Introduction: In recent years, machine tools have played a leading role in metal cutting processing, and have become one of the important indicators to measure the overall level of national economic development and industrial manufacturing in a country. The spindle is an important part of the machine tool, which plays an important role in improving the processing efficiency, expanding the range of processing materials, and improving the processing quality.
Keywords: soft starter machine spindle
Abstract: This article describes the application of soft starter with brake unit in the spindle motor control of the machine tool, which improves the working efficiency of the machine tool and prolongs the inspection period.
The article introduced the application of soft starter and braking unit in main axis motor control of machine tool.
The efficiency is improved and the keeping period is prolonged.
Keywords: CMC-S soft starter CMC-DZ brake unit
1 Introduction
In recent years, machine tools have dominated the metal cutting process, and have become one of the important indicators to measure a country's national economic development and the overall level of industrial manufacturing. The spindle is an important part of the machine tool, which plays an important role in improving the processing efficiency, expanding the range of processing materials, and improving the processing quality. At present, the spindle motor of the machine tool mostly adopts an AC spindle motor, which drives the spindle to rotate through a belt drive, or drives the spindle to rotate through a belt drive and a reduction gear in the spindle box (to obtain a larger torque). In order to improve the machining efficiency of the machine tool and reduce the processing time between the machined parts, the general spindle brake adopts the mechanical brake method. However, due to the large inertia of the spindle and the long stoppage time, the brake parts are easily worn out, so they must be checked regularly and replaced regularly.
2 system components
The spindle motor control system adopts the CMC-S soft starter manufactured by Xi'an Xichi Electric Co., Ltd. (This soft starter has multiple starting modes, analog signal control functions, Chinese and English display interfaces, and is equipped with advanced RS- 485 communication interface and other features) and CMC-DZ braking unit, as shown in the drawing. By setting the internal parameters of the soft starter, the spindle motor can be steplessly started during start-up, which avoids the influence on the power supply system of the workshop and reduces the internal mechanical impact of the machine tool; the spindle motor is set when the CMC-DZ brake unit is used during parking. Accurate and smooth stopping in time reduces the processing time between machined parts. This improves the efficiency of the machine tool and extends its service life.
3 soft starter parameter settings
When using the CMC-S soft starter, the following parameters are generally set to:
Starting time 1M00 5s
Initial voltage 1M01 20s
Braking time 1M06 3s
Current limit 1M08 2.5 times
The remaining parameters can be set according to the instructions.
4 soft starter control process
When the parameters are set, the spindle motor of the machine can start smoothly and smoothly from zero speed to rated speed within a set time. After starting, the soft starter stops output and the bypass contactor closes (forward and reverse through the bypass two contactors KM2 and KM3). At this time, the soft starter is switched to the monitoring state to protect the spindle motor.
When the spindle motor is stopped, the CMC-S soft starter cooperates with the CMC-DZ brake unit to achieve braking and stopping. The CMC-DZ braking unit is equipped with signal acquisition and PID control, and it is an energy-consuming braking method. Direct current is input between the three-phase windings of the spindle motor (the output voltage needs to be set). When the machine tool stops, the soft starter controls the bypass contactor KM2 or KM3 to open, the brake braking node closes, the KM1 closes, the output of the braking unit is connected to the spindle motor circuit, and the DZ brake unit passes through the speed sensor installed on the spindle. The motor speed is detected and the sampled speed signal is used to adjust the DC voltage of the input spindle motor. In the set braking time, when the motor speed is high, the output current of the braking unit is large, and the output current is also reduced to zero at zero speed, so that the spindle stops accurately and smoothly.
5 Concluding remarks
This soft start control system can accurately and reliably determine the rotation state of the spindle of the machine tool, avoiding the misoperation of the machine tool, reducing the auxiliary machining time of the spindle machining, and making the protection performance of the machine tool more perfect. It reduces the collision of mechanical parts during the braking process of the machine tool, prolongs the inspection cycle, and saves manpower and material expenses. In Xi'an Kunlun Plant, Baoji Machinery Factory and other users have been unanimously praised.