1.1 Installation of the CNC Machine Tool Body

1. Before the arrival of the CNC machine tool, the user shall complete the installation preparation in accordance with the machine tool foundation drawing provided by the machine tool manufacturer, and reserve holes at the positions where the anchor bolts are to be installed. After the CNC machine tool is delivered, the commissioning personnel shall transport the machine tool components to the installation site in accordance with the unpacking procedures, and position each major component of the machine tool on the foundation as described in the instruction manual. During positioning, the base plates, adjusting pads, anchor bolts and other parts shall be placed in their corresponding positions. Then assemble all components of the machine tool into a complete unit. After the assembly of components is completed, connect the cables, oil pipes and air pipes. The machine tool instruction manual contains electrical wiring diagrams and pneumatic/hydraulic pipeline diagrams, and relevant cables and pipelines shall be connected one by one according to the marks.

2. Notes for this stage are as follows:

(1) After unpacking the machine tool, first find the accompanying documents and data, locate the machine tool packing list, and check whether the parts, cables, documents and other items in each packing box are complete according to the packing list.

(2) Before assembling each component of the machine tool, first remove the anti-rust coating on the installation connection surfaces, guide rails and all moving surfaces, and clean the appearance of each component.

(3) Special attention shall be paid to cleanliness, reliable contact and sealing during connection, and check for looseness and damage. After plugging in the cables, be sure to tighten the fastening screws to ensure reliable contact. In the connection of oil pipes and air pipes, special care shall be taken to prevent foreign objects from entering the pipelines through the interfaces, which may cause faults in the entire hydraulic system. Each joint shall be tightened during pipeline connection. After the connection of cables and pipelines is completed, fix each pipeline in position and install the protective covers to ensure a neat appearance.

1.2 Connection of the CNC System

(1) Unpacking inspection of the CNC system. Whether the CNC system is purchased individually or as a complete machine with the machine tool, a careful inspection shall be conducted after unpacking upon arrival. The inspection includes the system itself, as well as the matching feed speed control unit and servo motor, spindle control unit and spindle motor.

(2) Connection of external cables. External cable connection refers to the connection between the CNC system and external MDI/CRT unit, high-voltage cabinet, machine tool operation panel, power lines and feedback lines of the feed servo motor, power lines and feedback signal lines of the spindle motor, as well as the manual pulse generator, etc. These cables shall comply with the provisions of the connection manual provided with the machine tool, and finally the ground wire connection shall be carried out.

(3) Connection of the CNC system power supply line. Connect the input cable of the CNC system power supply with the power switch of the CNC cabinet turned off.

(4) Confirmation of settings. There are many setting points short-circuited with jumpers on the printed circuit boards (PCBs) in the CNC system, which need to be properly set to meet the different requirements of various types of machine tools.

(5) Confirmation of input power supply voltage, frequency and phase sequence. Various CNC systems are equipped with DC regulated power supplies inside to provide the required DC voltages such as ±5V and 24V for the system. Therefore, before the system is powered on, check whether the load of these power supplies has a short circuit to ground. A multimeter can be used for confirmation.

(6) Confirm whether the voltage output terminal of the DC power supply unit is short-circuited to ground.

(7) Turn on the power of the CNC cabinet and check each output voltage. Before turning on the power, to ensure safety, the motor power lines can be disconnected first. After turning on the power, first check whether each fan in the CNC cabinet is rotating to confirm whether the power is connected.

(8) Confirm the settings of various parameters in the CNC system.

(9) Confirm the interface between the CNC system and the machine tool side.

After completing the above steps, it can be considered that the CNC system has been adjusted and is ready for online power-on commissioning with the machine tool. At this time, the power of the CNC system can be turned off, the motor power lines can be connected, and the alarm settings can be restored.

1.3 Power-on Test of the CNC Machine Tool

Lubricate the machine tool in accordance with the requirements of the CNC machine tool instruction manual, fill the lubrication points with the specified oil and grease, clean the hydraulic oil tank and filter, fill with the specified grade of hydraulic oil, and connect the external input air supply.

The power-on operation of the machine tool can be to supply power to all parts at one time, or to supply power to each component separately, and then conduct the total power supply test. During the online power-on commissioning of the CNC system and the machine tool, although the CNC system has been confirmed to work normally without any alarms, it is still necessary to be prepared to press the emergency stop button while turning on the power to cut off the power at any time. When checking the operation of each axis of the machine tool, move each axis with manual continuous feed, and check whether the moving direction of the machine tool components is correct through the display value of the CRT or DPL (Digital Position Indicator).

Then check whether the moving distance of each axis is consistent with the moving command. If not, check whether the settings of relevant commands, feedback parameters, position control loop gain and other parameters are correct. Then, move each axis at low speed with manual feed and make them touch the overtravel switch to check whether the overtravel limit is effective and whether the CNC system issues an alarm when overtravel occurs. Carefully check whether the parameter settings in the CNC system and PMC (Programmable Machine Controller) device comply with the specified data in the accompanying documents, then test various operation modes (manual, jog, MDI, automatic mode, etc.), spindle gear shifting commands, various speed commands, etc. to see if they are correct. Finally, perform a return-to-reference-point operation. The reference point of the machine tool is the program reference position for subsequent machining of the machine tool, so it is necessary to check whether there is a reference point function and whether the position of each return to the reference point is completely consistent.

1.4 Installation and Adjustment of the CNC Machine Tool

According to the documents of the CNC machine tool instruction manual, roughly check whether the main components of the machine tool function normally and completely, so that all links of the machine tool can be operated and moved. Adjust the level of the machine bed, roughly adjust the main geometric accuracy of the machine tool, then adjust the relative position of the reassembled main moving components and the host machine, pour quick-drying cement into the anchor bolts of the host machine and various accessories to fill each reserved hole flat, and wait for the cement to completely solidify.

On the solidified foundation, finely adjust the level of the main machine bed with anchor bolts and base plates. After leveling, move each moving component (column, slide carriage, worktable, etc.) on the machine bed, observe the horizontal variation of the machine tool within the full stroke of each coordinate, and adjust the geometric accuracy of the machine tool accordingly to keep it within the allowable error range. The detection tools used in the adjustment include precision level, standard square ruler, straightedge, collimator, etc. During adjustment, mainly adjust the base plates, and if necessary, slightly change the adjusting strips and preloaded rollers on the guide rails.

1.5 Operation of the Tool Change Device of Machining Center

Make the machine tool automatically move to the tool change position (programs such as G28 Y0 Z0 or G30 Y0 Z0 can be used), and adjust the position of the tool loading manipulator and tool unloading manipulator relative to the spindle manually. A calibration mandrel is used for detection during adjustment. If there is an error, the stroke of the manipulator, the position of the manipulator support and tool magazine can be adjusted, and if necessary, the setting of the tool change position point can be modified (by changing the parameter settings in the CNC system). After adjustment, tighten each adjusting screw and the anchor bolts of the tool magazine, then install several tool holders close to the specified allowable weight, and perform multiple automatic exchanges from the tool magazine to the spindle, requiring accurate and error-free actions without collision or tool dropping.

For machine tools with APC (Automatic Pallet Changer) exchange worktable, move the worktable to the exchange position, adjust the relative position between the pallet station and the exchange table surface to ensure stable, reliable and accurate movement during automatic worktable change. Then load 70~80% of the allowable load on the worktable surface, perform multiple automatic exchange actions, and tighten all relevant screws after ensuring accuracy and error-free operation.

1.6 Trial Operation of the CNC Machine Tool

After the installation and commissioning of the CNC machine tool are completed, the whole machine is required to run automatically for a long time under a certain load to comprehensively check the functions and working reliability of the machine tool. There is no unified regulation on the running time, generally it is 8 hours of operation per day for 2~3 consecutive days; or 24 hours of continuous operation for 1~2 days. This process is called trial operation after installation.

The assessment program shall include: use of main CNC system functions, automatic replacement and access to 2/3 of the tools in the tool magazine, maximum, minimum and common rotational speeds of the spindle, rapid and common feed speeds, automatic exchange of the worktable surface, use of main M commands, etc. During trial operation, the tool magazine of the machine tool shall be fully inserted with tool holders, the weight of the accessed tool holders shall be close to the specified allowable weight, and loads shall also be added to the exchange worktable surface. During the trial operation period, no faults are allowed to occur on the machine tool except for faults caused by misoperation, otherwise it indicates that there are problems in the installation and commissioning of the machine tool.

1.7 Acceptance of the CNC Machine Tool

After the machine tool commissioning personnel complete the installation and commissioning of the machine tool, the acceptance work of the CNC machine tool user is to measure part or all of the technical indicators on the machine tool's factory inspection certificate through the available detection means in accordance with the acceptance conditions specified on the certificate. After passing the acceptance, the acceptance results will be used as the technical indicator basis for future maintenance. The main acceptance work is as follows.

(1) Visual inspection of the machine tool. Before conducting a detailed inspection and acceptance of the CNC machine tool, conduct a visual inspection and acceptance of the appearance of the CNC cabinet, which shall include the following aspects.

① Appearance inspection: Visually check whether each unit in the CNC cabinet is damaged or contaminated, whether the bundled connecting cables are damaged, and whether the shielding layer is peeled off.

② Inspection of the fastening status of internal components of the CNC cabinet: Including inspection of screw fastening, connector fastening, and PCB fastening.

③ Appearance inspection of the servo motor: Especially carefully inspect the shell of the servo motor with a pulse encoder, especially its rear end.

(2) Test of machine tool performance and NC functions. Take a vertical machining center as an example to illustrate some main inspection items.

① Performance of the spindle system.

② Performance of the feed system.

③ Automatic tool change system.

④ Machine tool noise. The total noise of the machine tool during no-load operation shall not exceed 80dB.

⑤ Electrical devices.

⑥ Numerical control device.

⑦ Safety devices.

⑧ Lubrication devices.

⑨ Pneumatic and hydraulic devices.

⑩ Auxiliary devices.

⑪ NC functions.

⑫ Continuous no-load operation.

(3) Inspection of machine tool geometric accuracy. The geometric accuracy of a CNC machine tool comprehensively reflects the geometric shape errors of the key mechanical parts of the equipment and after assembly. The following lists the geometric accuracy detection contents of an ordinary vertical machining center.

① Flatness of the worktable surface.

② Mutual perpendicularity of movement in each coordinate direction.

③ Parallelism of the worktable surface when moving in the X-coordinate direction.

④ Parallelism of the worktable surface when moving in the Y-coordinate direction.

⑤ Parallelism of the side surface of the T-slot on the worktable surface 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 to the worktable surface.

⑩ Straightness of the spindle box moving in the Z-coordinate direction.

(4) Inspection of machine tool positional accuracy. It indicates the accuracy that the measured moving parts of the machine tool can achieve under the control of the numerical control device. The main inspection contents of positional accuracy are as follows.

① Linear motion positional accuracy (including X, Y, Z, U, V, W axes).

② Linear motion repeatability accuracy.

③ Return accuracy of the mechanical origin of the linear motion axis.

④ Measurement of lost motion of linear motion.

⑤ Positional accuracy of rotary motion (turntable A, B, C axes).

⑥ Repeatability accuracy of rotary motion.

⑦ Return accuracy of the rotary axis origin.

⑧ Measurement of lost motion of rotary motion.

(5) Inspection of machine tool cutting accuracy. The inspection of machine tool cutting accuracy is essentially a comprehensive assessment of the geometric accuracy and positional accuracy of the machine tool under cutting and processing conditions. In China, single-item processing is mostly used. For machining centers, the main single-item accuracies are as follows.

① Boring accuracy.

② Accuracy of milling plane with face mill (X-Y plane).

③ Hole spacing accuracy and hole diameter dispersion of boring holes.

④ Linear milling accuracy.

⑤ Oblique milling accuracy.

⑥ Circular milling accuracy.

⑦ Coaxiality of boring holes with the box turned around (for horizontal machine tools).

⑧ Square milling accuracy when the horizontal turntable rotates 90° (for horizontal machine tools).