Thermal Design
Right on the Mark

Weapon Offers Pinpoint Accuracy

Thermal Design Imagine if you will a weapon that offers the owner the ability to not only bathe a suspect or enemy combatant in bright light but can also pinpoint the accuracy of the gun holder's aim with a powerful laser. It may sound like something out of a sci-fi magazine, but according to Bob Cramblitt's March, 2008 article for Product Design and Development, a weapon that includes a mounted LED light and laser sight is already in the hands of our military and law enforcement officers. We owe it all to a company called SureFire and their impressive work with upfront thermal simulation.

THE OBJECTIVE

As a manufacturer of weapon-mounted illumination hardware (lights, lasers, etc.) SureFire's most consistent customers are the U.S. Military and law enforcement. SureFire set out to design the first ever light and laser mount, a product they affectionately called the X400.

THE PROBLEM

SureFire realized that making it lightweight and durable wasn't good enough. They wanted to assemble the product with a light that typical incandescent illumination couldn't equal. Thus they began looking at LEDs as a possible light source. According to Paul Kim, Vice President of Engineering, LEDs presented a big problem.

"In terms of thermal management, LEDs are like semiconductor devices," says Kim. "As you put out more light, you generate more heat. The cooler we can run the device, the more photons, or light, we can put out."
Since life and death situations are often faced by those who rely on SureFire product performance, having them not work as promised is unacceptable.

"When we say mission-critical, we mean that it must perform under all circumstances in all parts of the world," says Kim. "In many cases, the operation of the flashlight could make a difference between life and death."

THE SOLUTION

SureFire began employing upfront thermal analysis, which allowed them to virtually test designs and ideas before they become physical prototypes.

Initial design of the X400 started with Pro/ENGINEER, typical CAD software. It was then transferred over to CFDesign. According to Deepanjan Mitra, this allowed SureFire engineers to explore more options upfront in the design process.

"Using the CAD package, I can choose the complexity of my models," says Mitra. "For quick and dirty answers, I can suppress all cosmetic features and perform an analysis on the critical heat paths, which typically answers the more fundamental design questions."

CFDesign allowed engineers the opportunity to simulate heat conditions so they could get an accurate assessment of how quickly the temperature would rise in the LED light based on several external factors. This thermal analysis helped in determining how best to design and isolate the light unit.

Since the X400 also housed a laser, further complexities existed. Laser sights need to operate at a much lower temperature than that of the LED, thus housing it required that the two be insulated from one another.

"We simulated a bunch of scenarios with different housing materials and insulation thicknesses, which led to us being able to determine design requirements," says Mitra. " This is really simple, since it only amounts to changing the material property of the part in CFDesign and rerunning the analysis."

In the end, CFDesign allowed SureFire the opportunity to explore and simulate all facets of the design and engineering process. This virtual prototyping helped to save time and money by eliminating errors before physical prototyping ever took place.