Selection and Application of Fixtures in Large-Scale CNC Processing Plants

Generally, large-scale CNC parts manufacturers use fixtures to process various mechanical components. Below we will introduce relevant knowledge on the "selection and application of fixtures" from Dongguan Changyuanfeng Precision: 1.According to the characteristics of CNC machining centers and processing requirements, commonly used fixture types include special fixtures, modular fixtures, adjustable fixtures, group fixtures, and workpiece positioning and clamping systems based on a unified datum.

2.The high flexibility requirements of machining centers demand that their fixture structures be more compact and simpler than those of conventional machine tools, with faster and more accurate clamping actions, minimized auxiliary time, and more convenient, labor-saving, and safer operation, while ensuring sufficient rigidity and flexibility. Therefore, pneumatic and hydraulic clamping devices are commonly employed. 3.To ensure that all surfaces to be machined on the workpiece are fully accessible during positioning and clamping, fixtures should be designed as open as possible. The spatial positions of clamping elements should be kept low, and adequate space must be reserved for tool paths. 4.Taking into account the minimum distance between the machine spindle and the worktable, as well as the tool clamping length, the mounting position of the fixture on the machine worktable shall ensure that all machining operations on the workpiece can be completed within the spindle travel range.

Automatic tool changes and worktable exchanges must not interfere with fixtures or workpieces. 5.Positioning blocks on the fixture are sometimes used when installing workpieces. During machining, these blocks can be removed after the workpiece is clamped to avoid interference and enable machining at front, rear, left, and right positions. Therefore, consideration must be given to maintaining the workpiece’s positioning accuracy after the positioning elements are removed.

6.Clamping points should remain unchanged during machining wherever possible.