密级：
JINGGANGSHAN UNIVERSITY
外文翻译
题目 数控加工中心自动换刀系统的研究
学 院 机电工程学院 专 业 机械设计制造及其自动化 班 级 机制11(本1) 学 号
姓 名 指导教师 起讫时间
教 务 处 印 制
1
Machinery,2011,12(04)
Research on the automatic tool changer system of the
manching center
Abstract：The automatic tool changer(ATC),which includes a magazine, a tool changer and a control system, is one of the key compoments of the machining center (MC), General issues of the ATC, however, are its slowness and low stability during tool changes and the complexity of control system programming. To solve those problems, one type of software and its internal PLC technology were inverstigated. Based on an analysis of the fundamental structure and operating principle of the ATC system and a research of the control procedure of the “disc with arm”-type ATC,the PLC program and macro programs combined with ServoWorks CNC technology were developed.Finally, it was shown that newly designed control system can complete the whole process of changing tools in 4 to 6 seconds on the YY-1060 vertical MC. The results indicate that the process is rapid, accurate and reliable enough to completely meet the practical requirements.
Keywords: machining center(MC); automatic tool changer(ATC); programmable logic
controller(PLC)
1.Introduction
Using knife library (MAG) automatic tool change is the way of tool change, is widely used in machining center independent knife library vastly increases the storage quantity of cutting tool, which helps to expand the function of machine tool, and can be well isolated interference of various kinds of factors affecting the machining accuracy.Processing center of the library types are: a knife disc tool library and chain tool library.Library change tool way according to the presence of manipulator, tool change process into a manipulator tool change and no manipulator tool change.This study in order to YY - 1060 vertical machining center is equipped with DEX - A402 disc tool library manipulator automatic tool change mechanism as the object, study of automatic tool changer (ATC) system.
Programmable controller (PLC) is the core part of automatic tool change system.At present, the domestic control of the automatic tool change more than the
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traditional PLC (hereinafter referred to as hard PLC) and single chip microcomputer, such as mitsubishi FX series PLC, Siemens S7-200 series PLC, AT98C51 microcontroller.Hard PLC control method without special instructions of the tool, you need to write complex cutter PLC program, as well as simplify the process of nc programming by macro program;Adopt single chip microcomputer control circuit structures, complex, the system stability is low, programming complex.This research adopts the LadderWorks is a kind of built-in PLC system software based on the technology of ServoWorks type, can be between CNC rapid internal signal transmission.
2.Library structure and tool change movement
Automatic tool change main components include: motor, CAM, tool pot, dao library motor, cup, brake, pine clip round tool, the origin signal, etc.DEX - A402 automatic tool change is shown in figure 1.
Fig.1.Automatic tool change Fig.2.Sword arm action
Sword arm action driven by stepping motor, tool change action points 4 steps to complete.Single sword arm motor direction of rotation, through the automatic tool change mechanism of CAM mechanism to control the sword arm and reversing, the drive mode improves the sword arm rotation Angle precision, simplify the control of the motor at the same time.Sword arm movement of the specific process as shown in figure 2.
3.Transfer instructions
CNC programming instruction by T, M instructions to complete the automatic tool change action, tool change instruction decoded by the internal system, the target tool, and macro instruction, translated into the corresponding binary number saved to the system specified in the register.ServoWorksPLC system T instruction decoder to
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F26, M instruction decode to F10, users can according to the request of change knife action write macro program and PLC program.T directive specifies the tool, completing the library choose tool, tool library rotation direction judgment and determination of rotating interval;M directive specifies the macro program, according to the requirements in tool complete spindle back to zero, the Z axis point back to change the tool, the tool arm rotating direction, location and tool cup up and down movement.
3.1 The choice of cutter (T)
Cutting tool choice is tool library specified on the tool to change the cutter location, the action by the T instruction function.Automatic tool changer (ATC) system based on information from the position of the tool storage and T instruction, according to the given command and control system decide the knife library direction of rotation, the requirements of the steps, etc., generally, the memory can be used to model random control and mechanical control in two ways.Corresponding to their respective mechanical random control every tool set, usually between the spindle and the tool storage, to provide tool change \stochastic control using a pointer, pointer points out that the position of tool library rotation, each knives and tool set is not always one-to-one correspondence, the control mode change quickly and reliable.In according to the mechanical structure of the tool storage choices in tool control mode, the following system of pointer to a float switch tool way: by the user T directive specifies a tool, after decoding system, found in the floating of the pointer to the memory number corresponding to the cutting tool, the system use special instruction ROTB direction of rotation and rotation distance judgment the knife, tool library rotation to the target location choice tool finish tool, M6 instructions completed action in the tool, the specific process as shown in figure 3.
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Fig.3.Flow chart of choosing tools
3.2 Transfer instructions (M)
Auxiliary M instruction decoding through the system to the PLC \(internal relay), users write PLC program according to the action requirement.ATC auxiliary M instructions include M6 in knife, M19 spindle positioning, initialization M86 tool library, etc.Machining center library change knife process as shown in figure 4.
Fig.4.In flow chart
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