Characteristics of CNC toolholder types
(1) When machining curved parts, in order to ensure that the cutting edge of the tool is tangent to the machining contour at the cutting point and avoid interference between the cutting edge and the workpiece contour, a ball-end cutter is generally used, a two-edge milling cutter is used for rough machining, and a four-edge milling cutter is used for semi-finishing and finishing
(2) When milling larger planes, in order to improve production efficiency and improve the machining surface roughness, a blade-embedded disc milling cutter is generally used
(3) When milling small planes or step surfaces, a general-purpose milling cutter is generally used
(4) When milling keyways, in order to ensure the dimensional accuracy of the slot, a two-edge keyway milling cutter is generally used
(5) When machining holes, drills and other hole machining tools can be used
CNC toolholder structure:
The structure of CNC machine tool toolholders is divided into two types: integral and modular. The integral toolholder has a working part that clamps the tool and a handle that is used to install and position the tool on the machine tool. This type of toolholder has poor adaptability to the changes of machine tools and parts. In order to adapt to the changes of parts and machine tools, users must reserve toolholders of various specifications, so the utilization rate of toolholders is low. The modular tool system is a more advanced tool system, and each toolholder can be assembled through various serialized modules. According to different processing parts and machine tools, different assembly schemes can be adopted to obtain a variety of toolholder series, thereby improving the adaptability and utilization rate of toolholders.
The selection of toolholder structure should take into account both advanced technology and economic rationality: ① For some simple tools that are used repeatedly for a long time and do not need to be assembled, it is advisable to equip them with integral toolholders, so that the tools have good rigidity and are cheap (such as end mill toolholders, spring chuck toolholders and drill chuck toolholders for machining the outer contour of parts); ② When machining multi-variety and small batch parts with frequently changing hole diameters and hole depths, modular toolholders should be used to replace a large number of integral boring toolholders to reduce processing costs; ③ For CNC machine tools, especially when the machine tool spindle ends and tool change manipulators are different, modular toolholders should be used. Since the intermediate modules (connecting rods) and working modules (tool loading modules) used by various machine tools can be used universally, equipment investment can be greatly reduced and tool utilization can be improved.
Specifications of CNC toolholders:
Most CNC toolholders use 7:24 conical toolholders, and use the corresponding type of rivet tensioning structure to match the machine tool spindle. Toolholders have various specifications, and the commonly used ones are 30, 40 and 50. At present, ISO7388-1983, GB10944-1989, MAS403-1982, ANSI/ASMEB5.50-1985, etc. are widely used in my country. When choosing, the toolholder specifications should be considered to be compatible with the machine tool spindle and manipulator.
Specifications and quantity of CNC toolholders:
The integrated TSG tool system includes 20 types of toolholders, and the number of specifications is as many as hundreds. Users can select the variety and specifications of toolholders according to the CNC machining process of typical parts to be processed, which can meet the processing requirements without causing backlogs. Considering that a certain number of toolholders are in pre-adjustment or tool grinding while the CNC machine tool is working, the number of toolholders is usually 2 to 3 times the required toolholders.
Matching of CNC tools and toolholders:
Pay attention to the matching of toolholders and tools, especially when selecting tapping toolholders, pay attention to the size of the tap drive square head. In addition, the use of single-edged boring tools on CNC machine tools can avoid scratching the workpiece when retracting the tool, but attention should be paid to the position and direction of the tool tip relative to the keyway on the toolholder: some machine tools require the same orientation as the keyway, while others require it to be perpendicular to the keyway.
Choose high-efficiency and composite tool holders.
In order to improve processing efficiency, high-efficiency tools and tool holders should be used as much as possible. For example, a double-edged boring tool holder can be used for rough boring, which can not only improve processing efficiency but also help reduce cutting vibration; a powerful spring chuck can not only hold straight-shank tools, but also can hold tools with holes through adapters. . For typical workpieces with large batches and complex processing, composite cutting tools should be used as much as possible. Although composite cutting tools and tool holders are relatively expensive, the use of composite cutting tools on machining centers can combine multiple processes into one process and be completed by one tool, which is beneficial to reducing processing time and the number of tool changes, and significantly improving production. efficiency. For some special parts, specially designed composite tool holders can also be considered.