Siemens milling machine spindle motor and driver

Siemens milling machine spindle motor and driver are commonly used on machines. Let's get to know it today.

1. Siemens AC spindle motor

As shown in the figure for the Siemens 1PH7 AC spindle motor appearance and composition.

1PH7 AC milling machine spindle motor is a forced air-cooled asynchronous motor that is dissipated through a separately installed fan. The stator winding is embedded with a thermistor for detecting the temperature of the motor. The rotor shaft ends are connected to an encoder for detecting rotor speed and angular displacement. The encoder is connected to an external device via a cable plug or DRIVE- CLiQ interface, and the encoder can select an incremental encoder or an absolute encoder.

2. Siemens 611Ue driver

Siemens 611Ue driver is a DC common bus inverter, composed of power modules and power modules. 611Ue driver and Siemens SI-NUMERIK 802D CNC system supporting the use of milling machine spindle and servo drive. The appearance and composition of the 611Ue drive are shown in the figure.

The power module consists of rectifier module, filter capacitor and control circuit, etc., through the input of the three-phase AC rectifier, filtering, power module to provide DC bus voltage, while the power supply module also provides +5 V, +15 V and +24 V control power, through the equipment bus for the power supply module and power module internal control circuit. The control circuit, in addition to monitoring the DC bus, also performs temperature and operation monitoring, as well as enable control. There are two forms of power supply module, one is the uncontrolled power supply module (also known as feeding power module); Second, regenerative feedback power supply module (also known as feed / regenerative feedback power supply module).

The above is the basic introduction about Siemens milling machine spindle motor and driver.

FANUC milling machine spindle motor

FANUC AC spindle motors have αi series and βi series. The former is a high-performance milling machine spindle motor, and αi series of drives supporting; the latter for the ordinary spindle motor, and βiSVSP series drive matching. FANUC AC milling machine spindle motor is a variable frequency dedicated motor. As shown in the figure is FANUC αi / βi AC spindle motor appearance and composition.

FANUC αi AC spindle motor stator no chassis, stator core shape was polygonal. The core of the edge of the axial ventilation holes, the motor has a separate power supply at the end of the cooling fan, the milling machine spindle motor forced cooling, the stator core in the air directly heat; rotor and ordinary three-phase AC motor, in addition, the stator winding is also equipped with thermistor. When the motor due to overload or winding short circuit caused by winding temperature rise to a certain value, the thermistor resistance changes. The temperature detection circuit in the spindle amplifier monitors the change of the resistance value and is fed back to the CNC system via the serial bus. The CNC system can stop the control signal of the spindle immediately after the judgment and processing, and issue the alarm that the milling machine spindle motor is overheating or overload.

FANUC αi spindle motor in the magnetic sensor for rotor speed and angular displacement measurement, a 128 pulse/turn, 256 pulse/turn, 512 pulse/turn three specifications, without zero position signal (also known as a turn signal) for the Mi series, with zero position signal for the MZi series.

The above is about FANUC milling machine spindle motor basic introduction, you are welcome to continue to focus on updates.

CNC milling machine spindle motor (Part 2)

In the previous article we mainly introduced the composition of the CNC milling machine spindle motor, today we come to explore the operating principle of the spindle motor and frequency control mode.

1.Operating principle

CNC milling machine three-phase AC induction motor operating principle is shown in the figure.

Three-phase AC asynchronous motor stator winding into the three-phase AC generated after the rotating magnetic field, the speed no known as the synchronous speed. n_o = 60f/p, p for the stator winding pole pairs, f for the stator winding power supply frequency, change f to change n_o. The rotating magnetic field cuts the guide bar in the rotor core and generates an induced current in the guide bar. In this way, the rotor bar with induced current interacts with the rotating magnetic field to generate electromagnetic torque, and the rotor rotates with the rotating magnetic field at the rotational speed n_M under the action of the electromagnetic torque. Because the motor running state when the rotor speed can only be less than the synchronous speed, so called asynchronous motor; and because the rotor bar in the current from the rotating magnetic induction, it is also known as induction motor. When the power frequency f decreases, the rotating magnetic field speed no decreases, but because of the rotor mechanical inertia, the rotor speed n_M instantly remain unchanged, at this time, the rotor speed is greater than the rotating magnetic field speed, the motor is in the power brake state, the motor winding flows out.

2. Frequency control

Changing the power frequency of the milling machine spindle motor can realize the speed regulation of the motor. Three-phase AC induction motor frequency conversion speed is usually U/f and vector control. In order to meet the requirements of the three-phase AC asynchronous motor stator winding electromagnetic frequency requirements, in the rated frequency (50Hz) below the frequency control, change the frequency f at the same time also change the stator voltage U, and keep the voltage / frequency is not change. In this speed range, the maximum electromagnetic torque remains constant and constant torque is achieved. Rated frequency above the frequency control, the stator winding voltage U to maintain the rated voltage (380V) unchanged. In this speed range, the electromagnetic torque decreases with the frequency rise, and the electromagnetic power unchanged, to achieve constant power speed, as shown.

The above is a brief introduction about the CNC milling machine spindle motor operation principle and frequency control mode. 

CNC milling machine spindle motor (Part 1)

CNC milling machine spindle is driven by the spindle motor. CNC system through the control of the spindle motor to achieve the control of the spindle. At present, CNC milling machine spindle motor commonly used three-phase AC asynchronous motor and variable frequency drive.

Spindle motor drive has two configurations: First, the ordinary three-phase AC asynchronous motor and inverter; Second, the CNC system supporting the spindle motor and spindle drive. The former is often used in ordinary CNC milling machine, to achieve frequency control, positive, reverse start and stop and other basic control; the latter for multi-function CNC milling machine, in addition to the basic control of the spindle, but also to achieve orientation, positioning and spindle servo control.

Ordinary three-phase AC induction motor is consist of stator and rotor, as shown.

The stator includes a base, stator core and stator three-phase windings. The stator core is made of silicon steel sheet, and the inner circumference is covered with a coil groove. The coil groove is fitted with three symmetrical windings. The winding terminal is introduced into the junction box on the base frame and can be connected into a triangular winding or star winding. Made of silicon steel sheet stacked, the outer circumference are covered with a coil groove, coil groove cast with aluminum guide bar.

Ordinary asynchronous motor rotor is also installed on the cooling fan, when the ordinary three-phase AC asynchronous motor with the inverter speed, and the rotor speed is low, the cooling fan air volume is not enough to cool the motor, the motor easy to heat, serious will damage the stator winding insulation, resulting in short circuit. In order to meet the needs of frequency control, the development of a special frequency asynchronous motor, as shown. Frequency conversion special asynchronous motor has a special cooling fan motor, the motor body for forced cooling, fan motor power supply alone, the fan air flow and the motor speed has nothing to do. In addition, the frequency conversion asynchronous motor also improves the insulation performance of the stator winding, some frequency conversion special asynchronous motor stator winding is also embedded in the thermistor, for the motor temperature detection.

The above is the introduction about CNC milling machine spindle motor structure, welcome you continue to pay attention to the updated content.

CNC milling machine tool changer manipulator

For the use of disc magazine CNC milling machine, tool changer manipulator is essential. Cam-type tool changer manipulator and spindle with the ability to continuously achieve grasping knife, knife exchange and insert the action, the structure shown in figure.

1) Grasping the knife. The manipulator starts the motor for the first time. The motor drives the end cam and the cylindrical cam through the bevel gear. The cylindrical cam drives the cam roller to rotate the spline shaft. The spline sleeve drives the mechanical shaft by rotating it in the counterclockwise direction 65° or 75°, the manipulator grasping knife action. When the manipulator handle the knife in place switch is turned on, the robot electric brake immediately stops, completes the manipulator grasping knife control. During this time, the manipulator does not move axially.

2) Milling machine spindle loose knife mechanism action. The claws release the milling machine spindle handle, and issued the spindle release in place signal.

3) The second start of the manipulator motor, through the bevel gears simultaneously drive the end of the cam and cylindrical cam rotation, the mechanical hand shaft order to complete the knife, exchange and insertion of three movements: ①the end of the cam control rocker swing, so that the movement of the shaft , To achieve a knife action. During this time, the cam roller does not rotate, so the manipulator does not rotate. ②the end of the knife, the cylindrical cam through the cam roller to drive the spline shaft rotation, and then by the spline shaft drive the manipulator shaft rotation 180°, to achieve tool exchange action. During this period, the rocker arm does not swing, the manipulator does not move axially. ③the end of the cam again control the rocker swing, so that the movement of the robot shaft to achieve the knife action. During this time, the cam roller does not rotate, so the manipulator does not rotate. When the knife in place switch is turned on again, the manipulator brake immediately stops.

4) Milling machine spindle loose knife mechanism action, the claw clamping spindle in the handle, and issued a spindle clamping in place signal.

5) The third time the manipulator is started, the cylindrical cam drives the cam roll to rotate the spline shaft. The spline sleeve drives the mechanical hand shaft to rotate 65°or 75°clockwise to achieve the reset action. When the manipulator returns to its original position, the home switch is turned on and the manipulator's motor stops immediately.

The above is the work of CNC milling machine tool change manipulator. Tool changer through the cam and other mechanical transmission mechanism, with the manipulator motor 3 times start and stop, to achieve the original position → grasping knife → knife (spindle loose knife) → exchange → plug (spindle cutter) → reset the action process.

CNC milling machine disc tool magazine

The disc tool magazine is also a magazine that is often used in CNC milling machine. 

Disc tool magazine tool change process by the knife chopper, knife sets flip, tool changer and spindle and other action linkage to achieve. The entire tool change process by the CNC system control PLC. The disc magazine tool change is a random tool change, that is, after each tool change, the tool number and tool holder number is not necessarily the same. During the tool change, the robot can simultaneously grasp the knife from the magazine and the spindle, the knife and the knife, the tooling efficiency is high.

The disc magazine consists of cutter head motor, rotary cutter, indexing mechanism, knife cover and inverting mechanism. The cutter head motor drives the rotary cutter through the indexing mechanism. The cutter cover is fixed on the rotary cutter by the bracket, Rotate with the cutter head.

1. Select knife

When the T command is executed, the system first determines whether the tool is in the magazine. If not, the system will issue a T code error alarm. In addition, but also to determine whether the selected tool on the spindle, if already on the spindle, then complete the tool change control. And then determine the specific position of the selected tool in the magazine, if the selected tool is in the current tool change position, the turntable motor does not act, waiting for the robot to exchange the tool.

If the selected tool is not in the tool change position, the system determines the shortest path and the number of steps of the current position of the selected tool to the tool change position. The output control signal causes the turntable motor to turn forward or reverse, The count switch on the turntable moves once. When the selected tool to the tool change position, the turntable motor brake stopped to complete the T code of the knife control.

2. Knife sets flip

Since the tool axis in the magazine is perpendicular to the tool axis in the milling machine spindle, the tool holder is turned 90°downward before the tool change so that the tool axis in the tool holder is parallel to the axis of the spindle. After the tool change, turn the tool cover upside down 90°.

When the tool set of the selected tool is turned to the tool change position, the roller in the rear of the tool holder enters the fork, the front chamber of the cylinder is fed, the piston is moved up and the fork is driven to turn the tool cover 90°, knife cover down flip detection switch signal. When the cylinder is in the back chamber, the piston moves down and drives the fork to turn the tool cover up 90°, and the tool set reset detection signal is signaled.

The above is the composition of the CNC milling machine disc tool magazine and the process of change tool introduction.

CNC milling machine bamboo hat type tool magazine (Part2)

Today, let us talk about the tool change process of the CNC milling machine bamboo hat type tool magazine.

The bamboo hat type tool change is an absolute tool change, that is, after each tool change, the tool number and tool holder number is one-to-one correspondence.

Bamboo hat type tool magazine without the need to manipulate the tool, through the spindle box and spindle mechanism to achieve the linkage, the tool change process:

1) CNC system to get the tool change instructions, the spindle automatically return to the tool change point, while the spindle to achieve quasi-stop control.

2) The milling machine cutter rotates to the tool change point corresponding to the tool number (set to the old tool) on the current spindle.

3) The cutter head from the original position by the cylinder piston, when the clip to grasp the old tool on the spindle, the knife in place switch switch, said the grasping knife to complete.

4) Spindle knife action, the old knife loose, and the spindle cone hole blowing, when the spindle loose knife in place switch, said the loose knife to complete.

5) The milling machine spindle is moved up and the old tool on the spindle remains on the tool holder and the knife is finished.

6) The magazine rotates again, and the tool holder (set to the new tool) corresponds to the tool holder number to the tool change point.

7) The spindle is moved down again to the tool change point, the new tool is inserted into the spindle taper hole, and the tool change is completed.

8) Spindle knife action, the new tool in the spindle in the knife, when the spindle cutter in place switch, said the tight knife to complete.

9) Cutter cylinder cylinder retraction, when the knife reset switch is turned on, the tool change process is over.

The above is the tool change process introduction of the CNC milling machine bamboo hat type tool magazine, the next article we will introduce other types of tool magazines.