To understand the CNC milling process, we have talked about many types of milling operations. In this article, you can find the profile milling definition, process types, tool choices, and operation tips.
Profile milling is a type of milling process, usually used to semi-finish or finish the vertical or slanted surfaces, including multi-axis milling of convex and concave shapes in two or three dimensions. Profile milling CNC Sequence is a 2.5 axis sequence. The plan of a profile milling operation is important, especially for large workpieces and machines with complicated configurations.
From the design point, the profile has an open profile (created by using line, arc, and spline commands) and closed profile (created by using the circle, rectangle, polygon, or other closed loops) types, and profile milling is used for the closed profile. Based on the operation purposes, the process can be categorized into the following types:
– Roughing/Semi-roughing: primarily used to remove the bulk material and to shape the workpiece approximately towards the finished form
– Semi-finishing: partially finished or processed, suitable for further processing.
– Finishing: may be employed to improve the appearance and properties, remove burrs and other surface flaws, and control the surface friction.
– Super-finishing: often performed using high-speed machining techniques.
Semi-finishing and finishing operations are generally done after rough machining, may need to milling the remaining stock or materials, high-speed machining often used in super-fishing.
The milling cutters for profile milling including round inserts and concepts with radius for roughing and semi-roughing, and ball nose end mills used for finishing and super-finishing. Choose the proper tool for each profile milling process. Rough inserts have high stability, medium cutting depth, and high productivity. Ball nose indexable has average stability and medium cutting depth. Ball nose exchangeable head has average stability and small cutting depth. And ball nose solid carbide has low stability and small cutting depth.
– Cutters for roughing and semi-roughing: round inserts and concepts with radius
– Cutters for finishing and super-finishing: ball nose end mill and concept with radius
1. For continuous profile milling, especially for arc machining, it is necessary to arrange the in and out of the cutting tool, try to avoid repeated machining at the junction, otherwise obvious boundary traces will appear.
2. When CNC milling outer circle with circular interpolation method, set the cutter to enter the circle from the tangential direction, after the completion of the whole round, do not directly withdraw the cutter at the tangent point, but let it move for a longer distance, to exit along the tangent direction, then avoid collision between the cutter and the part surface when the cutter compensation is canceled, resulting in the workpiece scrapping.
3. When milling the inner arc, it is also necessary to follow the principle of cutting from the tangential direction.
4. By default, undercut is detected when degouging a 3-axis profiling tool path. If you want to machine undercuts, set GOUGE_AVOID_TYPE to TIP_ONLY.
5. 3-axis profiling clears the top horizontal edges of selected surfaces. If there is another surface bounding the top edge, select it as a Check Surface to avoid gouging.
6. 5-axis surface profiling can be used for swarf cutting. The tool axis will stay tangent to the surface being machined. Use the AXIS_SHIFT parameter to shift the depth of the cut along the tool axis and set the parameter to a positive value. A positive axis shift is used to change the contact point to the side of the tool.
7. Perform roughing and finishing in different milling machines with optimized cutting tools, to ensure the best accuracy and productivity. The finishing should be carried out in a 4/5-axis machine tool with advanced software and programming technology.
8. Minimizing vibrations through reducing the cutting depth, speed or feed.