appliance DESIGN IAM : Page 5lights more commonplace in the market. Some long-touted features and benefits of LED curing lights include: s (IGHELECTRICALEFFICIENCYAND instant on/off capability for lower operational costs s ,ONGSERVICELIFEELIMINATES bulb replacement and reduces maintenance costs s#OMPACTNESSTHATREDUCESTHE size and cost of light-curing systems s h#OOLvLIGHTRADIATIONEXTENDS curing capabilities for thermal-sensitive substrates s'REENATTRIBUTESELIMINATEMERCURY and ozone safety risks and handling costs s .ARROWWAVELENGTH SPECTRUM emission minimizes substrate thermal rise These beneficial traits help make manufacturing more efficient. These offerings are also driving the divergence from metal-doped arc lamps to LED semiconductors as a light source for adhesive spot curing. Natural selection is at work in the adhesive industry. Why Myths Exist In The Marketplace Unsubstantiated claims on the aforementioned benefits are an underlying cause for misinformation in the marketplace. These claims include: s -ERCURYARCLAMPPERFORMANCE long the industry standard, is improperly applied to LED technology. The two light sources differ substantially. s ,%$CURING EQUIPMENT manufacturers may ignore the MYTHS AND REALITIES Myth No. 1—LED light sources can seamlessly replace arc lamps in most curing processes. Reality The belief in this myth resulted in many application problems for manufacturers. As a consequence, particularly in Europe and North America, sales of LED curing lights HAVESLOWED -ANUFACTURERSWANT proof of compatibility. The good news is that LED curing lights can work well while offering savings and efficiencies, but changing from arc lamp to LED curing lights may not be a simple, DIRECTCONVERSION -ANYDETAILSMUST be considered, the most important of which are differences in the wavelength distribution of LED and arc-lamp light sources. Disparate Wavelength Distributions The wavelength distribution emitted by an arc lamp and an LED are quite different. The wavelength distribution from an LED light source is narrow and bell shaped and can peak in the UV or visible light range depending upon the selection of the LED. The wavelength distribution from an arc lamp has multiple energy peaks spread over a wide range of wavelengths (Figure 2). Arc-lamp-energy spectral distribution varies depending upon the design of the arc lamp and other components of the curing system. The disparity in the wavelength distribution curves illustrate that a light-curable chemistry optimized for an arc lamp may perform inadequately when cured with an LED light source. Replacing an arc lamp with an LED light source might be as simple as modifying curing parameters of an existing process, or more complex such as changing of the adhesive to one properly formulated for the spectral-distribution characteristics of the LED light source. While a direct replacement of your arc lamp with an LED curing light is possible, an evaluation of light/adhesive interdependence. #URINGLIGHTANDADHESIVE performance are relational . s ,%$TECHNOLOGY ASITAPPLIES to light-based curing, is still in the early stages of commercial and volume applications. LED manufacturers continue to develop LED technology for curing applications. In the meantime, myths have developed due to an absence of historical performance data. So let’s look at some myths that have been adopted and bring the realities into focus. From there, if applicable, you can move successfully to LED curing technology and reap the benefits it offers. International Appliance Manufacturing 2010 5 Publication List |
