For many machining workshops, machining high-strength titanium alloy workpieces is as difficult as climbing. In order to solve this problem, machine tool manufacturers have increased the rigidity of milling machines and lathes, improved the shock absorption performance of the spindle and the size of the machine tool frame, and improved the performance of the motor; these measures are to provide the required large cutting force while reducing Harmful machine tool vibration to avoid reducing the machining quality of the workpiece and shortening the service life of the tool. In the processing of titanium materials, in order to optimize the tool system and obtain the maximum metal removal rate, special attention needs to be paid to the performance of the machine tool that provides cutting force output, the characteristics of the cutting edge of the cutting tool and the contact part of the workpiece, and the connection between the machine tool and the tool Parts-spindle coupling device.
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The main design standard of the machine tool HPX63 includes a large cutting capacity, the maximum processing diameter is 1050 mm, and the workpiece height (Y axis) can be up to 1050 mm. The X-axis travel is 1000 mm, the Z-axis travel is 900 mm, and the tray size is 630 mm. The rotation speed of the B-axis turntable can reach 12rpm, with high torque and fast acceleration performance. The moving speed is fast, up to 32 meters / minute, the acceleration / deceleration rate is 0.5G, and the cutting feed rate is 12 meters / minute. The machine tool is designed for precision machining. The metallurgical process used makes the castings have the maximum rigidity. The axial slide of the spindle box is quenched, ground, and manually scraped. The positioning accuracy and repeated positioning accuracy are 0.001 mm. The spindle device of the Mitsui machine tool can automatically compensate for temperature changes and does not require warm-up time. This company provides a variety of spindle options to meet the needs of users to choose direct transmission and gear transmission, as well as the need for different torques and speeds.
All in all, the HPX-63 machine tool has good robustness, rigidity, and accuracy. It is very suitable for processing titanium, inconel, tool steel, stainless steel, and aluminum materials. It is suitable for the aerospace industry, energy industry, compressors, Mold, fixture and tooling equipment, automobile prototype parts manufacturing, and general high-precision processing. In order to optimize the tool system, the spindle coupling device is required to maximize the transfer of machine power. Most tool products on the market are integral tools, and the spindle clamping force is relatively low. The rigidity of the coupling device is very limited, and the radial fit needs to be kept at the minimum specified value. In order to obtain stable end-to-face contact performance, very tight tolerance levels are required, so the processing costs have increased significantly.
Cutting tool. Four different cutting tools were used in the test, which are
- (1) A 203.2 mm diameter face milling cutter with 7 square indexable inserts;
- (2) An end mill with the same diameter, with 7 round inserts;
- (3) A 76.21 mm diameter, 228.6 mm length corn milling cutter (HARVI UltraTM), with 5 spiral rows, each spiral row has 11 blades;
- (4) A 125 mm diameter flat bottom indexable drill (FBI) with 6 indexable inserts. Because the machine tool and the spindle have sufficient power output, and the spindle coupling device has
excellent clamping force, the test and processing results are excellent. The metal removal rate of the square insert face milling cutter reached 88.74 cubic centimeters per minute, the spindle speed was 64 min-1, the cutting depth was 12 mm, the cutting width was 45 mm, and the feed rate was 164.3 mm / min.
With a spindle speed of 73 min-1, a cutting width of 177.8 mm, a cutting depth of 3 mm, and a feed rate of 88.9 mm / min, the metal removal rate of the round blade end face cutter is 47.42 cm3 / min. The HARVI UltraTM corn milling cutter can simultaneously cut in the X-axis and Y-axis directions at a spindle speed of 171 min-1, a feed rate of 101.6 mm / min, a cutting depth of 40 mm, and a cutting width of 76.21 mm The metal removal rate can reach 309 cubic centimeters per minute. The FBI drill drilled a flat-bottomed hole in a titanium workpiece. At a spindle speed of 102 min-1, a feed rate of 10.2 mm / min and an aperture of 125 mm, the metal removal rate was 125.2 cm3 / min. After drilling the first hole, rotate the workpiece on the spindle at a 45-degree angle, and drill an oblique hole, which passes through the edge of the first hole. Although the machining process is severely interrupted, both the machine tool and the drill show good performance.