A Comprehensive Analysis of Tool Setting Methods in CNC Machining Centers
In the world of precision machining in CNC machining centers, the accuracy of tool setting is like the cornerstone of a building, directly determining the machining accuracy and quality of the final workpiece. The commonly used tool setting methods in drilling and tapping centers and CNC machining centers mainly include tool setting with a tool presetting device, automatic tool setting, and tool setting by trial cutting. Among them, tool setting by trial cutting has been less adopted due to its own limitations, while automatic tool setting and tool setting with a tool presetting device have become the mainstream by virtue of their respective advantages.
I. Automatic Tool Setting Method: A Perfect Combination of High Precision and High Efficiency
Automatic tool setting relies on the advanced tool detection system equipped in the CNC machining center. This system is like a precise “master of tool measurement”, capable of accurately measuring the length of each tool in each coordinate direction in an orderly manner during the normal operation of the machine tool. It utilizes advanced technical means such as high-precision laser sensors and infrared detectors. When the tool approaches the detection area, these sensitive sensors can quickly capture the subtle features and position information of the tool and immediately transmit them to the intelligent control system of the machine tool. The complex and precise algorithms preset in the control system are then activated immediately, just like a mathematical genius completing complex calculations in an instant, quickly and accurately obtaining the deviation value between the actual position and the theoretical position of the tool. Immediately afterwards, the machine tool automatically and accurately adjusts the compensation parameters of the tool according to these calculation results, enabling the tool to be accurately positioned in the ideal position in the workpiece coordinate system as if being guided by an invisible but extremely precise hand.
The advantages of this tool setting method are significant. Its tool setting precision can be regarded as a feast of micron-level or even higher precision. Since it completely eliminates the interference of subjective factors such as hand tremors and visual errors that are inevitable in the process of manual tool setting, the positioning error of the tool is minimized. For example, in the machining of ultra-precision components in the aerospace field, automatic tool setting can ensure that when machining complex curved surfaces such as turbine blades, the positioning error is controlled within a very small range, thereby ensuring the profile accuracy and surface quality of the blades and enabling the stable performance of the aero-engine.
At the same time, automatic tool setting also performs excellently in terms of efficiency. The entire detection and correction process is like a high-speed running precision machine, proceeding smoothly and taking very little time. Compared with the traditional tool setting by trial cutting, its tool setting time can be shortened by several times or even dozens of times. In the mass production of components such as automobile engine blocks, efficient automatic tool setting can significantly reduce the downtime of the machine tool and greatly improve the production efficiency, meeting the strict requirements of the automobile industry for rapid production and timely supply.
However, the automatic tool setting system is not perfect. Its equipment cost is high, like a mountain of capital investment, deterring many small enterprises. From the procurement, installation to the later maintenance and upgrading of the system, a large amount of capital support is required. Moreover, the automatic tool setting system has relatively high requirements for the technical level and maintenance ability of the operators. Operators need to have a deep understanding of the working principle of the system, parameter settings, and methods for troubleshooting common faults, which undoubtedly poses a challenge to the talent cultivation and reserve of enterprises.
II. Tool Setting with a Tool Presetting Device: The Mainstream Choice of Being Economical and Practical
Tool setting with a tool presetting device occupies an important position in the field of tool setting in CNC machining centers. Its greatest charm lies in the perfect balance between economy and practicality. The tool presetting device can be subdivided into an in-machine tool presetting device and an out-of-machine tool presetting device, each having its own characteristics and jointly safeguarding the precise tool setting in CNC machining.
The operation process of tool setting with an out-of-machine tool presetting device is unique. In the dedicated area outside the machine tool, the operator carefully installs the tool on the out-of-machine tool presetting device that has been calibrated to high precision in advance. The precise measurement device inside the tool presetting device, such as a high-precision probe system, begins to exert its “magic”. The probe gently touches each key part of the tool with micron-level precision, accurately measuring key parameters such as the length, radius, and microscopic geometric shape of the cutting edge of the tool. These measurement data are quickly recorded and transmitted to the control system of the machine tool. Subsequently, the tool is installed on the tool magazine or spindle of the machine tool. The control system of the machine tool accurately sets the compensation value of the tool according to the data transmitted from the tool presetting device, ensuring the accurate operation of the tool during the machining process.
The advantage of the out-of-machine tool presetting device is that it can make full use of the machining time of the machine tool. When the machine tool is engaged in an intense machining task, the operator can simultaneously carry out the measurement and calibration of the tool outside the machine tool, just like a parallel and non-interfering production symphony. This parallel operation mode greatly improves the overall utilization rate of the machine tool and reduces the waste of time in the production process. For example, in a mold manufacturing enterprise, mold machining often requires the alternate use of multiple tools. The out-of-machine tool presetting device can measure and prepare the next tool in advance during the mold machining process, making the entire machining process more compact and efficient. At the same time, the measurement precision of the out-of-machine tool presetting device is relatively high, capable of meeting the precision requirements of most conventional machining, and its structure is relatively independent, facilitating maintenance and calibration, and reducing the equipment maintenance cost of enterprises.
Tool setting with an in-machine tool presetting device is to directly place the tool on a specific fixed position inside the machine tool for measurement. When the machining process of the machine tool requires a tool setting operation, the spindle carries the tool gracefully to the measurement area of the in-machine tool presetting device. The probe of the tool presetting device gently meets the tool, and in this brief and precise contact moment, the relevant parameters of the tool are measured and these precious data are quickly transmitted to the control system of the machine tool. The convenience of tool setting with an in-machine tool presetting device is self-evident. It avoids the back-and-forth movement of the tool between the machine tool and the out-of-machine tool presetting device, reducing the collision risk during the tool loading and unloading process, just like providing a safe and convenient “internal passage” for the tool. During the machining process, if the tool wears or has a slight deviation, the in-machine tool presetting device can detect and correct the tool at any time, just like a guard on standby, ensuring the continuity and stability of the machining process. For example, in the long-term precision milling machining, if the size of the tool changes due to wear, the in-machine tool presetting device can detect and correct it in time, ensuring the size precision and surface quality of the workpiece.
However, tool setting with a tool presetting device also has some limitations. Whether it is an in-machine or an out-of-machine tool presetting device, although its measurement precision can meet most machining requirements, it is still slightly inferior in the field of ultra-high precision machining compared with the top-notch automatic tool setting system. Moreover, the use of the tool presetting device requires certain operation skills and experience. Operators need to be familiar with the operation process, parameter settings, and data processing methods of the tool presetting device, otherwise, improper operation may affect the tool setting precision.
In the actual CNC machining production scenario, enterprises need to comprehensively consider various factors to select the appropriate tool setting method. For enterprises that pursue extreme precision, have a large production volume, and are well-funded, the automatic tool setting system may be the best choice; for most small and medium-sized enterprises, tool setting with a tool presetting device becomes the preferred choice due to its economical and practical characteristics. In the future, with the continuous innovation and development of CNC technology, tool setting methods will surely continue to evolve, moving forward bravely in the direction of being more intelligent, high-precision, high-efficiency, and low-cost, injecting continuous impetus into the vigorous development of the CNC machining industry.