With the development of the economy, the technical improvement of various products, the quality is improving faster and faster, and the product cycle time is getting shorter and shorter, so in the machining, the machining accuracy is required to be higher and higher, and the machining cycle time is shorter and shorter. Some parts hope to achieve all the mechanical processing after a clamping, which puts forward the requirements of composite machining. Turning and milling composite machining is to achieve several different machining processes on one machine tool. Composite machining is the application of the pan, the difficulty of a processing method, that is, turning and milling composite machining. cnc machining center is equivalent to CNC lathe and machining center composite.
A milling parts, often need to go through several clamping, a vertical machining center and a horizontal machining center to complete the parts all processing requirements. As we all know, each after a clamping, will bring a clamping error, the more clamping times, the more errors generated. Therefore, if a vertical machining center and a horizontal machining center are combined together, so that the parts in a single clamping can complete all the milling process, avoiding the errors brought about by multiple clamping.
There are two kinds of composite machining centers, namely, vertical and horizontal conversion machining centers, one is table vertical and horizontal conversion, which is mainly for small parts, and one is spindle vertical and horizontal conversion, which is suitable for medium and large parts.
1 Table vertical and horizontal conversion
There are two structures of table vertical and horizontal conversion, one is to use 45° slope for vertical and horizontal conversion and positioning, the advantage is that 45° slope contact surface is large, table rigidity and load-bearing are better, and vertical and horizontal conversion does not affect the stroke. The positioning surface is not subject to force, which can ensure high accuracy. Another kind is called cradle type table (Fig. 3), because it adopts holding axis for positioning, so the positioning accuracy is poor, and the table's load-bearing is also lighter, which will be subjected to a large torque in the machining, which is unreliable in positioning. It will eat up a large stroke in the table vertical and horizontal conversion. Generally, it is used in the economic type machining center.
2 Horizontal spindle
There are also two types of spindle vertical structures. One is the 45° bevel for spindle vertical and horizontal changeover. Its advantage is that the 45 ° bevel contact surface is large, spindle rigidity is good, positioning using the mouse tooth disc, repeat positioning accuracy is high, and its tool center point position remains unchanged after the vertical and horizontal conversion, convenient programming, of course, its disadvantage is no negative angle.
The other form is A-axis, which has the advantage of a large X-angle, especially suitable for large-angle impeller processing. However, it has the very obvious disadvantage that the vertical and horizontal conversion will eat up the Z-axis travel. Generally speaking, the machine X, Y, Z axis in the Z axis is the shortest, if eaten a little more, it makes the machine tool machining range is greatly reduced.
Compared with the traditional CNC machining process, the outstanding advantages of turning and milling machining center are mainly reflected in the following aspects.
(1) Shorten the product manufacturing process chain and improve production efficiency. Turn-mill machining can be realized once the card to complete all or most of the machining process, thereby greatly shortening the product manufacturing process chain. In this way, on the one hand, it reduces the production auxiliary time caused by clamping changes, and at the same time reduces the manufacturing cycle and waiting time of the fixture, which can significantly improve production efficiency.
(2) Reduce the number of clamping times and improve machining accuracy. The reduction of the number of card loading avoids the accumulation of errors due to the change of positioning reference. At the same time, most of the current turning and milling machines have online inspection function, which can realize on-site inspection and precision control of key data during the manufacturing process, thus improving the machining accuracy of products.
(3) Reduce floor space and production cost. Although the single price of turn-mill machining equipment is relatively high, but due to the shortening of the manufacturing process chain, the reduction of equipment required for the product, as well as the reduction of the number of fixtures, workshop floor space and equipment maintenance costs, can effectively reduce the overall investment in fixed assets, production operation and management costs.
Turning and milling machining center through a clamping parts to complete a variety of machining processes, shorten the processing time, improve the processing accuracy, popular among users. CNC turning and milling machine tool is the main type of composite machining machine tool. Usually in the CNC lathe to achieve plane milling, drilling, tapping, milling grooves and other milling processing. With turning, milling, boring and other composite functions, can achieve a clamping, full processing of the processing concept.
