introduction

With the improvement of people's living standards, their clothing becomes more and more colorful, and the requirements for printing and dyeing products are getting higher and higher: there are many varieties of patterns and good performance. my country's printing and dyeing equipment has gradually developed from small-scale manual operations in the 1950s to small-scale jiggers and other small equipment in the 1960s, and single-power thyristor control cabinets with adjustable excitation voltage in the 1970s. In the late 1980s, it was developed into a sub-power thyristor control cabinet for adjusting the armature voltage. Although the synchronization performance of electrical equipment has been greatly improved, the DC motor and its control circuit are used in the printing and dyeing industry environment, and the corrosion is serious and the operation fails. The rate is very high, and this control mode requires the use of a lot of high-power transformers and a large number of speed regulating resistors, and the power loss is also large.

The printing and dyeing industry uses a large amount of tap water in the production process. High-temperature and high-pressure water vapor, compressed air, water gas and high-temperature oil all require high-power AC motors as power. The power demand in different periods of the production process varies greatly. For example, sometimes the demand in the middle of the night is very small or even zero, but the power of the motor is always the same. Although the power consumption is reduced, the waste of power is still serious. This problem has not been well resolved.

In addition, printing and dyeing electrical control equipment has other hidden problems, such as the large starting current of high-power motors, and the poor accuracy of some positioning devices that require precise positioning. These are problems that need to be resolved and improved.


The principle of stenter setting machine

In the process of continuous bleaching and printing and dyeing, the fabric undergoes many mechanical radial tensions, which causes the fabric to stretch radially and shrink in the weft direction, resulting in phenomena such as uneven width, uneven fabric edges, and weft skew. The above-mentioned shortcomings, the fabric must be tentered. The tentering finishing is based on the plasticity of cotton fibers in a wet state. During the drying process, adjust the warp and weft yarns in the fabric to stretch the fabric width to the specified size. , To achieve the effect of form stability. The stenter setting machine is a machine that realizes the stenter function.

The working principle of the stenter setting machine: the unshaped cloth is fed into the machine by the stripper open width, the operator hangs both ends of the cloth width on the needle plate, and both ends of the needle plate take the cloth width into the oven with the mechanical operation. The oven is heated by electricity and blown by a fan. It passes through several continuous constant temperature ovens with different temperature sections, and then enters the tail end to be stented.

It is composed of a cloth feeder, a rolling car, a weft straightening device, a drying cylinder, a hot air drying and a cloth dropping rack. When working, the setting machine clamps the edge of the cloth to gradually widen it and slowly dry it to obtain a temporary setting. The main transmission part is composed of two chains, the master and slave, and their positions are required to be highly synchronized. The weft slope during stable operation is at Within 5mm, the dynamic acceleration and deceleration process can be within 40mm, but it should be eliminated immediately during stable operation, and there should be no cumulative error.

The more popular solution now is to use PLC and inverter control methods. The master and slave chains are driven by two AC asynchronous motors respectively, and there is no mechanical connection. The PLC measures the position deviation and calculates the output frequency to control the two respectively. In order to achieve position synchronization.

Structure drawing of stenter setting machine



Robin Kang frequency converter application principle

1. The main technical characteristics of Robin Kang inverter:

(1) Provide quick debugging function to facilitate parameter setting and debugging;

(2) Has low motor operating noise;

(3) Abundant I/O interfaces can meet various control requirements;

(4) Provide multiple control methods, such as V/F control, open loop vector control, closed loop vector control, etc.;

(5) Provide multiple frequency setting methods, etc.;

(6) Provide multiple command sources, such as panel command source, terminal command source, communication command source, etc.;

(7) Provide multiple protection functions;

(8) Two analog output ports are provided, and the output signal range is arbitrarily set within 0-10V/0-20mA.

2. The application characteristics of the frequency converter on the setting machine

In the past, the sizing equipment used DC motors to control the main drive and the code reduction device for synchronous operation. At present, the synchronous control of the frequency converter is used at home and abroad to control the asynchronous motor for synchronous operation, so that the knitted fabric passes through the oven at a uniform speed on the setting machine, and can achieve the quality requirements of the control fabric, such as uniform thickness, streaking, and color difference.


3 Matters needing attention during the use of the inverter

Practice has proved that the application of frequency converter in printing and dyeing enterprises has great advantages, the specific operation is simple and easy, and the use effect is obvious. However, the frequency converter has its own characteristics,

There are several problems in the installation and debugging that need to be paid attention to, otherwise, it may not achieve its intended purpose or even work.

(1) When installing and wiring, fully consider the higher carrier frequency of the inverter, and keep the control wires away from the main wires and strong current wires. When assembling the electrical cabinet, put the power cord and strong wire behind the metal bottom plate, and put the control line in front of the bottom plate, and then tie them to the working point after coming out of the cabinet. The control wire (especially the FM control wire) must be shielded wire, and the wire should be as short as possible to change the habit of putting long wires in neat and beautiful pictures when assembling electric cabinets in the past.

(2) Since the power carrier from the inverter is much higher than the mains frequency, it will cause great interference to nearby electronic equipment (such as synchronization boards, thermostats, counting devices, etc.). Therefore, where the frequency converter is used, a power filter must be installed before the weak current equipment. Otherwise, these electronic devices will often fail and not work properly.

(3) The heat dissipation and corrosion resistance of the inverter must be fully considered. Printing and dyeing equipment is mostly in the atmosphere of acid, alkali, salt, steam, dust and fuzz. If the electrical cabinet is not properly sealed, the components will corrode quickly. If the sealing is too tight and the air is not circulating, it will affect the heat dissipation of the inverter. It is best to place the electrical cabinet in the control room far away from the machine and install an air conditioner. The electronic devices in the cabinet should be placed under or beside the inverter.

(4) The rise and fall times of the inverters of long machines must be adjusted to be consistent. The speed-up time should be longer, so that it will not produce excessive stall speed control, which is conducive to smooth start and synchronous operation. The deceleration time can be as short as possible under the premise that no overvoltage stall control is generated, so that the machine can stop quickly in the event of a mechanical failure and prevent the accident from expanding.

(5) For the units that drive the cloth forward by non-pressure friction, such as the doffing frame, hexagonal roller, etc., the cloth guiding speed and the rising slope are higher than other units, which can ensure that it is more convenient to synchronize during normal operation and avoid mechanical problems during start-up. Inertia and slow motion