Tlačiarenské stroje

SLANVERT SB80 Finishes Synchronization between Cylinder Printing Machine and Setting Machine

I  General Situation
Currently, the Company has realized synchronization between cylinder printing machine and setting machine by using SLANVERT SB80 engineering-type inverter. As a complicated one in print speed regulating system, rotary screen printing machine consists of cloth-in unit, printing unit, conduction band unit of drying room and doffing unit. The cloth will be sent into the setting machine after printing. In order to synchronize the conduction band of printing machine with the primary link of setting machine, variable frequency speed regulation technology is adopted to control their speed link.

II  Technical Requirements
1 The conduction band motor of the print machine adopts inverter for control and to keep speed with the primary link. Practically, PG is set on the primary link motor as the main setpoint of conduction band inverter.
2 The adjustment range of the conduction band speed on the printing machine must be between 0% and 10%, and is set with up/down buttons on the console.
3 The start, stop and emergency-stop of conduction band inverter of the printing machine must synchronize with the primary link of the setting machine.

III  Implementation Solution
Due to the client's requirement, the conduction band speed can be expressed as: PG+(1×MOP)=PG+PG•MOP, in which the range of MOP is between 0% and 10%.
To realize this formula, PG output of the primary link motor shall be the main setpoint of conduction band inverter. Since there is no PG in the main setpoint channel of SB80 inverter, the output must go through arithmetic units then to the main setpoint.
PG•MOP shall be taken as an auxiliary setpoint after doing multiply operation in arithmetic units. The range of MOP is 0-100% (unadjustable), so it will be limited between 0% and 10% in arithmetic units by multiply operation. See Fig. 5 for more details.

Fig. 5 Implementation Block Diagram of Rotary Screen Printing Machine PG Synchronization

Note: arithmetic unit 2 realizes the setpoint of PG. Arithmetic unit 1 realizes the multiply operation of PG and MOP. Arithmetic unit 3 realizes the range limitation of MOP.


Application of SLANVERT Inverter in Printing and Dyeing Equipment

I  Application of Inverter in Continuous Dyeing Machine
Most of the printing and dyeing device is the continuous dyeing machine at the length from tens of meters to more than one hundred meters. Several motors rotate the rolls, conduction band, dryer and various placing cloth racks, and the cloth speed in each unit must be unanimous, and the absolute error must be amended soon. DC motors in each unit are switched to AC motors controlled by SLANVERT SB100, SB70 series inverter, and then they are equipped with good-performance synchronous board, tension synchronous device, relaxation synchronous device, non-contact over-run protective device and conduction band deviation correcting device. Their synchronism and reliability are improved remarkably and the speed is stable, so the fault is reduced greatly, the quality of the product is improved, and electric fault seldom results in stop and defective product. Until now, our company has installed over eighty SLANVERT inverters on the continuous dyeing machine, such as the rotary screen printing machine, scouring and bleaching machine, mercerizing machine, setting machine, soaper, bleaching and washing combined machine and high-temperature stenter; and it is planed that other continuous dyeing machine will be controlled by variable frequency in the next year. Fig. 3 shows the variable frequency system control diagram of the continuous dyeing machine

Fig. 3 Variable Frequency System Control Diagram of the Continuous Dyeing Machine

II  Application of Inverter in such Equipment with High Load and Load Variation as Air Conditioner, Water Pump, Air Compressor and Circulating Oil Pump
The motor power of the equipment is greater and they do not stop during the production stage (repair once in a month as production halts). However, the load change is greater in each production time, for example, the load is small late at night and sometimes even is zero, while the equipment operates with constant power and same power consumption. If AC motor is controlled by the SLANVERT SB200 series inverter to regulate speed, and maintaining the required hydraulic pressure, vapor pressure, oil pressure, oil temperature and same room temperature, the motor will operate with a reduced speed and can greatly save electric energy.

III  Application of Inverter in Accurate Control of Displacement
Selvedge detector, selvedge guider and conduction band deviation correcting device in the printing and dyeing equipment should accurately control the cloth edge and conduction band edge, otherwise, the quality of the product can not be guaranteed. Detectors, such as mechanical contact, hall element, photoelectric switch, are used to control the motor and magnetic valve in the past, so as to regulate the displacement of the cloth edge and conduction band edge. Although these methods have taken some effects, the ideal accuracy requirement has not been achieved. Later, photo-potentiometers or combined photoelectric switches are used as detecting elements. Excellent control property of inverter is utilized to quickly start and stop the AC motor, so as to accurately control position of the cloth edge. The effect would be better if conduction band deviation correcting device developed by our company is used to control the position of conduction band in rotary screen printing machine. See Fig. 4 for system control diagram as below:

Fig. 4 System Control Diagram

IV  Complicated and Ponderous Mechanical Speed Regulation is Replaced by Variable Frequency Speed Regulation
For example, a steel-wire napper is driven by a big AC motor, which rotates the home roll, clockwise roll and counter-clockwise roll; ponderous mechanical gear box are used to regulate the speed of clockwise roll and counter-clockwise roll to achieve the napping effect. The operator’s feeling is the basis of speed regulation. The regulation accuracy will be greatly improved if mechanical regulation is replaced by SLANVERT inverter. With digital indicator, the SLANVERT inverter achieves a more ideal effect. 

V   Application of Inverter in Soft Start of Big Motor
Now, soft start of the induced draft fan and air blower in oil boiler is controlled by inverter. 

VI  Other Applications
DC speed regulation is replaced by variable frequency speed regulation in scraping and printing unit, curing machine, gassing machine, roll canister machine and calender of flat screen printing machine. The equipment operates smoothly with low fault rate and the effect is ideal.