Explanation of power supply requirements and usage errors in gantry drilling and milling machines

The following requirements are imposed on the power supply used in gantry drilling and milling machines:

1. Requirements for compressed air supply systems of gantry drilling and milling machines Gantry drilling and milling machines generally use a lot of pneumatic components, so a clean and dry compressed air supply system network should be connected to the plant. Its flow and pressure should meet the requirements. The compressed air machine should be installed away from the gantry drilling and milling machine. According to the layout of the plant and the amount of gas used, it should be considered to install refrigerated air coal machine, air filter, gas tank, valve and other equipment in the compressed air supply system network.
2. It is recommended to connect mechanical and electrical equipment to a single power supply. If other power supplies are needed to supply power to certain parts of the electrical equipment (such as electronic circuits, electromagnetic clutches), these power supplies should be taken from devices that constitute part of the mechanical and electrical equipment (such as transformers, transducers, etc.) as much as possible. For large and complex machinery, including many machines that work together in a collaborative manner and occupy a large space, more than one inlet power supply may be required, which depends on the configuration of the site power supply. Unless the mechanical electrical equipment is directly connected to the power supply by plug/socket, it is recommended that the power cord be directly connected to the power terminal of the power cut-off switch. If this is not possible, a vertical terminal block should be set for the power cord. The handle of the power cut-off switch should be easily accessible and should be installed between 0.6m and 1.9m above the easy-to-operate position. The upper limit is recommended to be 1.7m. This can cut off the power in an emergency and reduce losses and casualties.
3. The voltage fluctuation of the power grid should be controlled between +10% and -15%, while the power supply in my country has large fluctuations and poor quality, and also hides interference such as high-frequency pulses, plus human factors (such as sudden power outages, etc.). During peak power periods, such as about an hour before going to work or getting off work during the day and at night, there are often many deviations, even up to ±20%. The machine tool alarm cannot work normally and damages the machine tool power supply system. It even leads to the loss of relevant parameter data. This phenomenon has occurred on machine tools such as CNC machining centers or turning centers, and the frequency of occurrence is quite good, which should be taken seriously. It is recommended to configure an AC voltage-stabilized power supply system with automatic compensation and adjustment function in workshops where CNC machine tools are concentrated; a single CNC machine tool can be configured with an AC voltage stabilizer to solve the problem.

Errors in the use of gantry drilling and milling machines

1. Original manufacturing error of the machine tool: refers to the machine tool motion error caused by the geometric shape, surface quality, and position errors of the working surfaces of the components of the machine tool, which is the main cause of the geometric error of the gantry drilling and milling machine.
2. Test error of the detection system: the error of the measurement sensor feedback system itself caused by the manufacturing error of the measurement sensor and its installation error on the machine tool; the error of the measurement sensor caused by the error of machine tool parts and mechanisms and the deformation during use.
3. Errors caused by deformation of the process system caused by cutting load: including errors caused by deformation of the machine tool, tool, workpiece and fixture. This error is also called “cutting”, which causes the shape distortion of the machined parts. When processing thin-walled workpieces or using slender tools, this error is more serious.
4. Thermal deformation error: the error caused by the thermal deformation of the structure of the machine tool due to the internal heat source of the machine tool and the environmental thermal disturbance.
5. Machine tool control system error: including the servo error (contour following error) of the machine tool axis system and the CNC interpolation algorithm error.
6. External interference error: random error caused by changes in the environment and operating conditions.
7. Machine tool vibration error: during cutting, the gantry drilling and milling machine has a greater possibility of falling into the chaotic area due to the flexibility of the process and the variability of the process, thereby causing strong vibration. Resulting in surface quality and geometric shape errors of the workpiece.
8. Other errors: such as errors caused by programming and operation errors.

Introduction to the method of modifying the gantry drilling and milling machine

1. Install a simple tool setting device on the slide. After the load (friction, moment of inertia, etc.) calculation, the stepper motors that drive the tool holder to move up and down (Z coordinate axis) and left and right (X coordinate axis) are selected as 110BF003 and 130BF003 respectively. The pulse equivalent of these two coordinate movements is 0.01mm.
2. The manual adjustment tool holder is changed into a CNC tool holder driven by a stepper motor. The Z stepper motor controls the movement of the tool holder in the vertical direction, and the X stepper motor controls the movement of the tool holder in the horizontal direction.
3. Three proximity switches are installed at the position close to the slider at the base of the slide table, and a slider position mark block (iron block) parallel to the three proximity switches and close to the three switches during movement is fixed on the slider. The two are used together to detect the movement direction and position of the slider.
4. The original vertical tool holder and side tool holder of the gantry drilling and milling machine change the speed, feed amount and feed direction through the handle of the gearbox, and are driven by ordinary three-phase asynchronous motors without control. It is impossible to meet the control requirements of speed and feed amount for milling and grinding functions.