What safety precautions should be paid attention to in the production and processing of embossed aluminum plate?

Key safety issues in the production and processing of embossed aluminum plate

The production and processing of embossed aluminum sheet involves many processes such as metal melting, rolling, embossing, cutting, surface treatment, etc., and covers multiple safety risks such as high temperature, mechanical operation, chemical use, dust/noise, etc. It is necessary to establish the safety standard of the whole process from the four dimensions of "personnel protection, equipment control, process operation and environmental management". The specific precautions are as follows:

First, personnel safety protection: build a "full scene" protection system

There are different risks in each link of embossed aluminum sheet processing, so it is necessary to equip special protective equipment according to the process characteristics to prevent personal injury caused by "unprotected and wrong protection".

Protection of smelting/casting process (high temperature, metal splash risk)

Wear high-temperature flame-retardant clothing, high-temperature gloves (temperature resistance ≥300℃) and goggles/face screen to avoid splashing aluminum liquid (melting point about 660℃) to burn skin and eyes; It is forbidden to wear chemical fiber clothing (it is easy to melt and adhere to the skin in case of high temperature).

People with long hair must put their hair into the helmet, and the cuffs and trouser legs should be tightened to prevent them from being involved in transmission equipment or contacting high-temperature parts.

Protection of rolling/embossing process (mechanical pinch, metal burr risk)

Wear anti-smashing safety shoes (impact resistance ≥200J) and non-slip gloves during operation, so as to prevent the aluminum plate from slipping and hurting feet during handling, or being scratched by burrs on the edge of the rolled aluminum plate.

When entering large equipment areas such as rolling mills and embossing machines, it is necessary to wear tight work clothes to avoid clothes being involved in equipment gears and chains; It is forbidden to cross the transmission parts (such as roller table and conveyor belt) when the equipment is running.

Protection of surface treatment process (chemical corrosion, gas poisoning risk)

During pickling, passivation and spraying, you must wear acid alkali resistant gloves (such as nitrile), gas mask (choose the corresponding filter box according to the type of chemicals, such as Type A filter box for acid gas) and protective apron to prevent corrosive agents such as nitric acid and sulfuric acid from contacting the skin, or volatile gas (such as paint thinner) from being inhaled and poisoned.

Emergency shower device and eye washer should be set around the treatment tank to ensure that the washing can be started within 10 seconds when chemicals spill on the body (shower time ≥15 minutes, eye washing time ≥5 minutes).

General protection requirements

All personnel must undergo safety training and pass the examination, and be familiar with the risks of this post and emergency handling procedures (such as first aid methods for burns, electric shocks and chemical burns).

Smoking and eating are strictly prohibited in the operation area to avoid poisoning caused by chemical pollution of food; Change your work clothes in time after work, and wash your hands and face before eating.

2. Equipment safety control: check the whole process from "before startup" to "after shutdown"

The processing of embossed aluminum sheet depends on large-scale equipment such as rolling mill, embossing machine, shearing machine and melting furnace. The failure or improper operation of equipment may easily lead to mechanical injuries, fires, explosions and other accidents, and the whole process of "spot inspection-operation-maintenance" should be strictly controlled.

Before startup: equipment status confirmation

Check whether the transmission system (gear, chain and belt) of the equipment is loose and worn, and whether the protective cover is in good condition (it is forbidden to start the machine when it is missing or damaged); Whether the gap between the flower roller of the embossing machine meets the process requirements, so as to avoid the aluminum plate from being stuck and the equipment from being overloaded due to the small gap.

Confirm that the electrical system of the equipment (power cord, switch and grounding) is free from damage and leakage, and the motor is running without abnormal noise; The temperature control instrument and thermocouple of the melting furnace are calibrated normally to prevent molten aluminum from splashing due to overheating.

Check whether the equipment safety devices (emergency stop button, photoelectric fence, overload protection) are sensitive and effective. For example, the two-hand starting device of the shearing machine needs to confirm that "one hand can't start with a fist" to avoid hand injury caused by misoperation.

In operation: standardize operation and monitoring

It is forbidden to run the equipment "out of specification and strength". For example, the thickness and width of rolled aluminum plate should match the rated parameters of the rolling mill, and the pressure of the embossing machine should be adjusted according to the material of aluminum plate (such as 1060 pure aluminum and 3003 alloy aluminum) to prevent the equipment from being damaged by overload or the aluminum plate from cracking and splashing.

When the equipment is running, the operator should keep a safe distance (for example, both sides of the rolling mill are ≥1.5m), and it is forbidden to touch the rotating roller shaft and chain by hand, or use tools to reach into the equipment to clean up the waste; If you need to adjust parameters (such as flower roller pressure and rolling speed), you must stop the machine and cut off the power supply first.

Monitor the running status of the equipment in real time, such as whether the furnace body of the melting furnace is deformed or leaks, and whether the lubricating oil path of the embossing machine is smooth (the oil temperature is ≤60℃). If it is abnormal, press the emergency stop button immediately, and then troubleshoot the equipment after it stops completely. It is strictly forbidden to "run with faults".

After shutdown: maintenance and cleaning

After the equipment is shut down, it is necessary to cut off the power supply and turn off the air/water source first, and then clean and maintain the equipment after it cools down (for example, the temperature of the melting furnace drops below 100℃).

When cleaning the aluminium scrap and waste in the rolling mill and embossing machine, special tools (such as hooks and brushes) should be used. It is forbidden to grab them directly by hand. When cleaning the surface treatment tank, it is necessary to neutralize the chemicals in the tank (such as adding alkali to the pickling tank to neutralize it to pH=6-8), and then wear protective equipment for operation.

Regularly lubricate the equipment (for example, add lithium-based grease to rolling mill bearings) and tighten it (for example, bolts of embossing machine), and record the maintenance ledger to avoid safety accidents caused by wear and looseness of components.

Third, process safety: targeted prevention and control of key risks

There are unique risks in different process links of embossed aluminum sheet processing, so special safety measures should be formulated according to the process characteristics, focusing on preventing and controlling core risk points such as high temperature, chemicals and mechanical injuries.

Melting and casting (core risks: high temperature, molten aluminum splashing, gas explosion)

When charging, it is forbidden to put wet aluminum ingots and waste materials (water content ≥0.5%) into the smelting furnace to avoid "hydrogen explosion" caused by contact between aluminum liquid and water (2Al+3H₂O = Al₂O₃+3H₂↑, hydrogen is easy to explode at high temperature); The charging should be put in slowly to prevent the aluminum ingot from hitting the furnace wall and causing the furnace body to be damaged.

During the smelting process, aluminum liquid should be stirred regularly to avoid slagging at the bottom of the furnace due to local overheating; When adding refining agent (such as hexachloroethane) into the furnace, it is necessary to wear a gas mask to prevent chlorine gas (toxic) generated by the decomposition of refining agent from being inhaled, and at the same time, keep the workshop well ventilated (air exchange times ≥10 times/hour).

When casting, it is necessary to confirm that the crystallizer and dummy bar are not blocked, and the pouring speed of aluminum liquid is uniform (to avoid overflow caused by too fast); In case of aluminum liquid leakage, it should be covered with dry refractory (such as graphite powder) immediately, and it is forbidden to put out the fire with water (water will vaporize violently when it meets high temperature aluminum liquid, causing explosion).

Rolling and embossing (core risks: mechanical pinch, aluminum plate deviation, equipment overload)

Before the aluminum plate enters the rolling mill, it is necessary to clean up the oil stains and impurities on the surface, so as to prevent the roll from sticking and affecting the product quality, and at the same time prevent the impurities from getting stuck in the roll gap and causing the roll to deform or break.

In the embossing process, it is necessary to ensure that the aluminum plate is "centered and fed" to avoid burr or aluminum plate curling caused by edge collision with equipment due to deviation; If the aluminum plate is stuck, stop the machine and cut off the power supply, and then slowly take it out with special tools (such as crowbar). It is forbidden to forcibly pull the equipment during operation.

During multi-pass rolling, it is necessary to control the reduction of each pass (for example, the reduction rate of each pass is ≤30%), so as to avoid the tearing of aluminum plate and the overload and burning of equipment motor caused by excessive single reduction, and at the same time prevent the aluminum plate from cracking in subsequent processing due to excessive internal stress.

Cutting and forming links (core risks: mechanical shearing, waste splashing, dimensional deviation)

When cutting equipment such as shearing machine and punching machine are running, it is forbidden to put your hand into the "cutting area" (such as between the upper and lower cutting edges of shearing machine). If you need to adjust the position of aluminum plate, you must use auxiliary tools such as push rod and suction cup.

Trimmed aluminum scraps should be cleaned in time and piled up in the designated area (height ≤1.5m) to avoid tripping over people due to waste accumulation or being involved in equipment. Sharp scraps should be stored separately to prevent scratches during handling.

When bending and stamping, it is necessary to confirm that the mold is firmly installed and the aluminum plate is accurately positioned, so as to avoid the equipment from being stuck due to the deviation of the aluminum plate in the molding process or the finished product from being ejected and hurting people.

Surface treatment (core risks: chemical corrosion, volatile gas poisoning, fire)

The pickling and alkali washing tanks should be regularly checked for leakage, and anti-leakage cofferdams (height ≥15cm) should be set around the tanks to prevent chemical leakage and diffusion; Different chemicals (such as acid and alkali) should be stored separately, and it is forbidden to mix them to cause chemical reaction (such as mixing acid and alkali to generate a lot of heat, which may cause splashing).

During spraying and drying, it is necessary to keep the workshop well ventilated and install an explosion-proof exhaust fan (to avoid electric sparks igniting volatile paint solvents); The temperature of the drying furnace should be strictly controlled (it should not exceed the flash point of the solvent, such as the flash point of acrylic paint is about 30℃), and over-temperature drying is strictly prohibited.

Special fire extinguishers (such as foam extinguisher and dry powder fire extinguishers, for chemical and paint fires) shall be provided at the job site, and it is forbidden to bring kindling into the site; Operators should be familiar with the emergency treatment process of chemical leakage, such as neutralization with baking soda powder in case of acid leakage and neutralization with dilute acetic acid in case of alkali leakage.

Fourth, environment and emergency safety: building an all-round risk prevention and control network.

In addition to personnel and equipment management, workshop environment layout, safety warning and emergency handling capacity also directly affect production safety, so it is necessary to improve safeguard measures from the whole chain of "prevention-early warning-disposal".

Workshop environmental safety

The workshop passage should be kept clear, with a width of ≥1.2m, and it is forbidden to pile up raw materials, semi-finished products or waste materials; The distance between equipment shall be ≥0.8m, which is convenient for operators to patrol and evacuate in case of emergency.

Clear safety warning signs should be set in the operation area, such as "high temperature danger, no approaching" hanging in the smelting area, "toxic and harmful, protective articles must be worn" hanging in the surface treatment area, and "emergency stop button position" and "operation taboo" marked on the equipment operation panel.

The workshop floor should be kept dry and non-slip, and oil and water stains (especially in rolling and surface treatment areas) should be cleaned regularly to avoid people slipping; When working at heights (such as overhauling the top parts of the rolling mill), it is necessary to set up a stable scaffold or use a climbing platform, wear a safety belt (hanging high and using low), and it is forbidden to climb equipment.

Electrical and fire safety

The electrical equipment in the workshop (such as motor, distribution box and lighting) shall meet the requirements of explosion-proof and moisture-proof (especially in wet areas with surface treatment). It is forbidden to pull the wires without permission, and the wires shall be protected by wearing pipes to avoid being scratched by aluminum plates or aging by high-temperature baking.

The distribution room and control room shall be equipped with protective tools such as insulating gloves, insulating boots, electroscope, etc., and the insulation resistance of the line shall be tested regularly (the wire shall be replaced immediately when it is less than ≤0.5MΩ); High-power equipment such as melting furnace and drying furnace need to be laid with cables separately to avoid overload caused by sharing circuits with other equipment.

Set fire hydrants (at least one every 50m²) and fire extinguishers (one set every 20m) in the workshop according to regulations, and keep them in good condition and effective, and check the pressure and validity period regularly; Fire exits and exits should be kept clear, and it is forbidden to lock or block them. Emergency lighting and evacuation signs should be tested regularly (once a month).

Emergency response and training

Formulate a special emergency plan, covering common accidents such as "aluminum liquid splash scald, chemical burn, equipment pinch injury, fire and explosion", and clarify the emergency organization, personnel responsibilities and disposal procedures (such as immediately washing the scald with cold water → sending it to a doctor; Chemical burns should be washed immediately → neutralized → sent to hospital).

Organize emergency drills regularly (at least once a quarter) to ensure that operators are familiar with the use of emergency tools (such as fire extinguishers and shower devices) and escape routes (the workshop needs to post an evacuation plan) to avoid panic when accidents occur.

The workshop is equipped with a first-aid kit (including scald ointment, tourniquet, sterilized cotton pads, etc.), and a special person is appointed to take charge of it and replenish drugs regularly; Establish an emergency linkage mechanism with nearby hospitals to ensure that seriously injured people can be sent to the hospital for treatment within 15 minutes.

V. Special precautions: Prevention and control of risks related to aluminum material characteristics

The characteristics of aluminum material itself may bring additional security risks, which need to be prevented:

Risk of aluminum powder explosion: In the process of producing aluminum powder such as cutting and polishing (such as polishing the edge of embossed aluminum plate), it is necessary to install a dust collection device (such as a bag dust collector) to avoid aluminum powder accumulation in the air (the explosion limit of aluminum powder is 20-50g/m); Anti-static tools should be used when cleaning aluminum powder, and direct purging with compressed air is strictly prohibited (to avoid aluminum powder flying to reach explosive concentration).

Conductivity of aluminum: aluminum plate has good conductivity, so it is necessary to avoid contact with exposed electrical lines during processing to prevent short circuit from causing fire; When welding aluminum plate, it is necessary to cut off the power supply of peripheral equipment to avoid welding current interfering with the equipment circuit.

Characteristics of alloy aluminum: If alloy aluminum plates (such as series 3003 and 5052 containing magnesium and copper) are processed, it is necessary to pay attention to the high brittleness of some alloy aluminum (such as in low temperature environment), and control the temperature and pressure during rolling and bending to avoid the aluminum plates from breaking and splashing.

In a word, the safety management of the production and processing of embossed aluminum sheet should run through "the whole process, the whole staff and the whole equipment", and all kinds of risks should be controlled in the bud through standardized operation, normalized inspection and systematic training, so as to ensure that the production safety and product quality meet the standards.