Agricultural machinery as an important support for the development of modern agriculture, its performance and quality are directly related to the efficiency of agricultural production and economic returns.
The axis hole system parts of agricultural machinery are key components. Their machining accuracy and consistency greatly affect the assembly quality and overall performance of the machinery.
CNC systems have evolved from traditional two-axis machining to more complex three-axis and five-axis linkage machining. These systems can efficiently complete tasks involving complex surfaces and precision parts.
In the field of application, CNC machining technology is widely used in aerospace, automotive manufacturing, mold processing, medical equipment and other industries.
The deep integration of CNC systems and CAD/CAM software enables seamless digitalization from design to processing. This integration further promotes the advancement of intelligent manufacturing.
Key technologies for CNC machining of agricultural machinery base shaft system hole system parts
1. Benchmark selection and positioning technology
Benchmark selection and positioning technology is to ensure that the agricultural machinery base shaft system hole system parts processing accuracy of the core link.
Benchmark selection should follow the principle of unification of design benchmark, process benchmark and measurement benchmark to avoid cumulative errors caused by benchmark conversion.
Design benchmarks are established based on part drawings. Process benchmarks should select surfaces or holes that are easy to measure and operate. Measurement benchmarks must align with design and process benchmarks to ensure accurate test results.
In terms of positioning methods, commonly used methods include two pins on one side, V-block positioning, special fixture positioning and vacuum adsorption positioning.
One-sided two-pin positioning suits plane and hole parts. A plane and two pins limit the workpiece’s degrees of freedom, offering high precision and easy operation.V-block positioning suits shaft parts. It uses symmetry to achieve automatic alignment.
Specialized fixtures are used for complex shaped parts to ensure stability during machining;
Vacuum adsorption positioning is suitable for thin-walled or easily deformed parts to avoid deformation caused by clamping force.
Positioning accuracy control is the key to ensure machining quality.
The fixture’s manufacturing accuracy is usually 1/3 to 1/5 of the workpiece’s accuracy. Positioning elements like pins and blocks should be high-precision products. Positioning error impacts should be assessed using geometric error analysis and statistical methods.
During the machining process, the fixture and positioning elements should be checked regularly for wear and tear, and adjusted or replaced in time to ensure positioning stability.
2. Multi-axis linkage machining programming technology
Multi-axis linkage machining programming is key to handling complex geometric features in agricultural machinery shaft system parts. It is especially suitable for processing inclined holes, curved contours, and shaped grooves.
Multi-axis linkage, such as four-axis and five-axis machining, enables flexible tool movement in multiple directions. It reduces clamping times and improves machining accuracy and efficiency.
In multi-axis linkage machining, the control of tool axis is the key.
Programming needs to be based on the geometric characteristics of the part and processing requirements, reasonable settings for the tool tilt angle and trajectory.
For example, for the machining of inclined holes, by adjusting the alignment of the tool axis with the hole axis, the machining error caused by tool interference can be avoided;
For the machining of curved surface contour, it is necessary to ensure that the contact point between the tool and the surface is always in the best cutting state through continuous multi-axis motion.
Interference checking is an important part of multi-axis programming.
Due to the complexity of the motion of multi-axis machine tools, interference between tools, toolholders and workpieces and fixtures can easily occur.
Programming requires using CAM software’s interference check function. It simulates the tool path and machine movement. Potential interference areas are identified. Interference is avoided by adjusting the tool path or machine position.
Post-processing is the final step in multi-axis programming, where the toolpaths generated by the CAM software are converted into CNC code that is recognized by the particular machine tool.
Different machines have different control systems and motion structures. The post-processor must be customized for each machine’s specific parameters. This ensures the generated code accurately drives the machine’s motion.
The post-processing process also needs to take into account the machine’s zero point settings, coordinate transformations and motion smoothness to improve machining accuracy and surface quality.
3. Machine thermal deformation compensation technology
Machine thermal deformation is a main factor affecting high-precision machining. It occurs especially during long-time continuous machining or high-speed cutting. Friction, cutting heat, and environmental temperature changes cause this deformation. Thermal deformation significantly reduces machining accuracy.
Thermal deformation compensation technology uses real-time monitoring and dynamic adjustment to reduce the impact of thermal deformation on machining accuracy. It is a key technology to ensure high-precision machining of shaft system hole parts in agricultural machinery.
The sources of thermal deformation mainly include spindle heat, guideway friction, ball screw temperature rise, and ambient temperature fluctuations. These heat sources can lead to uneven expansion of the machine structure, which in turn causes relative position errors between the tool and the workpiece.
For example, thermal elongation of the spindle leads to dimensional errors in the Z-axis direction, while thermal deformation of the bed affects the positioning accuracy of the X- and Y-axes.
The core of thermal deformation compensation technology lies in real-time monitoring and dynamic adjustment.
First, temperature data are collected in real time by arranging temperature sensors in key parts of the machine tool (e.g., spindle, guideway, ball screw);
The thermal deformation model, such as a finite element analysis model or empirical formula, calculates the amount of thermal deformation. Then, the machine tool’s motion parameters are dynamically adjusted through the CNC system’s compensation function to offset the thermal deformation effects.
For example, SIEMENS 840D and other high-end CNC systems integrate a thermal deformation compensation module. This module automatically adjusts the tool path and coordinate offset based on temperature data to ensure machining accuracy.
4. Quality Control and Inspection Technology
Quality control and testing technology is the core link to ensure the machining accuracy and consistency of agricultural machinery based shaft system parts.
Through scientific testing methods and advanced quality control means, problems in the machining process can be found in a timely manner and corrective measures can be taken to ensure that the parts meet the design requirements.
Online inspection technology is one of the most important means of quality control. By integrating a probe system (e.g., Renishaw probe) into the machine tool, critical dimensions can be monitored in real time during machining. Measurement results are fed back to the CNC system to enable dynamic adjustment of machining parameters.
For example, in hole system machining, the probe can automatically measure the hole diameter and distance to ensure it meets design requirements, significantly improving inspection efficiency and reducing human error.
Hole positional accuracy is a key quality indicator for hole system parts in agricultural machinery base shafts. Common inspection methods include Coordinate Measuring Machine (CMM) and optical image measurement.
The CMM accurately measures the position, diameter and shape of the hole system by means of a high-precision probe, which is suitable for comprehensive inspection of complex parts;
Optical image measurement uses a high-resolution camera and image processing technology to quickly measure hole positional accuracy. It is suitable for fast inspection in mass production.
Surface roughness and form and position tolerance are important indicators that affect the functional performance of parts.
Surface roughness is usually measured using a profilometer or roughness meter, which evaluates the micro-geometric properties of the machined surface by analyzing the surface profile curve;
Form and positional tolerances (e.g. flatness, roundness, perpendicularity, etc.) are measured by CMM or special inspection equipment to ensure that the geometric shape and positional relationship of the part meets the design requirements.
During the machining process, surface roughness and form tolerance can be effectively controlled by optimizing cutting parameters and tool paths to further enhance the functional performance of the parts.
5. Intelligent and automation technology
Intelligent and automation technology is a key development direction in CNC machining of agricultural machinery-based shaft system parts. By introducing advanced control systems, sensors, and data analysis, the machining efficiency, accuracy, and consistency can be greatly improved. At the same time, manual intervention and production costs are significantly reduced.
In CNC machining, sensors such as vibration, temperature, and force sensors are integrated into the machine tool. These sensors collect real-time data during machining, including cutting force, vibration, and temperature. Intelligent algorithms, like machine learning and fuzzy control, are used to analyze this data. Based on the analysis, machining parameters—such as cutting speed, feed rate, and depth of cut—are dynamically adjusted to optimize the process.
For example, when vibration anomalies are detected during machining, the system can automatically reduce the cutting speed or adjust the tool path to avoid degradation of machining quality or equipment damage.
Automated production can be achieved using industrial robots equipped with vision systems or force sensors. These systems enable automatic clamping, positioning, and loading/unloading of workpieces. As a result, manual operations are reduced, while production efficiency and consistency are improved.
For example, when processing shaft system hole parts for agricultural machinery, the robot operates according to a preset program. It automatically grabs the workpiece and places it on the machine tool table. After machining is completed, the robot removes the part and transfers it to the next process. This enables fully automated production.
In addition, the robot can also be integrated with CNC machine tools, testing equipment, etc., to build flexible manufacturing cell (FMC) or flexible manufacturing system (FMS), to adapt to the needs of multi-species, small batch production.
Internet of Things (IoT)-based processing data acquisition and analysis technology provides data support for intelligent production.
Example analysis
To assess the effectiveness of high-precision CNC machining technology, a practical case is selected for analysis. The focus is on the hole system machining of a tractor gearbox shell from an agricultural machinery manufacturer.
The tractor gearbox shell is a key part of agricultural machinery. Its hole machining accuracy affects gearbox assembly and performance.
The enterprise faces the problems of high positional accuracy of the hole system, low machining efficiency and high difficulty of quality control in the machining process.
High-precision CNC machining and intelligent quality control have solved these problems. Production efficiency and product quality have improved significantly.
The hole machining of tractor gearbox shell has the difficulties of high precision requirement, complex structure and mass production demand.
For example, the hole system’s positional accuracy must be within ±0.02mm. The hole diameter tolerance must be within ±0.01mm. The surface roughness should reach Ra1.6μm.
At the same time, the distribution of a number of different diameters and depths of holes on the shell, some holes for the inclined holes, machining difficulties.
In order to meet these needs, the enterprise chose a high rigidity, high precision CNC machining centers, to ensure that the positioning accuracy of the machine tool to ± 0.005 mm, repeat positioning accuracy of ± 0.002 mm;
Using CAD/CAM software to generate optimized toolpaths and verifying the correctness of the program through simulation to avoid interference and overcutting problems.
Integration of a Renishaw probe system on the machine tool to monitor hole diameter and distance in real time, and feedback the measurement results to the CNC system for dynamic adjustment of machining parameters;
Temperature sensors monitor key parts of the machine tool for changes. The CNC system uses compensation functions to reduce thermal deformation effects on accuracy.
Statistical process control technology is used to monitor key machining parameters in real time. It detects and corrects anomalies promptly. This ensures high-precision machining of the gearbox shell hole system.
Conclusion
The CNC machining technology for agricultural machinery shaft system hole parts is analyzed. It focuses on high-precision process design and CNC programming. It covers the selection and setup of high-precision CNC machines. Quality control and inspection technologies are included. Intelligent and automation technologies are also discussed.
Through actual cases, the significant advantages of CNC machining technology in improving machining accuracy, efficiency and quality consistency are verified.
High-precision CNC machining technology can solve difficult problems in processing shaft system hole parts of agricultural machinery. Intelligent quality control also plays a key role. These methods support the technological upgrade of the agricultural machinery manufacturing industry.