Key Technical Points for Installation and Safe Operation and Maintenance of Fully Automatic Brick Forming Systems
Abstract ：This article, based on the engineering installation practice of automatic block forming machines (brick machines), systematically elaborates on the full-process technical specifications from transportation acceptance, electrical control system installation, main circuit and signal line connection, to pre-power-on inspection and daily maintenance. The content focuses on electrical safety, anti-interference measures, and vibration prevention, aiming to provide operable technical guidance for equipment operators and maintenance personnel to ensure long-term stable operation of the equipment.
I. Transportation Acceptance and Pre-Installation Environmental Assessment
After the equipment arrives, the first step is unpacking inspection and assessment of transportation damage. The following should be carefully checked:
Mechanical Structural Integrity: Check the main frame, hydraulic cylinders, mold guide columns, and vibration table for obvious bumps, deformations, or cracks. Pay particular attention to whether protective caps have fallen off or the sealing surfaces of hydraulic pipe joints are scratched.
Electrical Control System Status: Check the electrical control cabinet casing for dents and whether the cabinet door seals are intact. After opening the cabinet, inspect the internal components—including PLC modules, intermediate relays, switching power supplies, frequency converters, and terminal blocks—to check for loosening, dislocation, or bent pins due to transportation bumps. For plug-in components, press each one to confirm that its latches are in place.
Storage Environment Requirements: If the equipment needs to be temporarily stored before installation, the control box should be placed in a well-ventilated, dry warehouse free of conductive dust and corrosive gases. The recommended ambient temperature is -5℃ to +40℃, and the relative humidity should be below 85% (no condensation). For long-term storage, the dehumidifier inside the control cabinet should be powered on once a month to prevent the circuit boards from getting damp.
II. Control Box Installation and Vibration Isolation Measures
As the core of the entire machine's control, the installation quality of the control box directly affects the system's reliability:
Installation Posture and Heat Dissipation: The control box must be installed vertically, with a tilt angle not exceeding 5°. The distance between the back panel of the box and the mounting wall should be greater than 50mm to ensure natural convection heat dissipation. The ventilation openings on the top and sides of the cabinet must not be obstructed, and a minimum of 800mm of operating space should be maintained in front of the maintenance surface (usually the cabinet door side).
Vibration Protection: During the brick-forming process, the vibrating motor and eccentric block will generate periodic impact forces. To prevent vibration from being transmitted to the relays, contactors, and terminals inside the electrical control box, one of the following measures should be taken:
Install rubber vibration damping pads (thickness ≥10mm, Shore hardness 50-60) between the base of the electrical control box and the ground or support;
Alternatively, independently install the electrical control box on a rigid support column away from the vibration source (≥2m from the main machine foundation).
At the same time, all screws on the terminals inside the box should be reinforced with anti-loosening washers or thread-locking adhesive (medium strength) to prevent loosening after long-term vibration.
III. Power Cable Selection and Main Circuit Wiring Specifications
Main power supply wiring is crucial to equipment operation safety and current carrying capacity, and must strictly adhere to the following steps:
1. Circuit Breaker Selection: An independent three-phase molded case circuit breaker (ICB) must be installed before the incoming line to the control box. Its rated current should be selected based on the actual total power of the equipment. For example, a 63A frame rating should be selected for total power ≤ 30kW, and a 100A frame rating should be selected for 30～55kW. The circuit breaker should have thermal-magnetic tripping function, providing both overload and short-circuit protection.
2. Incoming Cable Cross-Section Determination: Three-core copper power cables (L1, L2, L3, excluding the neutral wire) should be used. The cross-section should be selected based on the actual load current and laying method. General reference values: 16mm² copper core wire for below 30kW, and 25mm² for 30～45kW. If multiple cables are run in parallel in conduits or underground trenches, the cross-section should be increased by one size. The cable sheath should be oil-resistant and abrasion-resistant.
3. Wiring Sequence: The external AC 380V three-phase power supply should first pass through the aforementioned circuit breaker, and then be introduced to the upper terminal of the main circuit breaker (isolator) inside the control box. All motor power lines (such as oil pump motors, vibratory motors, and fabric conveyor motors) have wire number markings and must be connected to the corresponding numbered terminals on the bottom terminal block of the control box. The phase sequence must not be interchanged. Incorrect phase sequence will cause the motor to reverse; in this case, any two phases must be swapped while the power is off.
4. Distinguishing Between Grounding and Neutral Wires:The control box casing must be connected to a separate, independent grounding electrode (grounding resistance ≤ 4Ω). The grounding wire should be a yellow-green bicolor wire with a cross-section not less than 1/2 that of the main phase wire. It is strictly forbidden to mix the protective grounding wire with the power supply neutral (N) wire; otherwise, when the three phases are unbalanced, the cabinet may become energized, posing a serious safety hazard.
IV. Control Signal Line and Aviation Connector Connection
In addition to the power lines, the electrical control box also needs to establish signal connections with actuators and sensors distributed throughout the machinery:
Aviation Connector Pairing: Multiple aviation connectors (pin count and quantity vary depending on the machine model, commonly 7, 12, or 19 pins) are located on the side of the cable tray at the bottom of the electrical control box. Each connector has a unique identifier (e.g., "YV1 - Oil Tank Solenoid Valve", "SX1 - Pressure Head Upper Limit", "SX2 - Mold Detection", etc.). Operators must use the dedicated aviation connectors provided with the equipment to insert them one by one and tighten the lock nuts to ensure IP65 protection rating.
Two Key Connection Target:
Small Control Box on the Oil Tank: This integrates a reversing solenoid valve, a proportional relief valve, and a pressure sensor for hydraulic system operation control.
Sensor Box on the Machinery: This houses proximity switches (for position detection), photoelectric switches (for material level detection), and encoder signal lines.
After connection, gently pull each cable to ensure it is secure. Excess cables should be bundled and secured within the cable tray to prevent them from dangling over moving mechanical parts.
V. Comprehensive Inspection and Insulation Test Before Powering On
Before powering on, the following verifications must be completed item by item to prevent wiring accidents:
a. Firmness and Correctness Check: Tighten all terminal block screws to the specified torque using a torque screwdriver (approximately 1.2 N·m for M4 terminals and approximately 2.5 N·m for M6 terminals). Check the wiring numbers against the electrical schematic diagram to ensure they match the drawing.
b. Missing Connection Check: Observe whether there are any unused cable guides in the bottom cable trays, ensuring that all motor and control wires are connected and there are no unconnected wire ends.
c. Short Circuit and Grounding Test:Using a digital multimeter (resistance mode) or a 500V megohmmeter, measure the insulation resistance between each phase (L1-L2, L2-L3, L1-L3) and between each phase and ground (L1-PE, L2-PE, L3-PE) sequentially. The insulation resistance should not be less than 2MΩ (new equipment is typically >50MΩ). If a short circuit or excessively low resistance is found, troubleshooting must be performed segment by segment until the fault is eliminated.
d. Motor Phase Reversal Safety Procedure: If, after initial power-on, the oil pump or vibratory motor rotates in the opposite direction to the indicator arrow, and phase reversal is required, the main power supply must be disconnected first. Wait until the inverter's DC bus capacitor has completely discharged (at least 3 minutes) before swapping any two phases at the circuit breaker output terminals. Live operation is strictly prohibited.
VI. Operational Prohibitions and Daily Maintenance Points
(I) Human-Machine Interface Protection The touchscreen uses a resistive or capacitive sensing layer. When operating, always use your finger or the included plastic stylus. Do not use screwdrivers, blades, keys, or other sharp or hard objects to click or scratch, as this may damage the conductive layer and cause touchscreen malfunction.
（II） Power Supply Voltage Adaptability The equipment's allowable operating voltage range is AC 380V±10% (i.e., 342V～418V). If the actual measured voltage exceeds this range, it is strictly forbidden to start the machine. Low voltage will cause insufficient motor torque and a surge in current, burning out the coil; high voltage will damage the switching power supply and PLC input module. It is recommended to install a voltage monitoring relay in the control box to achieve automatic over/under voltage protection.
(III) Dust Removal Cycle for Electrical Control Cabinet The brick-making site generates significant dust (cement, fly ash, and fine sand particles). The bottom plate and radiator inside the cabinet should be cleaned with a vacuum cleaner or dry brush every shift (8 hours). At least once a month, the inverter's cooling ducts and the surface of the PLC module should be blown with compressed air (pressure ≤0.3MPa, dry and oil-free). Dust accumulation significantly reduces heat dissipation efficiency and accelerates the aging of electrolytic capacitors.
(IV) Sensor Sensing Distance Calibration The nominal sensing distance of the proximity switches used on the machine (such as those detecting mold position or material cart arrival) is 5mm (usually 4-6mm). During installation, a feeler gauge or thickness gauge should be used to adjust the gap between the sensing surface and the metal stop block, ensuring it is within the range of 4.5-5.5mm. A gap that is too small can easily damage the sensor head; a gap that is too large will result in an unstable sensing signal, causing malfunctions or machine shutdowns.
(V) Regular Tightening of Terminal Blocks During the initial 100 hours of equipment operation and monthly thereafter, the tightness of all power and grounding terminals must be checked using a torque wrench while the power is off. Due to thermal expansion and contraction and vibration, creep may occur at the terminal crimping points, leading to increased contact resistance, overheating, and ultimately, burning.
(VI) Rigid Safety Procedures for Maintenance Operations Any maintenance work involving mechanical or hydraulic systems must strictly adhere to the triple safety confirmation:
- Turn off the oil pump motor (press the "Oil Pump Stop" button on the control panel);
- Press the emergency stop button (to disconnect all outputs from the safety relay);
- Disconnect the main power isolation switch in the electrical control box and hang a "Do Not Close" warning sign.
Unauthorized modification of the PLC program or skipping of safety circuits is strictly prohibited during maintenance. Electrical fault diagnosis must be performed by qualified personnel holding an electrician's operating certificate; unauthorized personnel are prohibited from opening the cabinet door for operation.
Conclusion
The stable operation of a fully automatic brick machine relies on standardized installation, precise wiring, and scientific maintenance. Thorough transportation and acceptance eliminate inherent defects; vibration reduction and grounding eliminate external interference; wire number matching and insulation testing ensure circuit integrity; and daily dust removal, tightening, and sensor distance calibration are strong guarantees for long-term operation. Strict adherence to the above technical procedures can not only significantly reduce the frequency of unplanned downtime but also effectively extend the service life of the electrical control system and hydraulic components, ensuring production safety and consistent brick quality. All operators should internalize "power-off operation and multiple confirmations" as basic operational skills to maximize equipment efficiency.
