What are the inspection standards for tool holders made of tool materials?
The tool holder is the link between the machine tool and the tool. Usually there is a high-precision inner taper hole in the machine tool spindle, whose taper is the same as the tool shank. The tool shank can be automatically pulled into the machine tool spindle through a rivet installed on the top. The lower part of the tool handle is the tool holder part, which is used to clamp the tool.
Usually the tool handle is composed of 4 parts:
1) Pull nail
2) Taper shank
3) Flange and V-shaped groove
4) Tool holder part
Type of taper shank: It depends on the way the tool holder is connected to the machine tool. The choice of the connection method between the tool holder and the machine tool spindle mainly considers the method of tool change (automatic or manual), the size of the clamping force (the size of the taper, the source of the clamping force) and the rotation speed. There are two most commonly used ones, namely steep taper shank SK (BT/CAT) with a taper of 7:24 and hollow cone shank HSK 1:10 (see 6.10-6.13 for details).
Steep tapered shank: referred to as SK type or BT type or 7:24 universal type. This kind of tool handle has a larger taper of 7:24 and is the most commonly used tool handle. It can withstand higher speeds and higher torques and is mostly used in automatic tool changing machine tools. The taper shank is directly installed in the taper hole of the machine tool spindle. There is a connecting bolt (pull nail) on the top of the tool holder. The clamp of the spindle in the machine tool clamps the rivet on the top of the tool holder and pulls it upward to pull the tool holder into the machine tool spindle. , and at the same time, it is mainly clamped by the friction between the tool holder and the machine tool spindle wall.
Tool shank specifications:
The tool shank has specifications of 30, 35, 40, 45, 50 and 60, which indicates somewhere on the taper shank (the specific location is in different standards are not different) diameter size. The specifications of the cone are usually selected by the machine tool manufacturer based on the effective power of the machine tool or the overall length of the tool used, and are also related to the country of production (DIN standard in Europe, ANSI standard in the United States, and JIS standard in Japan). Commonly used tool handle specifications are 30, 40, and 50, of which 40 is the most widely used.
Tool holder standards:
German standard DIN2080, DIN69871
DIN2080 type (NT or ST for short): without V-shaped groove (gripper groove) , mainly used for manual tool changing machine tools. It is used to pull the tool holder into the traditional machine tool through a tie rod and then clamp it.
DIN69871 type (SK, JT, DIN, DAT or DV for short): It is characterized by a V-shaped groove, which facilitates the manipulator to take out the tool from the tool chain or tool magazine and load it into the spindle. The clamp of the spindle in the machine tool is clamped on the rivet of the tool holder from the outside inward. When the machine tool rotates at a high speed, the centrifugal force causes the clamps to loosen outwards, reducing the clamping force and easily causing the tool handle to loosen or fall off. Therefore, it is often used for processing with low rotational speeds but large torque. It can be divided into the following 4 types:
-DIN69871A type: without central cooling water hole
-DIN69871AD type: with central cooling water hole
-DIN69871B Type: with side flange cooling water holes
-DIN69871AD/B type: with core and side flange cooling water holes
But the side holes are threaded holes . When internal core cooling is used, the sides can be blocked with bolts.
Japanese standard JISB6339 (MAS403BT) (abbreviated as BT)
BT type is a Japanese standard. Its dimensions are completely different from DIN69871, IS07388/1 and ANSI and cannot be interchanged. The symmetrical structure of the BT type tool holder makes it have better high-speed stability than the other three types of tool holders.
American standard ANSIB5.50 type (CAT for short)
The installation dimensions are similar to DIN69871 and ISO7388/1, but due to the lack of a wedge, the ANSIB5.50 type tool holder cannot be installed On DIN69871 and IS07388/1 machine tools, but DIN69871 and ISO7388/1 tool holders can be installed on ANSIB5.50 type machine tools.
Among the above four types of standards, except for DIN2080, which tightens the tool holder through a pull rod on a traditional machine tool, the other three types of tool holders are all tightened on the machining center through pull nails on the top of the tool holder. tension. At present, the two most commonly used tool holders in China are BT type and DIN69871 type (SK).