Shedding Light on Solid Imaging Technology

How can various lighting concepts be combined in a single lamp without overtaxing its design? The question provided the impetus for considerations made by designers Uwe Fischer and Johannes Fuchs. The result is "JONES," an upright lamp that performs three functions in one unit—it is a reading lamp, ceiling flood, and subdued room light all at the same time.

These different functions are not externally visible at first glance. The "JONES" upright lamp is appealing thanks to its simple design. Behind this outward appearance there is sophisticated technology with a high degree of functionality. The basic idea on which the lamp concept is based is a so-called "mother-child lamp." However, in this case a single lampshade is intended to serve several purposes simultaneously. Since the light source for the reading lamp and the room lamp are each at different heights, the only way to achieve this goal was with a block and tackle system.

Creating a Working Model
This technology, however, calls for highly complex components for holding the cable inside the tube that covers the square lamp stand. "Here, we chose 3D Systems’ solid imaging technology," says Jean-Marc da Costa, industrial designer at SERIEN RAUMLEUCHTEN in Rodgau, Germany. "This way we were able to test whether our design worked. An advantage of stereolithography was also the fact that the time and cost involved in a working model were saved, as well as the fact that we were closer to series production with this technology." Fifteen copies of the "JONES" lamp needed to be produced for its first public showing.

Although it sounds easy at first, it calls for technology that is extremely precise—and 3D
Systems’ SLA machine was ideal for this requirement. A total of four injection molds for four different functions needed to be produced for the mechanism to hold the cable inside the tube. The two middle plastic pieces on the tube covering are for precisely guiding the block and tackle along the square tube. "It is important that no friction is caused here," explains da Costa. To compensate for possible dimensional tolerances on the square tubing, the plastic parts were provided with flexible tabs that can be easily produced with stereolithography technology. In addition, they have to hold the blocks for diverting the cable and, therefore, need corresponding recesses. Here too, 3D Systems’ technology proved to be ideal, as stereolithography was able to easily produce the hollow spaces required in the models.

"3D Systems offered us the corresponding technology for making the plastic parts as prototypes and to check them for dimensional and functional suitability."
                                                                    Jean-Marc da Costa,
                                                                    Serien Raumleuchten

The two external injection molded parts are rigidly affixed to the tube and close it off without externally visible screwed connections. In addition, the top injection molded part must guide and hold the metal bracket of the lampshade. To this end, the part was provided with an additional back-cut tab that clicks into the recess in the metal bracket fixture. Thus, the plastic part also prevents torsion. "Such highly complex and precise components require an enormous amount of effort using conventional model building techniques," says da Costa. "Construction using a milling machine would have impaired the functioning of the parts. However, the geometry of the components needs to be authentic because they are so complex, and the component material needs to be matched to the various functions.

Stereolithography allows extremely precise simulation of the injection molded plastic parts envisioned for series production." In order to produce the stereolithography models, the components are first drawn in a CAD program. In the subsequent stereolithography process, a laser beam hardens liquid epoxy plastic and forms the components layer by layer.

Mission Accomplished
"3D Systems offered us the corresponding technology for making the plastic parts as prototypes and to check them for dimensional and functional suitability," says da Costa. Since the "JONES" upright lamp is expected to be available to retail customers by the end of this year, it was presented to the public for the first time at the International Furniture Fair in Cologne, Germany in January 1999. A total of 15 such lamps were presented at the fair.

"Without stereolithography for the production of the prototypes, it would scarcely have been possible given the time we had," according to da Costa. He states that the time and costs were reduced to roughly one-fourth to one-fifth what they would have been using traditional methods.