553 Каталог SUMITOMO 2015 Режущий инструмент и инструментальная оснастка Стр.549

Каталог SUMITOMO 2015 Инструмент и оснастка Стр. 549 0553 ENG Lab2u

Technical Guidance TECHNICAL GUIDANCE Chip Control Type of Chip Generation Spiralling Continuous chips with good surface finish. Steel, Stainless steel Shearing Chip is sheared and separated by the shear angle. Steel, Stainless steel (Low speed) Tearing Chips appear to be torn from the surface. Steel, Cast iron (very low speed, very small feed rate) Cracking Chips crack before reaching the cutting point. Cast iron, Carbon Easy-Large -Small -Fast- Work deformation Rake angle D.O.C. Cutting speed -Difficult -Small Large -Slow Factor of Improvement Chip Control (1) Increase Feed Rate (f mm/rev) f - fj j f f2>fi then t2>ti When feed rate increases, chips become thick and chip control improves. (2) Decrease Side Cutting Edge (0) tr i 2 f- - h f H h q- q2<< i then t2>ti Even if feed rate is the same, smaller side cutting edge angle makes chips thick and chip control improves. (3) Decrease Nose Radius (re) Even if feed rate is the same, a smaller nose radius makes chip thick and chip control improves. Cutting force increases in proportion with the length of the contact surface. Therefore, a larger nose radius increases back force which induces chattering. With the same feed rate, a smaller nose radius produces a rougher surface finish. Type of Chip Control Chip Types Depth Large Small NC Lathe (For Automation) General Lathe (For Safety) If H AflfV H S S H Good C type, D type (A type Twines around the tool or workpiece, damages the machined surface and affects safety. B type Causes problems in the automatic chip conveyor and chipping occurs easily. E type Causes spraying of chips, poor machined surface due to chattering, chipping, large cutting force and high temperatures. 1.0 1.5 Depth of Cut (mm) A B C D E H S J 549 Technical Guidance