The knowledge most needed by workshop supervisors! A comprehensive guide to the correct procedures for 17 types of work!

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I. The main types of injuries caused by mechanical accidents are as follows: 1. Injuries resulting from the rotational movement of mechanical equipment parts and components. For example, in machinery and equipment, components such as gears, idler wheels, pulleys, chucks, shafts, lead screws, screw rods, and shaft joints all perform rotational motion. The main forms of injury caused by rotational motion to people are entanglement and object strike injuries. 2. Injuries caused by the linear motion of parts and components of machinery and equipment. For example, the pressing components of hammers, punch presses, and sheet-cutting machines, the headstock of shaper machines, the bed surface of gantry milling machines, as well as the large and small cars and lifting mechanisms of bridge cranes, all move in a straight line. Injuries caused by components used for linear transportation mainly include crush injuries, impact injuries, and compression injuries. 3. Injuries caused by cutting tools. For example, the cutting tools used on lathes such as turning tools, those on milling machines like milling cutters, the drills used on drilling machines, the grinding wheels on grinders, and the saw blades on saws are all tools used for processing parts. The main injuries caused by cutting tools during part processing are burns, punctures, and cuts. 4. Injuries caused by the parts being processed. Mechanical equipment can cause injury to people while processing parts. Such injury accidents mainly include: ① Parts being processed not being secured properly and being flung out, thus injuring people; for example, if a lathe chuck does not hold the workpiece firmly, it will be thrown out during rotation and injure someone. ②The parts being processed may cause injuries from being lifted and handled. 5. Injuries caused by the electrical system. The mechanical equipment used in factories is powered mostly by electricity; therefore, each piece of equipment has its own electrical system. It mainly includes electric motors, distribution boxes, switches, buttons, local lighting fixtures, as well as neutral (ground) and power supply wires. The main harm caused by electrical systems to humans is electric shock. 6. Injuries caused by hand tools. 7. Other injuries. In addition to causing the various injuries mentioned above, mechanical equipment can also lead to other types of injuries. For example, some mechanical devices generate intense light and high temperatures during use, while others release chemical energy, radiation, as well as harmful dust and toxic substances, all of which can cause damage to the human body. II. What are the basic safety requirements for mechanical equipment? The basic safety requirements for mechanical equipment are mainly as follows: 1. The layout of mechanical equipment should be reasonable, to facilitate operators in loading and unloading workpieces, carrying out processing and observation, as well as removing debris ； It should also be easy for maintenance personnel to inspect and repair. 2. The strength and stiffness of the parts and components of mechanical equipment must meet safety requirements; they should be installed firmly to prevent frequent failures. 3. Mechanical equipment must be equipped with reasonable and reliable safety devices that do not interfere with operation, in accordance with relevant safety requirements. For example: (1) For parts that are in rotational motion, safety devices such as protective covers, guards, or railings should be installed to prevent entanglement injuries. (2) For components and parts that may lead to dangerous accidents due to overpressure, overload, excessive temperature, prolonged operation, or excessive travel distance, safety devices should be installed, such as overload limiters, travel limiters, safety valves, temperature relays, time switches, etc. These devices enable the elimination of potential hazards when such dangerous situations arise, thereby preventing accidents from occurring. (3) For certain actions that require warning or drawing people’s attention, signal devices or warning signs should be installed. Sound signals such as electric bells, horns, and buzzers, as well as various light signals and warning signs, all fall under this category of safety devices. (4) Interlock devices should be installed for those components or parts whose sequence of operation must not be reversed. That is, a certain action must be carried out after the previous action is completed; otherwise, it is impossible to perform that action. This ensures that accidents do not occur due to errors in the sequence of actions. 4. The electrical installations of mechanical equipment must meet electrical safety requirements, which mainly include the following points: (1) The power supply wires must be installed properly, with no damage or exposed copper areas. (2) The motor insulation should be good, and its wiring board should be covered with a guard to prevent direct contact. (3) Switches, buttons, etc. should be in good condition, and their live parts must not be exposed. (4) There should be a proper grounding or neutral connection system, and the wires connected must be secure with no breaks. (5) Local lighting fixtures should use a voltage of 36V; the use of 110V or 220V is prohibited. 5. The control levers and foot switches of mechanical equipment shall meet the following requirements: (1) Important levers shall be equipped with reliable positioning and locking devices. The coaxial handles should have a noticeable difference in length. (2) The handwheel can disengage from the shaft when in motion, to prevent injury from rotation along with the shaft. (3) The foot switch should be equipped with a protective cover or housed in a recessed part of the bed frame, to prevent falling parts from landing on the switch and starting the mechanical equipment, which could cause injury. (6) The working area for mechanical equipment should have a favorable environment, meaning that the illumination level should be appropriate, the humidity and temperature should be moderate, noise and vibration should be low, and parts, fixtures, and other items should be arranged neatly. This helps to keep the operator in a good mood, allowing them to work attentively and without mistakes. (7) Each piece of mechanical equipment should have safety operating procedures, as well as systems for inspection, lubrication, and maintenance, established based on its performance and operating sequence, so that operators can follow them. III. What are the common protective devices in machining workshops? What are their main functions? Common protective devices in machining workshops include guards, protective shields, safety fences, and protective nets. Protective devices must be installed on dangerous parts of mechanical equipment such as drive belts, couplings where gears are close to the ground, rotating shafts, pulleys, flywheels, grinding wheels, and electric saws. Safety devices must be installed on the spinning parts of pressure machinery such as presses, rollers, calenders, planers, and sheet shear machines. Protective covers are used to isolate exposed rotating parts, such as pulleys, gears, sprockets, and rotating shafts. Protective baffles and protective nets come in fixed and movable types, serving to isolate and prevent the splashing of metal shavings. Guardrails are used to prevent workers at heights from falling or to demarcate safe areas. Generally speaking, the main types of protective devices are fixed protective devices, interlock protective devices, and automatic protective devices. IV. What are the safety management regulations for operators of mechanical equipment? To prevent work-related accidents involving mechanical equipment, it is necessary not only for the equipment itself to meet safety requirements but also, more importantly, for operators to strictly adhere to safety procedures. Of course, the safety operating procedures for mechanical equipment vary depending on their type, but the basic safety rules are as follows: 1. Wear personal protective equipment properly. What needs to be worn must be worn, and what shouldn’t be worn must not be worn at all. For example, during machining, female workers are required to wear protective hats, as failing to do so could result in their hair getting caught. It is also required not to wear gloves, as if gloves are worn, the rotating parts of the machinery may wrap around them and injure the hand. 2. Before operation, a safety check of the mechanical equipment must be carried out, and it should be run without a load first; only after confirming that everything is functioning properly can it be put into use. 3. Mechanical equipment also needs to undergo safety inspections as required during operation. In particular, check whether the fastened items have loosened due to vibration, so that they can be tightened again. 4. Equipment must never be operated when faulty; it is absolutely not permissible to use it in a substandard condition to prevent accidents. 5. Mechanical safety devices must be used correctly in accordance with regulations; they must never be removed and left unused. 6. The cutting tools, fixtures, and workpieces used in mechanical equipment must be securely clamped and must not become loose. 7. It is strictly prohibited to adjust mechanical equipment by hand while it is in operation ； It is also not allowed to measure parts by hand, or to perform lubrication or clean up debris. If it must be done, the mechanical equipment should be shut down first. 8. When mechanical equipment is in operation, the operator must not leave their post to ensure that there is someone available to handle any issues that may arise. 9. After the work is completed, turn off the switch, remove the cutting tool and the workpiece from their working positions, clean the work area, arrange the parts and fixtures neatly, and clean the mechanical equipment. V. How can metal cold working workshops prevent work-related accidents? There are many types of machine tools in such workshops; by properly arranging the workspace, installing necessary protective and safety devices, and strictly adhering to safety operating procedures, work-related accidents can be effectively prevented. Requirements for the layout of machine tools: 1. Prevent parts or chips from being thrown out and causing injury. 2. The operator is protected from dizziness caused by direct sunlight. 3. It is convenient for transporting finished products and semi-finished products as well as for removing metal shavings. 4. The workshop should have safety passages to ensure unobstructed movement of personnel and vehicles. Guard requirements: 1. Guard cover: Isolates exposed rotating parts. 2. Guardrails. Guardrails with a height of not less than 1 m should be installed at those parts of machine tools that can easily cause injury during operation, as well as on machine tools that are not operated on the ground. 3. Guard shield: Prevents dust, chips, and coolant from splashing. Safety device requirements: 1. Overload safety device: Automatically disengages or shuts down when overloaded. 2. Travel stop device: It enables automatic stopping or returning of moving parts to a predetermined position. 3. Sequential action interlock device: The next action cannot be performed until the current action is completed. 4. Accident interlock device: In the event of a sudden power outage, the compensation mechanism can act immediately or stop the machine tool. 5. Braking device: Prevents loading and unloading of workpieces while the machine tool is rotating ； In the event of a sudden accident, the machine can be stopped promptly. VI. What safety precautions should lathes operators take? The safety precautions that lathes operators should observe include: 1. Wear tight-fitting protective clothing, with sleeves that are not left unfastened ； Long hair must be covered with a protective cap ； Gloves must not be worn during operation. 2. The installation and removal of the chuck on the machine tool spindle must be performed after the machine is stopped; do not use the motor’s power to remove the chuck. 3. It is advisable to use protective covers on the protruding parts of chucks, turntables, and C-clamps used to hold workpieces, to prevent clothing or other parts of the body from getting caught. If no protective covers are available, be careful to stay away when operating them and avoid getting too close. 4. When clamping the workpiece with a center punch, ensure that the punch and the center hole are perfectly aligned; do not use a damaged or misaligned punch. Before use, clean the punch and the center hole thoroughly, and make sure the tailstock punch is securely in place. 5. When turning long and slender workpieces, a center rest or follow rest should be used to ensure safety; the portion extending beyond the lathe must be marked. 6. When turning workpieces with irregular shapes, balance weights should be installed; after ensuring balance through a test run, cutting can then be performed. 7. The tool must be clamped securely; the protruding part of the cutting edge should not exceed 1.5 times the height of the tool body. The shape and size of the shims under the tool should match those of the tool body, and as many shims as possible should be used, with them being as flat as possible. 8. Use a hook to remove the cut strip-shaped chips and spiral-shaped long chips promptly; never pull them by hand. 9. To prevent broken chips from injuring people, transparent guards should be installed in appropriate locations. 10. Except for lathes equipped with measuring tools that perform automatic measurements during operation, the machine must be stopped to measure the workpiece, and the tool holder should be moved to a safe position. 11. When grinding the surface of the workpiece with sandpaper, move the tool to a safe position and be careful not to let your hands or clothes come into contact with the workpiece surface. 12. When grinding internal holes, do not use your fingers to hold the sandpaper; use a wooden stick instead, and keep the speed of rotation not too high. 13. It is prohibited to place tools, fixtures, or workpieces on the lathe bed and the spindle gearbox. VII. What safety precautions should millers take? The safety precautions that millers need to observe include: 1. When starting cutting, the milling tool must be fed into the workpiece slowly; there should be no sudden impacts, as this could affect the precision of the machine or damage the blade. 2. The workpiece must be leveled and secured to prevent it from coming loose during processing, which could lead to accidents. 3. Adjusting speed and direction, as well as correcting the workpiece and tools, must all be done after stopping the machine. 4. Gloves should not be worn while working. 5. Remove the chips on the bed surface with a brush at any time; to remove the chips from the milling cutter, the machine must be stopped first. 6. When the milling cutter becomes dull, the machine should be stopped to sharpen it or replace the cutter. Before stopping the machine, retract the cutter first; never stop the machine until the cutter has completely left the workpiece. VIII. What safety precautions should planer operators take? The safety precautions that planer operators should observe include: 1. The planing tool must be securely clamped, and there should be a certain gap between the blade and the workpiece before starting work. Do not cut too deeply at first to avoid damaging the blade or injuring anyone. 2. Do not stand directly in front of the planer while operating it, and never bend down to check the work in front of the planer. 3. Adjust the machine tool’s travel distance and tighten the bolts that control it. 4. Install an upright, flipable cylindrical protective shield around the surface of the planer table. 5. Collect the chips in a specially designed chip container to prevent cuts from injuring the feet. 9. What safety precautions should lathe operators take? The safety precautions that lathe operators should follow include: 1. Before starting the machine, it is necessary to check whether the workpiece is properly secured, whether the fastenings are reliable, and whether the magnetic chuck is functioning correctly; otherwise, the machine must not be started. 2. When driving the machine, use manual adjustment to maintain an appropriate gap between the grinding wheel and the workpiece; start with a small feed rate to prevent the grinding wheel from cracking. 3. Measuring the workpiece, adjusting the machine tool, and cleaning should all be carried out after the machine has been stopped. 4. To prevent injuries from debris in the event of a grinding wheel failure, grinders must be equipped with protective guards; it is prohibited to use grinding wheels without such guards for grinding. X. What safety precautions should drill operators take? The safety precautions that drill operators should observe include: 1. It is not allowed to operate the machine while wearing gloves, and it is strictly prohibited to use hands to remove metal shavings. 2. The head must not be too close to the drilling machine, and a hat must be worn while working. 3. Before drilling, the worktable must be secured first; for a swing arm drill press, the swing arm also needs to be fixed before drilling can begin. 4. When starting to drill and when the workpiece is nearly through, do not use excessive force. 11. What are the main contents of the safety operating procedures for stamping? When operating stamping equipment, operators must follow these safety procedures: 1. Before starting operation, it is necessary to carefully check whether the protective devices are in good condition, and whether the clutch and braking systems are functional and reliable. All unnecessary items on the workbench should be removed to prevent them from falling onto the foot pedal during operation, which could cause the punch press to start suddenly and lead to accidents. 2. When punching small workpieces, hands must not be used; special tools should be employed, and it is advisable to install an automatic feeding device. 3. The operator must be careful when controlling the foot pedal; the foot should be kept away from the foot pedal when loading and unloading workpieces. Strangers are strictly prohibited from staying around the foot pedal. 4. If the workpiece gets stuck in the mold, it should be removed using specialized tools; it is not allowed to handle it by hand, and one’s feet must be moved away from the foot pedal. XII. What safety precautions should a fitter take? The safety precautions that a fitter should observe include: 1. The tools used by a fitter must be inspected before use. 2. A wire guard mesh should be installed on the fitter’s workbench; when chiseling, care must be taken to ensure the safety of workers on the opposite side. It is strictly prohibited to use high-speed steel for chisels. 3. When sawing a workpiece with a hand saw, the saw blade should be properly tightened to prevent it from breaking and causing injury. 4. When using a sledgehammer, it is necessary to pay attention to the conditions around it in all directions – front, back, left, right, and above. No one is allowed to stand within the range of motion of the sledgehammer. It is not permitted to use a sledgehammer to strike a smaller hammer, nor is it allowed to use a smaller hammer to strike a sledgehammer. 5. When working at multiple levels or in a cross-functional manner, it is necessary to wear safety helmets and pay attention to following unified instructions. 6. After the equipment has been repaired, all safety protection devices, safety valves, and various audio-visual signals must be restored to their normal state. 13. How can metal hot working workshops prevent work-related accidents? The production process in metal hot working workshops is characterized by numerous steps and large amounts of material handling. During production, high temperatures, toxic gases, and dust are generated, which deteriorate the working environment and increase the risk of work-related accidents. Therefore, metal hot working workshops must implement some effective safety measures: 1. Carefully select the furnace materials to prevent contamination; the materials used must be thoroughly dried ； The added alloy needs to be preheated. 2. When the molten metal is taken out of the furnace, an electric, pneumatic, or hydraulic plug mechanism or a rotary front furnace should be used. 3. Strict measures must be taken for the pit to prevent groundwater and surface water from seeping in. 4. The containers for molten metal must meet manufacturing quality standards ； The molten metal in the ladle should not be too full. 5. The forging hammer should be operated by a manipulator or robotic arm to prevent hot forged parts, such as their oxide scales, from flying out and causing injury ； Isolation guards should be installed in front of the operator’s and the air hammer driver’s seats to prevent burns and provide thermal insulation. 6. Before being placed in the heat treatment salt furnace, both the tools and workpieces must be preheated, and railings or protective covers should be installed around the quenching oil tank. 7. The welding area should be isolated or provided with appropriate shielding; metal surfaces should not be used as shielding materials. Additionally, the workshop should have safety exits, the floor should be flat and non-slip, and it must remain unobstructed. The workshop should have sufficient lighting, and the plant design should facilitate both mechanical ventilation and natural ventilation. Without compromising production and transportation, various processes and workstations should be isolated from one another as much as possible. Equipment that may pose safety risks should also be isolated when necessary, with safety barriers or protective nets installed. Workers in metal hot working workshops must be equipped with necessary protective equipment such as safety helmets, protective glasses, and protective shoes. 14. What safety precautions should steelworkers take? The safety precautions that steelworkers should observe include: 1. It is prohibited to add wet materials or discarded weapons as scrap steel to the furnace, to avoid explosions. Molten steel and red slag must also not be poured into wet ladles, slag containers, or wet floors. 2. To prevent splashing and explosion accidents during melting, be careful not to add an excessive amount of oxidizer, and avoid vigorous stirring of the molten steel. 3. The molten steel ladle should not be filled to capacity; strict adherence to the operating procedures is necessary when lifting it with a crane, in order to prevent accidents involving the overturning of the ladle. 4. In the event of a furnace leak, a ladle leak, an interruption in the circulating water, or water leakage inside the furnace, appropriate safety measures must be taken immediately. 5. It is necessary to wear personal protective equipment; those who do not wear such equipment are not allowed to operate. 15. What safety precautions should foundry workers take? The safety precautions that foundry workers should observe include: 1. The casting area and the pits must be kept dry; there should be no water present to prevent molten iron from splashing and injuring people. 2. The tools used, such as tongs, fire rods, hooks, etc., should all be preheated. 3. The molten iron in the bag should not be filled to capacity; when lifting the bag, avoid tilting it or stopping suddenly, and ensure coordinated movement. 4. Before casting, the clamping irons on the upper and lower boxes of the sand mold should be firmly pressed in place, or secured with screws, and the risers should be checked to ensure that the air passages are properly arranged. 5. Do not look directly at the riser during casting; remove gas promptly to prevent explosions of gases inside the mold. 6. During casting, unauthorized personnel must not approach. Wear protective glasses when looking at the freshly cast nozzle. 16. What safety precautions should blacksmiths take? The safety precautions that blacksmiths should observe include: 1. When picking up or placing dies, punches, shims, etc. on the anvil, clamps must be used; it is strictly prohibited to use hands. 2. During manual operation, those using the sledgehammer must coordinate well with each other; it is strictly prohibited to walk or work within 2–5 meters behind the person using the sledgehammer. 3. When cutting the metal blank, be careful to strike gently to prevent the cut piece from flying out and hurting someone. The handle of the forceps held in the hand should not be directed straight at the abdomen. 4. When the pneumatic hammer is in operation, it is not allowed to operate it without a load, it is not allowed to measure the dimensions of the workpiece, and no part of the body shall enter the range of movement of the hammer head. The hammer head must be secured during inspection or repair. Note that flammable materials are not allowed to be stored near the heating furnace. 17. What kinds of injuries can occur in welding operations? During welding, welders are often exposed to flammable and explosive gases, and sometimes they have to work at heights, underwater, or in confined spaces ； During welding, toxic gases, harmful dusts, arc radiation, noise, high-frequency electromagnetic fields, and other substances can cause serious harm to the human body. At welding sites, work-related accidents such as explosions, fires, burns, poisoning, electric shocks, and falls from heights can occur. Welders can also suffer various injuries while working, leading to occupational diseases affecting the blood, eyes, skin, lungs, and other organs. Welders are considered special-type workers; they must undergo safety training and pass relevant examinations before being allowed to work independently.