How to choose the automatic tool change mode of nc machining center and its advantages
How to choose the automatic tool change mode of nc machining center and its advantages
At present, the technical level of the processing center independently developed and manufactured in China has surpassed the world level. However, due to the different standards of research and development, the automatic tool changing in the processing center is also diversified, so it is difficult to distinguish which one is the best. The editor has sorted out the three most common ways to change knives in the current market, and the three processing center to change the advantages and disadvantages of the knife, just for reference, does not represent the purchase standard!
In simple terms, the CNC machining center, like other CNC milling machines, has the ability to process complex curved surface and profile workpieces efficiently. It also has advanced features for automatic tool replacement. With the help of this processing characteristic, the machine can realize the automatic transfer processing of various types of workpieces, especially the complex workpieces. It can accomplish the work piece on a single processing equipment, centralize and automatically complete its drilling, milling, boring, hinge and tapping, and other processing contents. So much so that some say that the nc machining center is a multi-functional intelligent machining facility.
Numerical control machining center has the above higher automatic processing capacity, in addition to the control device and the processing program of the workpiece configuration, the hardware is mainly configured with the tool bank and automatic tool changing device. With the tool base, the tool can be stored and managed well in each working procedure of the workpiece. The automatic tool changing mechanism can make the tool change in time when each working procedure of the machine tool is finished. The tool changing mechanism is different according to the different tool base. This paper briefly introduces the common automatic tool change mode and its characteristics in nc machining center.
According to the different processing forms and processing requirements of the nc machining center, the common forms of tool bank mainly include bamboo hat type tool bank, disk manipulator tool bank, chain tool bank and so on. The corresponding tool changing modes can be divided into direct tool changing mode, mechanical hand tool changing mode and tower head rotating mode. In detail, let's take a look at their respective characteristics:
1. tool changing mode of mechanical hand
Generally equipped with a manipulator tool changing mechanism, the disc type tool library is often used. So - called mechanical hand change knife way, refers to when changing a knife, by mechanical hand grasp knife, select knife and change knife. Transfer the cutter between the tool store and the spindle of the nc machining center, send the replaced cutter back to the tool store, and push the needed cutter to the spindle. The feature of this method is that the new dao to be used and the old dao to be used are grabbed at the same time. That is to say, the grasping and changing of the blade are carried out at the same time. Therefore, compared with other ways of changing the blade, it has the characteristics of faster changing of the blade and smaller motion amplitude of each mechanical element. Is the more mainstream way of changing knives.
2. Direct tool change
The so-called direct tool changing means that the process of tool changing is completed by the combination of tool base and spindle box, which is the most direct tool changing method. General configuration of the sword library is a bamboo hat type. According to the tool changing process, there is no displacement in the tool bank to distinguish. The direct tool changing mode can be divided into two types: tool shifting mode and tool fixing mode. In the shifting mode of tool base, the tool base can be moved. Before changing the tool, the tool base enters the tool changing work area and exits the area after changing the tool. Because of the movement of the tool bank, the layout of this method is more exquisite and the flexibility and adaptability are poor. In the fixed mode of the tool bank, the selection of knives is mainly carried out by moving the spindle box. The tool holder can be either stationary or only rotating in position. The former can only be selected sequentially, which is suitable for CNC machining center with less number of cutter, while the latter can realize transposition of cutter. This method reduces the movement of the tool bank and greatly simplifies the design structure of the tool bank. Direct tool change is characterized by slow tool change speed and high fault rate, which is only used in early models.
3. change the knife way of turret head
The turret head is a method of changing the cutter to the corresponding position by rotating the brick tower. It is generally used for sequential tool changing, and has the advantage of compact structure and extremely short tool changing time. Generally, it is widely used in the processing of spindle-type workpieces, such as crankshaft and other slender workpieces, and it needs to complete a number of complex processes.
The automatic tool changing device of the rotating tower head is similar to that of the direct tool changing. The rotation of turret tool holder is realized through the rotation of turret head. The rotation tower is required to be equipped with the rotation tower for the tool change of the spindle head of the turret. However, the turret spindle is not connected with the tool holder, but with a number of different orientations, forming a separate spindle head with tentacular distribution.
In the nc machining center, by rotating the turret, each spindle head is rotated to the machining position in turn according to the program instruction, so as to realize automatic tool changing. This method of tool changing, because each sub-spindle is concentrated on a rotating tower, has higher requirements on the rigidity of the rotating tower spindle, and also has certain restrictions on the number of cutter spindle. This tool change mode is mainly used in the smaller CNC machining center.