The automatic tool changing device of machining center is composed of tool magazine and tool changing mechanism. There are many kinds of tool magazine, including disc type and chain type. The storage capacity of chain magazine is large.
In order to further shorten the non cutting time, some machining centers are equipped with two pallets which automatically exchange workpieces. One is loaded with workpieces for processing on the worktable, and the other is loaded and unloaded outside the worktable.
The tool change mechanism exchanges tools between the machine tool spindle and the tool magazine, commonly known as the manipulator; there are also no manipulator and the spindle directly exchanges tools with the tool magazine, known as the armless tool change device.
Machining center is divided into vertical type and horizontal type according to the arrangement of spindle. Horizontal machining center generally has indexing turntable or numerical control turntable, which can process all sides of the workpiece; it can also make joint movement of multiple coordinates to process complex space surface. The vertical machining center generally does not have a turntable, only for the top surface processing.
In addition, the machining center and spindle can be adjusted into horizontal axis or vertical axis of the vertical and horizontal adjustable machining center, they can process five surfaces of the workpiece.
The common lathe has a wide range of processing objects, a wide range of spindle speed and feed adjustment, and can process the internal and external surfaces, end faces and internal and external threads of the workpiece. This kind of lathe is mainly operated by manual workers with low production efficiency. It is suitable for single piece, small batch production and repair workshop.
Turret lathe and turret lathe are equipped with turret turret or return wheel turret which can hold multiple cutters. Workers can use different cutters to complete a variety of processes in one clamping process, which is suitable for batch production.
The automatic lathe can automatically complete the multi process processing of small and medium-sized workpieces according to a certain program. It can automatically load and unload materials and repeatedly process a batch of the same workpieces. It is suitable for mass production.
Multi Tool semi-automatic lathe can be divided into single axis, multi axis, horizontal and vertical. The layout of the single axis horizontal lathe is similar to that of the ordinary CNC lathe, but the two groups of tool holders are respectively installed in the front and back or up and down of the spindle, which are used to process disc, ring and shaft workpieces, and their productivity is 3-5 times higher than that of the ordinary CNC lathe.
The lathe can imitate the shape and size of the template or sample, and automatically complete the processing cycle of the workpiece. It is suitable for small batch and batch production of the workpiece with complex shape. The productivity is 10-15 times higher than that of the ordinary lathe. There are multi turret, multi axis, chuck type, vertical and other types.
The spindle of the lathe is perpendicular to the horizontal plane, the workpiece is clamped on the horizontal rotary table, and the tool rest moves on the beam or column. It is suitable for machining larger, heavier workpieces which are difficult to install on ordinary lathe. It is generally divided into single column and double column.
When lathe is turning, the tool rest makes radial reciprocating motion periodically, which is used for forming tooth surface of forklift milling cutter, hob, etc. Usually with grinding accessories, a small grinding wheel driven by a separate motor is used to grind the tooth surface.
Lathe is used to process a certain kind of workpiece specific surface lathe, such as crankshaft lathe, camshaft lathe, wheel lathe, axle lathe, roll lathe and ingot lathe.
The lathe is mainly used for turning, but after adding some special parts and accessories, it can also carry out boring, milling, drilling, inserting, grinding and other processing, with the characteristics of “one machine with multiple functions”, which is suitable for the repair work of engineering vehicles, ships or mobile repair stations.
Processing has the following advantages:
① The number of tooling is greatly reduced, and complex tooling is not needed to process complex parts. If we want to change the shape and size of the parts, we only need to modify the processing program of the parts, which is suitable for the development and modification of new products.
② The machining quality is stable, the machining accuracy is high, and the repetition accuracy is high, which can meet the machining requirements of aircraft.
③ In the case of multi variety and small batch production, the production efficiency is high, which can reduce the time of production preparation, machine adjustment and process inspection, and reduce the cutting time due to the use of the best cutting quantity.
④ It can process complex surface which is difficult to be processed by conventional methods, and even some parts which cannot be observed.
The working principle of CNC machining is divided into several points
Firstly, in the process of clamping, in order to simplify the machining origin of each positioning surface relative to the work center, there should be accurate coordinate dimensions. Secondly, the orientation of mechanical parts installation is consistent with the orientation of workpiece coordinate system and machine coordinate system selected in programming, and directional installation. In the production and processing of batch precision mechanical parts, it should be considered that the fixture suitable for new workpiece can be changed after a short time of disassembly. As the auxiliary time of machining center has been compressed very short, the loading and unloading of supporting fixture can not take up too much time.
In the production of the fixture, should have as few workpieces and higher stiffness. The fixture should be open as far as possible, the space position of clamping workpiece can be low as possible, and the installation fixture should not interfere with the tool path. In order to avoid affecting the processing process, ensure that the processing content of the workpiece is completed within the stroke range of the spindle!
When there is an interactive worktable, the fixture design must prevent the space interference between the fixture and the machine tool due to the movement, up support, down support and rotation of the worktable. Try to complete all the processing contents in one clamping. When it is not necessary to replace the clamping point, special attention should be paid not to damage the positioning accuracy due to replacing the clamping point. If necessary, it should be explained in the drawing processing technology.
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