- Mar 31, 2018 -
The machining of the machine tool is achieved by the relative movement between the tool and the workpiece. The motion can be divided into two types: surface forming motion and auxiliary motion.
The surface forming motion is the motion of the workpiece to obtain the required surface shape and size, which includes main motion, feed motion, and incision motion. The main movement is the movement that plays a major role when stripping excess material from the workpiece blank. It can be the rotation of the workpiece (such as turning), the linear movement (such as planing on a gantry), or the rotation of the tool (such as (Milling and drilling) or linear motion (such as plunging and broaching); feed motion is the movement of the tool and the workpiece to be machined to move towards it, so that the cutting can be continued. For example, the tool carriage slides along the machine guide when turning the outer circle. The movement, etc.; Plunge movement is a certain depth of movement of the tool into the workpiece surface, its role is to cut a certain thickness of material from the surface of the workpiece in each cutting stroke, such as the lateral cutting movement of the small knife holder when turning the outer circle.
Auxiliary movements mainly include the rapid approach and withdrawal of tools or workpieces, the adjustment of the position of machine components, the indexing of workpieces, the rotation of the tool post, the feeding of materials, the start, speed change, commutation, stopping, and automatic tool change.
The indicators that evaluate the technical performance of machine tools can ultimately be attributed to machining accuracy and production efficiency. The machining accuracy includes the dimensional accuracy, shape accuracy, position accuracy, surface quality, and accuracy retention of the machined workpiece. The production efficiency involves cutting time and auxiliary time, as well as the degree of automation and reliability of the machine. On the one hand, these indexes depend on the static characteristics of the machine tool, such as static geometric accuracy and stiffness; on the other hand, they are more related to the dynamic characteristics of the machine tool, such as motion accuracy, dynamic stiffness, thermal deformation, and noise.