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We knew from anecdotes that SCS was lasering faster than P&O or hot rolled black, but did not have hard facts to state how much faster or how to reliably achieve these improvements. Now we have both.

Systematic Tests Yield Valuable Laser Guidelines
Recently, a manufacturer who lasers SCS sheets enlisted the help of Don Vines, an expert consultant who starts up new laser operations and trains operators. Don was helping optimize their laser throughput by determining appropriate settings for lasering SCS (the company had still been using their settings for P&O).

Don began by putting the laser cutter back to the OEM's recommended settings (power, nozzle size, gas, focus) and made sure the resonator was in top shape. He then started cutting 11 gauge sheets of SCS, increasing speed until the laser quit cutting. He then increased nozzle size only, leaving focus and power unchanged. More sheets were cut while gradually increasing speed. The process was repeated until a maximum speed was attained that produced clean, high-quality cuts. Vines checked sensitivities to other laser parameters, but saw no real improvement in this top speed before he ran out of SCS sheets.

The speed Vines reached? 5500 mm/minute! Vines exclaimed, "This is amazing! I have NEVER seen any steel laser this fast. And since this customer was lasering their P&O at a top speed of 2200 mm/min., they have more than doubled their speed with SCS."

Don Vines codified his experience into a step-by-step procedure for optimizing laser speed with SCS. That procedure is now available for downloading through this link: Laser Recommendations. Note that Vines' tests were carried out using oxygen as the resonator gas. He is anxious to repeat his test with nitrogen, as nitrogen is popular because it prevents oxidation around the contoured part cut.

The Reasons for Speed Improvements
The characteristic cleanliness of SCS appears to be the primary reason why it lasers so much faster than P&O, hot roll black and temper pass. With no oil smoke to fog up the laser lens, no grit or dirt to cause beam deflection or dispersion, SCS allows the laser head to operate consistently on spec. Stretcher-leveling SCS blanks also helps, since the blanks are so flat that laser focus is always "dead on."

Stretcher-leveled SCS is also the key to lasering through two sheets at once. Vines lasered several stacked twin sheets of SCS during his trials, and has included the steps for optimizing double-stack lasering in the new guidelines. He found that when lasering through two sheets, he did not need to change laser power or focus, but needed to slow laser speed by about 30%. Even with that speed reduction, double-stack lasering still represents a 40% productivity improvement over the fastest single sheet lasering. You can view new photos of recent double-stacked laser cut parts through this link: Lasered Parts.

Help For Your Laser Optimization
Can other fabricators expect to see this doubling of laser speed when switching to SCS? Vines offered this observation: "Many will see that kind of improvement. But many have already worked hard to improve their laser speeds and are running near 4000 mm/minute. Still, even for this group, using SCS should get their speeds for cutting 10 to 12 gauge over 5000 mm/minute - and that's a 25% improvement. They'll jump at that ."

Vines has agreed to consult on TMW's behalf, assisting SCS users with optimizing their laser cutting performance. If you'd like to enlist Don's expertise, feel free to email TMW or call us at (618) 282-4200.

(left to right)               Bill Perry            Bill Carroll            Kerry Jones           John Bruzzese            Bob Jones        CAST focuses on bringing    productivity improvements to all    levels of the steel value chain in    Canada - mill to service center    to fabricator. To do business in    flat-rolled in Canada, call CAST    at (905) 388-1915 or email      info@appliedsteeltech.com