 |
 |
 |
 |
 |
 |
| Gilbert Riedelbauch Australian National University, School of Art, Australia Craft and new technologies, implications for practice: A match made in heaven |
The FDM process by Stratasys [7] has a build-head mounted on a mechanical stage able to move in the x and y dimensions to draw the cross-sections on a base. This build-head is equipped with two heated nozzles, one for the build-material and a second one for the support-material. While it is drawing the cross-sections, it extrudes a thin wire of melted ABS plastic. The base is then lowered to make room for the next build layer. The plastic hardens immediately after being deposited from the nozzle and fuses to the layer below. Support structures must be designed and fabricated for any overhanging geometries and are later removed during post processing. FDM seems to be the most practical Rapid Prototyping solution for an educational set-up as it is office friendly and quiet, it can be installed without an air extraction system or a separate break-out room to handle messy materials like resin or fine powder. It only needs mains power and spools of plastic wire. 2.2 About process and control Michael Rees, a sculptor in Kansas City, Missouri and a long-time user of Rapid Prototyping technologies, writes on his web-site [8]: 'Wysiwyg [What you see is what you get] also means that the facet structure of a model on the computer screen will show up identically in the model.' This statement is somewhat misleading as it omits the fact that every output device will leave its marks, traces of the process, on the produced part. Inherent to RP technologies is stair-stepping, these real surface features are artefacts created by the build process. These marks will not be visible during the design stage on a CAD program nor 'touchable' through a haptic device like the Phantom Haptic Device . To successfully apply these process features one needs to understand the interaction of software and hardware and the build process as well as being in control of every aspect of it. It is this knowledge of the process or its limitations, which could be used in a creative way by the maker. This process of Computer Aided Design and Computer Aided Manufacturing involves several levels of software and hardware. There is on one side the CAD software, running on hardware which in turn needs its own operating system. On the other side a different software is necessary to prepare the CAD data, the virtual model, to be processed by the next piece of hardware, the Rapid Prototyping machine, which then builds the part. Both have a host of settings and preferences to fine-tune their behaviour and influence the outcome of the built object. One could add to this line-up the controlling software for an input device (hardware) like the Phantom Haptic Device or the software to 'clean' the stl-file before it is passed-on to the RP software and finally there are the dials on the RP equipment itself. The usual aim is to achieve a built part as close as possible to the simulated CAD model. As a result the process inherent marks are kept to a minimum by optimising the built set-up. This relates well to the needs of engineers but suppresses creative possibilities with the potential for truly unique work. During my research, I noticed that the most important element to create successful work was my access to the all levels controls of this technology. The access to these controls is typically limited by the separation of the design from the making, a foreign concept to craft practitioners. Once a model has been created using a CAD software, the stl - file is then sent-on to be build by a bureau or in a research lab, which will be managing these expensive production technologies. During the next step the stl - file is prepared by a technician for the build process. That's the moment when crucial decisions could be made by the maker to influence the outcome of resulting object.
|
|
 |
|
| ChallengingCraft...Guest Speakers...Index of Papers...Sponsors...Contact | |
