1274 Каталог KORLOY 2020 Инструмент и оснастка для станков по металлу Стр.L14

Каталог KORLOY 2020 Инструмент для станков по металлу Стр. L14 1274 Lab2u

Turning O 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 Affects 1. If relief angle is big Flank wear decreases 2. If relief angle is big Cutting edge strength weakens 3. If relief angle is small Chattering occurs Selection system 1. Hard workpiece/When strong cutting edge is needed - Low relief angle 2. Soft workpiece/Workpiece turning to work hardening easily - High relief angle Workpiece: SNCM431 (HB) E E Grade: P20 S 0-3 Depth of cut: 1 mm S 0.2 Feed: 0.32 mm/rev Cutting time: 20 min 0.1 0.05 8" 10 12' 15" 20' Relief angle (a0) O 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 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 0° 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 fn (mm/rev) £ t 0° fn (mm/rev) fn (mm/rev) Approach angle 0° Approach angle 15° Approach angle 30° 14 Side cutting edge angle and 3 cutting forces 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 Technical Information Workpiece : 'o> SCM440 (HB250) 0 1 400 Grade: TNGA220412 o> £= vc: 100 m/min 300 ap: 4 mm fn: 0.45 mm/rev 200 100 i r Pr ncipal f orce :eed fo s ce >- - f Back f i jrce s 15" 30° 45’ Side cutting edge angle