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How to Machining Multi-Curved Complex Parts Using CNC Machine Tools
Explore best practices for machining multi-curved, complex parts using CNC — from precise 3D modeling and CAM tool-path planning to multiaxis machining, cutting-tool selection, and quality control. Learn how to ensure accurate surface contours and high finish quality for complex geometries.
Core Principle: Centered on “precise modeling + rational process planning + adaptive programming + stable machining,” combined with multi-axis linkage technology, to overcome challenges in surface contour accuracy and surface quality.
Preliminary preparation: 3D modeling and process planning (basic premise)
Accurate 3D modeling: Using professional software such as UG, Pro/E, CATIA, etc., a multi surface solid model is constructed 1:1 according to the part drawing, with a focus on ensuring the smoothness of the surface joints (avoiding modeling errors that may cause machining deviations). Complex surfaces can be optimized for accuracy through point cloud reverse modeling.
Process route planning:
1. Determine the machining sequence: follow the “rough machining → semi precision machining → precision machining”, first remove most of the excess (prioritize using large cutting tools to improve efficiency), and then gradually refine the surface contour;
2. Choose suitable cutting tools: end mills and bull nose cutters for rough machining, ball end mills for semi precision/fine machining (suitable for surface fitting), round nose cutters (balancing efficiency and accuracy), and extended edge cutting tools for complex deep cavity surfaces;
3. Determine the clamping method: Use pliers, fixtures, or vacuum suction cups to secure the clamping to ensure rigidity and avoid vibration during processing (for multi surface parts clamping, reserved space for tool movement should be reserved to prevent interference).
Core link: Programming and tool path optimization (key guarantee)
Programming software selection: Priority should be given to software with built-in surface machining strategies such as UG CAM and Mastercam. There is no need to manually write complex G-code, and strategies such as “contour milling, parallel milling, and streamline milling” can be directly called.
Tool path optimization:
1. Precision machining path: For multi surface parts, priority should be given to “streamline milling” (cutting along the surface contour for high fit) or “contour milling” (suitable for steep surfaces), and the cutting spacing should be adjusted according to the surface accuracy requirements (the higher the accuracy, the smaller the spacing);
2. Avoid interference: When programming, check “tool interference check” to automatically avoid collisions between the tool and the parts or fixtures. Deep cavity surfaces can be milled using “layered milling”;
3. Residual allowance treatment: After semi precision machining, check the surface residue and add a “root cleaning milling” path to the locally raised areas
Processing Execution: Equipment Selection and Parameter Debugging (Key to Implementation)
Equipment selection: For complex multi surface parts (such as mold cavities and irregular surface parts), priority should be given to using a five axis linkage CNC machine tool, which can adjust the tool posture from multiple angles to avoid blind spots in machining; Simple multi surface surfaces (such as shallow cavity surfaces) can be paired with a three-axis CNC machine tool and a rotating worktable.
Debugging of processing parameters:
1. Cutting speed: Depending on the material selection (80-120m/min for steel parts, 300-500m/min for aluminum parts), the speed for surface finishing should be appropriately reduced to ensure surface quality;
2. Feed rate: For rough machining, choose a large feed rate (0.2-0.5mm/tooth), and for precision machining, choose a small feed rate (0.05-0.15mm/tooth) to avoid surface scratches;
3. Cutting depth: For rough machining, the cutting depth is 2-5mm, and for semi precision/precision machining, the cutting depth is 0.1-0.5mm to prevent tool vibration from causing surface deformation.
Quality Control: Inspection and Correction (Closing Stage)
Sampling inspection during processing: Use a dial gauge and lever gauge to check the surface contour, and adjust the tool compensation parameters in a timely manner if any deviation is found;
Post processing precision inspection: Complex surfaces are scanned and inspected using a coordinate measuring instrument, and the three-dimensional model is compared to perform additional machining on areas that exceed the tolerance.
Please send us your part’s CAD drawings immediately. Our experts will provide you with a free manufacturing feasibility analysis and quotation, and work together to find the best solution.
