Research on thermal deformation error compensation method of NC machining accuracy of wooden door hi

Abstract: The demand for high precision in NC machining of wooden door hinge assembly holes necessitates the identification and mitigation of factors affecting machining accuracy. Thermal deformation error has been identified as a critical factor influencing the precision of machine tools. This study aims to establish a thermal deformation error compensation model for wooden door hinge assembly hole CNC machining, using genetic algorithm-based optimization techniques. The proposed model aims to achieve higher precision in CNC machining of wooden door hinge assembly holes.

The traditional method of processing holes and grooves on wooden doors for assembling hinges involves the use of general-purpose equipment such as routers and woodworking drilling and milling machines. However, this approach suffers from several drawbacks, including low efficiency, difficult equipment adjustment, poor production interchangeability, and low processing accuracy. To overcome these limitations, CNC processing methods have gained prominence. It entails using specialized machine tools for CNC machining of hinge assembly holes and grooves, employing multi-head drilling and milling devices, and utilizing CNC machining graphic parameters specific to hinge grooves. The focus of this study is to address the main factor affecting the processing accuracy of these machine tools, namely thermal deformation error.

CNC Machining of Wooden Door Hinge Assembly Hole Grooves:

The wooden door hinge assembly hole groove numerical control machine tool, designed and manufactured by Northeast Forestry University, serves as the basis for CNC machining of wooden door hinge assembly holes. The machine is driven by a high-precision servo motor and features a controller that integrates various wooden door hinge assembly hole groove shapes. Through graphical dialogue, the size parameters of the grooves can be modified to meet specific processing requirements. In addition to hinge assembly hole grooves, this machine can also process lock grooves, lock holes, and handle hole grooves. The simulation model of the shape of the wooden door hinge assembly hole groove provides a visual representation of the desired output.

Error Compensation Method for Machining Accuracy:

The machining accuracy of a workpiece on a CNC machine tool depends on the relative displacement error between the tool and the workpiece. Various factors contribute to this error, including geometric error, thermal deformation error, load error, and tool error. Methods to enhance machining accuracy can be broadly categorized into error prevention (hardware) and error compensation (software) methods. While error prevention focuses on improving the accuracy of machine tool components, reducing errors caused by load changes, and maintaining a constant temperature working environment, error compensation leverages the programmability and intelligence of CNC machine tools to achieve high-precision machining. For CNC machining of wooden door hinge assembly hole grooves, error compensation plays a vital role in achieving the desired accuracy.

Thermal Error Compensation Modeling Method:

During CNC machining, machine tools generate heat due to internal heat sources, temperature gradient changes, heat dissipation, cutting fluid effects, and ambient temperature fluctuations. These factors, coupled with thermal stress and hysteresis, contribute to thermal deformation error. Describing this error using mathematical models is challenging due to its time delay, time-varying nature, multi-directional coupling, and complex non-linear characteristics. To address this, extensive research has been conducted on thermal error compensation and control for CNC machine tools. One such approach is the use of genetic algorithms.

Genetic algorithms employ self-organizing and adaptive artificial intelligence technologies to solve optimization problems by simulating biological evolution processes. These algorithms rely on genetic mechanisms and concepts of biological evolution to search for optimal solutions. In this study, a genetic algorithm is employed to establish a thermal error compensation model for CNC machining of wooden door hinge assembly holes. The objective function is optimized to find the optimal solution for unknown coefficients. Real number coding is used to enhance the search space and achieve higher accuracy in the compensation model.

CNC machining of wooden door hinge assembly holes using thermal error compensation technology has emerged as a key technique to improve machining accuracy in high-precision, high-efficiency CNC machine tools. The proposed thermal deformation error compensation model, based on a genetic algorithm, aims to minimize thermal deformation errors between the spindle and the tool in real-time, enhancing machining accuracy. This advancement holds great promise for achieving higher precision and efficiency in the CNC machining of wooden door hinge assembly holes.