DV30, DV40, and DV50 are three specific types of interfaces specified by the DIN69871 standard.
DV30 refers to a tool shank with a 30-degree taper angle and a diameter ratio of 1:3. It is a smaller and less common interface compared to the others. It is mainly used for small- to medium-sized machine tools.
DV40 refers to a tool shank with a 40-degree taper angle and a diameter ratio of 1:2. It is a common interface used in many machine tools, it is used for medium- to large-sized machine tools, and is suitable for a wide range of cutting tools, including milling cutters, drilling tools, and reamers.
DV50 refers to a tool shank with a 50-degree taper angle and a diameter ratio of 1:1.5. It is a large and heavy-duty interface, and it is mainly used in high-performance and heavy-duty machine tools, such as those used for milling and boring operations, and for large cutting tools such as face mills and shell mills.
The DIN69871 standard also specifies the dimensions, tolerances, and other technical requirements for these interfaces, which ensure that tool holders can be securely and accurately connected to machine tool spindles.