Nc machine tools in order to be kept in a workpiece clamping complete multi-channel processing process, shorten the auxiliary time, reduce the error caused by workpiece installation for many times, must be with automatic tool change device. Automatic tool change device shall meet the tool change time is short, high repeat positioning accuracy, sufficient quantities of tools, knives, library cover an area of an area small and basic requirements, such as safe and reliable.

First, in the form of automatic tool change device

1. Rotary tool carriage tool change

Rotary tool rest is one of the most simple automatic tool change device, often used in the numerical control lathe. Can be designed to square head, turret or disc type axial loading tool rest, and other forms. Respectively installed on rotary tool rest four to six or more of the cutting tools, and follow the instruction in CNC gear knife.

Rotary tool holder must have good strength and stiffness in the structure, to withstand the rough machining of cutting resistance. Due to turning processing accuracy depends largely on the tip position, for numerical control lathe, the processing in the process of cutting tool position without manual adjustment, therefore it is necessary to select reliable positioning scheme and reasonable positioning structure, to ensure that rotary tool rest after each transfer, repositioning precision is as high as possible (generally 0.001 ~ 0.005 mm).

Under normal circumstances, the rotary tool carriage tool change action including tool post lift, turn head and head pressure, etc.

2. Changing spindles in knife (knives rotating movement)

Replace the spindle tool change is CNC machine with a rotating tool a simpler way of tool change. The spindle head is in fact a turret knife library, as shown.

Spindles are horizontal and vertical two kinds, usually replaced with a transfer to the turret spindle head, in order to realize the automatic tool change. In each turret on the spindle, equipped with rotary tools needed to each process in advance, when the tool change orders are issued, the spindle head position, in turn, to go to the processing, and through to the main movement, make the corresponding spindle drive the cutting tool. And the other in the processing of the main shaft position with the main movement off.

The replacement of the spindle tool change device, eliminating the automatic pine, clamp, unloading knife, knife and tool handling and so on a series of complex operations, so as to shorten the tool change time, and improve the reliability of the tool change. But because of the limitation of space position, make the spindle assembly structure size not too big, thus affecting the spindle system rigid. In order to ensure that the spindle rigidity, it is necessary to limit the number of main shaft, otherwise you will make structure size increases. Therefore, turret spindle head usually only applies to process without too much less, accuracy of machine tools, such as CNC drilling and milling machine, etc.

3. The knife library automatic tool change system

Because the rotary tool rest, cutter replacement device for cutting tool turret head type number cannot too much, can't satisfy the requirements of complex parts processing, therefore, the automatic tool change CNC machine tool with automatic tool change device with a knife library. With a knife library automatic tool change device is composed of knife library and tool change mechanism, tool change process is more complicated. First all the cutting tools used in the manufacturing process of respectively installed on the standard handle, in the closed size adjusted, in a certain way in a library. When change knife, the knife library first select knife, again by the tool change device out knives, knife library or spindle to carry on the exchange, the new sword into the main shaft, old dao back into the library. Knife library has a large capacity, can be installed in the side of the spindle box or above. As a result of the knife library automatic tool change device is only one root in the headstock spindle of CNC machine tool, the rigidity of spindle assembly, in order to meet the requirements of precision machining.

In addition, the knife rolls tool number is larger, and thus be able to more complex parts machining, greatly improve the adaptability of machine tools and machining efficiency. Take knife library automatic tool change system is suitable for the nc drilling center and processing center.