Key Technology Study On The Precision Cutting Lines Of Lng Shipbuilding Sections

LNG ship is the most important part as well as a necessary equipment within the LNG supply chain.LNG ship is called “bright pearl on imperial crown" in the international shipbuilding field,which,strictly demanded by the owners,has high requirements for construction as well as special regulations for the machining precision and efficiency,because LNG ship is designed not only for transporting liquefied gas at a temperature of minus 163 degrees Celsius which is flammable and explosive,but also long-term traveling far away across the sea under various complex conditions demanding high safety and complex technologies.Section steel cutting line is a key equipment for constructing LNG ship hull.Each ship requires more than 9000 pieces of section steel at least when calculated according to the minimum level of LNG carriers.In the course of construction,section steel cutting precision is the core factor to guarantee the ship assembly,directly affecting the precision and progress of ship construction.In order to meet the requirements of cutting large liquefied natural gas(LNG)shipbuilding sections and producing other high-tech ships,this project designed the line of LNG shipbuilding cutting and studied the key technical problems during the systematic designing process based on the introduction and digestion of foreign cutting technologies and patterns.This paper described the development status and trend of section steel cutting technologies,and determined the cutting system of LNG shipbuilding sections based on comparing cutting forms,systematic composition and cutting end types of existing section steels.This paper discussed the advantages and disadvantages as well as the precision analysis of laser sensors,capacitive sensors and inductive sensors.Moreover,combining with the actual application environment,this study determined the sensor types and the performance analysis demanded by compensating the length and deformation of LNG shipbuilding sections.This paper completed the fixed length compensation and deformation compensation of LNG sections cutting system—realizing the location identification and data measurement of LNG shipbuilding sections by using the inductive displacement transducer and approaching switchers as well as making section length compensation on line according to the collected data;collecting the sections deformation data by laser trigonometry,as well as proposing a kind of compensation algorithm according to the collected deformation measurement data and having formed software modules applied in the cutting system.The effectiveness and practicability of fixed length compensation and deformation compensation algorithm proposed in this paper have been verified through batch applications and tests.The installation,debugging and acceptance of sections cutting line have been completed.What?s more,it has been proved that LNG shipbuilding sections line can meet the production requirements through actual production work.