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 smoothes 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 as it is necessary to maintain a precise temperature during the process specific to the melting point of the powdered material of choice.
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 with SL or DLP, although generally the surface finish and accuracy is not as good. The most popular name for the process is Fused Deposition Modelling FDM , due to its longevity, however this is a trade name, registered by Stratasys, the company that originally developed it.
However, the proliferation of entry-level 3D printers that have emerged since largely utilize a similar process, generally referred to as Freeform Fabrication FFF , but in a more basic form due to patents still held by Stratasys.
The earliest RepRap machines and all subsequent evolutions — open source and commercial — employ extrusion methodology. 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. Stratasys has developed a range of proprietary industrial grade materials for its FDM process that are suitable for some production applications. At the entry-level end of the market, materials are more limited, but the range is growing. For FDM, this entails a second, water-soluble material, which allows support structures to be relatively easily washed away, once the print is complete.
Alternatively, breakaway support materials are also possible, which can be removed by manually snapping them off the part. Support structures, or lack thereof, have generally been a limitation of the entry level FFF 3D printers. However, as the systems have evolved and improved to incorporate dual extrusion heads, it has become less of an issue.
At the entry-level, as would be expected, the FFF process produces much less accurate models, but things are constantly improving. The process can be slow for some part geometries and layer-to-layer adhesion can be a problem, resulting in parts that are not watertight. Again, post-processing using Acetone can resolve these issues. As is the case with other powder bed systems, once a layer is completed, the powder bed drops incrementally and a roller or blade smoothes 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.
Advantages of this process, like with SLS, include the fact that the need for supports is negated because the powder bed itself provides this functionality. Furthermore, a range of different materials can be used, including ceramics and food.
A further distinctive advantage of the process is the ability to easily add a full colour palette which can be added to the binder. The parts resulting directly from the machine, however, are not as strong as with the sintering process and require post-processing to ensure durability.
Material jetting: a 3D printing process whereby the actual build materials in liquid or molten state are selectively jetted through multiple jet heads with others simultaneously jetting support materials. However, the materials tend to be liquid photopolymers, which are cured with a pass of UV light as each layer is deposited.
The nature of this product allows for the simultaneous deposition of a range of materials, which means that 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 a very smooth finish.
However, that is where any similarity ends. The 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.
After a new sheet of paper is fed into the 3D printer from the paper feed mechanism and placed on top of the selectively applied adhesive on the previous layer, the build plate is moved up to a heat plate and pressure is applied. This pressure ensures a positive bond between the two sheets of paper. The build plate then returns to the build height where an adjustable Tungsten carbide blade cuts one sheet of paper at a time, tracing the object outline to create the edges of the part.
When this cutting sequence is complete, the 3D printer deposits the next layer of adhesive and so on until the part is complete. And because the parts are standard paper, which require no post-processing, they are wholly safe and eco-friendly.
Where the process is not able to compete favourably with other 3D printing processes is in the production of complex geometries and the build size is limited to the size of the feedstock. The key difference is the heat source, which, as the name suggests is an electron beam, rather than a laser, which necessitates that the procedure is carried out under vacuum conditions.
EBM has the capability of creating fully-dense parts in a variety of metal alloys, even to medical grade, and as a result the technique has been particularly successful for a range of production applications in the medical industry, particularly for implants. However, other hi-tech sectors such as aerospace and automotive have also looked to EBM technology for manufacturing fulfillment.
The materials available for 3D printing have come a long way since the early days of the technology. There is now a wide variety of different material types, that are supplied in different states powder, filament, pellets, granules, resin etc.
Specific materials are now generally developed for specific platforms performing dedicated applications an example would be the dental sector with material properties that more precisely suit the application. However, there are now way too many proprietary materials from the many different 3D printer vendors to cover them all here.
Instead, this article will look at the most popular types of material in a more generic way. And also a couple of materials that stand out. 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 colour but it can be coloured — pre- or post printing. This material can also be combined in powder format with powdered aluminium to produce another common 3D printing material for sintering — Alumide. It is a particularly strong plastic and comes in a wide range of colours. ABS can be bought in filament form from a number of non-propreitary sources, which is another reason why it is so popular. PLA is a bio-degradable plastic material that has gained traction with 3D printing for this very reason.
It is offered in a variety of colours, including transparent, which has proven to be a useful option for some applications of 3D printing. However it is not as durable or as flexible as ABS. LayWood is a specially developed 3D printing material for entry-level extrusion 3D printers.
A growing number of metals and metal composites are used for industrial grade 3D printing. Two of the most common are aluminium and cobalt derivatives. It is naturally silver, but can be plated with other materials to give a gold or bronze effect. In the last couple of years Gold and Silver have been added to the range of metal materials that can be 3D printed directly, with obvious applications across the jewellery sector. These are both very strong materials and are processed in powder form.
Titanium is one of the strongest possible metal materials and has been used for 3D printing industrial applications for some time. Ceramics are a relatively new group of materials that can be used for 3D printing with various levels of success. The particular 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 — namely firing and glazing.
The company operates a notably different business model to other 3D printing vendors, whereby the capital outlay for the machine is in the mid-range, but the emphasis is very much on an easily obtainable, cost-effective material supply, that can be bought locally. There is a huge amount of research being conducted into the potential of 3D printing bio materials for a host of medical and other applications.
Living tissue is being investigated at a number of leading institutions with a view to 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 — meat being the prime example.
Experiments with extruders for 3D printing food substances has increased dramatically over the last couple of years. Chocolate is the most common and desirable. There are also printers that work with sugar and some experiments with pasta and meat. Looking to the future, research is being undertaken, to utilize 3D printing technology to produce finely balanced whole meals. And finally, one company that does have a unique proprietary material offering is Stratasys, with its digital materials for the Objet Connex 3D printing platform.
This offering means that standard Objet 3D printing materials can be combined during the printing process — in various and specified concentrations — to form new materials with the required properties. Up to different Digital Materials can be realized from combining the existing primary materials in different ways.
The customisation 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 — something similar to how Amazon operates its business. Shipping spare parts and products from one part of the world to the other could potentially become obsolete, as the spare parts might possibly be 3D printed on site. This could have a major impact on how businesses large and small, the military and consumers operate and interact on a global scale in the future.
The ultimate aim for many is for consumers to operate their own 3D printer at home, or within their community, whereby digital designs of any customizable product are available for download via the internet, and can be sent to the printer, which is loaded with the correct material s.
Currently, there is some debate about whether this will ever come to pass, and even more rigorous debate about the time frame in which it may occur. The wider adoption of 3D printing would likely cause re-invention of a number of already invented products, and, of course, an even bigger number of completely new products.
After all, the notion of doing your supermarket shopping on an iPad was like something out of Star Trek 20 years ago. But, like so many household technologies, the prices will come down and 3D printer capabilities will improve over time. Like all new technologies, the industry hype is a few years ahead of the consumer reality. Join thought-provoking conversations, follow other Independent readers and see their replies.
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Already subscribed? Log in. There are also different types of 3D printing depending on the size, detail and scope of a project. Each different type of printer will vary slightly on how an object gets printed. Here are a few cool examples of how 3D printing is changing the future:. In fact, if it can be pureed, it can be safely printed. Like something out of a sci-fi show, 3D printers layer on real pureed ingredients, like chicken and carrots, in order to recreate the foods we know and love.
You might want to order your meal ahead though. For example, a detailed piece of chocolate takes about minutes to print. Nonprofits and cities all over the world are turning to 3D printing to solve the global homeless crisis. New Story , a nonprofit dedicated to creating better living conditions, is actually printing homes right now. Using a foot long printer, New Story is able to churn out a square-foot home , complete with walls, windows and two bedrooms in just 24 hours.
Instead of the traditional organ donation process, doctors and engineers are teaming up to develop the next wave of medical technology that can create hearts, kidneys and livers from scratch. This breakthrough technology has the ability to change the medical industry as we know it and reduce the drastically high number of patients on the organ donation waitlist in the US. Perhaps most impressively, 3D printing technology has even fast-tracked production and durability of prosthetics while reducing costs, like how GE Additive has produced over 10, hip replacements through 3D printing from through Will the future of space travel rely on 3D-printed rockets?
Companies, like Relativity Space in California, think so. The company claims that it can 3D print a working rocket in just a few days and with one hundred times fewer parts than a normal shuttle. The rocket will be custom-printed using a proprietary alloy metal that maximizes payload capacity and minimizes assembly time.
The total payload capacity for this rocket reaches 1,kg about the weight of an average Rhinoceros. Not bad for something that came out of a printer. Not only are 3D printed materials easier to manufacture quickly and at lower costs but 3D printing also provides a way to reduce the total number of parts that need to be welded together while also significantly reducing weight and increasing strength.
Spare parts, tools, jigs and fixtures can all be produced on an as-needed basis while providing flexibility that would have been unimaginable to previous generations.
Additionally, 3D printing provides a way for automotive enthusiasts to customize their vehicles or restore old cars with parts that are no longer in production. Automotive repair shops can even utilize 3D printing when faced with unusual repair requests. Consumer products, without a digital or electronic build quality, such as footwear, eyewear, jewelry and more, can all be mass-produced through 3D printing.
While various other products can have their body or frame manufactured through 3D printing, any item that can be produced within a mold can also be produced through 3D printing.
What Is 3D Printing? How Does It Work? The U. Is Desperate for Ventilators and N95 Masks.
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