What is 3 Dimensional Printing?

3 Dimensional printing is the process of making three-dimensional solid objects from a digital model. 3 Dimensional Printing is a process under development at MIT for the rapid and flexible production of prototype parts, end-use parts, and tools directly from a CAD model. 3D printing is achieved using additive processes, where an object is created by laying down successive layers of material. 3D printing is different from traditional machining techniques as they mostly rely on the removal of material by drilling, cutting, etc.

3 Dimensional Printing provides a lot of flexibility. It can create parts of any geometry, and out of any material, including ceramics, metals, polymers, and composites. Furthermore, it can exercise local control over the material composition, microstructure, and surface texture.

3 Dimensional printing is usually performed by a materials printer using digital technology. Since the start of the twenty-first century, there has been a large growth in the sales of these machines, and their price dropped substantially.

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The technology is used in the fields of jewelry, footwear, architecture, engineering and construction (AEC), dental and medical industries, education, geographic information systems, civil engineering, and many others. It’s often used as a specialized manufacturing process as well as for concept modeling. Among the items manufactured using the process are false teeth, filters of various types, and casting patterns.

Basic Principal of 3 Dimensional Printing

The basic principle for using 3D printing is that it takes virtual designs from computer-aided design (CAD) or animation modeling software, transforms them into thin, virtual, horizontal cross-sections, and then creates successive layers until the model is complete. It is a WYSIWYG ( i.e what you say is what you get) process where the virtual model and the physical model are almost identical.

With additive manufacturing, the machine reads in data from a CAD drawing and lays down successive layers of liquid, powder, or sheet material, and in this way builds up the model from a series of cross-sections. These layers, which correspond to the virtual cross-section from the CAD model, are joined together or fused automatically to create the final shape. The primary advantage of additive fabrication is its ability to create almost any shape or geometric feature.

Three Dimensional Printing functions by building parts in layers. From a computer (CAD) model of the desired part, a slicing algorithm draws detailed information for every layer. Each layer begins with a thin distribution of powder spread over the surface of a powder bed. Using a technology similar to ink-jet printing, a binder material selectively joins particles where the object is to be formed. A piston that supports the powder bed and the part-in-progress lowers so that the next powder layer can be spread and selectively joined. This layer-by-layer process repeats until the part is completed. Following a heat treatment, the unbound powder is removed, leaving the fabricated part. The sequence of operations is depicted below.

3 Dimensional Printing Process Method

This 3 Dimensional printing method is very reminiscent of laser sintering, except that the laser is replaced by an inkjet head. The multi-channel jetting head (A) deposits a liquid adhesive compound onto the top layer of a bed of powder object material (B). The particles of the powder become bonded in the areas where the adhesive is deposited.

Once a layer is completed the piston (C) moves down by the thickness of a layer. As in laser sintering, the powder supply system (E) is similar in function to the build cylinder In this case the piston moves upward incrementally to supply powder for the process and the roller (D) spreads and compresses the powder on the top of the build cylinder. The process is repeated until the entire object is completed within the powder bed.

After completion, the object is elevated and the extra powder is brushed away leaving a “green” object. Parts must usually be infiltrated with a hardener before they can be handled without much risk of damage. No external supports are required during fabrication since the powder bed supports overhangs.

 A color-capable system was introduced in 2000 and greatly improved technology in 2004 with the introduction of a 24-bit color system. At present, 3D Systems offers an entry-level system based on 3DP technology for US$14,900.

Advantages:

• Speedy fabrication and low materials cost.
• Overall, it’s the fastest of all additive methods.
• It is also the only technology for which full-color output is available.
• This makes it an excellent choice for industrial design, scientific visualization, and architectural modeling applications.