480 Каталог TUNGALOY 2007 Режущий инструмент Точение Фрезерование Сверление Стр.474

Каталог TUNGALOY 2007 Режущий инструмент Стр. 474 0480 ENG Lab2u

Factors affecting chip control (1) Cutting condition Feed f Cutting depth ap Cutting speed Vc Of these feed has the greatest effect followed by cutting depth and cutting speed in order listed. Feed is proportionate to the thickness of chips. Cutting depth is proportionate to the width of chips. There are optimum values (effective range) in feed and cutting depth. Cutting speed is in inverse proportion to chip thickness. Effective range becomes narrow at high speed. (2) Work material Alloy element Hardness Heat treatment condition These are related to thickness of chips and ease of curling. Mild steel chips are thicker than those of hard steel. Hard steel chips liable to curl more than those of mild steel. Chips that do not curl are thin. As an exception in case of mild steel even if thick may not curl. (3) Shape of tool Side cutting edge angle Nose radius Side cutting edge angle is relative to chip thickness and width Side cutting edge angle is preferably small. Nose radius is relative to thickness and width and the direction of flowing out. In finishing small nose radius while for rough cutting large nose radius is better. (4) Shape of chipbreaker Rake angle Chipbreaker width Chipbreaker depth Rake angle is in inverse proportion to chip thickness. Depending on the work material there is an optimum value. Chipbreaker width is selected proportionately to feed. Narrow at low feed and wide at high feed. Chipbreaker depth is to be selected so as to be inversely proportionate to feed. Deep at low feed and shallow at high feed. Rake angle small Breaker width small Breaker depth large Rake angle large Breaker width large Breaker depth small ft Feed f (mm/rev) (5) Cutting fluid Effective range is wider with wet cutting. Especially at low feed range is liable to curl.