What are the disadvantages of twist drills?
29 3月 2018 | 没有评论 | posted by admin | in Article
(1) The rake angle at each point on the main cutting edge of a standard twist drill has a large difference between inside and outside. The rake angle of the main cutting edge at the outer edge of the drill bit is approximately +30°; near the core, the rake angle is approximately -30°, and the rake angle at the near core is too small, resulting in large chip deformation and large cutting resistance; near the outer edge When the front corner is too large, the strength of the cutting edge is often insufficient when machining hard materials.
(2) Longitudinal edge is too long, and the rake angle of the horizontal edge is very negative, reaching -54° to -60°, which will generate a large axial force.
(3) Compared with other types of cutting tools, the main cutting edge of a standard twist drill is very long, which is not conducive to chipping and chip breaking.
(4) The secondary backlash angle of the secondary cutting edge at the land is zero, resulting in increased friction between the secondary flank and the hole wall, increased cutting temperature, large wear at the outer edge of the drill, and deterioration of the machined surface roughness. .
What kind of drill bit?
28 3月 2018 | 没有评论 | posted by admin | in Article
A. Classified by structure
(1). End-welding drills, where the top of the drill is welded by carbides.
(2) Integral drill: The drill head, drill body and drill shank are integrally manufactured from the same material.
B. Classified by drill collar
(1) Taper shank bit: The shank of the bit is tapered, and its taper is generally Morse taper.
(2) Straight shank drill: The diameter of the drill is less than 13.0mm, all adopt straight shank.
Diamond tools
26 3月 2018 | 没有评论 | posted by admin | in Article
It refers to the use of bonding agents to consolidate diamond (generally referred to as synthetic diamond) into a certain shape, structure, size, and tool products for processing.
Broadly speaking, diamond abrasive pastes, rolling saw blades, cold-inlaid diamond wire drawing dies, cold-inlaid diamond cutting tools, and brazed diamond composite cutting tools are also diamond tools.
