Horizontal CNC boring and milling machines with automatic tool changer are collectively referred to as horizontal CNC machining centers. Horizontal CNC machining center is a kind of automatic processing equipment developed on the basis of CNC boring and milling machine. It can realize one-time clamping and multi-process processing through automatic tool change. The machine has the strongest function and wide application range.
The vertical movement of the tool (Y axis) of the horizontal machining center can only be realized by the movement of the box. Therefore, the structural difference of the machine tool should be reflected in the movement of the X and Z axes. It mainly includes table movement and column There are four basic types of movement, worktable/column stick movement and box movement. Among them, the box movement is a new structure of high-speed, high-precision horizontal machining centers. The relevant content will be described later.
1, movable table
Worktable moving horizontal plus L center is shown in Figure 6.2-1. The structure of the machine tool is similar to that of a horizontal boring machine. Its X and Z axis movements are realized by a cross slide. The general characteristics of the machine tool are as follows.
(1) Basic components
The movable horizontal machining center of the workbench usually adopts a frame-type vertical housing and a wide bed structure, which has good integrity, convenient installation and transportation, and high processing accuracy. The machine tool is generally equipped with a numerical control turntable or indexing table (B axis). In order to meet the needs of double-sided processing of deep holes and coaxial holes, the positioning accuracy of the turntable is usually high.
(2) Automatic tool changer
The size of the mobile horizontal machining center of the worktable is generally small. The tool magazine capacity of the machine tool is usually within 40 tools. The tool magazine is often placed on the side of the column or above the column. The tool can be changed without a robot or a robot.
(3) Automatic workbench exchange
It is difficult to exchange the worktable of a horizontal CNC machining center. It can only adopt a push-pull mobile exchange method, which takes a long time to exchange worktables and it is difficult to clean up iron filings. Therefore, there are relatively few cases of configuring a switching table.
The movable worktable is the traditional structure of the horizontal machining center. The machine tool also has problems such as complex structure, poor x-axis support rigidity, and difficulty in table exchange, so it is more suitable for small horizontal machining centers.
2. Column movable type
The horizontal machining center with the column moving is also called the moving column horizontal machining center. The movement of the X and Z axis is realized by vertical movement. The moving column machining center has a large x-axis stroke, but the weight of its moving parts is heavy, and the movement speed and positioning accuracy are subject to certain restrictions. Therefore, it is mostly used for large and medium-sized horizontal machining centers with fixed worktables and machine tools with interchangeable worktables.
3. Hybrid mobile
The worktable support rigidity of the mobile workbench machining center is poor, the X-axis movement range is small, and the weight of the workpiece directly affects the movement speed and accuracy of the machine tool; the column of the mobile workbench machining center needs to have a two-layer structure, and the moving parts are heavy. There are certain difficulties in improving the movement speed and positioning accuracy. For this reason, small and medium-sized horizontal machining centers often use the worktable/column mixed mobile structure shown in 6.2-3 to simplify the structure of the machine tool, increase the X-axis stroke, increase the load-bearing capacity of the worktable, and reduce the cost of moving parts of the column. weight.
Figure 6.2-3a is a horizontal machining center that adopts table movement for z-drawing and column movement for x-axis. The machine tool eliminates the x-axis sliding table of the worktable mobile machine tool and the Z-axis sliding table of the column mobile machine tool, which reduces the structural level and the weight of the moving parts. The machine tool has good rigidity, strong load-bearing capacity, and large rotary table specifications, but its x The axis stroke is generally short, so it is suitable for large and medium-sized horizontal machining centers for processing box parts.
Figure 6.2-3b is a horizontal machining center with table movement on the x-axis and column movement on the z-axis. The structure is similar to a planer CNC boring and milling machine. The machine tool with this structure eliminates the z-axis sliding table of the worktable moving machine tool and the x-axis sliding table of the column moving machine tool. It can also reduce the structure level, reduce the weight of moving parts, and improve the rigidity of the machine tool and the load-bearing capacity of the worktable. Compared with the structure shown in Figure 6.2-3a, the x-axis stroke of the machine tool is large, so it is suitable for processing long workpieces such as large molds, bed bodies, and beams.