5-axis machining of integrated impeller

Processing of the entire integrating impeller: processing of hubs and blades formed on the same blank, without the use of welding processes for hubs in the blade forming process. The processing scheme is as follows:

1. To improve the strength of the entire impeller, the blank is generally formed by forging, after which the reference plane is rotated to machine the basic shape of the impeller body.

2. Grooving the impeller air flow path The groove position must be selected in the middle position of the air flow path. Flat-bottomed taper shank cutters run parallel to the airflow passage and are used to ensure a certain amount of machining margin on the bottom of the groove and the surface of the hub.

The flat bottom taper shank milling cutter is a carbide cutter and has the following specifications.

• The flat bottom has a diameter of 3 mm and the half cone angle is 2 °.
• The diameter of the tool handle is 6 mm.
• The length of the tapered part is 20 mm.
• The spindle speed selected in this step is 10000r / min.
• The feed rate is 800 mm / min.

Cnc Machine tool control panels typically have spindle speed and feed rate trimming (magnification) switches that allow the spindle speed and feed rate to be adjusted according to the actual machining conditions during the machining process.

3. Grooving of the impeller air passage and roughing and slotting of the blades are processed by a spherical taper shank milling cutter, starting from the slot position. Make sure the blade has a certain finishing allowance by expanding the groove from the center of the blade expansion slot to the outer edge and to both sides. The surface of a grooved and finished milling hub is usually finished in a single pass. Due to the narrow impeller, high blades, and high strain, UG numerical control machining programming requires the cutting area to be determined according to the drive surface, so slot machining must be processed in two parts. First part: Select the drive surface as the hub surface and expand the slot. At this time, the surface of the hub cannot be machined and requires additional slotting.
Second part: slot expansion and blade roughing. The drive surface is selected as the offset surface of the blade surface and the grooves are further expanded while the blade is roughened.

Spherical taper shank milling cutter is a carbide cutter.
Its specifications are as follows:

• The diameter of the ball head is 3 mm and the angle of the half cone is 2 °.
• The diameter of the tool handle is 6 mm.
• The length of the tapered part is 20 mm.
• The spindle speed selected in this step is 20000r / min.
• The feed rate is 3000 mm / min.

4, Use blade and wheel hub finish, ball end milling cutter finish under uniform margin to ensure good surface treatment quality. This is because the minimum distance between adjacent blades is 3.1 mm and the deepest point of the blades is 17.15 mm. Considering interference, the rotor finishing tool uses a 2.5 diameter ball end bar milling cutter from Fraisa, Switzerland, with a 20 mm cutter avoidance.
Spindle speed during machining is 260,000 r / min,
The feed rate is 5000 mm / min.

5. The finish is rounded with large and small blades, and the left side is rounded. The fillet radius varies linearly from the leading edge to the trailing edge of the blade, from 1.25 mm to 2.2 mm to 1.25 mm. The maximum fillet occurs 22% near the trailing edge. The right side of the blade is a constant fillet of 1.25 mm. Rounding can be done in a single pass if the radius of the ball head is large enough to be the minimum radius of the rounded corners. Selected tools, spindle speeds, feed rates, blade and hub finishes. The above steps should process the entire hub or blade and perform the following steps to index and rotate to ensure uniform stress release and reduce machining deformation errors.