LSP Technologies, Inc. has developed a new high-power, diode-pumped laser peening system for laser peening, branded as Procudo® 200 LSP Systems.  The compact, self-contained LSP System makes laser peening more accessible to the production environment by making it easier for OEMs to integrate laser peening into their manufacturing lines.  The modular design of the Procudo® LSP System enables the equipment to be easily adapted to meet the requirements of any manufacturer’s shop.  With the Procudo® 200 LSP System, OEMs can now own and easily operate their own laser peeing facility at an affordable price.

The Procudo® 200 LSP System consists of three modules:

  1. the optical enclosure, which includes the laser and beam diagnostics components,
  2. the power cabinet, which houses all of the power supplies and power distribution hardware, and
  3. the control cabinet, which includes the system controller, the data acquisition, the storage system, and the environmental control system

These three modules are illustrated in Figure 4.

Optical Specifications of the Procudo® 200 LSP System

The heart of the Procudo® 200 System is a 200 Watt diode pumped laser, which consists of a diode pumped single longitudinal mode (SLM) and single transverse mode (TEM00) oscillator coupled to optical amplifiers.  The gain medium used in this laser is YLF assembled into a MOPA configuration.  The output pulse energy is 10 Joules operating at a repetition rate of 20 Hz, which is an output of 200 W.  The pointing stability of the laser is ≈0.11 mrad over 8 hours.

The laser is assembled onto a 4’x6′ table as shown in Figure 1.  Relay imaging is utilized to allow the laser beam to optimally fill each laser rod, providing maximum energy extraction efficiency.  Vacuum tubes (that do not require a vacuum pump) are used to eliminate air breakdown during the imaging process.  The setup is shown in Figure 2.

 

optical layout

Figure 1. Compact optical layout fits easily on a 4’x6′ optical table

 

Figure 2. Relay imaging is used to maximize energy output and create a flattop spatial profile

Figure 2. Relay imaging is used to maximize energy output and create a flattop spatial profile

 

The laser table is installed in an environmentally controlled enclosure, as illustrated in Figure 4 and photographically in Figure 3.

 

Figure 3. Photo of the assembled PROCUDO® 200 LSP System

Figure 3. The Procudo® 200 LSP System at LSPT’s Dublin facility

 

The Procudo® 200 LSP System utilizes a modular design, which allows it to be easily shipped, reassembled, and integrated into a production line at the OEM’s facility.  The modular components are shown in Figure 4.

 

Figure 4. Drawing showing the modular design of the PROCUDO® 200 LSP System

Figure 4. The modular design of the Procudo® 200 LSP System makes it easy to ship and assemble

 

Characteristics of the Laser Output of the Procudo® 200 LSP  System

Following is actual detailed data from the Procudo® 200 LSP System currently installed at LSPT’s facility in Dublin, Ohio, USA.

The oscillator output is Gaussian, as shown in Figure 5.  After the beam is relay imaged through the optical amplifiers, it becomes a flattop (at laser output) as shown in Figure 6. Energy variation across the flattop spatial profile is only 9.1% (this will produce uniform compressive residual stresses and improve the fatigue properties of laser peened parts).  A photo of the temporal beam at the output of the laser is shown in Figure 7.  Over a period of 8 hours, the pulse width had a stability of 0.07 ns rms with maximum variation of only 0.14 ns.  The natural pulse width of the laser oscillator is 22.6 ns.  However, the pulse width for optimizing laser peening can be selected between 8-16 ns by a pulse slicer that is installed after the oscillator.  Figure 8 shows the energy stability of the laser pulse over an 8 hour power stability test.

 

Figure 5. Photo showing Gaussian beam output of the PROCUDO® 200 SLM, TEM oscillator

Figure 5. The Gaussian beam output of the Procudo® 200 SLM, TEM00 oscillator

 

Figure 6. Photo showing the spatial beam quality at the output of the PROCUDO® 200 LSP System

Figure 6. The spatial beam quality at the output of the Procudo® 200 LSP System is very uniform

 

Figure 7. Photo of the temporal pulse width of the PROCUDO® 200 LSP System at the laser output

Figure 7. The temporal pulse width of the Procudo® 200 LSP System at the laser output is very stable

 

Figure 8. Graph showing power stability of the Procudo® 200 LSP System is only 0.28% RMS

Figure 8. The power stability of the Procudo® 200 LSP System is only 0.28% RMS

 

The incredible stability and consistency of the preceding data clearly illustrates the superiority of using a diode-pumped laser for laser peening: uniform processing, highly repeatable, reliable output, and extremely high beam quality.  Diode pumping has revolutionized the design of solid-state lasers to meet the changing needs of today’s OEMs.  The Procudo® 200 LSP System offers unique advantages that include: low power consumption, low heat generation, compact packaging, excellent laser beam quality, high pulse-to-pulse stability, high reliability and very high power.  The performance of the Procudo® 200 LSP System can efficiently be adapted to the specific requirements of any OEMs’ laser peening needs.

The Procudo® brand laser peening systems can be rapidly integrated into a production line and used with a wide variety of automated part handling robotics and CNC machines.  LSPT’s auto-control and diagnostics system enables a user to exercise complete control over the laser peening process, with real-time data analysis.

The high processing speed of the Procudo® 200 LSP System, which is a factor of 10 faster than any other commercial laser peening rate, will drive costs down, open new markets, and accelerate the proliferation of laser peening around the world.  The cost of laser peening is projected to drop by at least 60% by 2020.  High volume laser peening will drop to less than $10 per part.