High Intensity LEDs & Automotive inspection
In the past, inflexibility in lighting options for machine vision made finding reliable, effective lighting difficult. The short lifespan of fluorescent tube or fiber optic lights required frequent replacement, driving increased maintenance costs and decreased productivity. Vision integrators were commonly faced with relatively limited task oriented, high intensity illumination choices.
Historically, options for inspecting vehicle doors and body panels on the automotive manufacturing plant floor were often limited to either fluorescent tube or fiber optic lights. Although both light types provided adequate illumination for some vision inspections, there were also shortcomings: fluorescent lights were unstable, diffuse, and had a short life span, whereas fiber optic bundles and sources were bulky, expensive to install, and the light source had to be replaced approximately every 500 hours. In both cases, relatively frequent light changes required implementing a maintenance schedule, decreasing the efficiency of the inspection and increasing the actual per-hour cost of the light.
THE Ai SOLUTION
Able to light larger areas or project high intensity illumination greater distances than standard LEDs, high current LEDs combine significant illumination with many of the features that make LEDs a desirable light source – structured output, long life, low power consumption, and solid-state performance.
Taking advantage of the benefits of the new LED technology, Advanced illumination created a line of standard and custom length Bar Lights. A pair of custom length high current red (625nm) Bar Lights was tested for suitability in a B&W camera body panel inspection system. Other light options were tested and rejected, including a large area flood light as well as diffuse lights, along with a robotic arm mounted with a vision system and a smaller light source requiring multiple passes. The high intensity Bar Lights, placed opposite each other at a very low angle of incidence and at a large working distance produced dark field illumination, allowing the vision system camera, mounted directly above the production line, to detect very minor surface defects over a large area in a single pass as the parts passed below.
The use of red LEDs allowed the integrator to create a more efficient inspection through the use of a matched 635 nm red band pass filter fitted to the camera lens, effectively blocking light wavelengths not emitted by the Bar Lights. This technique is not possible using fluorescent or fiber optic lighting without severely diminishing the amount of light available for the inspections.
The advantage of the Bar Lights is their flexibility. Integrators have successfully used high current Bar Lights in robotic work cells where targeted illumination successfully replaced area fluorescent lighting. The high intensity Bar Lights also have application in hazardous work areas, such as welding sites, heavy stamping plants, or large robotic work cells. Conditions in these applications often require the lights to be placed at a safe distance, yet still produce intense, stable, targeted illumination. The high intensity Bar Lights are also effective in applications where higher light intensity is needed, but typically at the smaller fields-of-view and working distances of standard LED light applications.
Ai’s family of high current Bar Lights includes the MicroBrite Series AL295, available in 75 mm increments, the LL174 in 6” increments to 96”, and the AL126 and AL116 diffuse, close-work bars. The AL295 and LL174 are available in up to 16 wavelengths, from UV-365 nm to IR 940 nm. The AL126 and AL116 bars are available in red, white, and blue. Model-dependent options may include wash down, integral heat sink, different dispersion cone angle lenses, and a variety of light conditioning filters.
“Advanced illumination makes a quality product, and if there is ever an issue, they’re quick to respond and make every effort to fix it. I believe Ai is one of the leaders in industrial lighting, and we’re glad to have them as one of our leading partners and suppliers!”
– Todd, Account Manager | Regional Distributor
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