The automatic tool exchange system refers to a processing device that realizes the tool change requirements for continuous processing between part processes. The automatic tool exchange system consists of a tool magazine and a tool changing device. Among them, there are three main types of automatic tool change systems that are most widely used, namely, turret tool change system, spindle direct tool change system with disk tool magazine, and tool change manipulator tool change system with chain tool magazine. The tool magazine can be vertical or horizontal.
The tool exchange system of a machining center is also called an automatic tool changer (ATC). It usually consists of a tool magazine and a manipulator and is an indispensable part of the machining center. According to the tool exchange method, the tool exchange system of the machining center can be divided into two types: one is a tool exchange system with a manipulator; the other is a tool exchange system without a manipulator.
4. Classification of knife handles
The tool holder is an important part of the connection between the spindle and the tool of the machining center. Through the tool holder, various standard tools can be quickly and accurately installed into the machine tool spindle and tool magazine. The tool holder is also an important link that affects the concentricity and dynamic balance of machining. The concentricity determines whether the cutting amount of each cutting edge part is uniform when the tool rotates for one revolution; the dynamic balance affects the vibration amount of the tool when the spindle rotates. As the current spindle speed becomes higher and higher, the selection of tool holder has an increasingly important impact on the processing quality.
1. Classification by spindle taper hole
According to the spindle taper hole of the machining center, tool holders are divided into two categories: SK universal tool holders with a taper of 7:24 and HSK vacuum tool holders with a taper of 1:10.
(1) SK universal tool holder with a taper of 7:24 The SK universal tool holder with a taper of 7:24 adopts a separate taper surface positioning and is a type of tool holder with a longer taper shank. Through the tapered surface, the tool holder is accurately positioned relative to the spindle and the tool holder is clamped, as shown in Figure 2-31. SK universal tool holders with a taper of 7:24 usually have five standards and specifications, namely NT (traditional type, referred to as NT or ST), MAS BT (Japanese standard, referred to as BT), DIN69871 (German standard, referred to as JT, DIN, DAT or DV), ISO 7388-1 (International Standard, referred to as IV or IT), and ANSI/ASME (American Standard, referred to as CAT).
Figure 2-31 SK universal tool holder with a taper of 7:24
At present, the two most commonly used tool holders in China are DIN 69871 and MAS BT. ISO 7388-1 type tool holders can also be installed on machine tools with DIN 69871 and ANSI/ASME spindle taper holes, so the ISO 7388-1 type tool holders have the best versatility.
(2) HSK vacuum tool holder with a taper of 1:10 HSK vacuum tool holder is a type of tool holder that relies on the elastic deformation of the tool holder, and the cone surface and flange end surface are in contact with the spindle taper hole surface and end surface at the same time for positioning. Considering that the 7:24 universal tool holder with single-sided connection will retract due to the influence of tension during high-speed rotation, the double-sided contact system of HSK tool holder is excellent in high-speed processing, connection rigidity and coincidence accuracy. 7:24 universal tool holder, so HSK vacuum tool holder is more suitable for high-speed machining and is widely used in aerospace, automotive, precision mold and other manufacturing industries, as shown in Figure 2-32.
Figure 2-32 HSK vacuum tool holder with a taper of 1:10
The German standard for HSK vacuum tool holders is DIN 69873, which includes six standards and specifications, namely HSK-A, HSK-B, HSK-C, HSK-D, HSK-E and HSK-F. There are mainly three types of toolholders commonly used in production: HSK-A (automatic tool changer with internal coolant), HSK-E (automatic tool changer with internal coolant, high-speed type) and HSK-F (automatic tool changer with internal coolant, high speed type). There are two differences between HSK-A and HSK-E: First, HSK-A has a transmission groove but HSK-E does not, so relatively speaking, HSK-A transmits a larger torque and can relatively perform some heavy cutting, while HSK-A The torque transmitted by -E is relatively small, and it can only perform some light cutting; secondly, in addition to the transmission groove, the HSK-A tool holder also has manual fixing holes, direction grooves, etc., so the balance is relatively poor ; HSK-E does not have it, so HSK-E is more suitable for high-speed processing. The difference between HSK-E and HSK-F mainly lies in the difference in model and size. Compared with HSK-E and HSK-F tool holders, the taper size of HSK-F tool holder is smaller.
