Dispatch of net of machine tool of Chinese numerical control: About cutting tool life, depend on normally different workpiece and cutting tool material, and different cutting technology. A kind of way that life of quantitative analysis cutting tool ends a point is face of the knife after what set can accept is the biggest wear limit is worth (express with VB or VBmax) . Cutting tool life can strap formula to express with the peaceful that expects cutting tool longevity, namely VcTn=C, a formulary kind of more commonly used form is VcTn × Dxfy=C in type, vc is cutting speed; T is cutting tool life; D is cutting deepness; F is feed rate; X and Y are decided by the experiment; N and C are the constant that decides according to experiment or the technical material that already published, they show cutting tool material, workpiece and the character that feed leads. The matrix of optimal cutting tool of ceaseless development, coating and technology of cutting blade preparation wear away to restricting cutting tool and counteractive cutting high temperature is crucial. These element, add bits chamfer and radius of corner circular arc are broken in what can use on dislocation razor blade, decided the applicability that every kinds of cutting tool machines to different workpiece and cutting. All optimal combination of these element can prolong cutting tool life, make cutting is machined more economy, more reliable. Change matrix is passed in 1 - the size that carbonization tungsten changes inside limits of 5 μ M, tool manufacturer can change the matrix property of hard alloy cutting tool. The granuality of base material is having main effect to cutting function and cutting tool life. Size is smaller, the wearability of cutting tool is better. Conversely, size is larger, the obdurability of cutting tool is better. Fine grained matrix basically is used at processing aviation brand data (the alloy that be like titanium, Inconel alloy and alloy of other high temperature) bit. In addition, raise the cobaltic content of material of hard alloy cutting tool 6% - 12% , can obtain better tenacity. Accordingly, can satisfy the requirement that specific cutting machines through adjusting cobaltic content, no matter this kind of requirement is tenacity or wearability. The function of cutting tool matrix still can be close to outside face place to form rich cobaltic layer through be in, perhaps add other alloying element optionally through having in hard alloy material (wait like titanium, Tantalum, vanadium, niobium) and obtain increase. Rich cobaltic layer can be shown increase cutting blade strength, improve the performance of rough machining and interrupted cutting cutting tool thereby. In addition, when the cutting tool matrix that matchs in choice and workpiece material and treatment means photograph, return expression to consider character of additionally 5 kinds of matrix -- rupture tenacity, transverse rupture intensity, compressive strength, hardness and heat-resisting concussion function. For example, if hard alloy cutting tool appears to die along cutting blade the phenomenon of blade, should choose appliance to have rupture higher the base material of tenacity. And in blade of cutting tool occurrence cutting the circumstance of direct be no longer in force or damaged falls, the solution that employs possibly is to choose appliance to have taller horizontal stroke to rupture intensity or the base material of higher compressive strength. Taller to cutting temperature treatment circumstance (if do type cutting) , normally should the cutting tool stuff with first selection more expensive hardness. Close in the treatment field that can observe cutting tool produces hot crack (the commonnest in milling treatment) , the proposal chooses heat-resisting to pound the cutting tool stuff with better performance. Coating chooses coating to also conduce to the cutting performance that improves cutting tool. Current coating technology includes: ① nitrogen changes titanium (TiN) coating: This is a kind general-purpose PVD and CVD coating, can raise the hardness of cutting tool and oxidation temperature. ② carbon nitrogen changes titanium (TiCN) coating: Through carbolic element is being added in TiN, the hardness that raised coating and surface are bright and clean degree. ③ nitrogen aluminous titanium (TiAlN) with azotic titanium aluminium (AlTiN) coating: Alumina (Al2O3) the cutting tool life that layer and the compound application of these coating can improve high temperature cutting to machine. Alumina coating suits to do type cutting and close dry cutting especially. The aluminous content of AlTiN coating is higher, with titanium content taller TiAlN coating photograph is compared, have taller exterior hardness. AlTiN coating is used at high speed cutting to machine normally. ④ nitrogen changes chromium (CrN) coating: This kind of coating is had better fight felt function, it is the first selection solution of tumour of antagonism accumulating bits. ⑤ diamond coating: Diamond coating can show the cutting performance that improves treatment to be not cutting tool of material of iron a group of things with common features, suit to machine black lead, metal radical very much aluminium alloy of composite material, tall silicon and material of other tall abrasion. But diamond coating does not suit to process steel, because the chemical reaction of it and steel is met,destroy the conglutinate function of coating and matrix. In recent years, the market share of PVD coating cutting tool expands somewhat, its price also equallies matched with CVD coating cutting tool. The ply of CVD coating is normally 5 - 15 μ M, and the ply of PVD coating is about 2 - 6 μ M. When besmear Fu arrives on cutting tool matrix, CVD coating can arise to pull stress undesirably; And PVD coating conduces to pair of matrix form becoming beneficial pressing stress. Thicker CVD coating can show the strength that reduces blade of cutting tool cutting normally. Accordingly, CVD coating cannot be used at the cutting tool with requirement cutting very sharp blade. Cutting blade preparation falls in a lot of circumstances, the preparation of bit cutting blade (or call point passivation) the watershed that already became a decision to machine success or failure. Passivation craft parameter needs a basis to specific treatment asks and be decided. For example, use at high speed finish machining steel the bit requirement to point passivation differs somewhat with the bit that is used at rough machining. Point passivation applicable at treatment almost the razor blade of any type carbon steel or alloy steel, and on the razor blade that processing stainless steel and special alloy data, its application has certain restriction. Passivation quantity is OK small to 0. 007mm, also can arrive greatly 0.
05mm. Enhance the action of cutting blade to rise in the treatment with harsh condition, still can form band of tiny T arris through point passivation. Generally speaking, with the point passivation that at successive turning treatment and milling major steel and cast-iron razor blade need to have older rate. Passivation quantity depends on hard alloy brand and coating type (CVD or PCD coating) . Machine bit to spending interrupted cutting again, undertake weighing spending passivation to point or machine belt of a T arris to already became a kind of precondition. According to different coating type, passivation quantity is approachable 0.
05mm. As contrary as this, because machine the razor blade of stainless steel and high temperature alloy to form the tumour that accumulate bits easily, because this asks cutting blade keeps sharp, can undertake slight passivation only (but small to 0.
01mm) , OK still even custom-built smaller passivation amount. Same, the razor blade that machines aluminium alloy also asks to have sharp cutting blade. CNC Milling
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