China Henan Baishun Machinery Equipment Co., Ltd. Company News

As the wind installations continue to scale up globally, the demand for large-diameter precision-machined components has pushed vertical lathes to the front of wind turbine manufacturing lines. Slewing bearings, rotor flanges, and hub bodies — all characterized by heavy weight, large radial dimensions, and tight tolerance requirements — are among the most challenging workpieces in the renewable energy supply chain. Vertical lathes are increasingly the machine of choice for handling this class of part. Why Vertical Configuration Matters for Wind ComponentsWind turbine components such as main shaft flanges and pitch bearing seats regularly exceed 2,000 mm in outer diameter and can weigh upward of 8 to 15 tonnes as raw casting. Mounting a workpiece of this scale on a horizontal lathe introduces significant gravitational stress on the spindle and chuck system, making consistent clamping force difficult to maintain across the full cutting cycle. A vertical lathe — with its vertically oriented spindle and horizontal worktable — allows gravity to work with the setup rather than against it. The workpiece sits stably on the faceplate under its own weight, reducing clamping deformation and enabling uniform radial turning of large bores and face surfaces. Tolerance Requirements in Pitch Bearing Seat MachiningPitch bearing seats are among the most tolerance-sensitive surfaces in a wind turbine nacelle assembly. The mating surface between the bearing outer ring and the hub bore typically requires a cylindricity tolerance in the range of 0.05 to 0.10 mm over a diameter of 1,800 to 2,500 mm, depending on turbine class. Achieving this on a rigid, thermally stable vertical lathe bed — typically cast from high-grade grey iron or Meehanite cast iron — allows consistent material removal without the thermal drift that plagues lighter machines during extended roughing cycles. Growing Demand, Tighter Lead Times For machining contractors and in-house fabrication shops serving the wind sector, vertical lathe capability — particularly CNC models with live tooling and automatic tool changers — is increasingly viewed as a baseline qualification requirement rather than a competitive differentiator.

Chile is the world's largest copper producer, and its mining pump and valve demand centers on heavy-duty equipment such as slurry transport pumps, thickener underflow pumps, and high-pressure tailings pumps. The flow-path components of these pumps—impellers, front and rear wear plates, pump bodies—are commonly manufactured from high-chromium cast iron or duplex stainless steel, with part diameters frequently reaching 1,200–1,600 mm and individual piece weights exceeding two tons. A defining characteristic of these materials is their narrow cutting speed window. High-chromium cast iron typically measures HRC 58–62; exceeding the recommended cutting speed rapidly burns the tool edge. Duplex stainless steel has a strong work-hardening tendency; cutting speed below the optimal range produces built-up edge, degrading surface quality. Controlling cutting speed with precision is therefore a prerequisite for mining pump and valve machining in Chile. The Cutting Speed Dilemma of Manual VTLs on Large-Diameter Parts Manual vertical turret lathes typically offer fixed gear-selected speeds. On a common four-speed model, worktable speeds might be 10, 20, 40, and 80 rpm. This means: When turning a 1,500 mm OD, the four available speeds correspond to cutting speeds of 47, 94, 188, and 377 m/min. The recommended carbide cutting speed range for high-chromium cast iron is 60–100 m/min. Of the four speeds, only 20 rpm (94 m/min) falls within the recommended range. For roughing, which requires a lower speed, 10 rpm (47 m/min) is too low; for finishing, which requires a higher speed, 40 rpm (188 m/min) already exceeds the safe range. On the same part, the cutting speed ratio between a 1,500 mm OD and a 400 mm bore is 3.75:1. At a fixed spindle speed, no single gear setting satisfies reasonable cutting parameters for both OD and bore simultaneously. The typical Chilean shop practice is to machine them in two separate setups at different speeds—at the cost of concentricity deviation and additional labor hours. Process Value of Stepless Speed Control The CK5116A CNC vertical lathe offers a worktable speed range of 15–160 rpm, steplessly adjustable. This delivers three direct benefits for Chilean mining pump and valve machining: Precise material cutting window matching. For turning the OD of a 1,500 mm high-chromium cast iron impeller, the operator can set the worktable speed to 18 rpm, yielding a cutting speed of 85 m/min—precisely within the 60–100 m/min recommended window. This precision is unattainable with a fixed-gear VTL. OD and bore covered in a single setup. When machining an impeller, the 1,500 mm OD can be turned at 20 rpm (94 m/min cutting speed), while the 400 mm bore can be turned at 75 rpm (94 m/min cutting speed)—speed adjusts automatically with diameter, maintaining a constant cutting speed throughout. The OD and bore finish turning is completed without a second setup, preserving concentricity. Two-speed hydraulic gearbox for wide speed coverage. The machine employs an AC servo motor drive with a two-speed hydraulic gearbox transmission. The low-speed range handles large-diameter heavy roughing; the high-speed range handles small-diameter finishing. Hydraulic shifting avoids the impact and gear-face wear associated with mechanical fork shifting, sustaining drivetrain reliability across continuous production batches of mining pump and valve components.

Brazil hosts South America's largest pump and valve manufacturing cluster, concentrated in São Paulo state and Rio Grande do Sul. These factories supply centrifugal pumps, gate valves, and butterfly valves to the domestic oil and gas, mining, and agricultural irrigation sectors. In these products, the face parallelism of large-diameter flanges—typically 800–1,500 mm—is the decisive factor in sealing performance. During actual shop-floor assessments, a recurring finding emerges: flanges machined on manual turret lathes frequently exceed face parallelism tolerances in batch production. Where drawings specify 0.03 mm parallelism, actual measured values routinely fall in the 0.06–0.12 mm range. Process-Level Analysis of Parallelism Deviation Inconsistent clamping datums. The four-jaw chuck on a manual turret lathe is manually operated and independent per jaw, with clamping force entirely dependent on operator judgment. For the same batch of blanks, different operators—or the same operator at different times—apply varying clamping forces, resulting in inconsistent elastic deformation of the workpiece during machining. For a flange, a thin-walled disc-type component, a 10% variation in clamping force can measurably shift face flatness. Datum loss across multi-machine process flows. A single flange typically requires face turning, OD, bore, bolt-hole face, and seal-groove operations. In a manual shop, these operations are often distributed across different machines—a vertical lathe for the face and OD, a radial drill for bolt holes, and an engine lathe for sealing surfaces. Each re-clamping introduces a new locating error, which accumulates into the final face parallelism result. Delayed tool-wear compensation. Under manual turning, operators rely on visual inspection and feel to judge tool condition. By the time chatter marks or rising surface roughness signal tool wear, several pieces may have already been machined. These transition pieces, with substandard face quality, are rarely inspected piece by piece and frequently end up in accepted batches. Process Improvement Path with CNC Single Column Vertical Lathes Using the CK5116A CNC single column vertical lathe (max turning diameter 1,600 mm, table diameter 1,400 mm) as a reference, the improvement path for Brazilian pump and valve flange machining includes: Rigid clamping system. The tool shank cross-section of 30×40 mm represents a large-section specification among single column vertical lathes in this class. Combined with the worktable's 3.2-ton load capacity, the tool tip remains stable even under interrupted cutting conditions on heavy-stock flange blanks. This means the process system rigidity itself will not be a source of parallelism deviation. All operations in a single setup. The machine supports nine processes—including facing, ID/OD turning, drilling, reaming, and grooving—within a single clamping cycle. A flange's OD, face, bore, and sealing surfaces can be machined sequentially without releasing the chuck, eliminating the cumulative multi-machine transfer error common in Brazilian factories. Long-term stability of the spindle drive system. The main drive gears are manufactured from 40Cr alloy steel with a ground finishing process, paired with an AC servo motor drive and a four-speed stepless transmission. Under continuous operation exceeding eight hours, gear noise and precision degradation remain controllable. For the single-shift operating mode typical of Brazilian factories, this drive design sustains parallelism machining capability consistency over extended production runs.

South America's pump and valve manufacturing sector is entering a critical equipment replacement cycle. Factories in Brazil, Chile, and Peru have long relied on manual vertical turret lathes for machining medium-to-large flanges and valve body components. As end clients—mining operations, water treatment contractors, and oil and gas pipeline operators—tighten their consistency requirements year after year, the precision variability inherent in manual operation has become a non-negotiable delivery risk. The core issue with manual VTLs is not operator skill but the inherent limitations of the process system: feed rate depends on operator feel, meaning face parallelism within a single batch of flanges can drift between 0.05 mm and 0.15 mm; cutting speed on large-diameter workpieces cannot be adjusted in real time during a cut, requiring a machine stop and gear change between roughing and finishing passes, which introduces thermal deformation accumulation and dimensional shift. CNC Replacement Selection Reference: How Single Column CNC Vertical Lathes Can Solve These Three Pain Points A CNC single column vertical lathe such as the CK5116A (BAISHUN MACHINERY) offers targeted solutions for each issue above: Stepless feed replaces manual control. The tool post feed range of 0.25–90 mm/min is steplessly adjustable and precisely governed by the CNC system. Feed consistency no longer depends on operator feel. During finish-facing, the feed rate is locked at the programmed value, ensuring consistent surface quality across every workpiece in the batch. Stepless speed control covers the full rough-to-finish range. The worktable speed of 15–160 rpm is steplessly variable, working in tandem with a two-speed hydraulic gearbox to enable seamless switching from heavy roughing to finish turning within a single setup. Taking a 1,400 mm flange OD as an example: at 15 rpm, the cutting speed is approximately 66 m/min—well-suited for carbide tooling on medium-carbon steel; at 160 rpm, the speed reaches approximately 704 m/min, covering reasonable parameters for small-diameter bore work. Nine operations in a single setup. The machine supports facing, internal and external cylindrical turning, internal and external tapered turning, drilling, expanding, reaming, thread turning, slot cutting, and cutoff—nine processes total. For a typical flange component requiring OD, face, bore, bolt-hole, and seal-groove machining, all operations can be completed in one clamping, eliminating the dimensional shift introduced by multiple setups.

It is an event held to commemorate the 80th anniversary of the victory of the Chinese People's War of Resistance Against Japanese Aggression and the World Anti-Fascist War. The theme of the event is: "Remember history, cherish the martyrs, cherish peace, and create the future."

How to assemble a heavy duty cnc lathe machine   After unpacking, lift the base worktable, put the adjusting sizing block after threading the anchor bolt, place a leveling ruler on the surface of the worktable after falling, level the base front, back, left and right with a level gauge, grout the anchor bolt after adjusting to the complete level, align the horizontal worktable twice after the cement is completely solidified, and then lock the lock nut of the anchor bolt.  After leveling and fixing the base workbench, take out the three oil pipes on the right side of the base. When installing the right column, lift the column and thread it into the anchor bolt, and then thread the three oil pipes in the base from the inside of the column and out from the outside. Then, stick the column close to the base, and place the cushion block at the top screw position of the column anchor. There are two horizontal and vertical locating pins on the connecting surface between the column and the base. After roughly leveling by the locating pin hole, insert two connecting bolts in the front and rear positions of the column and tighten them until no gap can be seen. Then align the column with a level gauge. When aligning, the left and right columns need to be in the same plane. After the column is vertically aligned, insert the remaining bolts and tighten them, and align the column with a level gauge again, Finally, drive in the locating pin.    After the left and right columns are connected with the base, install the connecting beam. When installing the connecting beam, first lock the end without adjusting pad, and then place the adjusting pad between the connecting beam and the column and lock the bolts. Install the cross beam after the installation of the connecting beam. First place two equal height blocks on the upper surface of the workbench, hang the cross beam on the guide rail surface of the column, then place it on the equal height block, and install the left and right pressing plates and inserts of the cross beam. Make sure that the two equal height blocks are placed stably.   After the beam support is stable, screw in two beam lifting lead screws from top to bottom, and screw the lead screw to the lowest position to prevent the lead screw from bending when installing the cap. After the lead screw is screwed in, place the cap on the upper end of the column. The cap and the column are connected by pin positioning and bolt fastening. Adjust the height position of the lead screw until the thread at the shaft end exposes the upper end face of the worm gear. After the beam is leveled, install the left and right vertical tool holders, which are fastened and connected by the T-bolt between the ram seat and the sliding plate, and the angle is adjusted vertically by the worm on the upper part of the ram seat. The main motor and feed box motor have been disassembled before delivery, and the motor can be installed in any step of the installation process. So far, the mechanical part has been installed.

Why Lubrication is Important for Mechanical Equipment? 1. Reducing Friction and WearLubricants form an oil film on metal-to-metal contact surfaces, significantly reducing the coefficient of friction, reducing wear by over 90%, and extending component life. 2. Controlling Temperature and Heat DissipationLubricating oil dissipates approximately 30% of frictional heat through circulation, preventing deformation or failure of components due to overheating. 3. Anti-corrosion and Rust PreventionLubricants isolate air and moisture, inhibiting oxidation and rust on metal surfaces, and protecting mechanical components from corrosion. 4. Cleaning and SealingLubricating oil absorbs and removes impurities such as metal debris, while filling gaps and acting as a seal to prevent gas or liquid leakage. 5. Vibration Damping and CushioningLubrication ensures smoother movement, cushions shock loads, and improves the stability and reliability of equipment operation.

Overview According to available information, there are over 60 exhibitors showcasing turning machine tools at this exhibition, with more than 120 lathe products on display.      Main Features of Lathe Exhibits (1) Diversified Products: The lathe exhibits at this exhibition offer a wide range of models, with each exhibitor showcasing their unique products. The diversity stems from variations in the number and form of spindles and turret configurations, resulting in a variety of models. The overall structure of the machine tools includes vertical, inverted, and horizontal orientations. The spindle arrangements encompass single-axis horizontal, single-axis vertical, dual-spindle docking, parallel dual-spindle, and intermediate-drive dual-head spindle configurations. The turret arrangements include indexed turret, turntable turret, comb-shaped turret, dual turret, or multiple turret combinations. Some equipment is also equipped with large-capacity tool magazines and ATC mechanisms. Function-wise, there are general-purpose CNC lathes, turning centers, vertical lathes, as well as various types of specialized CNC lathes, such as pipe thread lathes, wheel hub lathes, and multi-axis multi-station dedicated lathes. Many machine tool exhibits adopt modular design, providing flexibility and excellent expandability. Exhibitors such as Emac, Tornos, Westinghouse, Murata Machinery, Mazak, Baoli Machinery, Indatex, Qinchuan Machine Tool, Taizhou Yijie, and others showcase their unique diversity.   (2) High Precision: High-precision electric spindles, linear motors, torque motors, roller guides, ball screws, linear scales, closed-loop control, and precision spindle bearings are extensively used in CNC lathes. These components ensure high positioning and repeat positioning accuracy, as well as minimal spindle axial and radial runout errors. The spindle runout of Xiaobulin is 0.3µm; Da Chang Huajia's ultra-precision CNC continuous contour machining machine tool uses a high-rigidity porous graphite-coated air spindle with spindle axial runout ≤4nm; Bogu Intelligent's high-precision lathe uses liquid hydrostatic guides and liquid hydrostatic headstocks, achieving an accuracy level of "X, Z-axis positioning accuracy of 1µm, repeat positioning accuracy of 0.5µm, and spindle axial and radial runout both

As we approach the midpoint of 2023, the machine tool industry, as the core sector in the equipment field, has drawn significant attention from the industrial sector. While the Chinese machine tool market is gradually recovering this year, domestic enterprises are expanding their vision overseas, and foreign companies are also placing more expectations on the Chinese market.   Experts predict market uncertainties   At the recently held 2023 European Machine Tool Exhibition in Hanover, Germany, representatives from machine tool associations around the world made predictions for the global machine tool market. Mao Yufeng, Chairman of the China Machine Tool & Tool Builders' Association, stated that in 2023, the industry witnessed changes in China's industrial structure adjustment and machine tool consumer market, including a decline in total automobile production but a significant increase in sales of new energy vehicles. In addition to the changes in the consumer market, he also emphasized some major challenges, including fragile economic recovery, persistent inflation, unstable financial markets, and increasing debt pressures, which have led to uncertainties in the prospects of the machine tool industry.   At the exhibition, Marcus Burton, Chairman of the Economic Committee of the European Association of Machine Tool Industries, predicted that although the machine tool production of European Association of Machine Tool Industries member countries is expected to grow by about 5.5% in 2023, reaching nearly 27 billion euros, the global machine tool production is projected to remain relatively stable, slightly lower than the level of 2022. He stated that considering the current situation, the association has slightly adjusted its expectations. Nevertheless, the association remains optimistic about the positive growth of European machine tool production in 2023 and sees positive preliminary signs for 2024. At the same time, he also emphasized upcoming major challenges, including a slowdown in global economic growth and rising interest rates, among other unfavorable factors. These factors, combined, exacerbate the uncertainty in the short-term demand pattern of the machine tool industry.     Kazuo Yuhara, Chairman of the Japan Machine Tool Builders' Association, stated that the Japanese metal cutting machine tool industry has shown significant growth. In 2022, the total value of machine tool orders in Japan soared to a record 1.7596 trillion yen, a 14.2% increase from 2021. In the same year, the production of metal cutting machine tools increased by 20.5% compared to 2021, reaching 1.0788 trillion yen, with strong growth trends in both exports and imports. Although the order volume of metal cutting machine tools declined from January to July 2023, Kazuo Yuhara also emphasized the positive impact of investment demand in green and digital-related fields and the optimistic expectation of market recovery in certain sectors.   Douglas K. Woods, President of the Association for Manufacturing Technology, stated that after experiencing a year of market consumption close to the average level, the U.S. machine tool industry will continue to stabilize in 2023 and 2024. In 2023, the impact of tightened U.S. monetary policy became evident, leading to a slight decline in machine tool consumption. However, there are signs indicating that machine tool production and imports in the United States will recover in 2024, while exports will stabilize.   China's market is highly regarded by multiple countries   Simultaneously, countries around the world are also looking towards the Chinese market. According to the 2022 Global Market Report published by VDM German Mechanical Engineering Network, the global machine tool industry had a total output value of approximately 80.3 billion euros in 2022, with China ranking first globally with an output value of 25.7 billion euros, accounting for a 32% market share. The global consumption in the machine tool industry in 2022 was 80.8 billion euros, with China again leading the market with a scale of 26 billion euros, accounting for 32%.   China is known as the "World's Factory," with manufacturers from various industries having factories in China, resulting in a significant demand for the Chinese machine tool market. For many years, China has been leading in machine tool production and consumption ahead of the world. Research from Gardner Intelligence, a US publisher, shows that in 2022, China's machine tool (cutting + forming) consumption was 27.41 billion US dollars, a decrease of 9.3% compared to 2021. The production value in the same year was 27.1 billion US dollars, a decrease of 2.9%. Despite the decline in quantity, both figures are far ahead of other countries. The import value was 6.6 billion US dollars, a decrease of 12% compared to 2021, remaining the world's largest machine tool importing country. The President of Fanuc Corporation, who also serves as the President of the Japan Machine Tool Builders' Association, Mr. Inaba Yoshiharu, stated, "At that time, various industries in China were in a state of recovery, especially with the expanding scope of remote work from home. The IT products industry, including personal computers, tablets, and smartphones that meet the demand for remote work, as well as the electrical and precision manufacturing industry, including the semiconductor sector, actively contributed to the recovery." As the demand for remote work weakened, the electrical and precision manufacturing industry showed a tendency towards stagnation. However, during this period, the demand for electric vehicles became more active, and infrastructure and construction equipment also experienced some recovery. The future of the Chinese machine tool industry continues to be promising.   Steady Recovery of China's Machine Tool Industry   Moreover, Chinese machine tool companies have a competitive advantage in occupying the domestic market, and this year, their product sales have shown signs of recovery. According to statistics from key contact companies of the China Machine Tool & Tool Builders' Association, from January to August 2023, the operating income of key contact companies increased by 3.6% compared to the same period last year, while the total profit decreased by 16.1%. All sub-industries remained profitable. New orders for metal processing machine tools increased by 0.5% year-on-year, and the backlog of orders increased by 10.0%. Overall, the machine tool industry has shown a stable recovery trend in the first eight months of 2023.   According to data released by the National Bureau of Statistics, the production of metal cutting machine tools by enterprises above a certain scale in China was 398,000 units from January to August, a year-on-year decrease of 1.0%. The production of metal forming machine tools was 101,000 units, a year-on-year decrease of 19.8%.   According to Chinese customs data, the total import and export value of machine tool industry reached 21.3 billion USD in the first eight months, a decrease of 4.3% compared to the same period last year. Among them, imports amounted to 7.49 billion USD, a decrease of 11.6% year-on-year, while exports amounted to 13.81 billion USD, a slight increase of 0.1% year-on-year.   At the same time, China has provided multiple supports to the machine tool industry through relevant policies. Recently, the Ministry of Finance and four other departments issued a public notice to increase the proportion of additional deductions for R&D expenses of integrated circuit and industrial mother machine enterprises. It is proposed that the actual R&D expenses incurred by integrated circuit enterprises and industrial mother machine enterprises that have not formed intangible assets and are not included in the current period's income and expenses shall be deducted in accordance with the regulations. From January 1, 2023, to December 31, 2027, an additional 20% deduction shall be made before tax based on the actual amount incurred. For those that have formed intangible assets, they shall be amortized before tax at 220% of the cost of intangible assets during the aforementioned period. This tax incentive policy is more targeted, only applicable to integrated circuit production, design, equipment, materials, packaging, and testing enterprises encouraged by the state, as well as enterprises that produce and sell products that meet the basic standards of advanced industrial mother machines. The policy also provides greater incentives for innovative enterprises.

CNC machine tools are highly efficient automated machines and their place in production is becoming increasingly important. Therefore, the troubleshooting and daily maintenance of equipment is very important, but most of the failures of CNC machine tools are in the form of integrated failures, so the maintenance is more difficult. Combined with the mechanism of CNC machine tools, we have summarized the four main methods, namely: look, smell& hear, ask and touch.   I. Look To find the cause of the fault through the human hand, eye and other sensory organs, which is also the most simple and direct method. When the machine tool failure, the first thing you need to understand is the phenomenon of failure and the causes and processes. If the fault can be reappeared, the process of the fault should be observed and the most basic situation should be mastered. At the same time, observe whether there is mechanical damage; and whether there are burn marks, whether the resistance and conductors have been discoloured; whether there are any abnormalities in the running and sealing parts, such as splashes, shedding, spills, oil, smoke, sparks, etc.; whether the circuit breakers, relays, etc. tripped, whether the fuse is melted; whether the machine power supply is out of phase, whether the three phases are seriously unbalanced, whether the machine voltage is normal; whether there are parts on the electrical components are off, broken wires, jammed, loose joints, etc.; whether the switch is suitable; whether the operator's processing procedures are correct, etc.     2. Smell& Hear Identify whether there is an odour. When the machine tool moving parts have violent friction, the electrical insulation will burn, while the oil, smoke, gas and insulation materials will produce a burnt smell; the machine will produce ozone smell when discharged, you will also hear the discharge sound.   3. Ask Ask what happens when a machine tool breaks down. When machining, it is advisable to have strict management measures in place so that operators can make detailed notes in the event of a breakdown. This can avoid the occurrence of faults when maintenance personnel are not around and can accurately reflect the specific circumstances of the fault. When a fault occurs in a CNC machine tool, the first thing to do is to stop the machine and protect the site, the operator to record the fault in as much detail as possible, where the important information is to be observed and recorded in detail. For example: when the fault occurs, the phenomenon of the fault occurs in the part of the machine as well as when the fault occurs in the state of the machine and the control system. If the fault occurs in the automatic machining mode, the machining program number, the program segment number where the fault occurred and the tool number used for machining should be recorded. In the event of a fault such as poor machining accuracy or excessive contour error, the number of the workpiece being machined should be recorded and the non-conforming workpiece retained for specific analysis. In the event of a fault, if the system has an alarm display, the alarm display and alarm code of the system should be recorded. If the fault occurs when machining a part, the probability of the fault occurring when machining a similar part should be recorded.     4. Touch Diagnosis and repair based on the phenomenon of failure; this step is also the most important one in the maintenance of CNC machine tools. Which can be divided into the following specific steps:   4.1 System parameters check Nowadays, the operating system of CNC machine tools is becoming more and more self-diagnostic, and most of the faults of CNC machine tools can be diagnosed. When a fault occurs in the CNC machine tool, sometimes an alarm message will be displayed on the monitor; sometimes the alarm device on the CNC unit, PLC unit and drive unit, such as the alarm light will flash, beep, etc. In this case, the first thing to do is to check the maintenance manual and check the corresponding parameter settings. Missing or incorrectly set system parameters can cause changes or failures in machine performance. For example, in the FANUC system machine tool automatic processing, the machine tool holder stops moving and the screen shows 500, 501 alarm, check the parameter manual to know the corresponding parameters for the storage travel limit positive and negative limit value exceeded, then the machine can be changed to manual state to adjust the tool holder to the correct travel range and correct the parameters, the alarm can be relieved.   4.2 Reset machine tool During processing, the system alarm caused by instantaneous fault can be cleared by hardware reset or turning on and off the system power supply in turn. In case of system confusion caused by power failure, unplugging and plugging of circuit board or undervoltage of battery in the working storage area of the system, the system must be initialized and cleared. Before clearing, pay attention to copy and record important data. If the fault still cannot be eliminated after initialization, carry out hardware diagnosis.   4.3 Diagnosis by measurement Measurement method is the basic method to diagnose equipment failure, we can use multimeter, oscilloscope, logic tester and other instruments to measure the electronic circuit. For example, to determine the phase sequence of the three-phase power supply of the CNC system, you can use the phase sequence meter. That is, connect the three-phase power supply line to the phase sequence meter, and when the phase sequence is correct, the phase sequence meter rotates in a clockwise direction, and vice versa. You can also use a dual-channel oscilloscope to measure, if the phase sequence is correct, the waveforms of each two phases differ by 120° in phase.   4.4 Principal analysis method   When other maintenance methods are difficult to solve the fault, you can check step by step from the working principle of the machine tool. For example, we once encountered the phenomenon of disordered teeth when machining threads on a machine tool using FANUC 0itd system. According to the basic principle of position control of NC system, it can be basically determined that the fault is on the rotary encoder, and it is likely that the feedback signal is lost. In this way, once the NC device gives the command position of feed rate, the actual position fed back will always be incorrect, and the position error cannot be eliminated, resulting in problems in thread interpolation. When the pulse encoder was removed for inspection, it was found that the filament in the encoder was broken, resulting in no feedback input signal, which was consistent with the phenomenon of principle analysis. After replacing the encoder, the fault was eliminated.   4.5 Component exchange method For some faults involving the control system, sometimes it is not easy to confirm which part is the problem, in the case of ensuring that there is no further damage, you can take the suspected faulty parts or components with the same spare parts or the same parts or components on the same type of machine tool or on other parts of this machine tool to replace them to determine whether a fault has occurred. If the fault is lifted after replacing the device, it can be determined that the device is damaged causing the fault; if the fault remains, the device is proven to be intact and can be tested by other methods.   These four methods are not only applicable to the maintenance of CNC machine tool faults, but also to other types of mechanical equipment faults.