1082 Каталог KORLOY 2016 Металлорежущий инструмент и станочная оснастка ENG Стр.L15

Каталог KORLOY 2016 Инструмент и оснастка Стр. L15 1082 ENG Lab2u

Turning Relief angle Relief angle avoids the friction between workpiece and relief face and makes cutting edge move along workpiece easily. Relationship between various relief angle and flank wear Workpiece: SNCM431(HB200) Grade: P20 Depth of cut: 1mm Feed: 0.32mm/rev Cutting time 20min 3' 6" 8“ 10 12" 15 20" Relief angle (a“) Affects Selection system 1. If relief angle is big Flank wear decreases. 1. Hard workpiece / When strong cutting edge is needed - Low relief angle 2. If relief angle is big Cutting edge strength weakens. 2. Soft workpiece / Workpiece turning to work hardening easily - High relief angle 3. If relief angle is small Chattering occurs Side cutting edge angle Side cutting edge angle has big influence on chip flow and cutting force therefore proper Side cutting edge angle is very important. Side cutting edge angle and Chip thickness '1 t 0 (3) Approach angle 0° Approach angle 15° Approach angle 30° Side cutting edge angle and 3 cutting forces 300 200 Pr ncipal orce :eed fo ce Back f orce i Workpiece SCM440(HB250) Grade TNGA220412 vc= 100m/min ap= 4mm fn= 0.45mm/rev 15' 30" 45° Side cutting edge angle As side cutting edge angle is getting bigger chips are getting thinner and wider(refer to left picture). At the same feed and depth of cut with approach angle O’ Chip thickness is the same as feed(t=fn) and chip width is equal to depth of cut (W=ap). t1 =0.97t, W1 =1.04W t2 = 0.87t, W2 = 1.15W Affects 1. Big side cutting edge angle with the same feed makes chip attaching length longer and chip thickness thinner. So that cutting forces scatter to long cutting edge therefore tool life gets longer. 2. Big side cutting edge angle for machining long bars can cause bending. Selection system 1. Deep depth of cut finishing / Long thin workpiece / Low machine rigidity - Side cutting edge angle 2. Hard and high calorific power workpiece / Roughing big workpiece / High machine rigidity - Side cutting edge angle Side cutting edge angle and Tool life Cutting speed vc(m/min) Side cutting edge angle and Cutting load Side cutting edge angle and Cutting performance fn (mm/rev) fn (mm/rev) (2) “Force P is scattered to P1, P2.” As approach angle gets bigger Back force gets bigger and feed force gets smaller. Specification Low Approach angle High Wear rate High .>- Low Workpiece Easy to cut material .Difficult to cut material Machining power Small Big Chatter Hard to occur .Easy to occur How to machine Finishing Roughing Workpiece rigidity Long thin workpiece Thick workpiece Machine rigidity In case of low rigidity .In case of high rigidity Technical Information 15