Lets get physical: how 3D printing works
Forget Express Post: in the not too distant future you may be able to send a small gift to your grandchild by emailing her a 3D data file then having her manufacture it on the spot using a 3D printer in her lounge room. Give it a few minutes and shell have a physical toy to pick up and play with.
It may sound just a few steps short of teleportation but its already becoming a reality as highly-specialised fabrication equipment leverages new economies of scale to be delivered into the home.
Thats a big step from the design firms doctors scientists engineers and others who work with physical objects who have long tapped into 3D printing technology also known as additive manufacturing to build physical objects using blueprints produced by a 3D design program. Working one microscopically thin cross-section at a time the printer builds up the model using one of a variety of techniques that ultimately produce a high-resolution physical model that can be touched painted manipulated or whatever else is required.
3D printers have been around since the early 1990s but its only within the last five years that the technologies to make it happen have become sufficiently commoditised to allow businesses to purchase bespoke systems for on-the-spot manufacturing. Vendors like 3DSystems Objet Geometries Stratasys and Z-corp for example all offer industrial-sized systems with five and six-digit pricetags.
One 3D printing technique selective laser sintering (SLS) directs a powerful laser at a thin layer of powdered medium typically plastic metal ceramic or glass thats spread in a thin layer on a flat bed. The heat from the laser melts the medium in a precise pattern that is controlled by the computer-aided design (CAD) system and represents a cross-section of the item to be manufactured; the bed is then lowered by a miniscule amount and the process repeated.
Because fused layers are surrounded by unfused medium manufactured products dont have to be self-supporting and can include discontinuous elements for example an action figure with an arm pointing downward which when built from the ground up would require the hand to be effectively floating in space until the device reached the layer where the arm met the body.
Accomplishing this using other techniques requires a different approach. For example Stratasys developed a 3D printing technique that uses fused deposition modelling (FDM) techniques to extrude a plastic or wax compound (polymer polycarbonate acrylonitrile butadiene or other materials) from a fine nozzle thats guided by a computer around a table along two axes. Because the system works on a purely cross-section basis even machines with moving parts can be manufactured.
Layers as thin as 0.125mm are laid down with a complementary water-soluble material available to build up supports for floating elements of the model; this material can then be dissolved by agitating the model within a heated sodium hydroxide bath. That makes it easier than stereolithography another approach which uses a stereolithography apparatus (SLA) to build its 3D models.
SLA uses a vat of liquid photopolymer that goes hard when exposed to intense ultraviolet (UV) light. A UV laser is used to trace each cross-section of the design then the layer is swiped with a blade that re-coats it with new liquid and the process is repeated. Floating elements must be structurally strengthened using manufactured supports which are manually removed after the model is complete.
A spinoff of SLA uses a digital light processor (DLP) projector to project an image of each cross-section onto the surface of a liquid photopolymer bath. Exemplified in 3D printers like Z Corporations ZBuilder each burst of DLP light lasts for several seconds then the model is moved down by around 0.2mm and a new layer printed. This technique is faster than SLA which has become a high-volume workhorse but is still expensive: machines can cost more than half a million dollars and the polymer resin costs up to $200 per litre.
Because of its precision and the hardness of the models it produces 3D printing has become a favoured way of prototyping new products without going to the expense of setting up full manufacturing lines. Its particularly popular in short-run manufacturing since products that are printed using any of these processes are the same price whether one unit is printed or 100. Its also possible to make many small objects at once by designing plans that have more than one object side by side.
Ever-smarter 3D design software has facilitated the process. For example software innovations allow a model to be analysed and necessary support structures automatically generated to ensure the model can be built using the current technology.
Paired with a 3D object scanner its possible to quickly scan a physical object in three dimensions then adjust it however you want in three dimensions or not at all and make a 3D replica in a relatively short time. This opens up immense possibilities for small manufacturing organisations that used to send out designs and wait days for models to be manufactured and its spurring imaginations in new directions as artists start designing interesting new shapes that would be all but impossible to make using other techniques.
Galleries at sites likethisandthisshow some of the artistic creations to emerge as artists get their collective hands on 3D printing technology. Finnish 3D printed design specialistFreedom of Creationfor one envisions 3D printing as a way of helping stores reduce inventory by producing clothes on demand that would fit perfectly and be produced as theyre required. Others envision using a sugar-based substrate for the printing process which would allow the printing of edible delicacies or other foods in fantastic designs.
Its a dramatic change to the way things are manufactured and its getting easier as the concept hits the mainstream. Vendors are pushing down the price of basic systems with 3DSystems desktopV-Flash Personal3D printer kit-based RapMan and BfB 3000 offering personal 3D printing at manageable prices. Grassroots efforts also flourish with Bath University-originated providing free software and plans for several build-your-own models that can be made for around $475 and can even be used to make new RepRap machines for your friends.
RepRap spinoffMakerBot Industriesoffers a 3D printer kit capable of producing products up to 10 x 10 x 13cm and this year secured US$10 million in venture-capital funding. And rs plans and software for an inexpensive home 3D printer that its inventors say can manufacture objects out of silicone cement stainless steel cake frosting and cheese.
For those who arent of the build-your-own inclination 3D printing bureaux like Ponoko PrintTo3D RapidArch Sculpteo and Shapeways or Australian firms including Prototype Labs ThingLab Australia and CnCProtos will fabricate them on your behalf based on 3D models that you email to them. All you need is a file in the .STL format which was developed in the late 1980s by 3D Systems and delineates every vertex of the object in a standard albeit bulky format. Other 3D printing setups accept .OBJ files of the type generated by tools like Maya and free applications like TopMod and Googles SketchUp!
Put it all together and youve got the ability to design and manufacture just about anything you can imagine. 3D printing is still a niche area but with more DIY options than ever its within the reach of determined enthusiasts. Its still easier to buy that gift from a shop and mail it but the rapid pace of development means soon youll be able to download your design customise it and send that personalised gift to your loved one.
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