The arrangements shown in Figure 2-1 are all very popular configurations, but none of them is standard. There is no such thing as a standard 5-axis machine. First, let s establish the definition of an axis. Any motion controlled by the NC controller, either linear or rotational is considered an axis. For instance, in the illustration in Figure 2-2, both the spindle head and the quill are capable of moving in the same direction, but are controlled by two separate commands. Movements of the head are controlled by Z and those of the quill by W.

Figure 2-2: The spindle head and the spindle quill move along parallel axes.

The terms multiaxis and 5-axis are often used interchangeably and these terms can be confusing. The widely recognized term in the industry is 5-axis, but it is misleading because 9-axis standard possibilities exist without adding additional sub-systems. In addition, a 4-axis machine is also considered to be a multiaxis machine. Despite the title of this book, the more accurate term multiaxis will often be used.

The following list provides the industry standard nomenclature for the basic 9-axis designations and directions.

• XYZ are linear axes where Z is aligned with the spindle of the machine.

• ABC are rotary axes rotating around XYZ respectively.

• UVW are parallel linear axes along XYZ respectively.

Unfortunately, different machine builders abide by this standard in different ways. Some builders allow the end user to change the machine s rotational directions...