Abstract: An auto-scraping apparatus for a work piece of a hard rail has a driving device, a linking device and a tool device. The driving device has a connecting frame, a driving motor and a cam. The driving motor is mounted in the connecting frame. The cam is mounted on a bottom of the connecting frame and has an abutting face. The linking device is connecting to the driving device and has a main frame, an upper connecting arm, a lower connecting arm, a linking arm and a rotating wheel. The main frame is connected to the driving motor. The connecting arms are pivotally connected to the main frame and the linking arm. The rotating wheel is rotatably mounted on the upper connecting arm and abuts the abutting face of the cam. The tool device is connected to the linking device and has a tool carrier and a relieving tool.

Abstract: A method of auto scanning and scraping a work piece for a hard rail has a preparing step, a scanning step, a detecting step, an auto-scraping step and an analyzing step. The preparing step comprises preparing an auto scanning and scraping apparatus with a multi-axis machine tool, a control computer, an auto-scraping device and a position detector. The scanning step comprises scanning the surface of the work piece to read the roughness value and transporting the data to the control computer. The detecting step comprises forming a 3D-appearance drawing of the work piece and detecting the 3D-appearance drawing with multiple detection steps. The auto-scraping step comprises scraping the surface of the work piece by the auto-scraping device. The analyzing step comprises detecting the 3D-appearance drawing of the work piece that has been scraped with the preceding detection steps and scraping the work piece to meet the preceding detection steps.