Talking about the Classification of NC Tools
Second, the recent scientific and technological status and development trend of new products of CNC tool materials
1, overview:
In recent years, the achievements of basic scientific research and new products of NC tool materials are concentrated in high-speed (ultra-high-speed), hard (including heat-resistant and difficult machining), dry and precise (ultra-precision) NC machining and other technical fields. The research and development of new tool materials has made rapid progress in the fields of superhard materials (diamond, surface modified coating materials, TIC-based cermets, cubic boron nitride, Al203, Si3n4-based ceramics), W and CO-based coatings, fine particle (ultrafine particle) cemented carbide matrix and Go-based powder metallurgy high-speed steel.
2. The field of superhard materials:
Various diamond (brazed polycrystalline and single crystal) tools have been rapidly applied to high-speed, high-efficiency and dry (wet) mechanical cutting of non-ferrous gold (alloy) and non-ferrous metal-nonmetal composite parts with high hardness and high strength. The general situation is as follows:
Automobile and motorcycle industries: Polycrystalline, artificial single crystal diamond face milling cutter, boring cutter, turning cutter, reamer, compound (combined) hole machining and other CNC tools are widely used in the automatic production line of high-strength and high-hardness silicon-aluminum alloy parts;
Bamboo and wood flooring and furniture industry: Polycrystalline, CVD thick film deposited diamond (composite) end milling cutter, three-sided forming milling cutter and face milling cutter are widely used in automatic production lines of high-hardness composite bamboo and wood flooring, furniture, doors and windows.
Aviation, aerospace, automobile and electronic information technology industries: Diamond CVD film-coated CNC tools (mainly monolithic WCO cemented carbide tools) are mostly used for milling, turning, drilling, reaming and reaming high-strength aluminum alloys (casting and forging), fiber-metal laminates, carbon fiber thermoplastic composites, magnesium alloys, graphite, ceramics and so on. To meet the requirements of high speed, long life and high efficiency. Various manufacturers are constantly improving diamond coating technology to improve the combination fastness and density of diamond film and tool substrate;
Technical field of fine (ultra-fine) machining: Single crystal natural and synthetic diamond tools are used for fine (ultra-fine, nano-scale) turning of various precision instruments such as lenses, mirrors, computer disks, copiers (video recorders) and magnetic drums.
Single crystal diamond tools are also used in fine cutting of ophthalmic corneal surgery and fine engraving of printing plates … and other industries.
Various manufacturers are constantly improving the grinding technology, grinding accuracy and grinding efficiency of various diamond tools.
● Surface modification coating materials mainly include: TiN, TiCN, TiALN, ALTiN, Al2O3, CrN, ZrC, MoS2, WS2…, etc. Computer-controlled PVD, PCVD and CVD coating technologies are adopted. The coating material is used for surface modification coating treatment of end mills, reamers, drill bits, composite (combined) hole machining tools, gear hobs, gear shapers, gear shaving cutters, forming broaches (push rods) and indexable blades of various machine tool fixtures (the matrix is high-speed steel, WCo cemented carbide and titanium-based cermets), and can process high-strength and high-hardness cast iron (steel) at high speed with long service life. Tool surface modification coating technology has the characteristics of low cost and quick effect, which can greatly improve the cutting performance of NC tools. This technology can flexibly change coating materials according to various cutting technical requirements, and it is superior in technology. Various manufacturers are constantly improving coating technology, improving coating materials and developing nano-scale multifunctional coating materials, aiming at continuously improving coating adhesion, wear resistance and impact toughness, and trying their best to expand the application scope.
Titanium-based cermets (TiCN series) numerical control tools such as indexable turning tools, boring tools, reamers, milling cutters, composite (combined) hole machining and integral vertical (ball-end) milling cutters and reamers are being applied to the automatic production lines of high-strength and high-hardness cast iron (steel) alloys, forged steel alloys, quenched steel alloys, heat-resistant alloys and powder metallurgy parts to meet the requirements of high speed. Various manufacturers are developing new cermet products by adding different trace elements and sintering technology, aiming at continuously improving their bending strength, impact toughness and wear resistance. Japanese cermet tools have accounted for 30% ~ 40% of the total cemented carbide tools. Worldwide, the application of such tools is also expanding rapidly.
● CNC tools such as cubic boron nitride polycrystalline composite chip milling cutter (face milling cutter, corn tooth end milling cutter, ball-end milling cutter), boring cutter, turning cutter, reamer, and composite (combined) hole machining (two structural forms of brazing and machine clamp indexable) are widely used in automatic production lines of high-strength and high-hardness cast iron (steel) alloy, forged steel alloy, quenched steel alloy, powder metallurgy and other parts to meet the requirements of high speed.
● Indexable turning tools, milling cutters, etc ●al2o 3 and Si3N4-based ceramic (whisker toughened) numerical control tools are applied to production lines of high strength, high hardness and wear-resistant cast iron (steel), forged steel, high manganese steel, hardened steel, powder metallurgy, engineering plastics and wear-resistant composite materials, meeting the technical requirements of high speed, high efficiency and hard dry machining. At present, by adding different trace elements to al2o 3 and si3n 4-based ceramic materials, various manufacturers have developed new types of medium-fine particle ceramic materials and functionally graded (multiphase) ceramic materials, aiming at continuously improving their bending strength and impact toughness.
3, tungsten, cobalt coating and fine particles (ultrafine particles) cemented carbide materials leading the market:
W, CO fine (medium) particle cemented carbide matrix material is developed to meet the coating technical requirements of various surface modified coating materials and meet the cutting performance requirements of various processing technologies for indexable inserts. The research and development and application of ultra-fine cemented carbide matrix materials are divided into two aspects: micro-drills and end mills used to process fiber-metal composite laminates in electronics and information technology industries, and their matrix materials develop in the direction of high toughness, and the surface of the tools is coated with diamond films to increase the surface hardness and wear resistance; Mould industry, aircraft, steam turbine, automobile and other manufacturing industries are used for cutting high-strength and high-hardness cast iron (steel), forged steel, aluminum alloy (cast forging) and powder metallurgy materials, integral end mills (ball-end mills), special extrusion mills, reamers (30mm < φ 4mm), drill bits and composite (combined) hole processing tools. Generally, it is not coated and reground many times.
4. Cobalt-containing powder metallurgy high-speed steel materials:
Innovative powder metallurgy high-speed steel (including Co) materials are made into various forming broaches (integral and combined), high-speed hobs, gear shaving (grooving) cutters, taps, wavy edge end mills, forming end mills and rolling (extrusion) cutters by improving the crushing and hot pressing processes and adding trace elements, which are widely used in the manufacture of automobiles, motorcycles, aero-engines and steam turbines. According to the different requirements of cutting technology, its surface is coated with coating materials such as TiN, TiCN, TiALN, CrN, MoS2, ZrC… to meet the technical requirements of high speed, high efficiency and hard precision machining.
CNC tool material is an active leading city in material science and technology. Every new product will make machining technology leap to a new level, and manufacturers have always attached great importance to the research and development technology of this leading city.
Three, the new structure of CNC tools, new varieties and technology development trend
1, overview:
In recent years, the scientific and technological achievements of CNC tools are mainly reflected in the research and development of multi-cutting functions and the improvement of cutting performance of blades, which meet the cutting technical requirements of high-speed (ultra-high-speed), hard (including heat resistance and difficult machining), dry and precise (ultra-precision) cutting and efficient CNC machining. With the progress of manufacturing technology of parts blank, the control of geometric size and cutting allowance of parts blank is more accurate. The research and development of new structure and new varieties of NC tools mainly focus on light and medium load cutting range, and the changes of five types of tools, such as special hole machining, broaching, rolling (extrusion) cutting, milling and turning, are more active, and the corresponding chip groove shapes of tool fragments are developed.
2, CNC tool system:
In recent years, there has been a development trend that "HSK" tool system gradually replaces other tool systems developed by various manufacturers. Developed countries in Europe follow the German DIN 69893- 1 HSK tool system standard, and the International Organization for Standardization has formulated the ISO/DIS standard for them. The HSK tool system has the characteristics of high dynamic and static stiffness, good positioning (rotation) accuracy and high allowable rotation speed (≤ 150000p.r.m). It not only facilitates the management of planning tools, but also saves the cost of tools and reduces the production cost as a whole. It was first used in machining centers and CNC boring and milling machines, and gradually extended to various lathes (turning centers), grinders (grinding centers), CNC special planes and CNC machining automatic production lines, covering almost all tool fields.
3, hole processing tools:
In the tool category, hole machining tools are a big family, and their minor changes and minor leathers emerge one after another. Here, the main outstanding new structures and varieties are briefly described as follows:
● CNC drill bit:
Integral bit: the cutting edge of the drill tip is improved from a symmetrical straight line to a symmetrical circular arc (r = 1/2d) to increase the cutting edge and prolong the life of the drill tip; The drill core is thickened to improve the rigidity of the drill body, and the traditional cross blade is replaced by an S-shaped cross blade (or spiral center blade) to reduce the axial drilling resistance and improve the service life of the cross blade; Using stepped drill tips and negative chamfering edges with different vertex angles to improve chip separation, chip breaking, drilling performance and hole machining accuracy; Embedded modular hard (superhard) material crown; Oil hole cooling and large helix angle (≤ 40) structure. Recently, monolithic fine-grained ceramics (Si3N4) and titanium-based cermet drills have been developed.
Machine-clamped drill bit: The drill tip adopts rectangular special symmetrical cutting edge and indexable blades with radial self-balancing drilling force, instead of indexable blades with other geometric shapes, and comprehensively synthesizes and balances the drilling force in the radial direction, so as to reduce drilling vibration and improve the self-centering performance, service life and hole machining accuracy of the drill tip.
● NC tool for machining compound (combined) holes;
It integrates the new structure and technology of drill, reamer, reaming tool and extrusion tool, and the research and development speed of integrated, machine-clamped and special compound (combined) hole machining NC tools is very fast. Generally speaking, it is the current development trend to adopt embedded modular hard (superhard) material cutting edge (including tooth crown), cooling in oil hole and large spiral groove.
● CNC reamer:
The cutting edge structure with large helix angle (≤ 45), edgeless extrusion reaming and oil hole cooling is its overall development direction, and the maximum reaming aperture has reached φ ≤ 400 mm
● Drilling tools:
Single-edge fine-tuning precision boring tool is being replaced by multi-edge reamer, reamer and special CNC tool for compound (combined) hole processing. A CNC intelligent precision boring tool has been developed abroad, which uses the axial movement of the push-pull rod in the tool system or the high-speed centrifugal force to move with the balance slider to bore and cut the back of the part once, which represents the development direction of boring tools.
● faucet:
A tap with large helix angle (≤ 45) is developed, and its cutting cone is designed with special rake angle and rake angle according to the soft and hard conditions of the machined parts.
Low reaming (reaming) knife:
At present, the development direction of reaming (countersinking) tool is the structure of multi-edge, multiple NC tool holders and modular adjustable micro tool holders.
4, CNC milling cutter:
Integral end milling cutter: the side edge of cemented carbide end milling cutter adopts the structure of large spiral angle (≤ 62), and the over-center end edge of end milling cutter head is often circular (or spiral center edge) and negative edge inclination angle, which increases the cutting edge length, improves cutting stability, workpiece table accuracy and tool life. Adapt to the requirements of CNC high-speed and stable three-dimensional space milling technology.
Machine-clamped end mill: The side teeth, end teeth and over-center edge end teeth (all short cutting edges) composed of indexable blades of various machine-clamped end mills (often with three-dimensional chip-breaking grooves) can meet the technical requirements of NC high-speed and stable three-dimensional space milling.
CNC milling cutter is formed and manufactured by computer aided design, cutting simulation and CNC machining technology.
Machine-clamped CNC face milling cutter: the cutter body tends to be light and high-strength aluminum-magnesium alloy, the cutting edge adopts large rake angle and negative edge inclination angle, and the indexable blades (with various geometries) have three-dimensional chip breaking grooves.
Numerical control milling cutter and special compound hole machining tool should adopt high-speed rotating body dynamic balance and safe clamping technology. Some high-speed rotating tool bodies also use aerodynamic principle and cyclone cold cutting edge to reduce the temperature of cutting edge during dry cutting and improve the tool life.
5, turning tool,
Slotted cutting turning tool is a multifunctional turning tool which integrates turning end face, excircle, copying, slotting, cutting and chamfering. The blade clamping mode adopts the structure of embedded elastic cutter body and self-positioning and fixing cutting force, which is very suitable and novel.
6, broach:
With the support of modern CNC machining technology, we have developed various special broaching tools for precision forming of outer contour, compound broaching and compound turning and broaching by using special CNC machine tools. The mass production efficiency of some automobile parts has been improved by dozens of times, and the product quality and accuracy are very stable.
7. Other tools:
The mass production technology of small-module involute external gears and spline shaft parts of automobiles and motorcycles adopts rolling and kneading chip-free processing technology to develop special tools and special CNC machine tools, which improves the mass production efficiency of specific workpieces by dozens of times and has very stable quality and accuracy.
Four. Concluding remarks
The innovative achievements of pulling, rolling, rubbing and extruding tools and compound (combined) hole machining CNC tools will often lead to great changes in machining concepts, and the integration of tool materials and innovative scientific and technological achievements in the field of special CNC machine tools will also produce great social and economic benefits.
In recent years, the rapid development of NC machining technology has created conditions for the basic scientific research of NC machine tool structure and the research and development of new products. There are many kinds of CNC machine tools produced by the world's major manufacturers, with many specifications and quantities, which are often dizzying and useless. In this paper, the popular science knowledge of CNC tools and their materials, structures, new products, scientific and technological status and development trends in recent years are summarized, so that CNC tools can understand the relevant new product information. Brief introduction of classification II. Overview of the scientific and technological status and development trend of NC tools and new products of NC tool materials 1,: In recent years, basic scientific research achievements have been used for high-speed (high-speed), hard (including heat-resistant and hard machining), dry and precise (ultra-precision) NC machining technology in new products of NC tool materials. The research and development of new tool materials has made rapid progress in the fields of superhard materials (surface modified diamond, coating materials, TIC-based cermets, CBN, Al-203, Si-3N-4-based ceramics), W, CO, coating and fine-grained (ultrafine-grained) Go-containing powder metallurgy high-speed steel and cemented carbide matrix. 2. Ultra-hard materials: Diamond (brazed polycrystalline and single crystal) tools are rapidly applied to the high-speed, high-efficiency dry (wet) processing industry of colored gold (alloy) and non-ferrous metal-non-metallic composite parts with high hardness and high strength. Their general situation is as follows: automobile and motorcycle industries: automatic production lines using polycrystalline, artificial single crystal diamond face milling cutters, boring cutters, turning tools, reamers and composite (combined) hole-making numerical control tools, such as silicon-aluminum high-strength and high-hardness alloy parts; Bamboo flooring and furniture industry: tools such as polycrystalline, CVD diamond thick film deposition (PDC) milling cutter, three-sided milling cutter and cutter are widely used in the automatic production line of high-hardness bamboo flooring, furniture and door decoration parts; Aviation, aerospace, automobile, electronics and information technology industries: CVD diamond film-coated CNC tools (WCO-class integral bonding) are suitable for milling, turning, drilling, reaming and machining high-strength aluminum alloy (casting and forging), fiber metal plate, carbon fiber reinforced thermoplastic composite, magnesium alloy, graphite, ceramics and other parts with feed heads, meeting the technical requirements of high speed, long service life and dry machining. Various manufacturers are constantly developing diamond coating technology to improve the bonding fastness and bonding density between diamond-like carbon film and tool substrate; Fine (ultra-fine) machining technology: Single crystal lens and natural and synthetic diamond tools are used for fine (ultra-fine and nano) turning of precision instruments, mirrors, computer disks and drum of copier (VCR); Single crystal diamond tools are also used in industries such as fine cutting of cornea surgery and fine printing plate carving. Manufacturers are constantly improving the grinding technology of diamond tools and sharpening their knives. ...