It Is The Same Gantry Boring And Milling Machine. Why Is The Machining Accuracy So Different? The Key Lies In These Three Points

The same gantry boring and milling machine is also a gantry boring and milling machine. Why is the machining accuracy so different? The key lies in these three points. Why is the processing accuracy so different? The key lies in these three points

The method to ensure the boring processing accuracy of machine tools with similar parameters, but the processing results are completely different. The method to ensure the boring processing accuracy . What is the problem?

When many factories purchase CNC gantry boring and milling machines, they will be attracted by the parameters given by the sales. The bed size, stroke range, and spindle power of the same model are basically the same. However, after they are actually put into production, some can stably process high-precision parts, while others frequently have dimensional deviations. This is not a matter of luck, but an essential difference in the inherent design of the equipment.

Structural rigidity of bed and beams

When boring large workpieces, the tool is subjected to long-lasting cutting force. If the machine bed and beam are not thick enough according to the structure, or the cast iron is not mixed to a certain proportion, the equipment will produce slight deformation when it bears the force. Such deformation may not be noticeable in a single machining process. However, as the processing time continues to accumulate, The dimensional accuracy of the workpiece will gradually develop in a direction that deviates from the design drawing requirements.

In order to reduce costs, some manufacturers will take measures such as reducing the wall thickness of the bed or reducing the specific number of reinforcing ribs. This approach can lower prices in the short term, but in the long term, equipment with insufficient rigidity is prone to vibration during the fine boring process, and it is difficult to ensure the consistency of hole diameters. When purchasing, you need to pay attention to the bed construction process and structural design, not just the surface size.

Matching of transmission system

Many purchasers have a misunderstanding that the bigger the motor power, the better. In fact, the quality of the transmission system depends on the overall mutual matching between the motor, screw, reducer and other components. If the motor torque is too large but the screw support stiffness is insufficient, resonance will occur during high-speed operation, resulting in reduced positioning accuracy.

A transmission system that meets the requirements must be comprehensively calculated based on the processing load and stroke range. Appropriate acceleration settings can keep the equipment in a stable state during rapid movement, avoiding overshoot due to emergency stops and starts. When a mismatched system is used for a long time, the screw and guide rails will wear out faster, and the precision life of the equipment will be significantly shortened.

Thermal deformation control ability

During the working process, components such as the motor, spindle, and hydraulic system of the CNC gantry boring and milling machine will generate heat. There is thermal expansion in large components. Although it is small, for high-precision boring, thermal deformation of a few tenths of a millimeter is enough to cause the workpiece to be scrapped. For equipment that lacks thermal balance design, the accuracy will drop significantly after a period of time after starting up.

Special thermal deformation control requires thermal analysis during the design stage, including rationally arranging the location of heating components, adding cooling channels, selecting materials with low thermal expansion coefficients, etc. Some high-end models are also equipped with a temperature compensation system that monitors temperature changes in various parts of the machine tool in real time and automatically corrects the processing coordinates to ensure accuracy and stability during long-term processing.

Maintenance of accuracy of spindle system

The core component of boring processing is the spindle, and the processing quality of the hole is directly affected by its accuracy. The high-quality spindle uses high-precision bearings and undergoes strict preloading to maintain radial and axial stability during long-term high-speed operation. An important indicator of spindle quality is thermal elongation.

Some cheaper models use ordinary spindles, and their performance is acceptable during short-term test operations. However, after continuous processing for several hours, the radial runout will increase due to the increase in spindle temperature. As a result, the roundness and position of the boring hole will exceed the tolerance range. When making a selection, you should focus on the spindle brand, bearing grade, and thermal elongation compensation design. These are extremely critical factors to ensure boring accuracy.

Control system and compensation technology

A modern CNC system with multiple error compensation functions, including pitch error compensation, backlash compensation, thermal error compensation, etc. These compensation functions must be realized with high-precision detection devices. The final actual processing effect will be affected by the resolution of the grating ruler and the interpolation accuracy of the system.

Although some equipment has a compensation function as standard, the actual compensation effect is limited due to the lack of accuracy of the detection components or the simplicity of the compensation algorithm. A mature control system can study the error patterns of the equipment and continuously optimize the compensation parameters, so that the equipment can still maintain the factory accuracy level after running for several months, which is difficult to achieve with low-priced models.

The importance of long-term accuracy stability

When purchasing a CNC gantry boring and milling machine, you can't just look at the detection data when it is just turned on. The real test of equipment quality is the ability to maintain accuracy after three months, half a year later, and even one year later. If a machine tool is well designed, it can continuously output stable processing results under various working conditions. This is the production tool that enterprises really need.

Investing in large-scale processing equipment is a considerable expense. When making a choice, long-term stability and after-sales technical support must be placed in a more critical position than the initial price. So what kind of equipment is good? Only equipment that can continuously guarantee the accuracy of boring processing can bring long-term economic benefits to the company, thereby avoiding many losses caused by frequent rework and scrapped workpieces.

Have you ever experienced a decrease in accuracy of the CNC gantry boring and milling machine you are currently using after a long period of use? You are welcome to share your experience in use in the comment area. If you find this article useful, please like it and forward it to more friends in need.