1.1 Installation of CNC machine tool body
1. Prior to the arrival of the CNC machine tool, the user needs to prepare the installation according to the machine tool foundation drawing provided by the manufacturer. Reserved holes should be made at the location where the anchor bolts will be installed. Upon delivery, the commissioning personnel will follow unpacking procedures to transport the machine tool components to the installation site and place the major components on the foundation following the instructions.
Once in place, shims, adjustment pads, and anchor bolts should be positioned correctly, and then the various parts of the machine tool should be assembled to form a complete machine. After the assembly, the cables, oil pipes, and air pipes should be connected. The machine tool manual includes electrical wiring diagrams and gas and hydraulic pipeline diagrams. The relevant cables and pipelines should be connected one by one according to the markings.
2. The precautions at this stage are as follows.
After unpacking the machine tool, the first step is to locate the various documents and materials, including the machine tool packing list, and verify that the parts, cables, and materials in each packaging box match the packing list.
Before assembling the different parts of the machine tool, it’s important to remove the anti-rust paint from the installation connection surface, guide rails, and various moving surfaces and thoroughly clean the surface of each component.
During the connection process, pay close attention to cleaning, ensuring reliable contact and sealing, and checking for any looseness or damage. After plugging in the cables, be sure to tighten the fixing screws to ensure a secure connection. When connecting the oil and air pipes, take special precautions to prevent foreign matter from entering the pipeline from the interface, which could cause the entire hydraulic system to malfunction. Each joint should be tightened when connecting the pipeline. Once the cables and pipelines are connected, they should be secured, and the protective cover shell should be installed to ensure a tidy appearance.
1.2 Connection of CNC system
1) Unpacking inspection of the CNC system.
After receiving a single CNC system or a complete CNC system purchased with a machine tool, it’s important to thoroughly inspect it. This inspection should cover the system body, the matching feed speed control unit and servo motor, as well as the spindle control unit and spindle motor.
2) Connection of external cables.
External cable connection refers to the cables that connect the CNC system to the external MDI/CRT unit, the power cabinet, the machine tool operation panel, the feed servo motor power line, the feedback line, the spindle motor power line, and the feedback signal line, as well as the hand-cranked pulse generator. These cables should comply with the connection manual provided with the machine, and the ground wire should be connected at the end.
3) Connection of CNC system power cord.
Connect the input cable of the CNC system power supply when the power switch of the CNC cabinet is turned off.
4) Confirmation of settings.
There are multiple adjustment points on the printed circuit board in the CNC system, which are interconnected with jumper wires. These need proper configuration to align with the specific requirements of different types of machine tools.
5) Confirmation of input power supply voltage, frequency, and phase sequence.
Before powering on various CNC systems, it is important to check the internal DC-regulated power supplies which provide the system with the necessary ±5V, 24V, and other DC voltages. Ensure that the load of these power supplies is not short-circuited to the ground. A multimeter can be used to confirm this.
6) Confirm whether the voltage output terminal of the DC power supply unit is short-circuited to the ground.
7) Turn on the power of the CNC cabinet and check the output voltages.
Before turning on the power, disconnect the motor power line for safety. After powering on, check if the fans in the CNC cabinet are rotating to confirm power.
8) Confirm the settings of the parameters of the CNC system.
9) Confirm the interface between the CNC system and the machine tool.
After completing the aforementioned steps, we can conclude that the CNC system has been adjusted and is now ready for an online power-on test with the machine tool. At this point, the power supply to the CNC system can be turned off, the motor power line can be connected, and the alarm setting can be reinstated.
1.3 Power-on test of CNC machine tools
To ensure proper maintenance of the machine tools, refer to the CNC machine tool manual for lubrication instructions. Fill the specified lubrication points with the recommended oil and grease, clean the hydraulic oil tank and filter, and refill it with the appropriate hydraulic oil. Additionally, make sure to connect the external air source.
When powering on the machine tool, you can choose to power all parts at once or power each component separately before conducting a total power supply test. When testing the CNC system and machine tool, even if the CNC system is functioning normally without any alarms, always be prepared to press the emergency stop button to cut off power if necessary. Use manual continuous feed to move each axis and verify the correct movement direction of the machine tool components through the display value of CRT or DPL (digital display).
Check the consistency of the movement distance of each axis with the movement instructions. If discrepancies exist, verify the relevant instructions, feedback parameters, position control loop gain, and other parameter settings. Move each axis at a low speed using manual feed, ensuring they hit the overtravel switch to check the effectiveness of the overtravel limit and whether the CNC system issues an alarm when overtravel occurs. Thoroughly review whether the parameter setting values in the CNC system and PMC device align with the specified data in the random data.
Test various operating modes (manual, inching, MDI, automatic mode, etc.), spindle shift instructions, and speed instructions at all levels to confirm their accuracy. Finally, perform a return to reference point action. The reference point serves as the program reference position for future machine tool processing. Therefore, it’s essential to verify the presence of a reference point function and ensure the consistent return position of the reference point each time.
1.4 Installation and adjustment of CNC machine tools
As per the CNC machine tool manual, a comprehensive check is conducted to ensure the normal and complete functioning of the main components, enabling all aspects of the machine tool to operate and move effectively. The cnc manufacturing process involves adjusting the bed level of the machine tool and making preliminary adjustments to the main geometric accuracy. Subsequently, the relative position of the reassembled main moving parts and the main machine is adjusted. Anchor bolts of the main machine and accessories are then filled with quick-drying cement, and the reserved holes are also filled, allowing the cement to dry completely.
Fine-tuning of the main bed level of the machine tool on the solidified foundation is carried out using anchor bolts and shims. Once the level is established, the moving parts on the bed, such as the main column, slide, and workbench, are moved to observe the horizontal transformation of the machine tool within the full stroke of each coordinate. The geometric accuracy of the machine tool is then adjusted to ensure it falls within the allowable error range. Precision level, standard square ruler, flat ruler, and collimator are among the detection tools used in the adjustment process. During the adjustment, the focus is primarily on adjusting the shims, and if necessary, making slight modifications to the inlay strips and preload rollers on the guide rails.
1.5 Operation of the tool changer in the machining center
To initiate the tool exchange process, the machine tool is directed to automatically move to the tool exchange position using specific programs such as G28 Y0 Z0 or G30 Y0 Z0. The position of the tool loading and unloading manipulator relative to the spindle is then manually adjusted, with the aid of a calibration mandrel for detection. If any errors are detected, the manipulator stroke can be adjusted, the manipulator support and the tool magazine position can be moved, and the setting of the tool change position point can be modified if necessary, by changing the parameter setting in the CNC system.
Upon completion of the adjustment, the adjustment screws and the tool magazine anchor bolts are tightened. Subsequently, several tool holders close to the specified allowable weight are installed, and multiple reciprocating automatic exchanges from the tool magazine to the spindle are performed. These actions must be accurate, without any collision or tool drop.
For machine tools equipped with APC exchange tables, the table is moved to the exchange position, and the relative position of the pallet station and the exchange table surface is adjusted to ensure smooth, reliable, and accurate action during automatic tool changes. Following this, 70-80% of the allowable load is placed on the work surface, and multiple automatic exchange actions are performed. Once accuracy is achieved, the relevant screws are tightened.
1.6 Trial operation of CNC machine tools
After the installation and commissioning of the CNC machine tools, the entire machine needs to run automatically for an extended period under specific load conditions to thoroughly check the machine’s functions and working reliability. There is no standard regulation on the running time. Typically, it runs for 8 hours a day continuously for 2 to 3 days, or 24 hours continuously for 1 to 2 days. This process is referred to as the trial operation after installation.
The assessment procedure should include testing the functions of the main CNC system, automatically replacing 2/3 of the tools in the tool magazine, testing the highest, lowest, and commonly used speeds of the spindle, fast and commonly used feed speeds, automatic exchange of the work surface, and using the main M instructions. During the trial operation, the machine tool’s tool magazine should be full of tool holders, the weight of the tool holder should be close to the specified allowable weight, and a load should also be added to the exchange work surface. During the trial operation time, no machine tool faults are allowed to occur except for faults caused by operating errors. Otherwise, it indicates problems with the installation and commissioning of the machine tool.
1.7 Acceptance of CNC machine tools
After the machine tool commissioning personnel have completed the installation and commissioning of the machine tool, the CNC machine tool user’s acceptance work involves measuring various technical indicators on the machine tool certificate. This is done according to the acceptance conditions specified in the machine tool factory inspection certificate using actual detection means provided. The acceptance results will serve as the basis for future maintenance of technical indicators. The main acceptance work is outlined as follows:
1) Appearance inspection of the machine tool: Before the detailed inspection and acceptance of the CNC machine tool, the appearance of the CNC cabinet should be inspected and accepted. This should include the following aspects:
① Inspect the CNC cabinet for damage or contamination using the naked eye. Check for damaged connecting cable bundles and peeling shielding layers.
② Inspect the tightness of components in the CNC cabinet, including screws, connectors, and printed circuit boards.
③ Appearance inspection of servo motor: In particular, the housing of the servo motor with a pulse encoder should be carefully inspected, especially its rear end.
2) Machine tool performance and NC function test. Now, take a vertical machining center as an example to explain some of the main inspection items.
① Spindle system performance.
② Feed system performance.
③ Automatic tool change system.
④ Machine tool noise. The total noise of the machine tool during idling shall not exceed 80 dB.
⑤ Electrical device.
⑥ Digital control device.
⑦ Safety device.
⑧ Lubrication device.
⑨ Air and liquid device.
⑩ Accessory device.
⑪ CNC function.
⑫ Continuous no-load operation.
3) The accuracy of a CNC machine tool reflects the geometric errors of its key mechanical parts and assembly. Below are the details for inspecting the geometric accuracy of a typical vertical machining center.
① Flatness of the worktable.
② Mutual Perpendicularity of movement in each coordinate direction.
③ Parallelism of the worktable when moving in the X-coordinate direction.
④ Parallelism of the worktable when moving in the Y-coordinate direction.
⑤ Parallelism of the side of the T-slot of the worktable when moving in the X-coordinate direction.
⑥ Axial runout of the spindle.
⑦ Radial runout of the spindle hole.
⑧ Parallelism of the spindle axis when the spindle box moves in the Z-coordinate direction.
⑨ Perpendicularity of the spindle rotation axis centerline to the worktable.
⑩ Straightness of the spindle box moving in the Z-coordinate direction.
4) Machine tool positioning accuracy inspection is an assessment of the achievable accuracy by the moving parts of a machine tool under the control of a CNC device. The primary inspection contents include the assessment of positioning accuracy.
① Linear motion positioning accuracy (including X, Y, Z, U, V, and W axis).
② Linear motion repeat positioning accuracy.
③ Return Accuracy of the mechanical origin of the linear motion axis.
④ Determination of the amount of lost momentum in linear motion.
⑤ Rotary motion positioning accuracy (turntable A, B, C axis).
⑥ Repeat positioning accuracy of rotary motion.
⑦ Return Accuracy of the origin of the rotary axis.
⑧ Determination of the amount of lost momentum in the rotary axis motion.
5) Machine tool cutting accuracy inspection involves a thorough evaluation of the geometric accuracy and positioning accuracy of the machine tool in cutting and processing operations. In the context of industrial automation in machining centers, accuracy in single processing is a primary area of focus.
① Boring Accuracy.
② Accuracy of the milling plane of the end mill (X-Y plane).
③ Boring hole pitch accuracy and hole diameter dispersion.
④ Linear milling accuracy.
⑤ Oblique line milling accuracy.
⑥ Arc milling accuracy.
⑦ Box turn-around boring coaxiality (for horizontal machine tools).
⑧ Horizontal turntable rotation 90° square milling cnc processing accuracy (for horizontal machine tools).
If you wanna know more or inquiry, please feel free to contact info@anebon.com
Anebon depends on sturdy technical force and continually creates sophisticated technologies to meet the demand for CNC metal machining, cnc milling parts, and aluminum die casting parts. All the opinions and suggestions will be greatly appreciated! The good cooperation could improve both of us into better development!
Post time: Jul-16-2024