求翻译：◆ 机床的总体布局为龙门框架结构，Y轴行程4m以下的机床，龙门框架采用固定式结构，Y轴行程4m以上的机床，龙门框架采用移动式结构；机床的主要部件均采用稳定性极高的高强度铸件，以确保机床在长期使用过程中各项精度的稳定性。是什么意思？

◆ the overall layout of the machine gantry framework structure, 4m below the y-axis travel machine, gantry framework with a fixed structure, the y-axis travel of more than 4m machine gantry framework movable structure; the machine parts are made of high stability high-strength castings, to ensure th

* * The machine's overall layout, and structure for portal framework Y stroke 4 m below the machine, and portal framework with fixed structures, Y Axis travel of more than 4M machine, based on the mobile portal framework structure; the machine's main parts are very high stability, high-strength cast

Overall layout of gantry frame structure of machine tools, machine tool y axis 4m, gantry framework uses fixed structure, y axis 4m machine, gantry framework used mobile structure; the main parts of the machine are made of high strength castings with high stability, to ensure the stability of the pr