Factors affecting high-speed cutting of vertical machining centers?

Efficient and refined processing of highly complex curved surfaces and multi-process workpieces is the most important processing feature of vertical machining centers.

With the continuous development of the processing and manufacturing industry, some highly complex curved workpieces and multi-process processing workpieces have become commonplace, and the requirements for refined processing have become higher. The requirements for the final machining accuracy and the surface quality are often 0.01mm or even higher. Such workpieces are difficult to be processed well by traditional processing machine tools. Especially for complex curved workpieces, because traditional processing equipment is manually controlled, it is impossible to perform high-precision curve positioning and therefore cannot be processed; for the processing of multi-process workpieces, it can only be said to be barely competent. However, the processing efficiency is very low.

We know that the traditional processing of multi-process workpieces on ordinary processing equipment needs to be carried out on several or even a dozen different processing machines. Multiple clamping, alignment and waiting for processing will consume a lot of non-processing time. Therefore, it is difficult to improve the processing efficiency. In order to break this processing limitation, it is not surprising that vertical machining centers are used in batches. The reason is that this kind of processing machine is not only controlled by the CNC numerical control system, but also equipped with a tool magazine and automatic tool changer. Through the control of these advanced functional components, it can achieve a high degree of automation and complex centralized processing capabilities. Therefore, it is the main production equipment for high-precision and high-efficiency processing of highly complex workpieces and multi-process workpieces. Based on many years of experience in front-line machining, the author briefly introduces several important aspects that affect the high-speed cutting of workpieces in vertical machining centers, and hopes to give you some enlightenment. (Guide: Convert as you wish: Hardness is no longer stupid and unclear!)

Efficient and refined processing of highly complex curved surfaces and multi-process workpieces is the most important processing feature of vertical machining centers. This kind of processing equipment is equipped with a tool magazine and an automatic tool changer, so that the machine tool can automatically replace the processing tools of the workpiece, and it also has the characteristics of high-speed processing. The spindle speed is generally 8000 revolutions per minute, and some models even reach tens of thousands of revolutions, and the rapid traverse speed of the feed system has reached more than 24 meters per minute. These excellent machine tool properties lay the foundation for high-speed cutting of workpieces. However, high-speed cutting is different from ordinary cutting, and there are many factors that affect the final machining accuracy and surface quality of the workpiece. In summary, there are several important aspects such as machine tool factors, tool factors, process system factors, machining process factors and workpiece factors. Let's focus on several more typical factors.

1. Factors in machine tool

The high-speed cutting of workpieces we refer to refers to the high-efficiency machining completed under the premise of ensuring the machining accuracy of the workpiece. Of course, the high-speed cutting performance of the machine tool is a necessary condition for high-speed cutting of the workpiece. As we said before, the vertical machining center has the characteristics of this high-speed machining.

In general, the realization of this type of processing machine tool needs to have the following:

1. Spindle and feed system with higher speed

The most core components of a vertical machining center are the spindle and the feed system. The rotation accuracy and rotation speed of the spindle system are the keys to ensure high-speed cutting of the workpiece. This requires the configured spindle system to be compact, light and rigid Several key indicators such as strong, minimal inertia and good corresponding characteristics.

The feed system is also the same as the spindle requirements. While ensuring high-speed feed, it must also ensure that the positioning accuracy and repeat positioning accuracy of the machine tool must meet the parameter requirements set by the machine tool.

2. More flexible lubrication and cooling methods

The high-speed operation of the machine tool spindle is bound to generate a lot of high temperature. In order to prevent the high temperature from deforming the spindle system, lubrication and cooling are a very important part. Generally speaking, for the vertical machining center spindle that runs at a high speed for a long time. We generally use an oil cooler for cooling. Lubrication is generally closed oil immersion type, through these two methods can ensure the accuracy of the machine tool spindle at high speed.

Two, the factor of the tool

The tool is a component that directly acts on the workpiece, and its quality is directly related to the normal high-speed cutting of the vertical machining center. In addition to the reasonable selection of geometric parameters, the material of the tool is the key factor.

Generally speaking, tool materials suitable for high-speed cutting of workpieces must have the following points:

First, the tool used must have high wear resistance. Only in this way can it be ensured that the tool is not easy to form intermittent chips with zigzag and thickness changes during high-speed cutting, and effectively prevents the dynamic balance of the tool from being damaged. Lead to accelerated tool wear.

The second is to have high hardness and toughness, and meet these two requirements at the same time to withstand the impact and vibration generated by the tool's high-speed rotation, without chipping and fracture.

Three. Factors in processing technology

We know that the vertical machining center completes its machining tasks by executing the machining program of the workpiece. The pros and cons of CNC machining programs directly affect the final machining accuracy and machining efficiency of the workpiece during high-speed cutting. The key to processing programming is the choice of workpiece process. The cutting process mainly includes the process route suitable for high-speed cutting, the cutting method, the cutting route, the optimized high-speed machining parameters, and the method of sufficient cooling and lubrication.

In principle, the tool trajectory of high-speed cutting mostly adopts layered circular cutting processing. Generally, the diagonal trajectory feed method is used. Directly downwards the tool is prone to chipping and other phenomena, so it is not suitable to use; diagonal trajectory feed The milling force of the method is gradually increasing, so the impact on the tool and the spindle of the vertical machining center is smaller than that of the vertical cutting tool, which can significantly reduce the phenomenon of cutting edge chipping.

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