1, Brittle material
Brittle materials such as ceramics, glass, and some hard alloys are a major challenge in CNC machining. These materials are prone to sudden fracture without plastic deformation when subjected to external forces, rather than gradual yielding or plastic deformation. In the CNC machining process, the tool needs to gradually remove the material layer to achieve the predetermined shape, but the characteristic of brittle materials makes it easy to produce defects such as cracks and chipping during the machining process, which seriously affects the machining quality and yield. In addition, brittle materials usually have higher hardness and more severe wear on cutting tools, further increasing processing difficulty and cost.
2, High melting point material
High melting point materials, such as tungsten, molybdenum, tantalum and other refractory metals and their alloys, are difficult to process through conventional cutting methods due to their extremely high melting points. Although CNC machining can cut materials with high-speed rotating tools, the heat generated during the cutting process is difficult to dissipate quickly when facing these high melting point materials, resulting in high temperatures in the cutting area. This not only exacerbates tool wear, but may also cause material surface melting, softening, and even combustion, seriously affecting machining accuracy and surface quality. Therefore, for such materials, other processing methods are usually used, such as electrical discharge machining, laser processing, or plasma processing.
3, High viscosity material
Highly viscous materials, such as rubber, certain high molecular weight polymers, and cohesive soils, are prone to adhere to the surface of cutting tools or workpieces during CNC machining, leading to difficulties in processing. This adhesion phenomenon not only affects cutting efficiency, but may also lead to increased tool wear and decreased machining accuracy. In addition, high viscosity materials may also generate a large amount of chips and waste during the cutting process, which can easily block the cutting area and further affect the smooth progress of the machining process. Therefore, for such materials, pre-treatment is usually required to reduce their viscosity, or special cutting techniques and tool designs are used.
4, Flammable and explosive materials
Flammable and explosive materials, such as magnesium, aluminum powder, hydrogen, etc., pose extremely high safety risks during CNC machining. These materials are prone to combustion or explosion when subjected to friction, impact, or high temperatures, posing a serious threat to equipment, personnel, and the environment. Therefore, strict protective measures and special processing methods must be taken for such materials to ensure the safety and controllability of the processing process. However, even with these measures taken, CNC machining may not be the best choice as other machining methods may be safer and more effective.
5, Materials with special properties
In addition to the above-mentioned materials, there are also some materials with special properties that are difficult or impossible to CNC machine. For example, materials with strong magnetism may be affected by the interference of machine tool magnetic fields during CNC machining, which may affect machining accuracy; Materials that are radioactive or toxic require special protective measures and processing environments to avoid harm to human health and the environment. These materials with special properties often require customized processing equipment and techniques to meet their processing needs.
