Do you know the safe operating procedures for vertical machining centers?

《Detailed Interpretation of the Safe Operating Procedures for Vertical Machining Centers》
I. Introduction
As a high – precision and high – efficiency machining equipment, the vertical machining center plays a crucial role in modern manufacturing. However, due to its fast running speed, high machining accuracy and involving complex mechanical and electrical systems, there are certain safety risks during the operation process. Therefore, it is extremely important to strictly abide by the safe operating procedures. The following is a detailed interpretation and in – depth analysis of each safe operating procedure.
II. Specific Safe Operating Procedures
Comply with the general safe operating procedures for milling and boring workers. Wear labor protection articles as required.
The general safe operating procedures for milling and boring workers are the basic safety criteria summarized through long – term practice. This includes wearing safety helmets, safety glasses, protective gloves, anti – impact shoes, etc. Safety helmets can effectively prevent the head from being injured by falling objects from heights; safety glasses can prevent the eyes from being injured by splashes such as metal chips and coolant generated during the machining process; protective gloves can protect the hands from being scratched by tools, workpiece edges, etc. during the operation; anti – impact shoes can prevent the feet from being injured by heavy objects. These labor protection articles are the first line of defense for operators in the working environment, and ignoring any of them may lead to serious personal injury accidents.
Check whether the connections of the operating handle, switch, knob, fixture mechanism and hydraulic piston are in the correct position, whether the operation is flexible, and whether the safety devices are complete and reliable.
The correct positions of the operating handle, switch and knob ensure that the equipment can operate according to the expected mode. If these components are not in the correct position, it may cause abnormal equipment actions and even lead to danger. For example, if the operating handle is in the wrong position, it may cause the tool to feed when it should not, resulting in workpiece scrapping or even damage to the machine tool. The connection state of the fixture mechanism directly affects the clamping effect of the workpiece. If the fixture is loose, the workpiece may be displaced during the machining process, which will not only affect the machining accuracy, but also may lead to dangerous situations such as tool damage and workpiece flying out. The connection of the hydraulic piston is also crucial as it is related to whether the hydraulic system of the equipment can work normally. And safety devices, such as emergency stop buttons and protective door interlocks, are the key facilities to ensure the safety of operators. Complete and reliable safety devices can quickly stop the equipment in an emergency to avoid accidents.
Check whether there are obstacles within the effective running range of each axis of the vertical machining center.
Before the machining center is running, the running range of each axis (such as X, Y, Z axes, etc.) must be carefully checked. The existence of any obstacles may hinder the normal movement of the coordinate axes, resulting in overload and damage of the axis motors, and even causing the coordinate axes to deviate from the predetermined track and triggering machine tool failures. For example, during the descent of the Z – axis, if there are uncleaned tools or workpieces below, it may cause serious consequences such as bending of the Z – axis lead screw and wear of the guide rail. This will not only affect the machining accuracy of the machine tool, but also increase the equipment maintenance cost and pose a threat to the safety of the operators.
It is strictly prohibited to use the machine tool beyond its performance. Select a reasonable cutting speed and feed rate according to the workpiece material.
Each vertical machining center has its designed performance parameters, including maximum machining size, maximum power, maximum rotation speed, maximum feed rate, etc. Using the machine tool beyond its performance will make each part of the machine tool bear a load beyond the design range, resulting in problems such as overheating of the motor, increased wear of the lead screw, and deformation of the guide rail. At the same time, selecting a reasonable cutting speed and feed rate according to the workpiece material is the key to ensuring the machining quality and improving the machining efficiency. Different materials have different mechanical properties such as hardness and toughness. For example, there is a big difference in cutting speed and feed rate when machining aluminum alloy and stainless steel. If the cutting speed is too fast or the feed rate is too large, it may lead to increased tool wear, decreased workpiece surface quality, and even tool breakage and workpiece scrapping.
When loading and unloading heavy workpieces, a reasonable lifting appliance and lifting method must be selected according to the weight and shape of the workpiece.
For heavy workpieces, if a suitable lifting appliance and lifting method are not selected, there may be a danger of workpiece falling during the loading and unloading process. According to the weight of the workpiece, different specifications of cranes, electric hoists and other lifting equipment can be selected. At the same time, the shape of the workpiece will also affect the choice of lifting appliances and lifting methods. For example, for workpieces with irregular shapes, special fixtures or lifting appliances with multiple lifting points may be required to ensure the balance and stability of the workpiece during the lifting process. During the lifting process, the operator also needs to pay attention to factors such as the bearing capacity of the lifting appliance and the angle of the sling to ensure the safety of the lifting operation.
When the spindle of the vertical machining center is rotating and moving, it is strictly prohibited to touch the spindle and the tools installed at the end of the spindle with hands.
When the spindle is rotating and moving, its speed is very fast, and the tools are usually very sharp. Touching the spindle or tools with hands is very likely to cause the fingers to be 卷入 the spindle or cut by the tools. Even in the case of seemingly low speed, the rotation of the spindle and the cutting force of the tools can still cause serious harm to the human body. This requires the operator to maintain a sufficient safety distance during the operation of the equipment and strictly abide by the operating procedures, and never risk touching the running spindle and tools with hands due to a momentary negligence.
When replacing tools, the machine must be stopped first, and the replacement can be carried out after confirmation. Attention should be paid to the damage of the cutting edge during the replacement.
Tool replacement is a common operation in the machining process, but if it is not operated properly, it will bring safety risks. Replacing tools in the stopped state can ensure the safety of the operator and avoid the tool from hurting people due to the sudden rotation of the spindle. After confirming that the machine has stopped, the operator also needs to pay attention to the direction and position of the cutting edge when replacing tools to prevent the cutting edge from scratching the hand. In addition, after replacing the tools, the tools need to be installed correctly and the clamping degree of the tools needs to be checked to ensure that the tools will not be loose during the machining process.
It is prohibited to step on the guide rail surface and paint surface of the equipment or place items on them. It is strictly prohibited to knock or straighten workpieces on the workbench.
The guide rail surface of the equipment is a key part to ensure the accurate movement of the coordinate axes, and its accuracy requirement is very high. Stepping on the guide rail surface or placing items on it will destroy the accuracy of the guide rail and affect the machining accuracy of the machine tool. At the same time, the paint surface not only plays a role in beautification, but also has a certain protective effect on the equipment. Damaging the paint surface may lead to problems such as rusting and corrosion of the equipment. Knocking or straightening workpieces on the workbench is also not allowed, because it may damage the flatness of the workbench and affect the machining accuracy of the workpiece. In addition, the impact force generated during the knocking process may also cause damage to other parts of the machine tool.
After inputting the machining program for a new workpiece, the correctness of the program must be checked, and whether the simulated running program is correct. Automatic cycle operation is not allowed without testing to prevent machine tool failures.
The machining program of a new workpiece may have programming errors, such as syntax errors, coordinate value errors, tool path errors, etc. If the program is not checked and simulated running is not carried out, and direct automatic cycle operation is carried out, it may lead to problems such as collision between the tool and the workpiece, over – travel of the coordinate axes, and wrong machining dimensions. By checking the correctness of the program, these errors can be found and corrected in time. Simulating the running program allows the operator to observe the movement trajectory of the tool before actual machining to ensure that the program meets the machining requirements. Only after sufficient checking and testing and confirming that the program is correct can the automatic cycle operation be carried out to ensure the safety and smoothness of the machining process.
When using the radial tool holder of the facing head for individual cutting, the boring bar should be first returned to the zero position, and then switched to the facing head mode in the MDA mode with M43. If the U – axis needs to be moved, it must be ensured that the U – axis manual clamping device has been loosened.
The operation of the radial tool holder of the facing head needs to be carried out strictly according to the specified steps. Returning the boring bar to the zero position first can avoid interference when switching to the facing head mode. MDA (Manual Data Input) mode is a manual programming and execution operation mode. Using the M43 instruction to switch to the facing head mode is the operation process specified by the equipment. For the movement of the U – axis, it is necessary to ensure that the U – axis manual clamping device is loosened, because if the clamping device is not loosened, it may cause difficulty in moving the U – axis and even damage the transmission mechanism of the U – axis. The strict implementation of these operation steps can ensure the normal operation of the radial tool holder of the facing head and reduce the occurrence of equipment failures and safety accidents.
When it is necessary to rotate the workbench (B – axis) during work, it should be ensured that it will not collide with other parts of the machine tool or other objects around the machine tool during rotation.
The rotation of the workbench (B – axis) involves a large range of motion. If it collides with other parts of the machine tool or surrounding objects during the rotation process, it may cause damage to the workbench and other parts, and even affect the overall accuracy of the machine tool. Before rotating the workbench, the operator needs to carefully observe the surrounding environment and check whether there are obstacles. For some complex machining scenarios, it may be necessary to conduct simulations or measurements in advance to ensure the safe space for the rotation of the workbench.
During the operation of the vertical machining center, it is prohibited to touch the areas around the rotating lead screw, smooth rod, spindle and facing head, and the operator shall not stay on the moving parts of the machine tool.
The areas around the rotating lead screw, smooth rod, spindle and facing head are very dangerous areas. These parts have high speed and large kinetic energy during the operation process, and touching them may lead to serious personal injury. At the same time, there are also dangers in the moving parts of the machine tool during the operation process. If the operator stays on them, he may be caught in a dangerous area with the movement of the parts or be injured by the squeezing between the moving parts and other fixed parts. Therefore, during the operation of the machine tool, the operator must keep a safe distance from these dangerous areas to ensure his own safety.
During the operation of the vertical machining center, the operator is not allowed to leave the working position without permission or entrust others to take care of it.
During the operation of the machine tool, various abnormal situations may occur, such as tool wear, workpiece loosening, and equipment failure. If the operator leaves the working position without permission or entrusts others to take care of it, it may lead to the failure to detect and deal with these abnormal situations in time, thus causing serious safety accidents or equipment damage. The operator needs to pay attention to the running state of the machine tool at all times and take timely measures for any abnormal situations to ensure the safety and stability of the machining process.
When abnormal phenomena and noises occur during the operation of the vertical machining center, the machine should be stopped immediately, the cause should be found out, and it should be dealt with in time.
Abnormal phenomena and noises are often the precursors of equipment failures. For example, abnormal vibration may be a signal of tool wear, imbalance or loosening of machine tool parts; harsh noises may be the manifestations of problems such as bearing damage and poor gear meshing. Stopping the machine immediately can prevent the failure from further expanding and reduce the risk of equipment damage and safety accidents. Finding out the cause requires the operator to have a certain amount of equipment maintenance knowledge and experience, and find out the root cause of the failure through observation, inspection and other means, and deal with it in time, such as replacing worn tools, tightening loose parts, and replacing damaged bearings.
When the spindle box and workbench of the machine tool are at or close to the motion limit positions, the operator shall not enter the following areas:
(1) Between the bottom surface of the spindle box and the machine body;
(2) Between the boring shaft and the workpiece;
(3) Between the boring shaft when extended and the machine body or the workbench surface;
(4) Between the workbench and the spindle box during movement;
(5) Between the rear tail barrel and the wall and oil tank when the boring shaft is rotating;
(6) Between the workbench and the front column;
(7) Other areas that may cause squeezing.
When these parts of the machine tool are at or close to the motion limit positions, these areas will become very dangerous. For example, the space between the bottom surface of the spindle box and the machine body may shrink rapidly during the movement of the spindle box, and entering this area may cause the operator to be squeezed; there are similar dangers in the areas between the boring shaft and the workpiece, between the boring shaft when extended and the machine body or the workbench surface, etc. The operator must always pay attention to the positions of these parts, and avoid entering these dangerous areas when they are close to the motion limit positions to prevent personal injury accidents.
When shutting down the vertical machining center, the workbench must be returned to the middle position, the boring bar must be returned, then the operating system must be exited, and finally the power supply must be cut off.
Returning the workbench to the middle position and returning the boring bar can ensure that the equipment is in a safe state when it is started next time, avoiding start – up difficulties or collision accidents due to the workbench or boring bar being at the limit position. Exiting the operating system can ensure that the data in the system is saved correctly and data loss is avoided. Finally, cutting off the power supply is the last step of shutting down to ensure that the equipment stops running completely and eliminate electrical safety hazards.
III. Summary
The safe operating procedures of the vertical machining center are the key to ensuring the safe operation of the equipment, the safety of the operators and the machining quality. Operators must deeply understand and strictly abide by each safe operating procedure, and no detail from wearing labor protection articles to equipment operation can be ignored. Only in this way can the machining advantages of the vertical machining center be fully exerted, the production efficiency be improved, and safety accidents be avoided at the same time. Enterprises should also strengthen the safety training for operators, improve the safety awareness and operation skills of operators, and ensure the production safety and economic benefits of enterprises.