News
Add: L4-19370 West Grand Gate, No.33, Two Period, International Trade City, YiWu City
Tel：0579-85191701
Fax：0579-85191702
Mob：13757916187
Web：www.shilitools.com
E_mail：shilitools@163.com
Location : Home > News
The disadvantage of twist drills
Author： Views：5305 Time：2013-03-14Twist drill geometry than flat drill reasonable, but surviving in the following disadvantages:
(1) at each point on the main cutting edge of the standard twist drill angle values inside and outside that much difference. The rake angle of the main cutting edge of the drill bit at the outer edge of about +30 °; proximity Zuanxin at the rake angle of about -30 °, the nearly Zuanxin at the former angle is too small, resulting in chip deformation is large, the cutting resistance; while near the outer edge at the rake angle is too large, the cutting edge strength in the machining of hard materials, often inadequate.
(2) chisel too long, the rake angle of the chisel edge is very negative, up to the -5 4 ° to -6 0 °, which will produce a large axial force.
(3) compared with other types of cutting tools, the main cutting edge of the standard twist drill long, is not conducive stars crumbs breaker.
(4) sub-rear angle of the secondary cutting edge of the blade with at zero value, resulting in minor flank with the hole intramural friction increase, cutting temperature rises, a larger the drill outer edge corner wear, deterioration of the surface roughness has been processed .
Above defects are often fast twist drill wear, and seriously affect the drilling efficiency and improve surface quality
(1) at each point on the main cutting edge of the standard twist drill angle values inside and outside that much difference. The rake angle of the main cutting edge of the drill bit at the outer edge of about +30 °; proximity Zuanxin at the rake angle of about -30 °, the nearly Zuanxin at the former angle is too small, resulting in chip deformation is large, the cutting resistance; while near the outer edge at the rake angle is too large, the cutting edge strength in the machining of hard materials, often inadequate.
(2) chisel too long, the rake angle of the chisel edge is very negative, up to the -5 4 ° to -6 0 °, which will produce a large axial force.
(3) compared with other types of cutting tools, the main cutting edge of the standard twist drill long, is not conducive stars crumbs breaker.
(4) sub-rear angle of the secondary cutting edge of the blade with at zero value, resulting in minor flank with the hole intramural friction increase, cutting temperature rises, a larger the drill outer edge corner wear, deterioration of the surface roughness has been processed .
Above defects are often fast twist drill wear, and seriously affect the drilling efficiency and improve surface quality
Copyright: China World Hardware Co., Ltd. （JINHUA JIUHENG INDUSTRY AND TRADE CO.LTD） Throughout the planning:www.zhongqi.cn