.

Modeling

If you want to print a 3D object, you naturally need to obtain a digital model of the object. Modeling will turn the object you want to print into a digital model that can be printed on a 3D printer. You can create 3D models with 3D modeling software (such as CAD software). Of course, you can also download the model files other users create. The STL files are widely used in rapid prototyping, 3D printing, and computer-aided manufacturing (CAM). There are many 3D websites out there where you can share and obtain 3D modeling models and settings files.

Thingiverse really has a whole universe of free 3D models! (Source: Thingiverse)

Slicing Software

When we have a designed model, we can use specific slicing software such as Simplify3D to slice the model. The purpose of slicing is to allow the 3D printer to calculate the route and the amount of filament required when printing the model. Just like building a house, you need to calculate the steps to build and the amount of wood needed. Simplify3D will generate a GCode file, which is essentially a long list of instructions, and then the 3D printer will read the GCode instruction to build the model. Simplify3D is a powerful slicing software, which can create personalised configurations according to different printers, filaments, and models, it can also automatically create precise support structures. Therefore, Simplify3D will provide you with more possibilities for creativity.

image of slicer software

Moose3D: Sureflap cat flap cover sliced using Simplify3d

Printing

After slicing is complete, you can upload the slice file to the printer, and calibrate the printer to prepare for printing. The extruders and the printing base need to be calibrated, to improve the accuracy of printing. During the printing process, you can observe the printing process a printer, or you can also monitor the printing progress remotely using Simplify 3d’s software. You will have a more intuitive and deeper understanding of the principles of 3D printing in this way. It will be a wonderful thing to observe the process of filaments accumulate layer by layer and monitor the printing progress!

image of a 3d printing printing an object

Post-Processing

Post-processing is the final stage of 3D printing. The post-processing of FFF 3D printing has the following steps (not all steps must be completed):

Removing Supports

After printing, you need to remove the support (if the model contains). Filament will remain on the surface of the model.

Credit: entiresia

Sanding the parts

You can use some sandpapers to make the model smoother.

Credit: Makerbot Learning

Gluing / Assembling

When you print a multi-part model or a large model, you can divide it into multiple parts, and then assemble the parts to form a complete model.

Credit: Makerbot Learning

Painting

You can paint the model according to your preference and add more details.

Credit: Makerbot Learning

Smoothing / Polishing

You can use apply a specific coating or other processes to make the model surface smoother and brighter.

Credit: 3D Sage

How Long Does 3D Printing Take?

The printing time depends on a number of factors, including the size of the part and the settings used for printing. The quality of the finished part is also important when determining printing time as higher quality items take longer to produce. 3D printing can take anything from a few minutes to several hours or days – speed, resolution and the volume of material are all important factors here.

What are the Advantages of 3D Printing?

Bespoke, cost-effective creation of complex geometries:

This technology allows for the easy creation of bespoke geometric parts where added complexity comes at no extra cost. In some instances, 3D printing is cheaper than subtractive production methods as no extra material is used.

Affordable start-up costs:

Since no moulds are required, the costs associated with this manufacturing process are relatively low. The cost of a part is directly related to the amount of material used, the time taken to build the part and any post processing that may be required.

Completely customisable:

Because the process is based upon computer aided designs (CAD), any product alterations are easy to make without impacting the manufacturing cost.

Ideal for rapid prototyping:

Because the technology allows for small batches and in-house production, this process is ideal for prototyping, which means that products can be created faster than with more traditional manufacturing techniques, and without the reliance on external supply chains.

Allows for the creation of parts with specific properties:

Although plastics and metals are the most common materials used in 3D printing, there is also scope for creating parts from specially tailored materials with desired properties. So, for example, parts can be created with high heat resistance, water repellency or higher strengths for specific applications.

What are the Disadvantages of 3D Printing?

Can have a lower strength than with traditional manufacture:

While some parts, such as those made from metal, have excellent mechanical properties, many other 3D printed parts are more brittle than those created by traditional manufacturing techniques. This is because the parts are built up layer-by-layer, which reduces the strength by between 10 and 50%.

Increased cost at high volume:

Large production runs are more expensive with 3D printing as economies of scale do not impact this process as they do with other traditional methods. Estimates suggest that when making a direct comparison for identical parts, 3D printing is less cost effective than CNC machining or injection moulding in excess of 100 units, provided the parts can be manufactured by conventional means.

Limitations in accuracy:

The accuracy of a printed part depends on the type of machine and/or process used. Some desktop printers have lower tolerances than other printers, meaning that the final parts may slightly differ from the designs. While this can be fixed with post-processing, it must be considered that 3D printed parts may not always be exact.

Post-processing requirements:

Most 3D printed parts require some form of post-processing. This may be sanding or smoothing to create a required finish, the removal of support struts which allow the materials to be built up into the designated shape, heat treatment to achieve specific material properties or final machining.

Where is 3D Printing Used?

Aerospace

3D printing is used across the aerospace (and astrospace) industry due to the ability to create light, yet geometrically complex parts, such as blisks. Rather than building a part from several components, 3D printing allows for an item to be created as one whole component, reducing lead times and material wastage.

Automotive

The automotive industry has embraced 3D printing due to the inherent weight and cost reductions. It also allows for rapid prototyping of new or bespoke parts for test or small-scale manufacture. So, for example, if a particular part is no longer available, it can be produced as part of a small, bespoke run, including the manufacture of spare parts. Alternatively, items or fixtures can be printed overnight and are ready for testing ahead of a larger manufacturing run.

Medical

The medical sector has found uses for 3D printing in the creation of made-to-measure implants and devices. For example, hearing aids can be created quickly from a digital file that is matched to a scan of the patient’s body. 3D printing can also dramatically reduce costs and production times.

Rail

The rail industry has found a number of applications for 3D printing, including the creation of customised parts, such as arm rests for drivers and housing covers for train couplings. Bespoke parts are just one application for the rail industry, which has also used the process to repair worn rails. 

Robotics

The speed of manufacture, design freedom, and ease of design customisation make 3D printing perfectly suited to the robotics industry. This includes work to create bespoke exoskeletons and agile robots with improved agility and efficiency.