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Tool magazine of machine tool vertical machining center 

     1、 Introduction

The main electrical power mechanism of the vertical machining center includes X, Y, Z three-dimensional space servo motor feed, spindle motor rotation, tool magazine rotation and tool arm positioning.

The control requirements of the frequency converter for the rotation of the cutter head and the positioning of the cutter arm are as follows: rapid acceleration and deceleration, stable constant speed, fast load switching without tripping.

     2、 Working principle

The tool magazine power of the vertical machining center is divided into the cutter head power and the cutter arm power. The cutter head is equipped with multiple processing tools. The cutter head power motor controls the cutter head to rotate and cooperates with the system to find the tool. After finding the target tool, it quickly stops in position. The power of the knife arm is controlled by the knife arm motor. The rotation axis of the knife arm is fixed at the center of the knife arm. The two ends of the knife arm are designed with buckles, which are used to buckle, insert, rotate, etc. the tool of the magazine and the spindle tool when the tool is changed. action.

 

 

Introduction of MV160 inverter 

MV160 is a brand-new low-power mini inverter developed by Megmeet Drives. It has the characteristics of compact structure, convenient installation, excellent performance, friendly interface, and easy debugging. It is widely used in various types of automatic transmission machinery, such as woodworking Machinery, glass machine, carving machine, textile machinery, etc.

 

 

Control scheme 

The periodic movement of the tool magazine is planned and controlled by the I / O signal of the machining center system. The frequency converter needs to respond quickly, and the frequency converter controls the tool disc and the arm in time-sharing. The output contactor is used for the selection of different power controls.

Because the knife arm moves quickly and the action cycle is short, the output contactor switches quickly, and it will switch even before the inverter is completely stopped, requiring the inverter not to trip during the switching process.

 

MV160 control advantages and features 

     1、 Rapid acceleration and deceleration

image.png         image.png

Acceleration time of knife arm picking positioning 83ms                              Deceleration time of knife arm picking and positioning is 62ms

image.png         刀臂送刀动作加速时间99ms.png

The total time of the knife arm picking and positioning process is 301ms                  A cceleration time of the knife arm feeding action is 99ms

 

 

image.png         The deceleration time of the knife arm feed motion is 46.6ms                                           Current waveform of knife arm feeding                  

image.png         刀臂、刀盘动作周期.png

Current waveform of knife arm picking, feeding, returning to zero                                     Action cycle of cutter arm and cutter head                     

    2. On-load breaking without tripping

 

When the frequency converter has not been completely stopped, disconnect the output load, and in the event of an arc, the frequency converter guarantees that it will not trip or report a fault.

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3 、 Good repeatability

Compared with the original servo-controlled tool magazine, although the accuracy is not as good, but it relies on the acceleration and deceleration performance of the inverter to stop and go, it can still achieve better repeatability and repeat positioning accuracy in the control of the tool arm tool change Within + -2 degrees, meet the work requirements while reducing costs.