3D Printing has been quoted as potentially being larger than the internet. Some believe it is true while others believe this is part of the extraordinary hype that exists around this technology. So, what is 3D Printing, who uses 3D Printers and what for? Read on to learn more about this amazing technology.
3D Printing Basics
3D Printing is an umbrella terms comprising a host of processes and technologies that offer a full spectrum of capabilities to produce parts and products in different materials. Essentially, what these processes and technologies have in common is the way production is carried out layer by layer in an additive process which contrasts with the traditional methods of production involving subtractive methods or molding/casting processes. This overview article aims to provide audience with reliable background on 3D Printing in terms of what it is, its history, application areas and benefits.
What is 3D Printing?
3D Printing is a process for making a physical object from a three-dimensional digital model, typically by laying down many successive thin layers of a material. It brings a digital object (its CAD representation) into its physical form by adding layer by layer of materials. 3D Printing brings two fundamental innovations: the manipulation of objects in their digital format and the manufacturing of new shapes by addition of material. The fundamental differentiating principle behind 3D Printing is that it is an additive manufacturing process. Components are made by adding material layer by layer. Thus this technology is radically different from other manufacturing technologies that are subtractive in nature where parts are made by removing material from existing block.
Traditional manufacturing has lot of limitations. Traditional manufacturing demand subtracting material from a larger block whether to achieve the end product itself or to a produce a tool for casting or molding processes and this is a serious limitation within the overall manufacturing process. For many applications traditional design and production processes impose a number of unacceptable constraints, including the expensive tooling, fixtures, and the need for assembly for complex parts. In addition, the subtractive manufacturing processes can result in up to 90% of the original block of material being wasted. In contrast, 3D printing is a process for creating objects directly, by adding material layer by layer in a variety of ways, depending on the technology used.
3D printing is thus an enabling technology providing unprecedented design freedom while being a tool-less process that reduces prohibitive costs and lead times. Components can be designed specifically to avoid assembly requirements with intricate geometry and complex features created at no extra cost. 3D printing is also emerging as an energy-efficient technology that can provide environmental efficiencies in terms of both the manufacturing process itself, utilizing up to 90% of standard materials, and throughout the products operating life, through lighter and stronger design.
In recent years, 3D printing has graduated from being an industrial prototyping and manufacturing process as the technology has become more accessible to small companies. Previously only huge multi national corporations used to own 3D Printers due to the scale and economics of owning a 3D printer but now many smaller 3D printers can now be acquired for under $1000. This has opened up the technology to a much wider audience, and as the exponential adoption rate continues apace on all fronts, more and more systems, materials, applications, services and ancillaries are emerging.
History of 3D Printing
The earliest 3D printing technologies first became visible in the late 1980’s at which time they were called Rapid Prototyping (RP) technologies. This is because the processes were originally conceived as a fast and more cost-effective method for creating prototypes for product development within industry. The origins of 3D printing can be traced back to 1986, when the first patent was issued for stereolithography apparatus (SLA). This patent belonged to one Charles (Chuck) Hull, who first invented his SLA machine in 1983. Hull went on to co-found 3D Systems Corporation — one of the largest and most prolific organizations operating in the 3D printing sector today.
3D Systems’ first commercial RP system, the SLA-1, was introduced in 1987 and following rigorous testing the first of these systems was sold in 1988. In 1987, Carl Deckard, who was working at the University of Texas, filed a patent in the US for the Selective Laser Sintering (SLS) RP process. This patent was issued in 1989 and SLS was later licensed to DTM Inc, which was later acquired by 3D Systems. In 1989, Scott Crump, a co-founder of Stratasys Inc. filed a patent for Fused Deposition Modelling (FDM) — the proprietary technology that is still held by the company today, but is also the process used by many of the entry-level machines, based on the open source RepRap model, that are prolific today. In Europe, 1989 also saw the formation of EOS GmbH in Germany, founded by Hans Langer with a greater focus on the laser sintering (LS) process. Today, the EOS systems are recognized around the world for their quality output for industrial prototyping and production applications of 3D printing. The company’s direct metal laser sintering (DMLS) process resulted from an initial project with a division of Electrolux Finland, which was later acquired by EOS.
Multiple other 3D printing technologies and processes were also emerging during these years, namely Ballistic Particle Manufacturing (BPM), Laminated Object Manufacturing (LOM), Solid Ground Curing (SGC) and ‘three dimensional printing’ (3DP). And so the early nineties witnessed a growing number of competing companies in the RP market but only three of the originals remain today — 3D Systems, EOS and Stratasys.
Throughout the 1990’s and early 2000’s a host of new technologies continued to be introduced still focused on industrial applications and while they were still largely processes for prototyping applications, R&D was also being conducted by the more advanced technology providers or specific tooling, casting and direct manufacturing applications. This saw the emergence of new terminology, named Rapid Tooling (RT), Rapid Casting (RC), Rapid Manufacturing (RM) respectively.
When it comes to commercial operations, Sanders Prototype and ZCorporation were set-up in 1996 Arcam was established in 1997, Objet Geometries launched in 1998, MCP Technologies introduced the SLM technology in 2000, EnvisionTec was founded in 2002, ExOne was established in 2005 and Sciaky Inc was pioneering its own additive process based on its proprietary electron beam welding technology. During the mid-nineties the sector started to show signs of distinct diversification with two specific areas of emphasis. First, there was the high end of 3D Printing which was geared towards part production for high value, highly engineered, complex parts. At the other end of the spectrum, we have ‘concept modellers’ that kept the focus on improving concept development and functional prototyping. At the lower end of the market, the 3D Printers that today are seen as being in mid range, a price war emerged together with incremental improvements in printing accuracy, speed and materials.
In 2009, the first commercially available low cost 3D Printer in kit form and based on the RepRap concept was offered on sale. This was closely followed by Makerbot industries in April the same year, the founders of which were heavily involved in the development of RepRap until they departed from the Open Source philosophy following extensive investment. In 2012, alternative 3D Printing processes were introduced at the entry level of the market. B9Creator came first in June followed by Form 1 in December. Both were launched via Kickstarter and both enjoyed huge success. 2013 was the year of significant growth and consolidation. One of the most notable moves was the acquisition of Makerbot by Stratasys.
3D Printing Technology
Starting point for any 3D Printing process is a 3D digital model which can be created using a variety of 3D software programs or scanned with a 3D scanner. The model is then ‘sliced’ into layers , thereby converting the design into a file readable by the 3D Printer. The material processed by the 3D Printer is then layered according to the design and the process. As stated, there are a number of different types of 3D Printing technologies, which process different materials in different ways to create the final object. Functional plastics, metals, ceramics and sand are now all routinely used for industrial prototyping and production applications. Research is also being conducted for 3D Printing bio materials and different types of food. At the entry level of the market, materials are much more limited. Plastic is currently the only widely used material, usually ABS or PLA but there are a growing number of alternatives, including Nylon. There is also a growing number of entry level machines that has been adapted for foodstuffs, such as sugar and chocolate.
How it Works
Different 3D printers employ different technologies to process materials. For example, some 3D printers process powdered materials that utilize a light/heat source to sinter layers of the powder together in the defined shape. Others process polymer resin materials and again utilize a light/laser to solidify the resin in ultra thin layers. Jetting of fine droplets is another 3D printing process. But the most common and easily recognized process is deposition, and this is the process employed by majority of entry-level 3D printers. This process extrudes plastics, commonly PLA or ABS, in filament form through a heated extruder to form layers and create the predetermined shape.
As parts can be printed directly, it is possible to produce very detailed and intricate objects, often with functionality built in and negating the need for assembly. Another important point to note is that none of the 3D Printing processes come as plug and play options. There are many steps prior to pressing print and more once the part comes off the printer.
3D Printing Processes
Stereolithography: Stereolithography (SLA) is widely recognized as the first 3D printing process of the various 3D Printing processes present in the market. SLA is a laser-based process that works with photopolymer resins. These resins react with the laser and cure to form very precise and accurate parts. The photopolymer resin is held in a vat with a movable platform inside. A laser beam is directed in the X-Y axes across the surface of the resin according to the 3D data supplied to the machine whereby the resin hardens precisely where the laser hits the surface. Once the layer is completed, the platform within the vat drops down by a fraction and the subsequent layer is traced out by the laser. This continues until the entire object is completed and the platform can be raised out of the vat for removal. Because of the nature of the SLA process, it requires support structures for some parts, specifically those with overhangs or undercuts. These structures need to be manually removed. In terms of other post processing steps, many objects 3D printed using SL need to be cleaned and cured. Curing involves subjecting the part to intense light in an oven-like machine to fully harden the resin. Stereolithography is generally accepted as the most accurate 3D printing processes with excellent surface finish. However certain limiting factors include the post-processing steps required and the stability of the materials over time, which can become more brittle.
Digital Light Processing: Digital Light Processing (DLP) process is very similar to that of stereolithography in that it is a 3D printing process that works with photopolymers. The major difference between SLA & DLP is the light source. DLP uses a more conventional light source, such as an arc lamp, with a liquid crystal display panel or a deformable mirror device (DMD), which is applied to the entire surface of the vat of photopolymer resin in a single pass, generally making it faster than SLA. Also like SLA, DLP produces highly accurate parts with excellent resolution, but its similarities also include the same requirements for support structures and post-curing. One key advantage of DLP over SLA is that only a shallow vat of resin is required to facilitate the process, which generally results in less waste and lower running costs.
Laser Sintering / Laser Melting: Laser sintering and laser melting are interchangeable terms that refer to a laser based 3D printing process that works with powdered materials. The laser is traced across a powder bed of tightly compacted powdered material in the X-Y axes. As the laser interacts with the surface of the powdered material it sinters, or fuses, the particles to each other forming a solid. As each layer is completed the powder bed drops incrementally and a roller smoothens the powder over the surface of the bed prior to the next pass of the laser for the subsequent layer to be formed and fused with the previous layer.
The build chamber is completely sealed to maintain a precise temperature during the process. Once printing is finished, the entire powder bed is removed from the machine and the excess powder is removed to leave the ‘printed’ parts. One of the key advantages of this process is that the powder bed serves as an in-process support structure for overhangs and undercuts, and therefore complex shapes that could not be manufactured in any other way are possible with this process. However, on the downside, because of the high temperatures required for laser sintering, cooling times can be considerable. Furthermore, porosity has been an historical issue with this process, and while there have been significant improvements towards fully dense parts, some applications still necessitate infiltration with another material to improve mechanical characteristics.
Laser sintering can process plastic and metal materials, although metal sintering does require a much higher powered laser and higher in-process temperatures. Parts produced with this process are much stronger than those manufactured with SLA or DLP processes, although the surface finish and accuracy is not as good.
Extrusion / FDM / FFF: 3D printing utilizing the extrusion of thermoplastic material is the most common 3DP process. The most popular name for the process is Fused Deposition Modelling (FDM). The process works by melting plastic filament that is deposited, via a heated extruder, a layer at a time, onto a build platform according to the 3D data supplied to the printer. Each layer hardens as it is deposited and bonds to the previous layer.
FDM processes require support structures for any applications with overhanging geometries. For Fused Deposition Modeling, this entails a second water-soluble material which allows support structures to be relatively easily washed away once the print is complete. Alternately, breakaway support materials are also possible which can be removed by manually snapping them off the part. Support structures have generally been a limitation for entry level FFF 3D Printers. However, as the systems has evolved and improved to incorporate dual extrusion heads, it has become less of an issue.
Binder Jetting: In Binder Jetting process, binder is jetted and is selectively sprayed into a powder bed of the part material to fuse it one layer at a time to create the required part. Once the layer is completed, the powder bed drops incrementally and a roller smoothens the powder over the surface of the bed prior to the next pass of the jet heads with the binder for the subsequent layer to be formed and fused with the previous layer.
Binder jetting has multiple advantages like the need for support is negated because the powder bed itself provides the functionality. Moreover, a range of different materials can be used like ceramics and food. Another distinctive advantage of the process is the ability to easily add full color palette which can be added to the binder.
The parts thus coming out of the machine aren’t as strong as with the sintering process and thus require post-processing to ensure durability.
Material Jetting: In Material Jetting process the actual build materials are selectively jetted through multiple jet heads. However, the material tend to be liquid photopolymers which are cured with a pass of UV light as each layer is deposited.
Material Jetting process allows for simultaneous deposition of a range of materials which means a single part can be produced from multiple materials with different characteristics and properties. Material Jetting is a very precise 3D Printing method producing accurate parts with very smooth finish.
Selective Deposition Lamination: SDL is a proprietary 3D Printing process developed by MCor technologies. SDL 3D Printing process builds parts layer by layer using standard copier paper. Each new layer is fixed to the previous layer using an adhesive which is applied selectively according to the 3D data supplied to the machine. This means a much higher density of adhesive is deposited in the area that shall become a part and much lower density of adhesive is deposited in the surrounding area that will serve as the support ensuring easy support removal.
Electron Beam Melting: Electron Beam Melting technique is a proprietary process developed by Swedish company ARCAM. This process is very similar to the Direct Metal Laser Sintering (DMLS) process in terms of the formation of parts from metal powder. Key difference here is the heat source which is an electron beam instead of a laser. EBM has the capability of creating full dense parts in a variety of metal alloys and as a result the technique has been particularly successful for a range of production applications in the medical industry. However other sectors such as aerospace and automotive also look into EBM technology for manufacturing fulfilment.
3D Printing Materials:
While the total available materials for 3D Printing is limited when compared to other manufacturing technologies, the range of materials has come a long way from the early days of 3D Printing. Now we have a wide variety of materials of different types that are supplied in different forms, namely powder, filament, pellets, granules, resin, etc. Specific materials are now generally developed for specific platforms performing dedicated applications with material properties that more suit the application.
Nylon or Polyamide is commonly used in powder form with the sintering process or in filament form with the FDM process. It is a strong, flexible and durable plastic material that has proved reliable for 3D Printing. It is naturally white in color but can be colored pre or post printing. This material can also be combined with powdered aluminum to produce another common 3D Printing material for sintering – Alumide.
ABS is another common plastic used for 3D Printing. This material is widely used in entry level FDM 3D printers in filament form. It is a particularly strong plastic and comes in a wide range of colors. ABS can be bought in filament form from a number of non-proprietary sources.
PLA is a bio-degradable plastic material that has gained traction with 3D Printing. It is mainly used in filament form for the FDM process. This material is offered in variety of colors, including transparent which has proven to be an useful option for some applications of 3D Printing. However, this material is not as durable or as flexible as ABS material. Laywood is specially developed 3D Printing material for entry level extrusion 3D Printers. This material comes in filament form and is a wood/polymer composite.
A growing number of metal and metal derivates are being used for industrial 3D printing. Two of the most common are aluminum and cobalt derivates. One of the strongest and most commonly used metals for 3D Printing is Stainless Steel in powder form for the sintering/melting/EBM processes. The material is naturally silver but can be plated with other materials to give a gold or bronze effect.
Titanium is one of the strongest possible metal materials and has been used for 3D Printing industrial applications. Supplied in powder form, this material can be used for the sintering/melting/EBM processes.
Ceramics is another material set that can be used for 3D Printing with varying degree of success. Important thing to note with these materials is that post printing the ceramic parts need to undergo the same processes as any ceramic part made using traditional methods of production.
Paper is a 3D Printing material employed by SDL process supplied by Mcor technologies.
There is a huge amount of research being conducted into the potential of 3D Printing biomaterials for a host of medical applications. Living tissue is being investigated at a leading number of institutions with a view of developing applications that include printing human organs for transplant, as well as external tissues for replacement body parts. Other research in this area is focused on developing food stuffs.
Experiments with extruders for 3D Printing food substance has increased dramatically over the last couple of years. Chocolate is the most common one. There are printers that work with sugar, pasta and meat. Research is being undertaken to utilize 3D Printing to produce finely balanced whole meals.
3D Printing Global Effects: 3D Printing is already having an effect on the way products are manufactured. The very nature of this technology permits new ways of thinking in terms of social, economic, environmental and security implications of the manufacturing process with universally favorable results. One of the key factors enabling this is 3D Printing has the potential to bring production closer to end user thereby reducing the current supply chain restrictions. The customization value of 3D Printing and the ability to produce small production batches on demand is a sure way to engage consumers and reduce or negate inventories and stock piling.
Shipping spare parts and products from one part of the world to the other could become obsolete as the spare parts shall be 3D Printed on site. This shall have a major impact on large and small businesses operate and interact on a global scale in future. The ultimate aim for many is for consumers to operate their own 3D Printers at home whereby digital designs of any product are available for download and can be sent to the printer.
The wider adoption of 3D Printing will likely cause re-invention of a number of already invented products and an even bigger number of completely new products. Previously impossible shapes and geometries can now be created using 3D Printer. 3D Printing is believed by many to have great potential to inject growth into innovation and bring back local manufacturing.
3D Printing Benefits & Value:
(a) Customization: 3D Printing process allows for mass customization. The nature of 3D Printing means within the same build chamber numerous products can be manufactured at the same time according to end user requirement at no additional process cost.
(b) Complexity: Advent of 3D Printing has seen a proliferation of products which involve levels of complexity that couldn’t be produced physically in any other way. This made a significant impact on industrial applications, whereby applications are being developed to materialize complex components that are proving to be both lighter and stronger than their predecessors. Notable uses are emerging in aerospace sector where these issues are of primary importance.
(c) Tool-less: For industrial manufacturing, production of the tools is the most complex, cost, time & labor intensive. For low to medium volume applications, industrial 3D Printing can eliminate the need for tool production and thus the costs, lead times and labor associated with it. This is an extremely attractive proposition that an increasing number of manufacturers are taking advantage of. Because of the complexity advantages stated above, products and components can be designed specifically to avoid assembly requirements with intricate geometry and complex features further eliminating the labor and costs associated with assembly processes.
(d) Environment Friendly: 3D Printing is also emerging as energy efficient technology that can provide environmental efficiencies in terms of both the manufacturing process itself utilizing up to 90% of standard materials but also throughout an additively manufactured product’s operating life by way of lighter and stronger design that imposes a reduced carbon footprint compared to traditionally manufactured products.
3D Printing Applications: The origins of 3D Printing were founded on the principles of industrial prototyping as a means of speeding up the earliest stages of product development with a quick and straightforward way of producing prototypes that allows for multiple iterations of product to arrive more quickly and efficiently at an optimum solution. This saves time and money at the outset of the entire product development process and ensures confidence ahead of production tooling.
Prototyping is still the largest application of 3D Printing today. The developments and improvements of the processes and the materials since the emergence of 3D Printing for prototyping saw the processes being taken up for applications further down the product development process chain. Tooling and casting applications were developed utilizing the advantages of different processes. Again, these applications are increasingly being used and adopted across industrial sectors.
Similarly for final manufacturing operations, the improvements facilitate uptake. In terms of industrial vertical markets that are benefitting greatly from industrial 3D Printing across all of these broad spectrum applications.
Medical & Dental: Medical sector is viewed as one of the early adopters of 3D Printing and also a sector with huge growth potential due to customization and personalization capabilities of the technologies and the ability to improve people’s lives as the processes improve and materials are developed that meet medical grade standards.
Aerospace: The aerospace sector was an early adopter of 3D Printing technologies in their earliest forms for product development and prototyping. Because of the critical nature of aircraft development, the R&D is demanding & strenuous, standards critical and industrial grade 3D Printing machines are put through their paces. Process and materials development have seen a number of key applications developed for the aerospace sector. High profile users include GE / Morris Technologies, Airbus/EADS, Rolls-Royce, BAE Systems and Boeing. While most of these companies do take a realistic approach in terms of what they are doing now with the technologies and most of it is R&D, some do get quite bullish about the future.
Automotive: Automotive is another great early adopter of Rapid Prototyping technologies. Many automotive companies, particularly at the cutting edge of motor sport & F1 have followed a similar trajectory to the aerospace companies. First using the technologies for prototyping applications but developing and adapting their manufacturing processes to incorporate the benefits of improved materials and end results for automotive parts.
Many automotive companies are now also looking at the potential of 3D Printing to fulfill their after-sales functions in terms of production of spare / replacement parts on demand rather than holding huge inventories.
Jewellery: Design and manufacturing process for jewellery has always required high levels of expertise and knowledge involving specific disciplines that include fabrication, mould-making, casting, electroplating, forging, silver/gold smithing, stone-cutting, engraving and polishing. Each of these disciplines have evolved over years and each requires technical knowledge when applied to jewelry manufacture. For Jewelry sector, 3D Printing has proved to be particularly disruptive. There is a great deal of interest based on how 3D Printing can contribute to the further development of this industry. From new design freedoms enabled by 3D CAD and 3D Printing through improving traditional processes for jewellery production all the way to direct 3D Printed production eliminating many of the traditional steps, 3D Printing continues to have a tremendous impact on this sector.
Art, Design & Sculpture: Artists and sculptors are engaging with 3D Printing in multiple ways to explore form & function in ways that aren’t possible previously. Whether purely to find new original expression or to learn from old masters this is a highly charged sector that is increasingly finding ways of working with 3D Printing and introducing the results to the world. There are a numerous artists that have now made a name for themselves by working specifically with 3D Modelling, 3D Scanning & 3D Printing technologies.
Architecture: Architecture models have long been a regular application of 3D Printing processes for providing accurate demonstration of an architect’s vision. 3D Printing offers a relatively fast, easy and economically viable method of producing detailed models directly from 3D CAD, BIM or other digital data that architects use. Many successful architectural firms now use 3D Printing as a critical part of their workflow for increased innovation and improved communication.
Fashion: As 3D Printing processes have improved in terms of resolution and more flexible materials, one industry has come to the fore. 3D Printed accessories including shoes, head-pieces, hats and bags have all made their way on to global cat-walks. Some even more visionary fashion designers have demonstrated the capabilities of the tech for haute couture.
Food: Food is another emerging application of 3D Printing that has the potential to truly take the technology into mainstream. Initial forays into 3D Printing food were with chocolate and sugar and these developments have continued apace with specific 3D Printers hitting the market. Some other early experiments with food include the 3D Printing of meat at the cellular protein level.
Consumers: The holy grail of 3D printing vendors is consumer 3D Printing. Currently, consumer uptake is low due to the accessibility issues that exist with entry level 3D Printers. There is a headway being made in this direction by the larger 3D Printing companies such as 3D Systems and Makerbot. There are currently three main ways that the person on the street can with 3D Printing tech for consumer products.
In total, 3D Printing is going to change the way products are manufactured. 3D Printing doesn’t even contribute 1% of the overall manufacturing and has lot of scope for growth in days to come.