I recently had the opportunity to interview Nadarajah Narendran, Professor, Director of Research, Lighting Research Center at Rensselaer Polytechnic Institute, on the topic of 3D printing for an article I wrote for the April 2019 issue of tED Magazine, the official publication of the NAED.
DiLouie: What is 3D-printed lighting?
Dr. Narendran: Additive manufacturing, or 3D printing, is a technique that is just starting to receive interest from the lighting industry. Additive manufacturing mostly uses materials such as polymers, metals, ceramics, glass, and their composites and printer equipment to deposit these materials in a layer by layer approach using digital information from a computer-aided design (CAD) model. With 3D-printed lighting, it may be possible to manufacture individual lighting components, such as heat sinks, electrical traces, or optics, and eventually complete fixtures.
DiLouie: What are the benefits of 3D-printed lighting?
Dr. Narendran: The ability for a manufacturer to provide a custom product and a unique design that matches the aesthetics of a space is one of the biggest benefits of 3D printing for lighting. Being able to print a fixture on-site and on-demand, would benefit the customer, the manufacturer, and the local construction industry, would help bring manufacturing back to local economies, and would minimize the environmental impact through reduced shipping. For solid-state lighting, the benefits include custom components, rapid prototyping, faster new product introductions, and reduced fixture cost. 3D printing will also enable the design of parts that cannot be manufactured by traditional methods, which will benefit not only the aesthetical aspect but the functional as well.
DiLouie: What are typical applications for 3D-printed lighting? Do you envision this for prototypes, custom luminaires, modification, or all luminaires?
Dr. Narendran: While prototyping, to check for form, fit, and appearance, is currently the most common use for in-house 3D printing, there is a potential to use 3D printing for both individual functional components and complete fixture housing to create custom finished luminaires. However, research is still needed to advance to this next stage. An LED system requires electrical optical, thermomechanical, and structural components. All these have different requirements; for example, a heat sink needs to have the right thermal qualities to conduct heat away from the LEDs to keep the lighting system cool. Therefore, a 3D-printed heat sink must be manufactured from the right type of material with the right thermal conductivity to be effective. Because 3D-printed lighting is still at the very early stages, research is now taking place to investigate what types of printing materials and printer equipment will be most effective for lighting. At the Lighting Research Center, we have conducted initial investigations into the potential for printing thermal, electrical, and optical components.
3D printing a luminaire at LRC.
Dr. Narendran:
New technologies and materials are being developed for 3D printing all the time. New hybrid fabrication technologies are invented for new applications and markets. The most common 3D printing processes include material extrusion, vat photopolymerization, powder bed fusion, and material or binder jetting. For the hobbyist using smaller desktop 3D printers, the most common technology is fused filament fabrication (FFF), which is a material extrusion technology in which a thermoplastic filament is heated and extruded through a nozzle that moves in the x-y (horizontal) plane to deposit the extruded material on a platform to complete a single layer. Repeated x-y plane material deposition creates the three-dimensional structure. The oldest 3D printing process is called stereolithography (SLA), which is a vat photopolymerization process. With SLA, an object is made by selectively photopolymerizing a thin liquid layer of photopolymer resin and then curing each subsequent photopolymer resin layer one by one with a UV laser. Another common print process called powder bed fusion uses thermal energy from an electron beam or laser to selectively fuse regions of a thin layer of powdered metal, glass, ceramic, or thermoplastic polymer material. In material jetting, a photocurable or thermocurable plastic resin is deposited using piezoelectric or thermal print heads where droplets of build material are selectively deposited, while in binder jetting, a liquid bonding material is selectively deposited to join a powder material.DiLouie: How would a typical project involving 3D printed lighting work from the manufacturer, lighting designer/engineer, and distributor’s point of view? What unique problems would it solve during this process?
Dr. Narendran: In the case of new construction, the lighting and fixture designers together with the architects will conceptualize the lighting fixture needed to meet the functional and aesthetic requirements. The engineering team of the manufacturer will identify the materials and printer needs to manufacture the lighting fixtures and seek distributors who will carry the required materials and subassemblies to make the fixtures. Fixtures will be printed at a nearby location to the construction site. At the time of installation, a few fixtures will be initially printed and tried out within the structure to assess appearance and form and fit within the building. If the architects and the designers think that the fixtures need modification, the designers will modify the digital files and print the fixtures and install them to better suit the design goals.
DiLouie: What is the current level of adoption? What manufacturers in the lighting industry are currently using it, and for what purpose?
Dr. Narendran: 3D printing of lighting components for functional parts and final part production is still relatively rare. While it is possible to 3D print prototypes and simple systems, we are not at the point yet of printing fully integrated light fixtures. However, several manufacturers are now innovating in this area. These include Philips Lighting (Signify) Telecaster, which was started in Europe to provide custom lighting products; Gantri, a San Francisco-based company that provides custom design and 3D printing technology to enable designers to create novel lighting products; Tempo Lighting, a linear lighting fixture company in Southern California that has been leveraging 3D printing to make cost-effective components for LED fixtures; and LG, one of the leading OLED lighting panel manufacturers in South Korea, has been promoting the creation of OLED light fixtures by 3D printing.
DiLouie: What do you see as adoption of 3D printed lighting in the near and longer-term future? Who will be early adopters? How close is the technology to prime time?
Dr. Narendran: In the near term, lighting manufacturers will use 3D printing to create functional prototypes and build custom components for lighting fixtures. In about five years, 3D printing will become more popular among lighting fixture manufacturers to deliver custom light fixtures.
DiLouie: What potential impacts will 3D printed lighting have on product development and possibly its democratization?
Dr. Narendran: 3D printing will allow for rapid design changes to lighting fixtures and fast delivery of custom fixtures. Furthermore, it will enable on-site, on-demand lighting fixture manufacturing and thus bring back manufacturing jobs closer to the building site, rather than making them half way across the globe and shipping them to the job site, creating a large carbon footprint. This could improve the local economy and jobs.
DiLouie: What potential impacts might 3D printed lighting have on manufacturers and their overall supply chains?
Dr. Narendran: Because of rapid developments in LED technology and market growth for LED lighting, manufacturers are forced to stock an ever-growing number of systems and parts (SKUs) to service their customers for years after a sale. This is another area where 3-D printing can benefit manufacturers by reducing stocking requirements for fixtures and parts. If a customer orders a part, it can be printed on demand instead.
DiLouie: What potential impacts will 3D printed lighting have on electrical distribution, where distributors traditionally carry standardized inventory?
Dr. Narendran: It is possible in the future that distributers will maintain 3D printers and materials and digital design files to print components on-demand that would reduce the need for maintaining large warehouses to stock slow moving spare parts that cost a lot of money.
DiLouie: Will electrical distributors and contractors require new skills to work with 3D printed lighting?
Dr. Narendran: With the ultimate goal being localized or on-site, on-time and on-demand fabrication of lighting fixtures, the role of both electrical distributors and contractors will change. As an example, the parts and fixture inventories maintained by electrical distributors will drastically change with no SKUs in stock other than the digital files of the parts required to be maintained. Localized manufacturing facilities with 3D printing facilities or demand site facilities would be used to fabricate the required components and fixtures.
DiLouie: What standards are in effect here? How will 3D printed lighting, which has the potential to diffuse product development and manufacturing, work with safety standards such as UL?
Dr. Narendran: There have been initiatives taken by ASTM and UL to streamline the standardization for functional performance and safety performance of 3D-printed components. Unlike material properties tested with ASTM or equivalent standards and safety standards similar to UL, in 3D printing the material and the printing process and the manufacturing parameters used in the fabrication are required to be standardized. This is due to the end product properties, such as density, tensile strength, elongation, glass transitioning temperature, optical transmission, thermal conductivity, electrical conductivity, dielectric constant, etc., and safety parameters, such as maximum service/operating temperature, flame retardant index, flammability, etc. These all depend on print material, print technology used, printer used, print orientation, and print parameters.
DiLouie: If you could tell the U.S. electrical industry just one thing about 3D printed lighting, what would it be?
Dr. Narendran: Start preparing to cater to the needs of 3D printing of electronic and electrical products. Component designs should keep 3D printing of systems in mind when designing them so that products can be built seamlessly and cost effectively.
DiLouie: Is there anything else you’d like to add about this topic?
Dr. Narendran: Seeing the potential of 3D printing for lighting, the Lighting Research Center started a new initiative to research 3D printing for lighting applications a couple of years ago. The LRC is dedicating nearly a day of its three-day LED Lighting Institute to 3D printing to allow participants to better understand the possibilities of creating custom LED luminaires. At the 2019 Strategies in Light conference in February, the LRC moderated a panel discussion with 3D printer and materials, lighting fixture, and LED light engine manufacturers to highlight the promises and challenges of using 3D printing for lighting and to initiate a dialogue among the different stakeholders in the industry. Additionally, the LRC organized a “discovery workshop” and get-together with industry leaders to discuss and develop a plan for transforming the industry to provide custom lighting fixtures, made on-site and on-demand, that will elevate the appearance, value, and experience of the built environment.
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