The process of processing, material processing and material transformation, including the production process and quality inspection. In order to facilitate the preparation, implementation and production management of process planning, it is necessary to divide the process into different levels of units. They are process, installation, work station, work step and tool feeding. Let’s take a look at what each unit means.
A process is a process in which one or a group of workers continuously complete one or several workpieces on a working place or a machine tool. It is the basic unit in the process and also the basic unit of production planning. Whether the working place is changed or not and whether the working process is continuous is the basis for dividing the cnc machining process. For example, when machining a batch of shaft parts on a lathe, it is possible to roughen and finish each shaft continuously, or roughen the whole batch of shafts first, and then finish them in turn. In the first case, rough machining and finishing can be included in one process; in the second case, because the continuity of processing is interrupted, although the processing is carried out on the same machine tool, it must be performed as two processes.Installation unit
Clamping is the process of clamping the workpiece in the correct position of the machine tool or fixture in the machining process. The installation refers to the part of the process that is completed after the workpiece is clamped once. Sometimes, the workpiece in the machine tool need to go through several clamping to complete a process. For example, to process shaft parts on a lathe, it is necessary to first process part of the surface from one end, and then turn around to process the other end. In this way, the same process includes two installation processes.
When using indexable or movable fixture, rotary table or multi axis machine tool to process workpiece, the workpiece needs to go through several positions for processing after one clamping on the machine tool. The part of the process that the workpiece completes in each position is called the station. More generally speaking, the station is the part of the process that the workpiece occupies each processing position relative to the machine tool or tool. It can be seen that one or more stations may be included in one clamping. The use of the fixture which can change the position of the workpiece, such as the rotary table, reduces the clamping times, so that the workpiece is processed in several different positions in one clamping process, which reduces the clamping time and the resulting precision reduction problem.
Work step is a process content that is completed continuously under the condition that the machining surface and the machining tool do not change. It is also called “feed” in production. A complete process consists of several processes, each of which can include one or more steps. Each working step includes one or more working trips. In order to improve productivity, the process of machining several surfaces with several cutters at the same time is called composite step, which can also be regarded as a process step. For example, when a combined drilling machine is used to process holes in a porous box, multiple bits simultaneously drill different surfaces of the box, which can be regarded as a work step.
Tool feed unit
Tool feeding is the process that the cutting tool completes once on the machined surface. For example, machining shaft parts often need to cut off a very thick metal layer, so it is difficult to complete the cutting at one time, and it needs to cut several times. At this time, each cutting is called a tool feed. Therefore, under the premise of constant cutting speed and feed rate, the tool completes a feed motion, which is called a tool feed. Each step includes one or more passes.