There are two types of machine frame: welded model and assembled model. The former is for small and middle size, and the latter is for big size. The welded type adopts large arc fillet and low stress welding method, greatly reduces the concentration stress which ensures rack equal strength in all directions, high impact resistance, even force, low failure rate. Assembled uses advanced modularization and non-welded frame structure design of high fatigue strength and high reliability. Meanwhile machine assembly design makes transportation, and installation more convenient, especially suitable for installation in narrow and small places like undermine and high altitude mining.