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What is Turning and machining ?
Turning and machining - Auto industry
Turning and machining - Aerospace industry
Turning and machining - Advantages
Turning and machining, is widely applied in the auto industry. Turning and machining complement each other. Turning and machining consumes at least five times more energy per metal removal. Turning and machining of gray cast iron with PCBN at high speeds is very successful in many applications. Turning and machining new materials is new method used in aerospace industry. Turning and machining using PCD toosl offers industry long tool life & deliver more parts per edge. Hard turning and machining is generallly defined as turning Steel of Rockwell Hardness C-45 and above.
PCBN tools can be very effectively utilized for this purpose.
Kindly consult your PCBN Tool manufacturer for further details.
New PCD tool materials, designed to be tougher and to resist chipping, cannot
be ruled out, and neither the development of new machining techniques.PCD tools
are now largely used for machining. For machining hardened ferrous materials
there are wide variety of PCBN products available.
Polycrystalline cubic boron nitride tool inserts, which were introduced commercially
in 1975, consist of a layer of CBN sintered with a tungsten carbide substrate
to form an integral blank. These can be braized directly to tool shanks or used
as indexable inserts to machine high temperature alloys & hard ferrous materials.
A new product in which ceramic grains are added to the sintering process, was
introduced in 1991. The ceramic component of this product provides high chemical
stability, while the pcbn supplies superior hardness & resistance to abrasion
& chipping. This product holds tighter tolerances than ceramic tools, while
providing resistance to the chemical reaction that can cause cratering in other
cbn tools. These new CBN/ceramic inserts perform at high speeds & achieve
material removal rates from 4-10 x over conventional grinding.
Although numerous operations are performed on the gray cast iron engine block,
superabrasives have generally been used in the boring, milling & honing
processes. High volume transfer lines which are typically used for engine block
processing have benefited tremendously from increased productivity resulting
from changes to superabrasives from conventional tooling.
When evaluating engine production for the use in automotive applications, we
find the worldwide production was approximately 36 million engines. As stated
above, Europe was the largest producer in this category with 15.1 million engines,
followed by the pacific region with 12.3 million & the Americans with 8.6
million.
The cylinder bore of an engine block is typically machined in
a three step process-rough, semi-finish & finish. When tungsten carbide
tooling was used, the cutting speeds were generally below 800 ft./min. The progression
to alumina based ceramics allowed cutting speeds to be increased to approx.
1800 ft./min. with marginal tool life. When silicon nitride & PCBN were
introduced, cutting speeds increased to 4000 ft./min. & higher. The use
of PCBN in these volume applications allows for considerably greater productivity
and superior cylindricity. The boundary between cutting and grinding is slowly
diminishing.
