What Are The Precautions For Using And Purchasing Automatic Turning And Milling Compound CNC Machine Tools?

What are the precautions for using and purchasing automatic turning and milling compound CNC machine tools?

Standardized operations are the bottom line for safety

Turning and milling compound CNC machine tools integrate turning and milling functions, and their operation complexity is much higher than that of ordinary machine tools. In 2024, when I was instructing a mold factory in Zhejiang, I discovered that workers were accustomed to using high speeds to straighten workpieces, which eventually caused the chuck to fly off, almost causing casualties. The correct approach is to perform turn-milling composite machining maintenance . Only pull the chuck by hand or turn on low speed for alignment. High-speed operations are strictly prohibited. Before starting the machine every time, you must check the lubrication status of each axis and the coolant level to ensure that the system is normal before starting.

The operation manual is not just a mere appearance, but a life-protection guide! I once met an experienced master who mistakenly adjusted the speed of the milling spindle to 12,000 rpm because he did not check the instruction manual. He also used it for heavy-duty turning operations. Eventually, the spindle bearings were damaged in just half an hour! The stroke range of each machine tool, as well as cutting-related parameters, and tool clamping methods are all clearly defined, and they must be carefully compared one by one and then executed! Before new workers officially take up the job, they must undergo at least 72 hours of theoretical study and practical training, so that they can operate independently!

Routine maintenance determines lifespan

As precision components, machine tool guide rails and screws need to be cleaned and applied with special lubricant every day. In 2023, a company in Suzhou failed to clean the chip conveyor for three months, resulting in the accumulation of iron filings, which caused the Y-axis screw to become stuck. The maintenance cost was as high as 80,000 yuan. When cleaning, use a soft cloth and special cleaning agent. It is strictly prohibited to directly blow the guide rail surface with compressed air, otherwise impurities will be embedded in the sliding surface.

The key point is to regularly inspect the hydraulic system and cooling system. The water content and acid value of the hydraulic oil need to be tested every 500 hours. The coolant needs to be replaced every two weeks, otherwise it will cause bacteria to breed and corrode the pipeline. The spindle taper hole must be wiped with alcohol cotton after each tool change to prevent the tool holder from not being firmly attached and affecting the machining accuracy. The machine tool level must be calibrated once every quarter, because foundation settlement will cause the accumulation of machining errors.

Don’t be careless about protective equipment

When operating a turning and milling machine tool, you must wear protective equipment. In 2025, an accident occurred in Guangdong. A worker did not wear goggles, causing iron filings to fly into his eyes, which caused retinal detachment. Proper equipment includes impact goggles, cut-resistant gloves, a hard hat and noise-proof earplugs. Long hair must be tucked into a hat and cuffs must be tied tightly. Fire extinguishers and first aid kits should also be equipped in the processing room, and their locations should be eye-catching and easily accessible.

Safety is directly affected by the surrounding environment of the machine tool. The width of the aisle in the working area must be maintained at more than 1.2 meters. Oil stains and stumbling phenomena caused by cables are not allowed on the ground. The accumulation of debris behind the machine tool is the most typical safety hazard I have seen. If the tool breaks and gets stuck, the operator will not be able to carry out emergency evacuation. Each machine tool must be equipped with an emergency stop button sign, and the sensitivity of the emergency stop function is tested once a month.

Accuracy requirements determine model selection

When purchasing a machine tool, the tolerance level of the processed parts is the primary indicator. If the required accuracy of the part is IT6 level (tolerance zone 0.013 mm), then you must choose a model with a positioning accuracy within 0.005 mm. In 2024, a precision parts factory in Changzhou purchased an ordinary-grade turning-milling machine for cheap. In the end, when processing automobile turbine blades, the dimensions were out of tolerance, causing the entire batch to be scrapped and a loss of 600,000 yuan.

Different materials that have requirements for machine tool rigidity vary greatly. When processing stainless steel, the spindle torque is required to be greater than 200 Nm. For aluminum alloy processing, more emphasis is placed on the speed reaching more than 10,000 rpm. As for cast iron parts, the bed is required to be made of Meehanite cast iron and undergo secondary aging treatment. Otherwise, the bed will deform during the machining process. Before purchasing, provide typical workpiece drawings to the supplier and ask them to issue a cutting force analysis report.

Core performance parameters need to be verified

The material used in the bed and its structure will have a direct impact on the stability. High-quality machine tools generally adopt a 45-degree inclined bed design, which is matched with a high-strength cast iron or mineral cast stone bed, which can greatly absorb the vibration generated during cutting. In 2023, I tested two machine tools with the same nominal parameters in a valve factory in Shandong. The result was that the surface roughness of the machine tool with poor rigidity increased by 0.8 microns. The reason is that the layout of the ribs inside the bed is different.

To make the spindle power and speed match the processing requirements , what are the precautions for the use and purchase of automatic turning and milling composite CNC machine tools? Heavy cutting processing requires the spindle power to be above 15 kilowatts, while high-speed milling requires the electric spindle speed to be higher than 20,000 rpm. The feed system is suitable for selecting linear motors or ball screws combined with grating rulers for closed-loop feedback, and its repeatable positioning accuracy can reach 0.003 mm. The load-bearing capacity of the workbench must be calculated in advance. Exceeding the rated load will accelerate wear of the guide rails.

Programming capabilities and after-sales service cannot be ignored

Modern turn-milling machine tools must support ISO code and G code, and it is best to be compatible with Mazak or Siemens programming environments. In 2025, a company in Zhengzhou was just trying to keep the price low when purchasing. As a result, the machine tool only supported its own closed language, which made it impossible to interface with mainstream CAM software, and the programming efficiency was reduced by 40%. When purchasing, ask the supplier to demonstrate on-site five-axis linkage machining and test post-processing compatibility.

After-sales service requires checking the time of response and the status of parts in stock. The regular supplier should promise to conduct remote fault diagnosis within 24 hours, and to conduct on-site maintenance operations within 48 hours. Core accessories such as spindle units and servo motors require domestic spare parts warehouses. The suggestion I give is to clearly stipulate the warranty period and training related terms in the contract. For example, at least 5 days of on-site training should be provided free of charge to cover operations, program development, daily maintenance, etc. to ensure that the team can get started independently.

What kind of pitfalls have you encountered when purchasing or using turning-milling compound machine tools? Welcome to share your experience in the comment area, like and bookmark this article so that you can check it at any time.