Cast iron plate (cast iron platform) in the scraping process is generally experienced rough scraping, thin scraping, fine scraping 3 sections. Rough scraping section: The primary task of rough scraping should first solve the error as the wrong shape. Such as lathe swipe dovetail rails at both ends of the parallelism, if not resolved, leaving a rough scratch and then solve the parallelism, not only time-consuming work and delay the construction period. Rough scraping knife but also generous, to be drastic, scraping each one only do not scratch the second. Knife direction is the same direction along the water, each transformation change. After repeated cycles of scraping research, the black spots from the sparsely populated, uneven distribution to uniform distribution, when any scratch (25mm × 25mm) dp gc 4 ~ 6:00, the surface roughness Ra1.6 ~ Ra3.2 that Shall rough scraping stage. Thin scraping section: thin scraping scraping on the basis of rough scraping the task to solve the surface quality problems, namely the contact accuracy, geometric accuracy (flatness reached 0.01mm / 500mm2), the surface roughness recommended straight push plus twist method , Positive "6" block "" 6 "block knife better, when any scraper reaches 10 to 12 points to persuade the scraping phase that is to stop.Scraping stage: fine scraping is carried out on the basis of thin scraping, fine The task of scraping is to improve the surface quality of scraping, taking into account the verification shape error.Sharp scraper to grind a flat scraper, to be sharp, the knife must be stable to light, in particular, to avoid the knife angle scratched the surface, fine scraper width 5 ~ 7mm, even narrower and shorter, depending on the size of the scraping plane changes, the knife suggested the use of left twist method or right twist method, the scraping force should be small, black dots increased to every arbitrary party 20 to 25, The end, the cast iron flat (cast iron platform) plane accuracy of 0.01mm / 500mm2 hair, the surface roughness of Ra0.8 ~ Ra1.6.