In the CNC machining of the impeller blades, the machining of large impeller blades is the most difficult. Mastering the measures to solve the processing difficulties of large blades has a very positive effect not only on the large blade itself, but also on the impeller moving blades, impeller stationary blades, guide impeller blades and impeller end blades.
Inclined CNC parts are often encountered in the production process. Need to punch, boring, and milling shapes on the inclined surface. Or it is necessary to process several inclined surfaces with different directions and different slopes in the same clamping, and each inclined surface has a higher geometric tolerance requirement.
With the increase in the design of multi-faceted and complex curved parts, 5-axis machining will account for an increasing proportion of CNC machining. Because 5-axis CNC machining adds two degrees of freedom of rotation, it increases the difficulty of CNC machining motion simulation calculation and tool interference checking, especially when machining parts with extremely complex shapes.
What can be done with a 5-axis milling machine?
It may sound strange, but if the Renaissance artist had traded the hammer and chisel for a numerical control (CNC) and milling machine, we would have thousands of statues of David made from all kinds of materials today.
There are many reasons for the deformation of machined aluminum parts, which are related to the aluminum material, the shape of the part, and the CNC machinery and equipment. There are mainly the following aspects: blank internal stress, cutting force, deformation caused by cutting heat, and deformation caused by clamping force.
For CNC machining of aluminum parts with a large margin (large, thin-walled, aluminum cavity parts), in order to have better heat dissipation conditions during the machining process and avoid heat concentration, symmetric machining should be used during machining. If there is a 90mm thick aluminum sheet that needs to be machined to 60mm, if one side is milled, the other side should be milled immediately, and the flatness can only reach 5mm after processing to the final size at a time;
Turning and milling thin parts (aluminum, aluminum alloy, pure titanium, copper, magnesium alloy) are always prone to deformation during machining. Oval or “waist shape” with a small middle and large ends, which makes it difficult to ensure the quality of parts. Its clamping design is often the most discussed point. Let’s take a look at two design examples of thin-walled fixtures on turning and milling parts, and how they solve the deformation problem.
In milling, an important characteristic of titanium alloys is extremely poor thermal conductivity. Due to the high strength and low thermal conductivity of titanium alloy materials, extremely high cutting heat (up to 1200°C if not controlled) is generated during processing. The heat is not discharged with the chips or absorbed by the workpiece, but is concentrated on the CNC cutting edge. Such high heat will greatly shorten tool life.
Set the geometric parameters of turning and milling titanium tools to improve the product quality of titanium alloy parts. Products are delivered quickly and on time.
(1) The rake angle of the tool γ0: The contact length between titanium alloy chips and the rake face is short. When the rake angle is small, the contact area of the chip can be increased, so that the cutting heat and cutting force are not excessively concentrated near the cutting edge. Improve the heat dissipation conditions, and can strengthen the cutting edge and reduce the possibility of chipping. Turning titanium generally takes γ0=5°～15°.
When titanium alloy is milled at low speed in an inert gas medium, the milling deformation coefficient is greater than 1.0; But in the atmosphere, when the milling speed Vc=30 m/min, the chip deformation coefficient is less than 1.0. This is because titanium alloys have a great affinity for oxygen and nitrogen in the atmosphere during high-temperature milling.
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