【正文】 , the spindle itself index. Thus the bars of stock are carried to the various end working and side working tools. Each tool operates in only one position, but tolls operate simultaneously. Therefore, four to eight workpieces can be machined at the sa me time. Vertical Turret Lathes A vertical turret is basically a turret lathe that has been stood on its headstock end. It is designed to perform a variety of turning operations. It consists of a turret, a revolving table, and a side head with a square turret for holding additional tools. Operations performed by any of the tools mounted on the turret or side head can be controlled through the use of stops. Machining Centers Many of today39。 as far as possible the elimination of drive space and reduce deadzone inverse error and improve displacement precision. Linear Roller Guides outstanding advantage is seamless, and can impose prepression. By the rail body, the slider, ball, cage, end caps and so on. Also known as linear rolling guide unit. Use a fixed guide body without moving parts, the slider fixed on the moving parts. When the slider moves along the rail body, ball and slider in the guide of the arc between the straight and through the rolling bed cover of Rolling Road, from the work load to nonwork load, and then rolling back work load, constant circulation, so as to guide and move the slider between the rolling into a ball. Bridge Crane Bridge crane is having an elevated track running in a bridgetype crane, also known as the crane. Bridge Crane in the laying of the bridge on both sides along the elevated track on the vertical run, lifting trolley along the bridge laying on the track in the horizontal operation, a scope of work of a rectangle, it can take full advantage of having the space below lifting materials from the ground equipment hindered. Bridge Crane widely used in indoor warehouses, factories, wharves and open storage yard and other places. Able to carry items, stood up, lifting status, and adjust operations, mainly for the workshop, sections and steel production lines yard, etc.. Lifting capacity usually in the 10 to 100 t. Bridge crane itself for horizontal movement, the winch frame for the vertical movement of the winch suspended from the hook for vertical movement, the direction of movement of three of the crane can work. In order to prevent bridge crane driver not clear in the specific hook campaign, on the ground are equipped with lifting the general mand or folder, put hook. If hanging overhead crane hoisted electromagic lifting plate, often operated by the drivers themselves. Bridge cranes can be divided into general overhead crane, simple girder bridge crane for bridge crane and metallurgical three. Ordinary general overhead crane from lifting trolley, having run institutions, having posed of a metal structure. Lifting up from the car and from institutions, agencies and the car running small frame consists of three parts. Lifting bodies, including the motor, brakes, reducer, and the pulley drum group. Motor through the reducer, driven rotating drum so that the wire rope around or down to lifting weights. Small frame is from the brackets and install or run agencies and institutions, such as car parts rack, usually welded structure. Crane running the driving mode can be divided into two categories: one category is the concentrated drive, which uses a motordriven initiatives on both sides of the drive shaft driven wheel。s Certificate and is not allowed to drink driving cranes. (4) Operating must focus on the spirit, not talk, smoking or do not do. (5) To cl。 Some of the clamp punctured ingot mould, with Ingot filed small pair of pliers. Feeding Crane: Charge will be added to the open hearth furnace. Trolley bottom of the column with the pickand inciting material to me and it into the furnace. The main column to bypass the vertical axis rotation, pickand rotary can swing from top to bottom. Deputy car repair furnace for such auxiliary operations. Fing Crane: to meet with hydraulic fing large workpieces. Trolley displayed on the main hook up special feeder to support and flip the workpiece。 transmission ponents to ensure accuracy, the use of prerational, the form of a reasonable support to enhance the stiffness of transmission。 (c) friction。 (b) stiffness, under load。s more sophisticated lathes are called machining centers since they are capable of performing, in addition to the normal turning operations, certain milling and drilling operations. Basically, a machining center can be thought of as being a bination turret lathe and milling machine. Additional features are sometimes included by the versatility of their machines. Numerical Control One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control(NC). Prior to the advent of NC, all machine tools were manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools. Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader. Numerical control was developed to overe the limitation of huma n operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are f