How Exactly Does 3D Printing Work? Explained Simply


I was sitting here thinking, 3D printing is pretty complex and it’s not very straightforward how it works. That’s why I decided to do this post and explain in simple terms just how 3D printing works to clear any confusion that people may have. Keep reading to find out how exactly 3D printing works from start to finish!

How exactly does 3D printing work? It works in 3 main different stages: 3D modelling to create the look and design of a print, 3D slicing software to create the digestible information that the 3D printer can understand and implement, then 3D printing to build layer upon layer of material to physically create the actual print itself, called additive manufacturing.

This is the simple way of explaining how it works, but I’m going to dive into more depth about each process so you understand how it’s really done. There is a lot of technical processes at work, which is made simpler for beginners to be able to understand and 3D print in a matter of hours.

Firstly, What is a 3D Printer?

3D printers are a modern machine created with several moving parts which work together to create real life objects, directly from 3D design models. They generally use a gear to push material, a hot end to melt the material and a nozzle to lay the material down.

3D printers can use a variety of materials to print objects with, and more materials are being designed on a regular basis such as composite/hybrid filaments.

3D printing or additive manufacturing comes in many forms but they all follow a general process to print objects:

  • Create or a find a 3D CAD (Computer Aided Design) model
  • Get your CAD model and convert it into an STL file/format (most popular for 3D printers)
  • Transfer the STL file to your 3D printer using either an SD card, Wi-Fi, or an Ethernet cable
  • Load the file on your 3D printer and begin your print
  • Wait for the printer to create your object then remove it from the build plate
  • Depending on what you printed, clear up the print using post-processing techniques like sanding, washing etc.

Now that we have a good idea of what a 3D printer is, lets move into how exactly they work through each stage of the process.

1. 3D Printing & CAD Modelling

The first step for 3D printing is creating a blueprint or design for the object that you want to print. You can use modelling software like Blender to create your own unique designs, or go to a 3D print design archive website like Thingiverse, Shapeways or Cults3D to find designs that other users have created and shared for free.

The best part about 3D printing is it’s open-source and community-rich nature where people aim to help out others whether it comes to customization for a specific application or giving advice on how do things efficiently.

There are plenty of videos that you can watch as a beginner, or even an expert to learn new skills in 3D modelling to get the results and object creation that you desire. It will take some time to learn, but before you know it, you’ll be designing useful, functional objects that make your life easier.

Once you’ve either created your 3D model or used one from another user, it’s time to send the model to your slicing software.

2. 3D Printing & Model Slicing

There are many different slicing software which all aim to do the same job, which is convert your 3D model to an STL file. This STL file is a language that your 3D printer understands and uses to guide it’s movements and details of your print in real time.

Essentially, slicing is the process of dividing your 3D model into numerous tiny horizontal layers, similar to how your 3D printer will create your print, layer by layer. In some cases, your 3D printer will have a built-in slicer which will allow you to transfer the CAD files or the direct STL files without edits.

Once your file is sliced and ready to go, it can be transferred to your 3D printer using a number of different methods, being through a USB, SD card, or through the internet. After your printer receives the sliced file, you simply have to tell your printer to start printing.

Now the slicer is where a lot of things are determined, and where you will hear a lot about settings being adjusted. It gives you the ability to edit your file in a way that gives your prints extra strength, by using techniques such as different infill patterns like honeycombs or triangles.

The settings that your slicer usually contains are:

  • Layer Height
  • Perimeters
  • Infill
  • Infill Patterns
  • Fill Density
  • Infill Optimization
  • Support Material
  • Raft, Skirt or Brim Layers
  • Speed
  • Acceleration & Jerk
  • Extrusion Width and many more.

There are many types of slicing software, some of the popular ones being Cura, AstroPrint, Slic3r, and KISSlicer. They have different suitability levels and features depending on what you desire. Many slicing software are created for one specific brand of printer, while others are open-source and are cross-platform apps that give you more freedom to slice in your preferred app.

The slicing stage of 3D print gives many advantages to your final printed object, in the form of strength, durability and customization. Since 3D printed objects can’t be printed in mid-air, your slicing software can automatically add supporting structures to give your prints a foundation to be built upon.

After all is complete with your slicing software, the file to send to your 3D printer is ready to be processed and turned into your awaited object.

3. 3D Printing Your Object

When your modelled and sliced file has been created, it can simply get sent to your 3D printer usually in the form of an STL file.

These are the 3D printing industry standard for files to send to your printer in a language it can understand to begin the printing process.

The language is called G-Code which is a long series of very precise movements for your printer to create the object using a layer by layer technique.

Whether you are using the more popular FDM (Fusion Deposition Modelling) printer, resin, or sintering, the 3D printing process is additive manufacturing meaning it is done layer by layer.

With FDM, your materials come in the form of plastic filament spool which is heated and pushed through a nozzle through a device called an extruder.

The extruder consists of a geared system either called a Bowden setup or a Direct Drive setup to physically push the filament through, and a hot end which melts the plastic filament and gets pushed through a small nozzle, normally 0.4mm wide.

When your melted plastic filament is pushed through the nozzle, your printer has instructions to move, using the G-Code and this is how your object is 3D printed. Layer by layer you’ll see the object you designed or used be created right in front of you with great accuracy and detail.

After plastic is extruded onto a printer surface, it must be cooled with fans so it sets in place, or it would be a gooey mess.

Using a smaller nozzle allows you to get more detailed prints because the lines/layers are smaller and show up less, similar to a picture having more smaller pixels making a clearer image.

How Does Each Type of 3D Printing Work?

How Does FDM (Fused Deposition Modelling) Printing Work?

It is an layer additive manufacturing technique which uses specially prepared thermoplastic materials to create an object in layers. It accurately produces fine details and objects and results in a high strength, durable product.

Thin thread-like spools of plastic are melted and extruded through a thin nozzle, which is then laid down several times on a printing surface to create an object. You’ll usually be left with layer lines with FDM printing but they can be processed to reduce the visibility of these line and make the parts smoother.

This type of printing is ideal for concept models, functional prototypes, manufacturing aids, and low-volume end use parts. It has a wide range of applications from the automotive industry, to aviation, to medical uses and simple functional objects for your home.

You can build threads and snap fitted mechanisms to connect your prints together to build into a bigger object.

How Does Resin/SLA (Stereolithography) Printing Work?

Stereolithography is a type of printing which uses a photochemical process of light cross-linking with specific materials which react to it to create a solid object. It’s known to be one of the faster types of 3D printing and has many applications in the medical field, computer hardware and prototype development.

It’s more accurate than FDM printing and is also referred to as rapid prototyping. A vat of UV curable photopolymer (resin) is needed within an SLA 3D printer to create the object. It’s printed layer by layer using an ultraviolet laser that is directed by X and Y scanning mirrors.

Although more accurate and faster than FDM printing, it also comes at a higher cost on average. This is where you can decide whether you want to pay extra for quicker, more accurate prints or not.

How Does SLS (Selective Laser Sintering) Printing Work?

Selective laser sintering is a type of 3D printing that uses lasers as it’s main tool to create a 3D object. It uses powdered material such as Nylon or Polyamide and aims a laser at specific points from your 3D model, resulting in the material binding together to make a hardened object. SLS is usually used for rapid prototyping and low-volume production of component parts.

It’s a fairly modern type of 3D printing and is definitely on the rise in terms of it’s development and ability to produce specific models.

Typical uses for SLS 3D printing are tools and fixtures, flight-rated components for aviation, fuel tanks, air ducts, architectural models, automotive designs and much more.

PolyJet Technology

PolyJet printing is done through jetting numerous photopolymer droplets onto a printer’s surface then hardening the material using a UV light. To date, it’s one of the most accurate and fastest types of 3D printing available out there.

PolyJet is the patented name by Stratsys, with the general printing term being called MultiJet, but there are slight differences between the two.

How this works is a liquid photopolymer resin is poured into the printer’s material container then heated. Once the photopolymer gets to a certain state of liquidity, the printing process arts by moving the carriage across the build platform.

While moving, the print heads ‘jet’ the resin into droplet form straight onto the build platform where the UV light then cures these droplets, gradually creating a solid object throughout the process.

The good thing about this type of printing is that there are several print heads, which give you the opportunity to print different materials on the same platform. If you have a part requiring supports, it can be built at the same time as your main object.

What Kind of Ink or Material Does a 3D Printer Use?

Now, 3D printers don’t use ink, but they have their own specific materials which you can print with. These depend on what type of printing you are doing as discussed above. The most popular materials that 3D printer users print with has to be PLA, followed by ABS then probably PETG.

Printing with PLA

This is the most popular material for a number of reasons, the main one being it’s ease of use and cheap price. The material itself has great properties that thrive when used for the average prints that people make around the home and with other functional parts.

It is pretty durable, is widely used in other products that you have around the home, and is a great base material for many other composite materials to be created. PLA is also the safest material to print with and is used for food containers and other products.

Printing with ABS

ABS is similarly present in many household products and is the material that LEGOs are made out of. It is more durable than PLA but has the downside of being harder to print with.

Beginners usually stay away from ABS until they have a bit more experience with printer settings and temperatures to be successful printing with ABS.

ABS tends to give issues while printing such as warping, which is when the plastic cools too quickly compared to the rest of the print, causing the plastic to shrink at different rates and start curving. It also gives off bad fumes which can affect people with high sensitivity to pollutants.

Once you have your settings optimised and you troubleshoot some common issues, printing with ABS can be great, so don’t be put off with it.

Printing with PETG

PETG is another good all-round filament which has good strength, durability and is pretty easy to print with. You will have seen PETG used in products like plastic bottles, cups and even phone cases.

I would say PETG is in the middle of PLA and ABS in terms of it’s properties, price and ease of use. The good thing about it is it’s shock and impact resistant, has a very low amount of warping, great adhesion to the print bed when printing and fully recyclable.

Other Materials That Users Print With

There are numerous materials that you can print with, even solely with FDM printing. When you get into different types of 3D printing it opens up another huge selection of materials to print with, from resins, to powders to even metals.

I’ve put together an extensive post of 3D printing filament & materials to give you a proper insight of what kind of materials people right now are printing with.

A quick list of materials you can print with are:

  • PLA+ – Stronger version of PLA
  • Nylon – One of the best filaments
  • HIPS – Great support material, stronger than ABS and PLA
  • PVA – Water soluble filament
  • Polycarbonate – Transparent plastic, one of the strongest filaments
  • ASA – Alternative to ABS, improved weather resistance
  • TPU – Flexible filament used for wearable, mechanical parts etc.

If you have certain functions and applications in mind with an object, you can choose a material to best do what you desire. If you want a food container, you can pick a food-safe printing material and even post-process it to be more food safe.

If you want a mechanical part for a vehicle, you can pick a strong, durable material which is ideal for moving parts.

There are many possibility and creative ideas that arise from 3D printing due to it’s customization and specialised manufacturing nature. It is a industry that thrives on open-source creations and constant development to make things better.

PLA+ is an example of these ideas being put to use, which is a developed version of PLA to give it the desired strength and durability, while being easy to print with.

How Fast Can You Do 3D Printing?

Technically, from the time you unbox your 3D printer set it up and have it running, you could start 3D printing within an hour.

There are 3D printers out there that are almost ready out of the box so you simple need an STL file which already contains your 3D model and it’s G Code language that your 3D printer understands.

From there it’s simply starting your print, which if it’s a small object, can be printed in a matter of minutes.

I’ve written a post about how long it takes to 3D print different objects and how settings affect timing so check it out if you’re interested.

An experienced designer can create a simple, unique CAD model in 30 minutes. If you want to design something basic like a container, vase, or holder of some kind, this could be done in 10 minutes or less with little experience.

More complex models can definitely take several hours of modelling to get perfect so it really depends what you are trying to achieve on how fast you can get it done.

Slicing is a fairly simple process where you are playing around with settings such as temperature, infill, perimeters and so on. Many slicer software will have default options that are input for your specific 3D printer. A few adjustments here and there shouldn’t take long at all, and sometimes doesn’t actually need any edits to get printing.

The printing itself can be a few minutes to a few days depending on the size, resolution, complexity and 3D printer’s capabilities. If you want to print something quick it can be pretty quickly, for example, a 3D Benchy with normal settings should take about an hour.

What Applications Does a 3D Printer Have & What Can it Make?

3D printers have a very wide range of applications in basically all the fields you can think of. Think of 3D printing as a hobby for other hobbies.

In recent times, 3D printing has been used in the following fields:

  • Dental
  • Optometry & glass frames
  • Prototyping architecture & new products
  • Prosethetics
  • Fossil & artifact reconstruction
  • Reconstructing damaged evidence from crime scenes
  • Movie props
  • Cosplay
  • Aviation & aerospace
  • Nerf guns
  • Remote control cars & drones
  • Home construction
  • Automotive parts & repairs
  • Jewelry
  • Footwear
  • Bio-printing organs

That’s a pretty long list and not at all extensive either. 3D printing really has taken over some fields and forms of manufacturing in record timing. One prime example is in the hearing aids industry.

Think about how big this industry is, and realise that 3D printing, in a matter of a few years took over this industry by being the main manufacturing method of over 90% of hearing aids.

The manufacturing methods of 3D printing gave users fast delivery on personally customized hearing aids at a much lower price, so it was a no-brainer for companies to switch to 3D printing.

Now after reading this post I hope you guys have a better understanding of how 3D printing works and know how useful it is in today’s world. If you want to read more about 3D printing I would recommend reading the 25 best upgrades you can do for your printerwhether 3D printing is a worthy investment or waste of money.

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