Serialize and standardize the tools with strong versatility and the tools for supporting clamping, which becomes the commonly called tool system.
That is to say, the tool system is developed by requiring that the tools matched with the CNC machine tools must be fast changing and efficient cutting.
It is the interface between the tools and the machine tools (see Fig. 8-1).
In addition to the tool itself, it also includes the positioning, clamping, grasping and tool protection mechanisms necessary for tool quick change.
The tool handle is the last link between the machine tool and the tool, which plays an important role in the performance of the entire tool system.
As the tool system is affected by centrifugal force in high-speed cutting, it is required that the tool system has smaller quality, higher balance accuracy and the ability to maintain clamping force.
To this end, major tool manufacturers have introduced new tool systems (see Fig. 8-2) to meet the processing requirements of high-speed and heavy load cutting.
Fig. 8-1 Tool System in Use
Fig. 8-2 Various Tool Systems
1. Introduction to tool system
In addition to the characteristics of ordinary tools, the CNC machine tool system mainly has the following requirements:
(1) Accuracy requirements.
High tool change accuracy and positioning accuracy.
(2) Stiffness requirements.
NC machining often has large feed rate, high speed and strong cutting, and requires high rigidity of tools.
(3) Requirements for convenient handling and adjustment.
(4) Requirements for standardization, serialization and generalization.
This “three integration” facilitates the installation of tools on turrets and tool libraries, simplifies the structure and action of manipulators, reduces the cost of tool manufacturing, reduces the number of tools, expands the scope of application of tools, and is conducive to NC programming and tool management.
2. Classification of tool systems
（1） Classification by structure
CNC machine tool system is divided into boring and milling CNC tool system and lathe CNC tool system.
They are mainly composed of two parts: one is the tool part, and the other is the clamping tool part such as tool handle (tool handle), extension rod (extension handle) and collet.
NC tool systems for boring and milling can be divided into integral tool system (TSG) and modular tool system (TMG) according to their structures.
1. Integrated structure (TSG tool system)
The tool handle of the integrated tool system (see Fig. 8-3) is connected with the working part of the clamping tool.
This tool handle has good rigidity and high accuracy, but it has poor adaptability to the transformation of machine tools and parts.
In order to adapt to the transformation of parts and machine tools, users must store tool handles of various specifications, which makes the variety numerous and management inconvenient, so the utilization rate of tool handles is low.
Fig. 8-3 Integrated structure (TSG tool system)
2. Modular structure (TMG tool system)
The modular tool system (see Fig. 8-4) is a relatively advanced tool system. Each tool handle can be assembled by various serialized modules.
Different assembly schemes can be adopted for processing different parts and using machine tools to obtain a variety of tool handle series, thus improving the adaptability and utilization of the tool handle.
It is economical, flexible, fast, reliable, and versatile, However, because the tool handle needs to be assembled with various and multiple modules during use, its accuracy is not as good as the integral structure.
Fig. 8-4 Modular structure (TMG tool system)
3. Selection principle of knife handle structure
The selection of the structural form of the tool handle should not only consider the progressiveness of technology, but also be economical and reasonable.
The specific requirements are as follows:
(1) For some simple tools that are repeatedly used for a long time and do not need to be assembled, it is better to equip an integral tool handle to make the tools rigid and cheap (such as the end mill tool handle, spring collet tool handle and drill collet tool handle for machining the outer contour of parts).
(2) When machining a variety of small batches of parts with frequently varying hole diameters and depths, modular tool handles should be selected to replace a large number of integral boring tool handles and reduce processing costs.
(3) When there are many CNC machine tools, especially the intermediate module (extension bar) and working module (tool mounting module) used by the machine tools can be used universally, selecting a modular tool system can greatly reduce equipment investment and improve tool utilization.
（2） Classification by design
At present, tool systems can be roughly divided into two categories according to design:
1. The 7:24 large taper and long taper handle structure are adopted to maintain the good strength of the tool body and high dynamic radial stiffness, which is an improvement on the original taper handle structure, such as BT tool handle, BIG plus tool handle, etc.
2. Structural design for changing taper of taper shank
The typical structure is the taper handle structure design with 1:10 taper and 1:20 taper, such as CAPTO tool handle, HSK tool handle, KM tool handle, etc.