Although traditional machine tools are cheaper than vertical machining centers, the value of China CNC vertical machining center lies in production efficiency. Good design and processes determine that vertical machining centers have more advantages over traditional machine tools. Let's divide the specific advantages below.
The efficiency of vertical machining centers is higher than that of traditional machine tools. This requires measures to be taken to significantly reduce the single-piece processing time. Time compression includes two aspects: On the one hand, the development of new tool materials, such as doubling the cutting speed, greatly restores the official cutting time; on the other hand, the use of automatic tool change system to transform operations, greatly reduces auxiliary time.
These measures greatly improve production efficiency and have achieved good economic benefits with VMC vertical machining center and CNC vertical turning lathe machine, and 5 axis CNC vertical machining center. However, they have also significantly increased the load on the machine tool and machining center in terms of structural design. Therefore, their basic large parts usually adopt a closed box structure and reasonably arrange the reinforced plates and reinforced contacts to enhance the static and dynamic demeanor.
In addition, adjusting the quality of parts may change the natural vibration frequency of the system. Increasing damping can improve the damping characteristics of the machine tool and is an effective measure to improve its dynamic behavior.
The structural stiffness of the machine tool bed, guide rail, worktable, tool holder, and spindle box will affect their own geometric accuracy. Due to the deformation of these factors, numerical control machine tools require high static stiffness.
Vibration during the cutting process not only directly affects the machining accuracy and surface quality of the parts, but also reduces the tool life and affects the continuous operation of the machining center. It cannot be artificially adjusted during the machining process (such as changing the cutting amount or changing the tool geometric angle) to eliminate or reduce the vibration. Therefore, it is also necessary to improve the dynamic stiffness of the machining center.
During the process of internal and external heat such as cutting heat and friction heat, the parts will undergo varying degrees of thermal deformation, which will affect the accuracy of the work.
Because the spindle speed, feed speed, and cutting amount of vertical machining centers are all greater than those of traditional machine tools, and the process is automated and often continuous, heat is controlled by methods such as liquid cooling; the structure of the machine tool has also been improved so that thermal deformation occurs in non-error sensitive directions of the parts.
The displacement of the worktable of the machining center is the minimum unit of pulse equivalence, and the speed of motion is high at the cutter. This requires the worktable to accurately respond to the instructions issued by the numerical control device, which is related to the friction characteristics of the moving parts. The machining center adopts rolling guide rails, and the static friction force of the rolling guide rails is small. Under the action of lubricating oil, the friction force decreases as the speed increases, effectively avoiding the phenomenon of low-speed crawling, thereby improving the stability and positioning accuracy of the machining center.
Using ball screws instead of sliding screws in the feed system is based on the same principle. In addition, using pulse compensation devices for lead compensation, clearance transmission systems, and some gearless transmission pairs of machine tools.
A good lubrication system ensures the service life of vertical machining centers. The guide rails, feed screws and spindle components all use new wear-resistant materials and can maintain good accuracy during long-term use.