Super-Hard Cutting Tools Introduction
The super-hard cutting tools include synthetic diamond composite pieces(PCD cutting tools) and cubic boron nitride composite pieces(PCBN cutting tools),with their high wear-resistance,hardness,thermal-conductivity and low friction coefficient to achieve high precision,efficiciency and surface roughness after machined on non-ferrous and wear-resistance non-metal materials. This type of cutting tools are divided into welding-PCD tools and PCD indexable inserts in terms of structure. In recent years, the welded PCD tools with standard holders have been developed very quickly such as PCD milling tools, boring tools,reamers,which all with holders, meanwhile the holder type is consist of cylindrical, taper and HSK shaft. This tools(especially for the one with abundant teeth) featured with very small runout between cutting edge and shaft(for instance, the flute length as 30mm HSK holder milling tools, the runout of cutting edge is only 0.002mm),very suitable for massive machining on various parts profile-forming faces, holes and steps. For example, taking PCD high speed milling tool with aluminum-base(six-flutes,dia100mm with highest cutting speed at 20).The super-hard cutting tools include diamond and PCBN ones,indexable PCD insert is welded on the tungsten carbide base and formed by means of profile-sharpening, which is capable to be fixed onto different CNC holders, tool holder and cutter heads for massive and stable machining work. With development and popularity of CNC equipements,CNC center and automatic producing line, the indexable PCD inserts have been used more and more, which wear-resistance performance is 10 times more than the tungsten carbide ones.
The PCBN cutting tools also divided into welded and indexable one. The welded PCBN cutting tools make the PCBN insert weld on the steel base and formed by profile-sharpening process, mainly include turning, boring and reamer tools.Meanwhile,the PCBN cutting tools are mostly for ferrous material process with good wear-resisitance,so its cutting edge angle unavailable to be too small, the rake angle usually is between -5 ° ～ 5 °,clearance angle range 3 ° ～ 10 °,and taking negative-chamfering for intermittent turning. On the other hand, the indexable PCBN inserts(mainly for turning and milling inserts) generally get a PCBN pieces weld onto the a corner of indexable tungsten carbide insert, in ddition,considering to repeated sharpening and high cost of the PCBN blank, usually it is only made with one cutting edge.Lastly,as improvement of welding capability and technique, its trimming toughness is reaching 0.78kg/m2,in the meantime with the PCBN blank size smaller and smaller, the one-time PCBN insert cost is also reduced accordingly.
