仿形铣削 is milling with cutting tools equipped with indexable inserts featuring rounded cutting edges. The milling cutter is either fully equipped with rounded cutting edges (indexable inserts for disc milling cutters or ball-nose end mills) or is partly equipped with rounded cutting edges. Profile milling cutters include sleeve milling cutters, end mills with spiral shanks, modular (spiral) end mills, etc.
Profile milling tools in die & mold manufacturing
When the die/mold cavity has a complex sculptured surface that is difficult to decompose into several simple surfaces for machining, profile milling is a good choice. Profile milling has high efficiency and is especially suitable for rough machining of cavities.
Profile milling covers multi-axis milling of 2D and 3D convex and concave shapes. The larger the part and the more complex the features to be machined, the more important process planning becomes. Typical profile milling operations involve sculptured surfaces and contours in die/mold manufacturing.
Profile milling is mainly used for the milling of convex and concave surfaces as well as contours. It is commonly applied for machining die/mold contours. Profile milling cutters often use rounded cutting edges. Compared to common end mills, under the same feed conditions, profile mills can achieve smaller scallop height and thus improve surface finish.
The key characteristics of profile milling tools
Profile milling cutters use round inserts, providing profile milling tools with many advantages enabling small scallop height and high feed rates, supplementing high-speed machining trends. Profile milling cutters have the following characteristics: 1. Strong ramping ability. Some profile mills can ramp or plunge into the workpiece like a drill bit. 2. Helical interpolation. Profile mills combined with helical interpolation can easily and quickly machine large-diameter holes. 3. Cutting edge strength. The rounded cutting edges can withstand larger tool deflection and vibration, allowing higher speeds and feeds during machining while reducing the risk of chipping. 4. Number of cutting edges. Round inserts offer more usable cutting edges. Depending on insert size and depth of cut, round inserts can have 4-8 effective cutting edges, removing at least twice as much material compared to common rhombic and square inserts. This advantage reduces tool change frequency, improving efficiency and economy. 5. Efficient cutting. Using round inserts, high metal removal rates can be achieved without requiring high machine power. Because of their strength, larger feed rates can be used compared to square-end mills, even allowing heavy roughing on light machines.
Higher surface finish after roughing. Surfaces produced by round insert milling do not show the distinct peaks and valleys left by square tools. Instead, scallop height is lower, resulting in higher surface quality after roughing, suitable for semi-finishing.
Selection of profile milling cutters
Profile milling cutters mainly include round insert cutters and ball nose end mills. Round insert cutters: Small inserts have good versatility, and low cutting forces, and are suitable for finishing and unstable conditions. Large inserts have high strength and metal removal rates, suitable for roughing and stable conditions. Modular design: The same tool body can use different types and lengths of shanks based on needs. The same shank can also fit different tool heads. Selection by machining stage: Roughing generally uses round insert cutters, and finishing uses solid carbide ball nose end mills or modular end mills with replaceable carbide inserts.
Application strategies
In die/mold machining, common tool failures are thermal cracks, flank wear around cracks, build-up edges, and finally edge collapse. Improper tool selection or parameters can cause various issues like tool breakage, thermal wear, vibration, burrs, and chip evacuation problems.
When such problems occur, including tooling issues or other causes, timely and accurate diagnosis of the root cause and appropriate corrective actions can avoid production accidents and achieve lower costs and higher efficiency.
What causes tool breakage and how to solve it?
Causes: 1. Excessive feed rate; 2. Too much depth of cut;3. Excessive overhang;4. Severe flank wear on cutting-edge
Solutions: 1. Lower feed rate; 2. Reduce depth of cut;3. Minimize overhang;4. Resharpen in time;5. Reduce the length of the cut and overhang as much as possible
What causes thermal wear and how to solve it?
Causes:1. Cutting speed too high; 2. Rake angle too small;3. Workpiece hardness is too high
Solutions: 1. Lower cutting speed, use cutting fluid;2. Adjust the side rake angle appropriately; 3. Use dry-soluble-non-soluble fluid order, surface treatment
What causes vibration during cutting and how to solve it?
Causes: 1. Cutting conditions improper;2. Workpiece clamping unstable;3. Overhang too long;4. The side angle is too large
Solutions:1. Adjust cutting parameters; 2. Optimize clamping;3. Minimize the length of cut and overhang;4. Reduce side angle
What causes burrs and how to solve it?
Causes:1. Feed rate too high; 2. Cutting edge worn;3. The depth of cut is too large
Solutions: 1. Lower feed rate;2. Resharpen in time;3. Reduce the depth of the cut
What causes poor chip evacuation and how to solve it?
Causes: 1. Cutting fluid pressure too low;2. Chip space too small; 3. The depth of cut is too large
Solutions:1. Increase cutting fluid amount and pressure;2. Use cutters with fewer flutes;3. Reduce the depth of the cut
conclusion
To perform profile milling, rigid solid carbide tools should be selected, tool parameters optimized, and spherical grinding applied to the tools. Meanwhile, the machining spindle and tool holders must have sufficient rigidity. During machining, cutting parameters need to be reasonably selected to control cutting forces and chips, ensuring machining quality.
Profile milling has been widely applied in fields like die & mold, medicine, and aerospace. With the development of high-speed milling, advancement in tool materials, and optimization of machining strategies, the application prospects of profile milling are very broad, and it will significantly enhance machining efficiency and product quality in mechanical manufacturing.
