What is 3D Printing and How Does it Work?

by Jason King on February 15, 2017

What is 3D PrintingIn simple terms 3D printing is the process of creating 3D objects from digital files.

Another less commonly used name for 3D printing is additive manufacturing and for good reason.

Additive manufacturing differs from traditional subtractive manufacturing in that only the material required to create an object is actually used during the manufacturing process.

Traditional subtractive manufacturing usually starts with a solid block of material. This material block is then cut, milled, drilled and grinded to create the final object. This can produce a lot of waste, with some shapes producing far more waste than the amount of material in the finished object.

Additive manufacturing (3D printing) on the other hand creates 3D objects by starting with no material at all. The object is then built up layer by layer using only the material required to create (and possibly stabilise) the object.

3D printing can result in far less waste than traditional manufacturing methods. It’s also more environmentally friendly and allows the manufacturing of semi hollow objects with lattice infills.

Lattice infills can achieve excellent strength to weight ratios that cannot be achieved using traditional methods. We’ll go into more detail about these and the many other advantages later on.

Obtaining 3D Printable Designs

OpenSCAD 3D DesignThe process of 3D printing ultimately starts with a digital file representing a 3D object.

However, for completeness I’ll start by describing the different methods of obtaining such files.

The three main methods are scanning, designing or downloading, but you can sometimes combine these if required.

Scanning

Many existing objects can be scanned using 3D scanners to produce a 3D printable electronic file. Many different scanning technologies exist, with prices varying massively depending on their quality and the technology used. They can range from a few hundred dollars to over a million dollars.

Designing

For those who want to create their own designs there is plenty of design software available (many of which are free like Tinkercad and OpenSCAD) that can export in 3D printable formats. If inventing or product development is your thing then you’ll probably want to Design Your Own Stuff.

Downloading

Most people (especially 3D printing beginners) prefer downloading their electronic designs rather than creating them, as it’s usually much easier than scanning or designing. Online repositories like Thingiverse and Pinshape have made this even easier with literally millions of designs available for 3D printing. Thingiverse celebrated their 1 millionth upload in late 2015 and many more designs have been added since then.

How Does 3D Printing Work

Assuming we have used one or more of the above methods to obtain a 3D printable file or two, we can move on to the 3D printing process itself. 3D printable files resulting from scanning, designing or downloading are often in a .STL format. 3D printers generally won’t understand this format directly and the file will need slicing first.

Slicing

Slicing software takes the .STL file and converts the design into horizontal layers (hence the name slicing). It takes various user entered parameters (like layer height, print speed, raft and support requirements) before outputting another file containing machine code instructions which your 3D printer will understand.

3D Printing

There are many different 3D printing technologies currently available, but they all take this machine code file and build up your object layer by layer. Using a desktop FFF 3D printer as an example (these are very popular for home use) a roll of plastic filament is fed into an extruder which then melts and extrudes the plastic to build up the object layer by layer.

PLA and ABS are the most common materials used in this thermoplastic extrusion process. Many more pure and composite materials are available though, including those infused with Wood, Metal and Glow in the Dark Plastic.

Supports and Rafts

Some designs require removable support structures and rafts in order to create the object. Support structures enable overhanging parts to be 3D printed as it’s not possible to 3D print in midair using extrusion. Rafts can help prevent warping and can also help prevent tall thin objects from toppling over during printing.

Finishing

After 3D printing using any technology some degree of post processing may be required. For desktop FFF 3D printers mentioned earlier, removing supports and rafts and then trimming with a modelling knife may be required. We can also sand, paint or Dry Brush to create a better finish if required.

For more information about support structures and rafts, please read my previous post about Designing Specifically for 3D Printing where I explain these in much more detail.

3D Printing Technologies

The 3D printing world is full of Acronyms and Terms, many of which are just different names for the same technology or process.

MakerBot Replicator 2The manufacturers don’t help with terminology either, by insisting on using their own proprietary names for what is essentially the same technology.

Fortunately attempts have been made by the International Standards Organisation (ISO) and the American Society for Testing and Materials (ASTM) to standardise the terms used in additive manufacturing (3D Printing).

Although this standard isn’t yet widely adopted, it’s only right that I do my small bit to help by using the terms from the ISO/ASTM 52900:2015 standard to help describe the main 3D printing technologies currently available.

Binder Jetting

Binder jetting is the process in which a liquid adhesive (binding agent) is sprayed on to successive layers of powder in order to selectively bind the powder together to create an object.

Direct Energy Deposition

Direct energy deposition involves depositing layers of powder while at the same time using a focused heat source such as a laser to fuse the material together into an object.

Material Extrusion

Material extrusion requires semi-liquid material such as melted plastic to be fed though a nozzle in order to build up objects layer by layer.

The most common form of this is known as Fused Filament Fabrication or FFF and is the technology used in most low cost desktop 3D printers.

Material Jetting

Material jetting is the process of depositing droplets of liquid build material, which is then solidified (using heat or UV light for example) in order to build up the successive layers of an object.

Powder Bed Fusion

Powder bed fusion involves using a laser or other heat source to selectively fuse together regions of a powder bed, in order to build up a solid object.

Sheet Lamination

Sheet lamination is a means of building a 3D object by bonding together layers of cut material, typically paper, plastic or metal.

Vat Photopolymerization

Vat polymerisation involves curing successive layers on the surface or base of a vat of liquid photopolymer in order to build up a 3D object.

Uses for 3D Printing

3D printing is currently being used in a very diverse range of industries. It is continuing to be used more and more in manufacturing, not only for Rapid Prototyping but also increasingly for final production.

RC Truggy TyreTraditionally 3D printing was used mostly in rapid prototyping.

This is because the process of 3D printing, assessing, tweaking and re-printing is very quick and cost effective when compared to using other manufacturing methods.

Whilst 3D printing is still used extensively for rapid prototyping, it’s also being used more and more for final production parts.

This is commonly known as Direct Digital Manufacturing (DDM). Here’s a few examples of industries which use 3D printing and why they use it.

Sculptors

Sculptors are using 3D printing more and more nowadays, as it’s possible to rapidly create sophisticated designs and objects which were previously very difficult and expensive to produce. What used to be impractical or impossible designs are now being made and sold by Sculptors all over the world.

Aviation

The aviation industry is adopting 3D printing as it’s also now possible to make complex parts in one piece that previously required many sub parts to be made and welded together. The ability of 3D printing to make parts which are semi hollow, with a lattice infill allows very light parts to be made, whilst maintaining strength. This is perfect for the Aviation Industry.

Outer Space

NASA are using 3D printers in space and on the International Space Station to 3D print tools, parts and even Foods Like Pizza on Demand. Where else are these things less available than in space? So with the ability to 3D print tools, parts, food and anything else on demand, 3D printing opens up a whole new world of potential even beyond the planet we currently inhabit.

Dentistry

Dentists have been using 3D printing for years now, scanning models of their teeth or even the inside of patients mouths to create custom crowns and braces on demand. Dentistry is an area which can benefit a great deal from 3D printing, as practically everything in Dentistry is customised for each patient. One thing 3D printing is great for is customisation of objects.

Medical

In the medical industry 3D printing is already saving lives by enabling the production of Customised Titanium Implants. It’s also being used to make Pre-Surgery Models of Internal Organs being worked on, so that the surgeons can see and feel exactly what they need to do before surgery even begins.

Bioprinting

Bioprinting takes this one step further, with companies like Organovo already 3D printing living human tissues that can survive and be used for pharmaceutical testing. Bioprinting means that less human/animal trials will be required and new drugs can be bought to market much quicker and more cheaply. The goal of Bioprinting Companies is to 3D print entire human organs and they are making surprising progress towards this already. It may sound like science fiction but it’s real.

This is just a summary of what 3D printing is currently being used for, but hopefully it gives you a flavour of what 3D printing is actually capable of. It’s not just about plastic toys being printed in peoples homes.

Advantages of 3D Printing

Whilst not always being perfectly suited to all types of manufacturing, 3D printing can still claim many advantages over traditional manufacturing methods.

Some of these have already been mentioned as it’s difficult to talk about 3D printing without pointing out at least some of it’s amazing benefits. Here are a few of the benefits that 3D printing can bring to those who are brave enough to embrace it.

Speed and Cost

Rapid prototyping can be difficult using traditional methods but with 3D printing it becomes much easier, cheaper and faster. Anyone with a little design knowledge, some design software (often free) and access to a 3D printer can now do their own rapid prototyping.

The process of Inventing Something, making it, testing it, tweaking the design and then re-making the tweaked design becomes very easy using 3D printing. I did this myself with every single part of the 3D Printed RC Land Yacht I’m making. Without 3D printing this land yacht project would never have happened as it would be too expensive and difficult.

Shipping and Inventory

Using the land yacht as an example. When it’s complete I’ll make the 3D files available to anyone in the world, by uploading them to Thingiverse, Pinshape and my website. This way, anyone with access to a 3D printer can make the yacht for themselves and I’ll have no manufacturing, parts inventory or shipping to worry about.

This is a big deal when you scale this up to everything else in the world which can be 3D printed. Manufacturers will no longer need to keep parts for old and near obsolete machines, as the parts can sit there online in electronic form waiting for someone to download and 3D print them. Delivery will be immediate too and at no cost as shipping will involve a simple and fast file download.

Waste Material

As we mentioned earlier using additive rather than subtractive manufacturing creates almost no waste. For some 3D printing technologies Disposable Rafts and Supports may sometimes be required but for more advanced technologies these are almost never required. Parts can also be made hollow which also saves a lot of material.

Reduced waste means lower cost and less use of the planets limited resources. This lack of waste, shipping and inventory we have just mentioned brings us to the next big advantage. The environment itself.

Environment

Storing inventory takes up valuable space. Shipping worldwide takes up time, space, energy and always results in toxic emissions into the Environment.

3D Printing EnvironmentWaste material (including product packaging) needs to go somewhere and if it cannot be Recycled (which also costs money) then it will probably end up in landfill somewhere.

3D printing removes all of these issues, with zero inventory, zero shipping, zero packaging for parts made and in many cases zero waste.

With the planets resources (including time and space) being limited it’s looking like 3D printing could go a long way to solving most of the issues involved in traditional manufacturing.

Impossible Parts

There are numerous objects which cannot be made in one piece (usually due to their internal structures) by traditional manufacturing. Some theoretically useful objects (the Gear Bearing for example) can only be made with all parts in situ by using 3D printing, so until recently we have never actually seen them as tangible functional objects.

This opens up a whole new world of new parts which are easier to make or which can be made for the first time. As mentioned earlier the airline industry is now making parts in one piece that previously had to consist of many sub parts welded together.

Strength and Weight

The airline industry is also benefiting from the strength and weight advantages of 3D printing. As well as using rapid prototyping the airline industry is now able to quickly create semi hollow parts using lattice infills. If you look at nature and how birds bones are constructed (hollow or semi hollow), we can now replicate this design for the first time in Aircraft Parts.

The strength and weight advantages achievable when using 3D printing are incredible. I’ve 3D printed hundreds of objects myself but have only printed a few as solid objects. The vast majority were using 5-10% honeycomb infill to save time, material and weight. Why would I ever make solid objects again, unless pure strength was the main requirement.

Downsides of 3D Printing

As with any technology there are upsides and inevitably some downsides. No discussion about 3D printing would be complete without mentioning the downsides.

Admittedly some of the downsides are either temporary or just scaremongery, but I’ll mention them here for completeness.

Cost, Speed and Complexity

Hang on, didn’t I list speed and cost as an advantage earlier and aren’t the principles of 3D printing actually quite simple? Yes, that’s true, but let me explain.

In the context of Why Hasn’t 3D Printing Become Mainstream, which I wrote about a couple of years ago, then it is costly, slow and complex, when compared to other household goods. 3D printing had been around since the eraly 1980s so if it’s so great then why doesn’t every household have one?

Until recently the Cost of 3D Printers for home/office use were well beyond what many people could afford. They also make objects quite slowly with some objects taking 20+ hours to 3D print. 3D printers are also nothing like other household goods, in that they require frequent tweaking, setting up and fixing.

So, when it comes to their popularity amongst the masses, they are still a little too expensive, a bit slow at printing and require more ongoing care than many people would wish to give them.

Criminals

It’s difficult to name many new technologies which don’t have some kind of Criminal Element. The technology you’re using to read this article (the internet) is a classic example.

3D Printed LiberatorThere are many ways in which criminals can and already are using 3D printing to their advantage.

This includes the creation of Guns (The Liberator) and High Security Keys, which I have written about before.

Although guns are legal in the USA for example, to create your own untraceable weapons is illegal. Single shot guns can also be 3D printed entirely from plastic too (see Liberator above link), making them invisible to metal detectors. This is a scary prospect.

Forgery and even drugs are also a problem. Whilst 3D printing legal drugs might be seen as having many advantages, 3D printing illegal drugs using their base elements (like hydrogen, carbon and oxygen) could be a real problem. According to many it is theoretically possible so maybe it’s just a matter of when.

Intellectual Property

With the ability to scan in objects then distribute the electronic files around the world for 3D printing, where does this leave intellectual property rights?

The duplication and distribution of electronic media like music has been a real problem in recent years. With the increasing availability of 3D printing this has now extended to physical goods.

Could this be the end intellectual property rights as we know them? Who knows, because it’ll soon be impossible to enforce, even with physical goods. This is at least the beginning of a legal minefield in this area so expect to hear more about this (even in the mainstream media) as the problem escalates.

Emissions

Although 3D printers can be very Environmentally Friendly for a good number of reasons, the most popular desktop 3D printers use thermoplastic extrusion. This involves melting plastic before extruding it in layers to create objects.

The melting process emits fumes which could be toxic. The two most common plastic filament types are ABS and PLA. ABS is petroleum based and does emit toxic fumes, although the degree of toxicity is still in question. PLA is made from organic materials so is known to be much safer.

However, until we know more about the effects of these fumes then we have to consider this a disadvantage, especially as many desktop 3D printers have no enclosed build area or ventilation built in. This is mostly due to existing patents and cost saving.

Safety Features

As well as a lack of enclosed build areas and ventilation, desktop 3D printers often have very few safety features built in. When things go wrong during 3D printing (as they often do) most 3D printers will just carry on, creating a tangled mess of plastic using temperatures up to around 260 degrees Celsius.

A couple of years ago I wrote quite a large, detailed article about the Dangers of Desktop 3D Printers so feel free to have a read of that if you’re interested in this area. In summary though, any machine which isn’t enclosed and has hot moving parts powered by mains electricity will have some safety concerns, so use common sense and never leave a 3D printer unattended or somewhere where it’s accessible by young children.

Lost Jobs

With the increasing use of 3D printing where previously manual labour may have been required, it’s easy to forget about the possible loss of jobs. I don’t see lost jobs as an immediate threat though as with any new technology, it might reduce the need for old skills, but will introduce the need for new skills.

3D printers don’t run themselves, so where some job opportunities will inevitably close, new ones will open up. Take the internet for example. Since the internet became mainstream shopping habits and changes in the way we search for information has led to the closure of banks, shops and libraries.

However, it has also led to a whole new world of information technology jobs, like this blog you’re reading now and even my 3D printing work. 3D printing has it’s good and bad sides, but I hope I’ve helped demonstrate in this article that the good easily outweighs the bad.

3D Printing Companies

3D Systems LogoWith so many 3D printing companies around nowadays it’s good to get a flavour of who’s who and how they contribute to the 3D printing industry.

I’ve tried to stick with the larger companies in each sector as new, smaller companies are cropping up all the time and many don’t have a significant impact on the 3D printing world yet.

Pure Play Manufacturers

  • 3D Systems – founded in 1986 by Charles Hull (widely known as the father of 3D printing), 3D Systems provides a comprehensive range of high end 3D printing products and service. In recent years they have grown by acquiring over 20 3D printing companies.
  • Stratasys – operating on a similar scale to 3D Systems, Stratasys originally concentrated on their high end industrial clients like Boeing, Ford and Intel. However, after purchasing MakerBot in 2013 they now play a major part in serving the consumer and prosumer market.
  • Organovo – concentrating primarily on bio printing, Organovo is a very interesting company at the cutting edge of organic bioprinting research. In 2010 they used their NovoGen MMX bioprinter to create the first human blood vessels. Since then they have successfully 3D printed muscle, bone, Liver and kidney tissue and have begun selling these to pharmaceutical companies.
  • ExOne – founded in 2005 ExOne is a spin off from the Extrude Hone Corporation, who specialised in unconventional manufacturing processes. They now specialise in binder jetting which is used to create 3D objects in metal, casting sand or glass.

Mainstream Manufacturers

  • HP – Hewlett Packard have been a world leading IT company since they were founded back in 1939. While being involved in 3D printing since 2010, HP unveiled a jet fusion 3D printer in 2016 which it claims to be able to 3D print high quality objects up to 10 times as fast and at half the cost of current 3D printers.
  • Canon – originally an imaging and print company Canon recently announced that it would start distributing 3D printers made by 3D Systems. In 2015 they also announced that they are developing their own 3D printer which will use a resin based lamination process.
  • Toshiba – manufacturing giant Toshiba have been developing a laser metal deposition printer, which they expect to be made commercially some time this year (2017). They claim it will be cheaper and 10 times faster than existing powder bed fusion printers.
  • Ricoh – electronics giant Ricoh are also claiming a piece of the 3D printing pie. They started like Canon, by distributing third party printers. They have since developed their own powder bed fusion printer, which can print in Nylon and polypropylene.
  • Mitsubishi – in 2004 Mitsubishi teamed up with Matsuura to start selling hybrid powder bed fusion and CNC milling machines. This enables metal objects to be 3D printed before the milling part of the machine finishes off the object to a very high standard.
  • GE – after announcing in 2016 that they were acquiring Arcam and SML Solutions GE also announced the importance of 3D printing in their digital manufacturing plans. The acquisition of SLM solutions was eventually dropped, but GE did finally acquire a 76% controlling stake of Arcam.

Software Developers

  • Autodesk – established in 1982, Autodesk soon became the largest design and animation software company in the world. In 1985 they floated on the US stock market. Their products allow exporting in the .STL format so are widely used by 3D printing enthusiasts. Many of their products also integrate directly with some of the major online 3D printing service companies.
  • Trimble Navigation – most Autodesk applications (excluding Autodesk 123D Design) are high end, making them expensive, complex and difficult to learn. The most popular low end design software is SketchUp which is now owned by Trimble. Originally SketchUp was created by @Last Software in 1999. @Last Software was then purchased by Google in 2006, who to everyones surprise and despite it’s popularity, sold SketchUp to Trimble Navigation in 2012. SketchUp has won a number of awards for it’s ease of use and for this reason is likely to be popular for many years to come.

Service Providers

  • Shapeways – as one of the largest 3D printing services, marketplaces and communities in the world, Shapeways allows anyone to have their designs 3D printed and delivered to them, even if they Don’t Own a 3D Printer. They even allow users to sell their designs in the Shapeways Shop, by 3D printing the designs on demand in over 50 different materials. I Have Used Shapeways Myself many times and have even designed Customised Jewellery to have 3D printed and gold plated by them.
  • Materialise – after being established in 1990, Materialise finally floated on the NASDAQ stock market in 2014. Materialise help produce prototypes, final products and develop software for medical and engineering use. Just like Shapeways, they have an online 3D printing service called i.materialise and can 3D print in many different materials. They also have a shop in which users can upload and sell their 3D printed products to consumers.
  • Sculpteo – being very much like their larger competitors Shapeways and Materialise, Sculpteo have tried to make their online 3D printing and shop service as simple and accessible as possible. They provide a number of plugins so that their services are directly accessible from design software like SketchUp. They even provide apps to make the design of Customised 3D Printable Keyrings, Phone Cases and Pictures.
  • 3D Hubs – taking a completely different approach to 3D printing services are 3D Hubs. They strive to connect individual 3D printer owners with people locally who require their services. People can choose the 3D printer type and material before deciding whether they would like to pick up the 3D printed object in person or have it delivered. With so many people wanting to utilise 3D printing but not wanting to own a 3D printer, 3D Hubs has a very interesting business model with a lot of potential growth.

The History of 3D Printing

3D printing has had an interesting journey to arrive where it is today. There have been many significant developments in the last 35 years or so, but here are some of the most noteworthy, just to give you a flavour of the history of 3D printing.

In 1981, Dr Hideo Kodama of Nagoya Municipal Industrial Research Institute reported on his new rapid prototyping system. He details how a solid object could be built up layer by layer, with each layer corresponding to a horizontal slice of the object. He had made the patent application for this in 1980 but missed the one year deadline to file the full patent. This was particularly unfortunate as he was himself a patent lawyer.

Charles Chuck HullIn 1983, Charles (Chuck) Hull first thought of the idea of using UV light to cure liquid photopolymer for 3D printing.

He was using UV light at the time to cure the coating on tabletops. Later in 1986 his patent entitled Apparatus for Production of Three-Dimensional Objects by Stereolithography was issued.

This is where he defined the term stereolithography, meaning to build up an object from a digital file, layer by layer using UV curable photopolymer liquid.

In 2005, the RepRap Project was launched as an open source project with the goal of developing a 3D printer that can 3D print itself. Currently it can make it’s own plastic parts, but the metal and electronic parts will pose more of a challenge. In 2008 the original Darwin was released, but many other models have been developed since then.

In 2006, scientists at Wake Forest Institute for Regenerative Medicine 3D printed the scaffolds of a human bladder. After coating the scaffolds with human bladder cells the newly grown tissue was implanted into the patients. Due to the fact that the cells were originally taken from the same patients, there was very little chance of the new bladder cells being rejected.

In 2007, a major step towards the creation of affordable 3D printers was made. 3D Systems developed the first $10,000 3D printer, where previously 3D printers cost much more. Unfortunately the new printer didn’t take off as well as expected, but it was still a notable milestone in Reducing the Cost of 3D Printing technology. The real goal at the time was to break the $5,000 mark, making 3D printers more affordable to consumers and prosumers.

In 2009, Bre Pettis, Adam Mayer and Zach Smith, who were involved in the RepRap project, broke away from the open source model and founded MakerBot Industries. MakerBot are one of the most popular desktop 3D printer manufacturers and as mentioned earlier were purchased by Stratasys in 2013.

In 2009, Kickstarter was also founded. With the 3D printing community contributing so much towards the direction 3D printing is taking, crowdfunding company Kickstarter has played a large part in promoting the development of many new and innovative 3D printing projects.

In 2011, the first 3D printed car, Urbee was developed. With a fuel consumption of 200mpg and very little waste produced during it’s production it has been described as one of the most Environmentally Friendly cars ever created.

Since 2011, many more developments have been made in the 3D printing industry. Many of these involved company takeovers as well as more technological developments and interesting 3D printing projects. Hopefully the above timeline is enough to give an overview of how far 3D printing has progresses since the mid 1980s.

The Future of 3D Printing

I’ve you’ve managed to read this far you’ll already have an appreciation of how 3D printing has progressed since it’s birth in the mid 80s.

You’ve also learned about the technologies, the major companies involved and the wide range of applications for and industries making use of 3D printing.

So, where is 3D printing heading and what does the future hold for it?

As technology continues to improve and costs continue to fall it’s clear that 3D printing has a great future ahead of it. However, a few years back many people thought it’s future was in home users since desktop 3D printers for home use finally became more affordable.

In reality this doesn’t look like the case as 3D printing is seeing most growth in the industrial sectors. Although 3D printing at home is becoming more popular, many people would prefer to have the occasional product customised and 3D printed for them but have no wish to own and run their own 3D printer.

This brings us back to 3D Printing Service Companies. The Real Growth in 3D Printing is likely to be in local 3D printing service companies, where consumers can share the printers and have their items delivered or pick them up themselves.

This model beings with it many of the environmental advantages of 3D printing as mentioned earlier, but keeps costs down for the consumer and means that individuals don’t have to own, run and maintain their own printers.

Bioprinting Human EarIndustrially, there are not many sectors which aren’t utilising 3D printing already.

I always find the medical industry to be the most interesting, especially with 3D Printed Prosthetics and the work that Bioprinting companies like Organovo are doing.

Imagine a world where human organs can be 3D printed on demand, using cells from the patient themselves. The problem with the increasing shortfall of organ donations would disappear.

Although bioprinting organs is slightly scary, I think it is the single most exciting area of 3D printing and the one with the most life changing potential. It’s also becoming a reality and as I mentioned earlier, it’s no longer just science fiction.

I hope this has given you a good overview of what 3D printing is, how it works and what the various technologies are capable of, as that was the intention of this article all along.

For more information you can download my FREE Beginners Guide to 3D Printing at Home eBook or join in the discussion on our 3D Printing Facebook Group.

Thanks for taking the time to read this large and detailed article, you did well to get this far.

Feel free to Like and Share it with your friends if you found it interesting.

{ 0 comments… add one now }

Leave a Comment

Previous post: