The selection of cutting tools requires a comprehensive assessment of various factors, including the properties of the material being machined, the shape and dimensions of the workpiece, and specific machining requirements. The tool material should be compatible with the workpiece material; for instance, carbide tools are recommended for high-hardness materials such as steel, whereas high-speed steel tools are suitable for softer materials like aluminum alloys. Specific tool selection guidelines also exist for materials such as copper alloys, graphite, aluminum alloys, and resins.
The geometry of the cutting tool should be adapted to the shape of the workpiece; for example, flat-bottomed end mills are typically chosen for planar milling, while ball-nose or tapered end mills are preferred for milling curved surfaces. In slotting operations, tool selection is primarily determined by the required slot width and depth; depending on the specific slot profile, options may include side milling cutters, end mills, or long-edge milling cutters.
Tool dimensions must be appropriately matched to the workpiece dimensions; specifically, the tool diameter should be slightly smaller than the machining allowance of the workpiece to ensure both machining quality and cutting efficiency . Common standard diameters for milling cutters include 2mm, 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mm, and 20mm.
When utilizing cutting tools, proper and secure mounting is essential to ensure a firm and reliable connection between the tool and the tool holder. Tools must be kept sharp through regular resharpening, thereby maintaining the symmetry and balance of the cutting edges.
Tool usage must strictly adhere to specified cutting parameters, including cutting speed, feed rate, and depth of cut. For end milling operations, the spindle speed (RPM) is calculated using the formula: N = (1000 × V) / (π × D).
Operating a milling machine requires strict adherence to safety protocols. Prior to commencing work, all machine systems must be inspected to ensure they are safe and fully functional. Tool holders and workpieces must be securely clamped; furthermore, taking measurements or touching the machined surface with one's hands while the machine is in operation is strictly prohibited. When mounting or dismounting end mills, a wooden block or protective pad must be placed on the machine table surface; manually supporting the cutter head with one's hands is forbidden.
Regarding tool wear, specific evaluation methods exist for assessing the wear on the bottom cutting edges of cylindrical end mills; these methods allow for the determination of key evaluation metrics, such as the area of the wear zone and the height of the wear band. By improving tool structure-such as incorporating roughing, finishing, and burnishing teeth into thread milling cutters designed for high-hardness materials-wear can be mitigated to extend tool life.
