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INTRODUCTION
This brief document will consider the applications and usefulness of three-dimensional printing (3DP) technologies for metal artists. The term 3DMP only denotes the process is dedicated to metal printing. But all 3DP processes are inter related. Currently, most of these processes are now readily accessible and affordable for anyone willing and able to produce the required digital software models. These emerging technologies allow for the production of remarkably complex geometries. In some cases 3DMP allows the designer to produce forms that would be impossible, or nearly so, by any other means. The cost for producing metal objects via 3DMP is now often competitive with traditional casting and foundry services. These methods allow multiple parts or single prototypes, to be produced directly in a wide variety of mediums including: plastics, metals, ceramics and glass. All of which present new possibilities for the rapid production of almost any part shape. The capabilities of these technologies are constantly improving, to the point that sometime in the near future it will likely become a rather common mode of creativity.
Basic Skill Sets:
New computer based skill sets are required to exploit the possibilities allowed by 3DP. The nomenclature for these new tools and skill sets is rather mind boggling at times. So I will attempt to reduce the information in this document to the very basics. Separate supplementary pages are included in this document describing different software tools and the resources associated with getting involved with 3DP.
In order to produce a real world, three-dimensional print, a three-dimensional digital model must first be created. A 3d digital model is not simply a drawing representing a shape. It is a virtual reality model with all dimensional and volumetric proportions of an object precisely stored within a computer file. Typical drawing and paint type software is not capable of producing true 3dmodels! The universal language of all 3d printing (hardware) systems requires that a Stereo Lithography file be created. This file format is referred to as an .STL file. In some cases existing objects maybe laser scanned to produce the required .STL file, but this process is by no means simple, direct or fool proof. To fully control the outcome of computer generated models most artists will prefer to use software packages tailored to the purpose. There are two basic types of software used to create three-dimensional digital models. The first types are referred to as solid modelers.
Solid modelers use a vector point system to represent forms and surfaces. By manipulating and joining lines, arcs, and curves in the virtual reality of a computer highly accurate geometries may be built that precisely represent all the dimensions and volumes of a real object. This software type excels where close tolerances and hard-edged geometries are desired. These modeling functions are included in many, but not all, CAD software packages. The second basic software types are referred to as mesh modelers. Mesh modelers approximate and represent surfaces through the use of polygonal geometry. Complex organic forms are most easily created by using mesh modelers. But at the cost of some precision and accuracy. It is not uncommon for some artists to use both types of software on a single project. The learning curve for mastering these new tools is undeniably steep. But 3DP technologies can be used to produce forms that would be impossible, or nearly so, by any other means.
New Modes of Commerce:
New modes of creative commerce have coincided with the expanding interest in 3DP. Several on-line companies now bring 3d print services to the general public at costs that were formerly impossible only a few years ago. Some of these companies now function beyond that of simple service bureaus. Web forums and on-line storefronts managed by 3d printing companies such as Shapeways and I.Materialise allow artists and designers access to an international marketplace. After the point of uploading a design file the service provider manages the entire transaction, manufacturing, sales and distribution. In effect, this business model allows the artist /designer the freedom to create without the more traditional duties of an entrepreneur.
It should be noted that not all artists would find themselves comfortable with learning or using software modeling tools. But, the possibility for hiring a specialist to perform these tasks is in itself becoming a new form of industry. Much like hiring the services of a draftsman. Inversely, training in these high-level computer skills at colleges and universities is increasingly more common now. Revenue streams await anyone with the skills to create 3d models to client standards. As mentioned above, on-line 3DP companies allow and encourage the posting of wants and needs related to 3d modeling. Brave new world indeed.
The Basic 3-d Print Process
The original concept and development of this technology began at The Massachusetts Institute of Technology in Cambridge Ma, U.S.A. Several different modes of operation and technical capabilities employing this technology are offered by commercial companies today.
The three dimensional printing systems have remarkable flexibility. This additive, free form fabrication process can build parts of almost any geometry. Designs including undercuts, overhangs and internal cavities are possible. It can create these forms from almost any powdered material, including plastics, glass, ceramics, and metals. Using a technology similar to ink-jet printing, specialized print heads function to selectively apply liquid binders to sequentially added layers of powdered media. Literally building a design object from the ground up, one thin layer at a time.
To accomplish the build process a computer (CAD) model is first subjected to a slicing algorithm. This converts the computer model into a detailed series of vertically stacked layers. The machine process begins when a hopper like mechanism, known as a re-coater spreads a thin layer (.004”-.1mm) of powdered media onto a vertically indexed/movable platform, known as the build table. Four fixed, vertical walls surround this table. This assembly is known as the build box and it serves to constrain the successive build up of the powder media. These layers of powder make up the powder bed. As parts are being formed the powder bed itself completely supports the part-in-progress so no secondary materials or added scaffolding are required A mechanical piston attached to the table allows the powder bed, and the emerging part, to move downward, so that after each pass of the print head, the table descends one increment and the re-coater spreads a fresh layer of powdered media on top. This layer-on-layer process repeats until the part design is completed. When the build process is finished the build box is now completely filled with un-bound in which nestles the newly formed 3d part.
The build box is now carefully drained of excess powder (which may be recycled). In the case of glass, ceramic or metal parts, the emerging green parts will now be subjected to a thermal sintering process to burn off the binders and consolidate the part into a near finished state.
To see a video from “How it’s Made” go to: http://www.youtube.com/watch?v=20R9nItDmPY
3DP RESOURCES
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