Общий каталог Sumitomo 2018 - 2019 - страница 560

Technical Guidance Chip Control Type of Chip Generation Type of Chip Control a b c d Feed rate A B C D E Large feed rate Shape Influence factor Application Condition Continuous chips Chip is sheared Chips appear to Chips crack before Small feed rate with good surface and separated by be torn from the reaching the cutting finish. the shear angle. surface. point. NC lathe (For automation) 5 5 Steel, Stainless steel Steel, Cast iron (Very low General lathe Steel, Stainless steel (Low speed) speed, very small feedrate) Cast iron, Carbon (For safety) 5 ~ 5 { Good : C type, D type Easy Work deformation Difficult A type : Twines around the tool or workpiece, damages the machined surface Large Rake angle Small and affects safety. Small D.O.C. Large Poor B type : Bulky, causes problems in the automatic chip conveyor and chipping occurs easily. Fast Cutting speed Slow E type : Causes spraying of chips, poor machined surface due to chattering, chipping, large cutting force and high temperatures. Factor of Improvement Chip Control j Increase feed rate Depth of cut (mm) 4,0 t1 t2 >t1 f1 f2 >f1 2,0 0,1 0,2 0,3 0,4 0,5 When feedrate increase, chips become thick and chip control improves. Feed rate (mm/rev) k Decrease side cutting edge Side cutting edge angle 1 2< 1 45° t1 t2 >t1 f f 15° Even if feed rate is the same, smaller side cutting edge angle makes chips thick and chip control improves. 0,2 0,25 0,3 0,35 Feed rate (mm/rev) l Decrease nose radius 1,6 r2 < r1 t1 r 1 t2 Nose radius (mm) t2 >t1 f f 0,8 Even if depth of cut is the same, smaller nose radius makes chip thick and chip control improves. * Cutting resistance increases in proportion with the width of the contact surface. Therefore, with 0,4 Technical Guidance a larger nose radius, cutting resistance and back force increases, chattering may also occur. However, with the same feedrate, a smaller nose 0,2 0,25 0,3 0,35 radius would produce a poorer surface finish. Depth of cut (mm) N5