Chapter Four Electrical Control of Black Zone Process 4.2 Lost Matrix Production Line


4.2.1 Brief introduction of sand treatment system

1、The main role of sand treatment is to transport sand and cooling sand, as well as the role of slag removal and dust removal. The fluency of the whole sand treatment system control directly affects the production efficiency. A good sand treatment system can use the limited space to maximize the amount of sand treatment and enhance the cooling capacity. This allows the customer to save a portion of the sand for the cooling cycle.

2、The sand flow of the whole treatment system starts at the sand drop point of the turning box and ends in the sand storage hopper. When the starting process starts first from the rear stage, the material level detection device in the sand storage hopper is started first, then it is started forward in turn, and finally the sand drop valve of the turning box is started. The stop process is opposite to the start-up process. The turn-over and drop sand valve is closed first, and the material level meter of the sand hopper is stopped at last.

3、The temperature sensor plays a major role in the whole control system, and the whole system needs to control the sand flow according to the sand temperature. The system should have perfect protection units, such as motor overload protection, hoist slip protection, front and rear interlocking protection.

4、operation control system

The entire operating system is divided into three modes: automatic operation, manual operation, and debugging operation.

In the debugging mode, all equipment can be started and stopped separately, only subject to its own overload protection, not subject to the interlocking protection of the front and rear equipment, and all material level signals have no effect.

In the manual mode, a section of equipment can be started and stopped separately, but the material level and temperature control mode has been added, and the start and stop interlocking mode of front and rear equipment has been provided.

In the automatic mode, it has a relatively perfect signal acquisition, analysis and judgment function. It can automatically stop the fault equipment and related equipment according to the fault alarm to avoid the expansion of the accident.

5、 Wiring requirements: all accessThe signal input lines of PLC are all shielded wires, and all power load equipment shall use 4-core power lines. The equipment must be grounded and protected.

4.2.2 Operation flow of sand treatment system

1.EquipmentStart

(1) close the circuit breaker, check the voltmeter display power supply voltage is normal, check the thermostat display is normal, check the work of the indicator is normal.

⑵ Turn the "manual/automatic" knob to the automatic position, release the "emergency stop" button, and start the equipment in sequence:

Level meter→ dust collector, circulating water cooling, tower cooling → belt conveyor → belt hoist → horizontal air cooling → horizontal cooling machine → chain hoist → screening cooling → screening machine → flapper valve. when starting each equipment, a time interval of 30 seconds is required to ensure the equipment reaches the normal operation state. special attention should be paid during "manual" operation.

⑶ Shutdown sequence: flapper valve → screening machine → screening cooling → chain hoist → horizontal cooler → horizontal air cooling → belt hoist → belt conveyor → dust collector, circulating water cooling, tower cooling → material level meter, in which the horizontal cooler is stopped after the chain hoist is stopped for 5 minutes, and other equipment is stopped at intervals of 30 seconds.

2. Precautions

(1) After the equipment is started, the operator shall not leave the work post without permission, and shall concentrate his thoughts and operate carefully according to the process requirements.

⑵ In case of abnormality, stop the operation of the equipment immediately and check and eliminate the abnormal situation.

Do not touch switches, motors and control circuits with wet hands.

It is forbidden to start the equipment with load, and it is forbidden to use the equipment with overload.

(5) During equipment maintenance and overhaul, the power supply must be cut off and a "no closing" warning sign must be hung at the power supply and control end to ensure the safety of on-site maintenance personnel.

3.Fault handling

(1). Alarm: all faults shall be warned by sound and light alarm; chain hoist, belt hoist, material level gauge and special warning lights shall be provided for prompt.

(2). The system is controlled by PLC. All buttons correspond to a PLC input point (X indicates). When there is an input signal, the indicator light of the corresponding input point of PLC will light up to indicate that there is an input signal at this point. When the output point (Y indicates) is output, the corresponding output indicator light of PLC will light up to indicate that the point is outputting.

When a device is not working, you canTurn the "manual/automatic" knob to manual, press the start button of the corresponding equipment, observe whether the indicator lights of the input point and the output point indicate correctly, and observe whether the corresponding intermediate relay corresponding to the output is closed. If it is closed, check whether the corresponding circuit and contactor are in good condition and whether the thermal relay is protected. If the intermediate relay is not closed, check the circuit from the PLC output point to the intermediate relay, or remove the wiring of the common point (indicated by C) and the output point, and measure the common point and the output point with the ohm gear of a multimeter: A, whether the output point is on when it has output (on when it is normal); B, whether the output point is disconnected when it does not output (disconnected when it is normal). If the line is good, check whether the motor is damaged and whether the corresponding mechanical parts are stuck.

4.2.3 Brief Introduction of Operation Control System

The sand box running cabinet is the core mechanism of the automation of the whole lost-vanishing mold production line, which controls the circulation process of empty sand box, bottom sand addition, buried box modeling, pouring, cooling, turning box and empty sand box. It can complete the automatic operation control of multi molding line, multi pouring line and multi cooling line. It is mutually controlled and connected with bottom sand vibrating cabinet, vibrating table cabinet, automatic docking cabinet and box turning machine to reduce the staffing at bottom sand vibrating and box turning machine. Sand box operation system can greatly improve production efficiency. Generally, the production line is divided into molding section, casting section, cooling section, turning box section and empty box rotation section. Sometimes several sections are combined and arranged according to site and process requirements. In the operation control system, will increase the vibration table control breakpoint, turn over the box machine interlocking control. There are relatively perfect interlocking mechanisms in the operation of the trolley, the pushing mechanism of the sand box, and the positioning and clamping mechanism of the sand box.

4.2.4 Operation flow of running system

1.Equipment Control Requirements

The control of the running car should have a high stop position accuracy, which is generally realized by frequency conversion technology. The control process can be divided into debugging, manual, automatic mode debugging mode can control the start and stop of each load end separately,

The manual mode can perform single-step operations, such as a shift of the running trolley or a push-up movement of the sand box.

The automatic mode control command is generally given near the modeling control. At this time, the whole action process is that the operation vehicle transports the empty box to the designated station, and then the operation vehicle on the other side moves the full box to the corresponding station, and pushes the box again until an empty box is transported to the starting position, and an automatic cycle is completed.

2.Operation flow introduction

The lost vanishing mold production line generally adopts a ring structure, with the buried box modeling position as the starting point of the process, and the production line is controlled by the modeling station personnel to start operation. After the molding of the buried box is completed, after the forward button is pressed, the pushing mechanism at the tail of the sand box pushes the sand box to move to a station. The car ferry at the front end loads a full box and runs to the casting line to wait for casting. The finished sand box moves to the turning station under the action of the pushing mechanism. The turning machine turns over the box. The empty box moves to the empty box operating vehicle during this pushing and is loaded to the tail of the molding station to stop. At this point an automatic cycle is completed.

3.Sensor system

A large number of sensors are used in the operation control system, such as the movement of the ferry car, the positioning and clamping state, the travel of the pushing mechanism, the online control of the seismic platform control system, and the linkage operation of the box turning machine control. Therefore, in the installation process of these sensors, multi-core shielded wires should be used as much as possible to avoid interference pulses to the greatest extent and prevent misoperation during operation.

 

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