1 Overview:
In recent years, the scientific and technological achievements of CNC tools are mainly reflected in the development of more than one cutting function and improved cutting edge cutting performance, adapting to high speed (super high speed), hard (including heat, difficult to process), dry, fine (super fine) Cutting and high efficiency CNC machining cutting technology requirements. With the advancement of part blank manufacturing technology, the geometrical dimensions and cutting allowance of the part blank are more precise. The development of new structure and new varieties of CNC tools is mainly concentrated in the light and medium load cutting range, and the special hole machining, broaching and rolling The five types of tools, such as pressing, rolling and pressing, milling and turning, are more active, and they are equipped with corresponding blade chipbreakers.
2. CNC tool system:
In recent years, the development trend of other types of tool systems developed by various manufacturers has been gradually replaced by the “HSK” tool system. Developed countries in Europe follow the German HSK tool system standard DIN69893-1, and the International Standardization Organizing Committee has established ISO/DIS standards for it. The HSK tool system has the characteristics of high dynamic and static stiffness, good positioning (twisting) accuracy, and high allowable speed (≤150000p.rm). It not only facilitates the management of tools, but also saves tool costs and reduces production costs. It is first applied to machining centers, CNC boring and milling machines, and gradually expanded to various types of lathes (turning centers), grinding machines (grinding centers), CNC special machines and CNC machining automatic lines, covering almost all tool fields.
3, hole processing tools:
In the tool category, the hole machining tool is a big family, and its small reforms are endless. Here, the main new structures and new varieties are briefly described as follows:
●CNC drill:
Integral drill bit: The cutting edge of the drill tip is improved from symmetrical linear type to symmetrical circular arc type (r=1/2D) to increase the cutting edge and improve the life of the drill tip. The drill core is thickened to increase the rigidity of the drill body. The type of chisel edge (or spiral center blade) replaces the traditional chisel edge to reduce the axial drilling resistance and improve the life of the chisel edge. The stepping tip and the negative edge of the different top angle steps are used to improve the chipping, chip breaking and drilling performance. And hole processing precision; inlaid modular hard (super hard) material crown; oil hole cooling and large spiral angle (≤ 40 °) structure. Recently, a monolithic fine-grain ceramic (Si3N4), Ti-based cermet material drill has been developed.
Machine-clamping drill bit: The drill tip adopts a special symmetrical cutting edge with a rectangular shape and a radially self-balancing indexable insert with a drilling force to replace other geometric shapes and a drilling force. Small drilling vibration improves the self-centering performance, life and hole machining accuracy of the drill tip.
●Composite (combined) hole machining CNC tool:
The new structure and new technology of the drill bit, the reamer, the expansion boring tool and the extrusion tool are combined. The development of the integrated tool for the integral type, the machine clamp type and the special composite (combination) hole processing is very fast. In general: the use of inlaid modular hard (ultra-hard) material cutting edge (including crown) and oil hole cooling, large spiral groove and other structures is its current development trend.
●CNC reamer:
The large spiral angle (≤45°) cutting edge, bladeless extrusion reaming and oil hole cooling are the overall development direction, and the maximum reaming aperture has reached φ≤400mm.
●Sickle:
The single-edged fine-tuning precision boring tool is being replaced by a multi-blade expansion (锪) hole cutter, reamer and composite (combination) hole machining special CNC tool. In foreign countries, the use of the tool system internal push-pull rod axial movement or high-speed centrifugal force to balance the slider movement, one-time pass to complete the boring spherical surface (curved surface), inclined surface and reverse machining of the back part of the CNC precision precision boring tool, representative The development direction of the sickle.
