Occupational Hazards In The Machinery Industry Are Explained. There Are Instructions For Every Industry In Metal Processing. Safety Is Very Important.
Mechanical manufacturing is an ancient but young discipline and the foundation of various industries. The level of machinery manufacturing is an important indicator of the level of industrialization and development of a country. The machinery manufacturing industry covers a wide range of areas and has a large team of industrial workers. According to incomplete statistics, there are approximately 1.5 to 2 million workers engaged in machinery manufacturing across the country. Its basic production processes are casting, forging, heat treatment, machining and assembly, etc. So, what are the occupational hazards in the machinery manufacturing industry? The machinery manufacturing industry has a wide scope, including the manufacturing of various machinery such as transportation vehicles, machine tools, agricultural machinery, textile machinery, power machinery, and precision instruments. There are generally casting, forging, heat treatment, machining, assembly and other workshops. There are many types of work, but the hazard factors of the occupations are generally the same.
1. Casting:
It can be divided into two categories: manual modeling and mechanical modeling. Manual modeling refers to the process of completing the main operations such as sand tightening, demoulding, trimming, and box closing by hand. The labor intensity is high, workers are directly exposed to dust, chemical poisons and physical factors, causing great occupational hazards. Case 1 occurred in this production environment. Mechanical molding has high productivity, stable quality, low labor intensity for workers, few opportunities for workers to be exposed to dust, chemical poisons and physical factors, and relatively small occupational hazards.
1. Dust hazard: A large amount of sand and dust will be generated during the processes of modeling, casting sand, cleaning, etc. The nature and hazards of dust are mainly determined by the type of molding sand. For example, when quartz sand is used for molding, it can be hazardous due to its high free silica content. maximum. In 2005, according to our inspection of the dust concentration in the workplace of the modeling workshop of a machinery factory, the results were 27.5 to 62.3 mg/cubic meter, with an average of 39.5 mg/cubic meter.
2. Harm from toxic substances and physical factors: High temperature and thermal radiation are generated during coal drying, smelting, sand molding, sand core pouring, etc.; if coal or natural gas is used as fuel, carbon monoxide, sulfur dioxide and nitrogen oxides will also be generated; if High Frequency Induction When heating in a stove or microwave, high frequency electromagnetic fields and microwave radiation are present.
2. Forging:
Forging is a processing method that applies external force to a blank to partially or completely plastically deform it to obtain a forging.
1. Hazards caused by physical factors: Noise is the most harmful occupational hazard factor in the forging process. Forging hammers (air hammers, pressure hammers) will produce strong noise and vibration, usually pulse noise with an intensity greater than 100dB (A). In 2005, according to our company's noise detection in the forging workshop of a machinery factory, the result was 83-100.2dB(A), with an average of 92.08dB(A). Punch machines and shearing machines also produce high-intensity noise, but their intensity is generally smaller than that of forging hammers.
The temperature of the heating furnace is as high as 1200°C, and the temperature of the forgings is also between 500-800°C. During the production process, high temperatures and strong radiant heat will be generated in the workplace.
2. Dust and toxic hazards: Forging furnaces and forging hammers will produce metal dust, coal dust, etc. during the loading, unloading, and forging processes. Fuel industry kilns are particularly polluting. Combustion forging produces harmful gases such as carbon monoxide, sulfur dioxide and nitrogen oxides.
3. Heat treatment:
The heat treatment process mainly changes the properties of the metal parts (hardness, toughness, elasticity, conductivity, etc.) without changing the shape of the metal parts, in order to achieve the performance required by the process, thereby improving product quality. Heat treatment includes normalizing, quenching, annealing, tempering, carburizing and other basic processes. Heat treatment can generally be divided into ordinary heat treatment, surface heat treatment (including surface quenching and chemical heat treatment) and special heat treatment.
1. Toxic gases: Heat treatment processes such as normalizing, annealing, carburizing, and quenching of mechanical parts require a variety of auxiliary materials, such as acids, alkali, metal salts, nitrates, cyanide salts, etc. These excipients are highly corrosive and toxic substances. For example, if barium chloride is used as the heating medium, when the process temperature reaches 1300°C, a large amount of barium chloride will evaporate, producing barium chloride smoke and dust, which will pollute the workshop air; during the chlorination process, a large amount of ammonia will be discharged into the workshop air Medium; Cyanide salts (potassium ferrocyanide, etc.) are used in carburizing, cyanidation and other processes; molten nitrates in the salt bath furnace interact with oil stains on the workpiece to produce nitrogen oxides. In addition, organic reagents such as methanol, ethanol, propane, acetone, and gasoline are also commonly used during heat treatment.
2. Hazards caused by physical factors: normalizing and annealing of mechanical parts. Heat treatment processes such as carburizing and quenching are performed at high temperatures. Various heating furnaces, salt baths and heating operations in the workshop are heat sources. These heat sources will create a working environment with high temperature and strong heat radiation. Various motors, fans, industrial pumps and mechanical operating equipment generate noise and vibration. However, the noise intensity in most heat treatment workshops is not high, and it is rare for the noise to exceed the standard.
4. Mechanical processing:
Various machine tools are used to perform cold processing such as turning, planing, drilling, grinding, and milling on metal parts; in the mechanical manufacturing process, metal parts are usually made into blanks through casting, forging, welding, stamping, etc., and then processed into qualified materials through cutting. parts and finally assembled into a machine.
1. General machining: Occupational hazards in the production process are relatively small, mainly due to the emulsion used in metal cutting and the impact of cutting on workers. Commonly used emulsions are emulsions composed of mineral oil, naphthoic acid or oleic acid and an alkali (caustic soda). Due to the high-speed transmission of the machine tool, the lotion splashes everywhere, which can easily contaminate the skin and cause skin diseases such as folliculitis or acne.
During mechanical processing, a large amount of metal and mineral dust will also be generated during rough grinding and fine grinding. Artificial grindstones are mostly made of emery (aluminum trioxide crystals), which contain very little silica, while natural grindstones contain large amounts of free silica, which can lead to aluminosis and silicosis. The mechanical noise generated by most machine tools is between 65-80dB(A), and it is rare for the noise to exceed the standard.
2. Special mechanical processing: Occupational hazard factors in special mechanical processing are related to processing tools; such as metal smoke and dust in electric discharge processing, high temperature and ultraviolet rays in laser processing, electron beam X-rays and metal smoke, etc.; metal smoke and dust exist in In ion beam processing, ultraviolet radiation and high frequency electromagnetic radiation. If tungsten electrodes are used, there is also the hazard of ionizing radiation; the hazards of electrolytic machining, liquid injection machining and ultrasonic machining are relatively small. In addition, equipment operation will produce noise and vibration.
5. Mechanical assembly:
There are few occupational hazard factors in simple mechanical assembly processes, and their hazards are basically the same as those in general mechanical processing. However, the occupational hazard factors existing in the complex assembly production process are mainly related to special assembly processes. If you need to use various types of electric welding, there will be occupational hazards caused by welding; if you need to use adhesives, there will be occupational hazards caused by adhesives; if you need to use a coating process, the coating process will cause Occupational Hazards.
6. Protective measures:
Occupational disease hazards in the machinery manufacturing industry are mainly concentrated in the hazards of silica dust in the casting production process (such as case 1), the hazards of organic solvents such as benzene and its homologues in the coating production process (such as case 2), and welding (smoke) during welding operations. )dust. Occupational hazards (Case 3). For this reason, the occupational hazard protection issues in the machinery manufacturing industry include:
1. Reasonable layout: In the workshop layout, the problem of cross-contamination that reduces occupational disease hazards must be considered. For example, the smelting furnace in the casting process should be placed outdoors or in a public place away from crowds; the riveting and (painting) processes should be arranged separately.
2. Dust prevention: When casting, molding sand with low free silicon content should be used as much as possible to reduce manual molding and sand cleaning operations. Sand cleaning is the part with the highest dust concentration in foundry production, and protection should be focused on, such as installing a high-power ventilation and dust removal system, implementing wet spray operations, etc., to reduce the dust concentration in the air in the workplace. And take personal protection and wear dust masks that comply with relevant national standards.
3. Poisoning prevention and emergency rescue: For equipment that may produce chemical poisons during heat treatment and metal smelting, sealing measures should be taken or local ventilation and detoxification devices should be installed. For workplaces that produce highly toxic gases such as high concentrations of carbon monoxide, hydrogen cyanide, formaldehyde, and benzene, such as certain special quenching, painting, and adhesive-using positions, emergency rescue plans for acute occupational poisoning accidents should be formulated, and warning signs should be set up. . , equipped with gas masks or respirators, etc.
4. Noise control: Noise is one of the important occupational hazards in the machinery manufacturing industry. Noise control mainly includes the control of high-intensity noise equipment such as air hammers and air compressors in casting and forging, as well as the control of high-intensity noise equipment such as grinding, polishing, stamping, shearing, and cutting in mechanical processing. High-intensity noise sources can be arranged centrally, and sound insulation covers can be installed. Aerodynamic noise sources should be silenced at the air intake or exhaust. Sound insulation and sound absorption measures should be taken in centralized control rooms and post operation rooms. Noise-proof earplugs or earmuffs should be worn when entering a workplace where the noise intensity exceeds 85dB(A).
5. Vibration control: Vibration is a common occupational hazard in the machinery manufacturing industry. Vibration equipment such as riveting, forging presses, molding sand tamping machines, falling sand, sand cleaning, etc. should take vibration reduction measures or implement rotation operations.
6. Radio frequency protection: Appropriate shielding and protective materials should be selected to shield equipment that generates high frequency, microwave and other radio frequency radiation or implement distance isolation protection and time protection.
7. Heatstroke prevention and cooling: Personnel engaged in high-temperature operations such as casting, forging, heat treatment, etc. should do a good job in heatstroke prevention and cooling in summer. Comprehensive measures should be taken from the aspects of engineering technology, health care, labor organization management, etc., such as rationally arranging heat sources, supplying cold and salty drinks, taking turns to work, and setting up air conditioners in centralized control rooms and operating rooms. , ETC.
