3D PRINTING

3D PRINTING

ABSTRACTThree-dimensional printing, also known as additive manufacturing, is the process of using additives to form solid 3D objects of virtually any shape from a digital model. This is achieved using specially formulated additives, such as plastics, that are formed into successive layers of material typically laid down on a platform in different shapes. The first published account of a printed solid model was made by Hideo Kodama of Nagoya Municipal Industrial Research Institute in 1982. The first working 3D printer was created in 1984 by Charles W. Hull of 3D Systems Corp. Of course, 3D printing in the early days was very expensive and not feasible for the general market. As we moved into the 21st century, however, costs drastically dropped, allowing 3D printers to find their way to a more affordable market. With the introduction of 3D printing technology, you can go for a mass production. You can increase the production with less capital as they will be controlled by the same controller. Medical science is also taking the help of this technique. According to these futurists, 3-D printing will make life as we know it today barely recognizable in 50 to 75 years. "Realistically, we're going to be living to 100 -110. With bio-printed organs, living to 110 won't be anything like living to that age today," contends Jack Uldrich, a technology trend expert. "We're already printing skin, kidneys, a replica of a beating human heart. If a person loses a limb, we'll be able to print, layer by layer, a replacement. It's theoretically possible."There are many companies that offer 3D services to consumers. They need to upload their design in the website and your design will be ready within a few hours. Just imagine you can print a solid object from a device connected to the computer. It sounds like a world of star trek.

1.Introduction to 3D Printing

As every designer knows, theres magic in transforming a great idea into a tangible and useful object you can hold in your hand. It can be a consumer good on a store shelf, a critical component of an industrial machine, or even an early physical prototype that unveils your new idea to the world.

Physical prototypes basic and blocky or wonderfully realized in shape, texture and color go far beyond drawings or computer models to communicate your vision in a dramatic way. They empower the observer to investigate the product and interact with it rather than simply guess what it might be like. Before the product is ever produced, people can touch it; feel it; turn it left, right and upside down; and look inside. They can test it, operate it and fully evaluate it long before the finished product is brought to market.

Until recently, a quick and affordable physical prototype has been an oxymoron. Obtaining prototypes wasnt quick. It meant contracting with a fabricator who handcrafted them or used a complicated stereo lithography machine. In either case, it took weeks, and it wasnt affordable. You were billed thousands of dollars for your trouble.

And who needs just one prototype? Successful product developers revise a design repeatedly until they approach their ideal. Physical prototypes available on demand in sample quantities accelerate the design process, and more quickly send a better product to market.

This ideal is in fact a reality for some of the worlds most accomplished and demanding designers and engineers. Available within a couple of hours of hitting print on a quiet, clean and sleek machine in an everyday office setting, on-demand prototypes today help engineering organizations: improve communication within the product development organization; shorten design cycles put superior products on the market ahead of the competition stretch R&D dollars improve accuracy eliminate costly mistakes trigger unexpected ideas drive innovation and quality Improve collaboration among engineering, sales, marketing and the executive team. This paper will cover the inception and evolution of 3D printing; then explore in depth how a 3D printer produces a physical model; and finally, examine the defining attributes of a 3D printer and the technology decisions that produced them.

1.1 What is 3D PRINTER?

3D printing or additive manufacturing (AM) is any of various processes for making a three-dimensional object of almost any shape from a 3D model or other electronic data source primarily through additive processes in which successive layers of material are laid down under computer control3D Printers are machines that produce physical 3D models from digital data by printing layer by layer. It can make physical models of objects either designed with a CAD program or scanned with a 3D Scanner. It is used in a variety of industries including jewelry, footwear, industrial design, architecture, engineering and construction, automotive, aerospace, dental and medical industries, education and consumer products.

2. History of 3d Printing

The technology for printing physical 3D objects from digital data was first developed by Charles Hull in 1984. He named the technique as Stereo lithography and obtained a patent for the technique in 1986.

While Stereo lithography systems had become popular by the end of 1980s, other similar technologies such as Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS) were introduced. In 1993, Massachusetts Institute of Technology (MIT) patented another technology, named "3 Dimensional Printing techniques", which is similar to the inkjet technology used in 2D Printers.

In 1996, three major products, "Genisys" from Stratasys, "Actua 2100" from 3D Systems and "Z402" from Z Corporation were introduced. In 2005, Z Corp. launched a breakthrough product, named Spectrum Z510, which was the first high definition color 3D Printer in the market. Another breakthrough in 3D Printing occurred in 2006 with the initiation of an open source project, named Reprap, which was aimed at developing a self-replicating 3D printer.

3. Current 3D Printing Technologies

3.1 Stereo lithography

Stereo lithographic 3D printers (known as SLAs or stereo lithography apparatus) position a perforated platform just below the surface of a vat of liquid photo curable polymer. A UV laser beam then traces the first slice of an object on the surface of this liquid, causing a very thin layer of photopolymer to harden. The perforated platform is then lowered very slightly and another slice is traced out and hardened by the laser. Another slice is then created, and then another, until a complete object has been printed and can be removed from the vat of photopolymer, drained of excess liquid, and cured. Fused deposition modeling - Here a hot thermoplastic is extruded from a temperature-controlled print head to produce fairly robust objects to a high degree of accuracy.

3.2 Selective laser sintering (SLS)

This builds objects by using a laser to selectively fuse together successive layers of a cocktail of powdered wax, ceramic, metal, nylon or one of a range of other materials.

3.3 Multi-jet modeling (MJM)This again builds up objects from successive layers of powder, with an inkjet-like print head used to spray on a binder solution that glues only the required granules together. The V-Flash printer, manufactured by Canon, is low-cost 3D printer. Its known to build layers with a light-curable film. Unlike other printers, the VFlash builds its parts from the top down. Desktop Factory is a startup launched by the Idea lab incubator in Pasadena, California.3.4 Fab@homeIt is an experimental project based at Cornell University, uses a syringe to deposit material in a manner similar to FDM. The Inexpensive syringe makes it easy to experiment with different materials from glues to cake frosting.

3.5 Inkjet 3D printingIt creates the model one layer at a time by spreading a layer of powder (plaster, orresins) and inkjet printing binder in the cross-section of the part. It is the most widely used 3-D Printing technology these days and the reasons beyond that are stated below.This technology is the only one that Allows for the printing of full color prototypes. Unlikestereo lithography, inkjet 3D printing is optimized for speed, low cost, and ease-of-use. No toxic chemicals like those used in stereo lithography are required. Minimal post printing finish work is needed; one needs only to use the printer itself to blow off surrounding powder after the printing process.

4. MANUFACTURING A MODEL WITH THE 3D PRINTER

To set up this new process, two steps are necessary: the amount of the printed material must be reduced to a minimum, and the dosed material mustnt be a part of the desired object.

This will be achieved by separation of the process in information transfer and material deposition. The minimum information to create the cross section of an object is the boundary line. This outline will be printed by means of a droplet generator. Thus a thin shell of the model will be formed. For example, the shell material could be a release wax with a high melting point. In the next step the layer is filled with building material by a rapid application. This material could be also wax with a lower melting point or a fast curing resin etc.

Figure shows the new printing method for making a three-dimensional body:

1 2 3

4 5 6

Figure 4: 3D Printing Process

The repeated steps are:

1) Lowering the platform according to the layer thickness.

2) Applying a release wax in its liquid state onto selected areas of a building platform by a multi-jet printhead, using a pattern according to the cross-section of a thin-walled shell around the three-dimensional body, and a grid pattern (not shown in Figure 1) across the remaining area of the building platform.

3) After finishing of the pattern of the current layer, the areas enclosed by the release wax are filled with the building wax.

4) Smoothing and planing of the layer in order to expose the upper surface of the release wax.

5) Ready for the next layer. Repetition of the steps 1) to 4) with patterns according to the current cross-section of the three-dimensional body, thereby making the body itself.

6) Removing the structures not belonging to the body by dissolving the release wax. 3D Printing

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5. WORK FLOW OF 3D PRINTING

The workflow can be easily understood with the help of the flowchart given below.A 3-D prototype of a desired object is created in three basic steps and these steps are: Pre-Process 3-D Printing Post-Process

FIGURE 5.1 Process of 3D Printing

5.1 CAD Preparation (Pre-Process):Computer-aided design(CAD), also known ascomputer-aided design and drafting (CADD), is used to prepare a 3-D or 2-D model of the desired object. Modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle.Most 3D printers require a special file (typically .stl format) to print. Additionally, we need to modify the design to make up for limitations of the printer and build material.

FIGURE 5.1 Pre-Process of 3D Printing

5.2 3D Printing:

The 3D printer runs automatically, depositing materials at layers ~.003 thick. This is roughly the thickness of a human hair or sheet of paper. The time it takes to print a given object depends primarily on the height of the design, but most designs take a minimum of several hours. The average cost for printing a full color prototype is somewhere between 50 - 100$.

FIGURE 5.2 Printing an Object

5.3 Cleaning 3D Printouts (Post-Process):

Every 3D printer uses some sort of material to support parts of the design that have an overhang. Some printers use a loose powder which can be blown off and reused in future models.

FIGURE 5.3 Post-Process of 3D Printing

5.3.1 Powder Removal:

This is the sculpture with most of the support dust removed and it is then dipped in special glue that makes them stronger and more colorful.

FIGURE 5.3.1 Powder Removal

5.3.2 Heating

The models are heated to set the glue. It is funny to see the oven in this picture is a standard consumer grade.

FIGURE 5.3.2 Heating

5.3.3 Finishing Touches

The output of all existing 3D printers isrough. The textures vary from pronounced wood grain to merely sandy, With a little elbow grease you can get stunning results.

FIGURE 5.3.3 Final Touch up

6. Benefits of 3D Printing

The most successful companies have adopted 3D printing as a critical part of the iterative design process to:

Increase Innovation Print prototypes in hours, obtain feedback, refine designs and repeat the cycle until designs are perfect.

Improve Communication Hold a full color, realistic 3D model in your hands to impart infinitely more information than a computer image. Create physical 3D models quickly, easily and affordably for a wide variety of applications.

Speed Time to Market Compress design cycles by 3D printing multiple prototypes on demand, right in your office.

Reduce Development Costs Cut traditional prototyping and tooling costs. Identify design errors earlier. Reduce travel to production facilities.

Win Business Bring realistic 3D models to prospective accounts, sponsors and focus groups

7. Applications

7.1 Design Prototypes:

3-Dimensional Printing concept model, functional prototypes and presentation models for evaluating and refining design, including Finite Element Analysis (FEA) results and packaging. Size: 3.5 x 2 x 0.7 inches (9 x 5 x 2 cm) Printing Time: 0.5 hoursNow, here we have created a dummy of a Nokia mobile phone for further study and demonstration:

FIGURE 7.1 Demo Model

7.2 Education:

Engage students by bringing digital concepts into the real world, turning their ideas into real-life 3D color models that they can actually hold in their hands.

Here an electronic device circuit has come to life with the help of a 3-D Printer:

Size: 8 x 5 x 2.5 inches (20 x 13 x 6 cm) Printing Time: 3 hours

FIGURE 7.2 an electronic device circuit Created by 3D Printer

7.3 Healthcare:

Rapidly produce 3D models to reduce operating time, enhance patient and physician communications, and improve patient outcomes.

A 3-D Prototype of the horizontal crossection of a human skull has been prepared to allow its better study:

Size: 9.8 x 7.9 x 3.9 inches (25 x 20 x 10 cm) Printing Time: 5.5 hours

FIGURE 7.2 3-D Prototype of a human skull

8. Conclusion

Nothing communicates ideas faster than a three-dimensional part or model. With a 3D printer you can bring CAD files and design ideas to life right from your desktop. Test form, fit and function and as many design variations as you like with functional parts. In an age in which the news, books, music, video and even our communities are all the subjects of digital dematerialization, the development and application of 3D printing reminds us that human beings have both a physical and a psychological need to keep at least one foot in the real world. 3D printing has a bright future, not least in rapid prototyping, but also in medicine the arts, and outer space. Desktop 3D printers for the home are already a reality if you are prepared to pay for one and/or build one yourself. 3D printers capable of outputting in color and multiple materials also exist and will continue to improve to a point where functional products will be able to be output. As devices that will provide a solid bridge between cyberspace and the physical world, and as an important manifestation of theSecond Digital Revolution, 3D printing is therefore likely to play some part in all of our futures.

9.REFRENCES

[1]en.wikipedia.org/wiki/3D_printing. [2]http://www.newscientist.com/article/mg21128236.100-3d-printing-the-technology- that-changes-everything.html[3] http://www.stratasys.com/3d-printers/design-series/dimension-1200es[4] http://replicatorinc.com/blog/2008/12/a-major-advance-in-3d-printing

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