Application of the hottest machining center in bla

2022-08-09
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The application of machining center in blade production

preface

machining center is an efficient automatic machine tool composed of mechanical equipment and CNC system, which is suitable for machining sub complex parts. Because it has an automatic tool change device, after the workpiece is clamped once, the CNC system can control the machine tool to automatically select and change the tool according to different processes, automatically change the spindle speed of the machine tool, the feed rate, the motion path of the tool relative to the workpiece and other auxiliary functions, and complete the multi process processing on several surfaces of the workpiece in turn. This multi process centralized processing method can reduce many non processing time, such as workpiece clamping, measurement, machine tool adjustment, workpiece turnover, and so on, so that the cutting utilization rate of the machine tool is times higher than that of the ordinary machine tool, which greatly reduces the labor intensity of the operator and has high processing accuracy, so it has good economic effect. It can be seen that the application trend of machining centers is unstoppable

Shanghai turbine Co., Ltd. has successively introduced four axis CNC horizontal machining centers and four axis CNC vertical machining centers in recent years. The application of this equipment has raised the blade manufacturing level to a new level and provided a new development direction

1 working principle of machining center

first, store the program manually prepared by the technician or automatically prepared by the computer on the information carrier (such as magnetic disk), send the information carrier to the input device to read out the information and send it to the numerical control device, and turn it into a pulse signal after a series of calculation and processing. Some pulse signals are sent to the servo system of the machine tool, after conversion and amplification, and then through the transmission mechanism to drive the relevant parts to make relevant movements according to the trajectory specified in the program. Some pulse signals are sent to the programmable controller to sequentially control the internal auxiliary actions of the machine tool, realizing the automatic exchange of tools

2 basic structure of machining center

1) numerical control system

is composed of CNC device, he Fu driving device, programmable controller, etc. it is the control center for the machining center to perform sequential actions and complete the machining process

cnc device is composed of central processing unit and input/output interface. Its main characteristics are that input/storage, data processing, differential compensation operation and other control functions are completed through software, adding many functions that are difficult to be realized by logic circuit. Computers and other devices can be connected through interface equipment. When the control object or function changes, only the software and interface need to be changed. The function of servo driving device is to convert some pulse signals from CNC device into the movement of moving parts of machine tool; Its performance is one of the main factors that determine the machining accuracy, surface quality and production efficiency of machine tools. The detection device is used to measure the displacement of the moving parts of the machine tool and feed back to the numerical control device. The programmable controller controls the actuating mechanism to realize the selection and exchange of interruption in the state of tool experiment without breaking

2) mechanical body

simple structure, high taper and good rigidity. Including basic components, spindle components, automatic tool change device, etc

the foundation component is composed of the bed column and the workbench. It is the component with the largest weight and area of the machining center and is the structural foundation of the machining center. It is required to bear the static load of the machining center and the cutting load during machining, so the rigidity requirement is high. The spindle component is the key component of machining center, which is composed of spindle box, motor, spindle and bearing. Its starting and stopping speed are controlled by the numerical control system, and participate in the cutting movement through the tool installed on the spindle. It is the power output component of cutting processing, and its structure has a great impact on the performance of the machining center. The automatic tool change device is composed of tool magazine, manipulator, driving mechanism and other components. The tool magazine is a device for storing all the tools to be used in the processing process. When the tool needs to be changed, the tool is taken out of the tool magazine and loaded into the spindle hole by the manipulator or other methods according to the instructions of the NC system

3) auxiliary system

includes lubrication, cooling, chip removal, protection, hydraulic pressure, etc. Although it does not directly participate in the cutting movement, it plays a role in ensuring the machining efficiency, machining accuracy and reliability of the machining center, and is an indispensable part of the machining center

the horizontal machining center is a four axis linkage double workbench machining center produced by Japan only. Workbench size is 500 × 500mm is equipped with two pallets for automatic workpiece exchange. A pallet is used to install the workpiece and process it on the workbench; The other is located outside the factory workbench for disassembling and installing workpieces. When the workpiece on a pallet is processed, the pallet will be automatically exchanged for the processing of new parts, which can reduce the auxiliary time and improve efficiency

the vertical machining center is a four axis linkage machining center produced by Taiwan xiehong. The long and narrow worktable is equipped with f320mmm vertical CNC disc rotating worktable and tailstock with ejector pin. The taper of the main shaft adopts iso50, and the three-axis guide rail is all sliding guide soft. This combination enhances the strength and rigidity of the machine tool

3 plus the basic concept and programming basis of the center

1) the coordinate system of the machining center

z coordinate - the skin supported by the spindle that transmits cutting power achieves better tightening effect. The position is generally the Z coordinate, and the direction of increasing the distance between the tool and the workpiece is the positive direction of the Z axis; X coordinate - the horizontal direction is generally X coordinate. When the Z coordinate is horizontal, when looking at the workpiece from the tool spindle, the X positive direction points to the right. When the Z coordinate is vertical, for single column machine tools, when looking at the column from the tool spindle, the X positive direction points to the right; Y coordinate - determined according to the right-hand Cartesian coordinate system according to the X and Z coordinates. Rotating motion a, B and C correspondingly represent the rotating motion whose axis is parallel to the X, y and Z coordinates. A, B and C in the positive direction represent the forward direction of the right spiral in the positive direction of X, y and Z coordinates

the machine tool coordinate system is the basic coordinate system of the machine tool and cannot be changed at will; The working coordinate system is a coordinate system established at a certain point in the work

the horizontal machining center is a four axis linkage system, i.e. x, y, Z, B4 directions, and the vertical machining center is also a four axis linkage system, i.e. x, y, Z, A4 directions

2) control mode of CNC system

point position control: when moving from one position to another, no matter how the middle moving track is, as long as the tool can finally reach the target position accurately, it can be used for rapid positioning. Linear control is used for linear machining parallel to the coordinate axis, and it can also be used for machining 45. The oblique line of is used for plane machining. Contour control: during machining, it is necessary to control the cutting direction and feed speed of X, 9 and Z coordinates of each position of the tool for profile machining

3) basic programming knowledge

preparation function g: used to specify the action mode of the machine tool. Spindle function s: used to specify the spindle speed of the machine tool. Feed function f: used to specify the feed speed of the coordinate axis. Tool function T: used to select tools. Auxiliary function M: used to specify the auxiliary action and status of the machine tool. According to the differences between the programming of the two machine tools, the conversion program is compiled to enhance the universality of the program

4 application of machining center in blade production

horizontal machining center is mainly used for the processing of blade intermediate and shroud. The vertical machining center is not only used for the machining of blade middle body and shroud, but also for the rough and finish machining of blade surface and the base surface machining of die blade

fixture design: due to the centralized multi process processing of blades, in_ Nine fixtures include rough milling, fine milling and drilling. It should be required that the fixture can withstand large cutting force and meet the requirements of positioning accuracy. As the rough and finish machining is a continuous process, it requires a large clamping force and can not deform the parts. Since the internal space of the equipment with protective cover is limited, and the fixture generally needs to be rotated, the fixture should be as small as possible to avoid interference with tools and equipment. The fixture must be easily disassembled to avoid increasing the auxiliary time. At the same time, pay attention to the connection between the fixture and the workbench. There are only screw holes on the Japanese horizontal workbench. For the convenience of work, machine tool accessories with T-slots are designed. In addition to the horizontal workbench with T-shaped groove in the vertical machining center, the vertical turntable also has T-shaped groove and turntable center positioning hole

when processing square steel blank intermediates, the back radial surface is positioned, the inner diameter is tightened to the surface, the steam inlet side is positioned, and the steam outlet side is clamped. When the length is appropriate, the intermediates and shroud parts can be exposed at the processing place, the fixture is connected to the rotary table, and the rotation of the rotary table is used for processing. When machining the blade surface, install the blade root positioning fixture on the vertical rotary table, and install the thimble at the shroud as the auxiliary support. When machining the base surface of the blade of the die section, three ejector pins are used for positioning, the double ejector pin seat is installed on the vertical rotary table, and the other ejector pin can move according to the length of the blade and can be fixed on the workbench and supported at the shroud

tool selection: the tool handle adopts HSK short cone structure, and its short cone part and end face are in contact with the spindle, with good rigidity and high positioning accuracy; It is made of alloy tool steel and has strong toughness and strength after special heat treatment. The structure of clamping knife row is divided into side fixed type, collet type and other types. The blade is generally imported, which has a large cutting force. For example, the rectangular indexable end milling cutter from Israel is used for the finishing of intermediates. It has good toughness and sharp. The cross section is rectangular, with two cutting edges, large rake angle and spiral angle. The material is ic328, the cutting depth is 3 ~ 4 mm, f=250 mm/min, s=800 r/min, the cutter head diameter is 32mm, and 5 teeth. Israeli butterfly indexable face milling cutter is used for rough machining of profile, with strong impact resistance, octagonal section, 8 cutting edges, material ic928, cutting depth of 3 ~ 4mm, f=800 mm/min, s=600 r/min, cutter head diameter of 63mm, 5 teeth. Israeli indexable ball head end milling cutter is used for surface finishing. It is rigid and sharp. The section is semicircular, with large front angle. The material is ic328, the cutting depth is 2 ~ 4mm, f=800 ~ 1000 mm/min, s=2000 ~ 30000 r/mm, the cutter head diameter is 12mm, 2 teeth or 20mm in diameter, 2 teeth

5 economic benefit analysis and outlook

when machining with machining center, the original multi process multiple clamping is changed into one-time clamping, the process benchmark is unified, the processing time is reduced, the tooling is saved, the machine tool accuracy is high, and the product qualification rate is 100%, while some related auxiliary costs such as personnel costs and machine tool maintenance costs are also reduced. It can be seen that the machining center has good economy in processing quality, improving productivity and reducing costs

horizontal machining centers are generally about twice as expensive as vertical machining centers, and the required man hours are also more than vertical machining centers. Therefore, it is well known and economical to use vertical machining centers for the same production, but the processing range of vertical machining centers is not as wide as that of horizontal machining centers. Therefore, the production department can purchase equipment according to specific conditions. Reasonable configuration can greatly improve the blade production capacity, and also prepare for the development of blade flexible system (FMS) in the future. (end)

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