Original Date: 02/10/2003
Revision Date: 01/18/2007
Best Practice : Laser-Assisted Oxygen Cutting
In November 2002, Bender Shipbuilding and Repair Company, Inc. implemented Laser Assisted Oxygen Cutting technology, which produces quality cuts in thick steel sections by using very low carbon dioxide laser power and high pressure oxygen.
In the past, Bender Shipbuilding and Repair Company, Inc. was using subcontractors to cut 5% to 12% of total thick steel parts with oxy gas or high-power plasma systems. These cuts were inaccurate and had large kerf angles because the parts were not compatible with laser cut material; they required post processing. Additionally, because parts were processed outside of Bender, they were not fully integrated into the material management system.
In order to improve its thick steel cutting process, Bender decided to pioneer the implementation of Laser Assisted Oxygen Cutting (LASOX) technology in shipbuilding. LASOX was originally developed by BOC Gases at the University of Liverpool (United Kingdom) to cut thick steel with low laser power. The National Shipbuilding Research Program funded the development and implementation of this technology in shipbuilding. Bender teamed with Caterpillar, Alabama Laser, Electric Boat, and BOC for this implementation.
In November 2002, Bender started production cutting with LASOX. LASOX technology is now used routinely to cut one and one-half to three-inch thick steel, and produces cuts with near zero kerf angle and ± 0.007 inch accuracy. Bender’s future plans include applying LASOX technology to steel up to four inches thick.
The LASOX cutting head (Figure 2-1) starts cutting pieces by piercing the plate, which produces a clean-through hole in about one second, as compared to one to two minutes with oxy gas. Smooth precision cutting proceeds at seven to 12 inches per minute using a tightly controlled supersonic gas jet. The power required for this process is below two kilowatts for both piercing and cutting. This process allows common line cutting of parts. In LASOX, oxygen is the process driver and the laser provides the preheating, as opposed to conventional laser cutting where the laser is the process driver.
As a result of using LASOX technology, Bender is able to cut thick material more accurately and integrate thick material into the material management system. In addition, LASOX cuts more accurately than plasma or oxy gas. Bender no longer depends on subcontractors for steel work and saves money on piercing, hole drilling, and post processing time. Furthermore, post machining or drilling holes and slag removal have been eliminated. This technology has been beneficial for thick steel applications such as foundations, insert plates, bedplates, and lifting padeyes.
Figure 2-1. LASOX Head
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