Printing Luminaires: A Study of the Light Filtering Characteristics of 3-D Translucent Printing Materials


Presented by: William Riehm, Robin Carroll, and Lauren Black

Issue
3-D printing is advancing and becoming an integral part of interior design education due to reduced costs and availability of a wider range of printing materials (see Bull et al. 2010; Koltick 2014; Ransdell 2014 ). Makerbot Industries, a major manufacturer of desktop 3-D printers, recently introduced translucent printing materials. These cornstarch based filaments, polylactide (PLA), are now commercially available in a range of colors.

The questions posed in this presentation are, what are the characteristics of these translucent materials when used as a filter for artificial light, and what are the potential applications for these materials as part of a lighting design curriculum?

Method
Using a Makerbot Replicator2 3-D printer, 6”x6” panels of translucent natural, yellow, blue, and red where printed in thicknesses of 1/16” and 1/8”. These panels were placed over a sealed light box and readings for luminance (foot candles [FC]) and color temperature (kelvin[K]) were taken for each panel using a Cooke Corporation Cal-color 400 light meter placed one foot away. As a control, readings were also taken with no material in place.

Seven different lamps were used in the light box, two halogen (2800K and 3000K), three compact fluorescent (2700K, 3500K, and 6500K), and two LED (2700K and 5000K). Each lamp was a 100 watt incandescent equivalent. This range of lamps allowed for a comprehensive examination of the impacts the materials have on the quality of light (see Karlen, Benya, and Spangler 2012, 62-64).

Findings
All of the translucent materials reduced luminance.  Although the control, unfiltered, luminance of the lamps varied from 43FC to 86FC, the impact of the materials on luminance was proportional for each lamp. The color of the material, though, greatly affected luminance with the natural PLA reducing luminance an average of 46%, blue 56%, yellow 60%, and red a dramatic 92%. 

The compact fluorescent and halogen lamps had no noticeable variation in color temperature for natural, blue, and yellow within an average variation of 4%, 2%, and 8% of control respectively. (It should be noted that the reduction of luminance by the red material and the nature of the color temperature measurement scale led to unreliable or not applicable readings of color temperature for the red material (see Gordon 2003, 45).) In contrast, the LED lamps’ color temperature readings were noticeably impacted by the yellow material with an average warming by the yellow material of almost 1000K or 22%.

Application 
These data were incorporated into a pilot lighting design charrette assignment where an individual student designed a luminaire to utilize these translucent materials. The student’s response, a pendant luminaire, was modeled digitally using Rhinoceros 3-D software, and a series of scale prototypes were printed. Each was lit with a 1 watt 5000K LED type E12 (nightlight) lamp. These pendants capture the variation of the material; in red they hold and temper the light, while in blue and in yellow, the color temperature and clear luminance give individual character.

Implications 
This research reveals two important trends in lighting design and lighting curriculum, the role of rapid prototyping and exploration of materials in conjunction with design development as well as the impact of color temperature rendition by LED lamps. This research calls for a deeper examination of these materials, and perhaps with more academic investigation, printer and filament manufacturers might be called upon to develop materials specifically for lighting prototyping.

References:

  • Bull, Glen, Cleb Maddox, Gary Marks, Anita McAnear, Denise Schmidt, Lynne Schrum, Sharon Smaldino, Michael Spector, Debra Sprague, and Ann Thompson. 2010. "Educational Implications of the Digital Fabrication Revolution." Journal of Research on Technology in Education 42, no. 4: 331-38.
  • Gordon, Gary. 2003. Interior Lighting for Designers. Hoboken, NJ: John Wiley & Sons, Inc.
  • Karlen, Mark, James R. Benya, and Christina Spangler. 2012. Lighting Design Basics. Hoboken, NJ: John Wiley & Sons, Inc.
  • Koltick, Nicole. 2014. “Design-led Research: Work from the Design Futures Lab.” Abstract. In Interior Design Educators Council 2014 Annual Conference, coord. John C. Turpin, 743-50. New Orleans: IDEC.
  • Ransdell, Marlo. 2014. “Products OnDemand: What Can Rapid Prototyping offer Creative Thinking?” Abstract. In Interior Design Educators Council 2014 Annual Conference, coord. John C. Turpin, 751-52. New Orleans: IDEC.

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