The machine tool used in five axis horizontal machining center is usually called five axis machine tool or five axis machining center. Five axis machining is commonly used in machining fields, such as body parts, turbine parts and impellers with free-form surfaces. When describing the motion of CNC machine tool, the right-hand rectangular coordinate system is adopted; The coordinate axis parallel to the spindle is defined as Z axis, and the rotation coordinates around x, y and Z axes are a, B and C respectively. Generally, five axis linkage refers to the linear interpolation movement of any five coordinates in X, y, Z, a, B and C.

五軸臥式加工中 心的回轉軸結構有兩種方式：

There are two kinds of rotary shaft structure in five axis horizontal machining center

一種是通過主軸頭的回轉實現五軸聯動。主軸前端是一個回轉頭，能自行環繞Z軸360度，即C軸?；剞D頭上還帶可環繞X軸旋轉的A軸，一般可達90度以上，實現上述同樣的功能。

One is to realize five axis linkage through the rotation of main shaft head. The front end of the spindle is a rotary head, which can rotate 360 degrees around the Z axis, that is, the c axis. The rotary head is also equipped with a-axis which can rotate around the x-axis, generally up to more than 90 degrees, realizing the same function as above.

這種設置方式的優點是主軸加工非常靈活，工作臺也可以設計的非常大、船舶等領域的大型零部件都適合在這類加工中 心上加工。

The advantage of this setting method is that the spindle processing is very flexible, and the worktable can be designed to be very large. Large parts in ship and other fields are suitable for processing in this kind of machining center.

這種結構的加工中 心在高精度模具曲面加工領域的應用非常多，這是工作臺回轉式五軸加工中 心難以做到的。

The machining center with this structure has many applications in the field of high-precision mold surface machining, which is difficult to be achieved by the five axis rotary machining center.

另一種是通過工作臺回轉實現五軸聯動。機床床身上的工作臺可以環繞X軸回轉（A軸），A軸一般工作范圍+30度-120度。工作臺的中間還設有一個回轉臺，可以環繞Z軸回轉（C軸），C軸都是360度回轉。

The other is to realize five axis linkage through the table rotation. The worktable on the machine bed can rotate around the x-axis (a-axis). The general working range of a-axis is + 30 degrees to - 120 degrees. There is also a rotary table in the middle of the worktable, which can rotate around the z-axis (c-axis), and the c-axis rotates 360 degrees.

這樣通過A軸與C軸的組合，固定在工作臺上的工件除了底面之外，其余的五個面都可以由立式主軸進行加工。A軸和C軸如與XYZ三直線軸實現聯動，就可加工出復雜的空間曲面。

In this way, through the combination of a-axis and c-axis, the other five surfaces of the workpiece fixed on the worktable can be processed by the vertical spindle except the bottom surface. If a axis and C axis are linked with XYZ three linear axis, complex space surface can be machined.

這種結構的加工中 心主軸的結構比較簡單、主軸剛性非常好、制造成本比較低，但一般工作臺不能太大、承重也較小。

This kind of structure of machining center spindle structure is relatively simple, spindle rigidity is very good, manufacturing cost is relatively low, but the general table can not be too large, bearing is also small.