Analysis of Scraping Process (The Applied Force to and the Movement of Scraper)

Abstract

Scraping is very much dependent on manual skill and is thus labour intensive. Mastering it requires a long period of apprenticeship. The purpose of this investigation is to obtain the fundamental data to enable a robot to do scraping. The cutting force and the pushing force applied to a tool handle were measured independently and simultaneously. The movement of the handle was also measured at the same time using a video camera. Analyzing the work of a skilled worker who has 26 years experience in scraping, the following results were obtained: (1) The skilled worker discriminates between rough cutting, moderate cutting and fine finishing very clearly. The cutting force reaches 454 N in rough cutting, while in fine finishing 178 N. (2) He keeps an amazingly stable pace all through the work. The average time required for one cut and its standard deviation is 0.44±0.019 sec for rough cutting. (3) One scraping cut consists of three clearly distinguishable stages. What a scraping robot must do in each stage of cutting became evident.