Effect of feed rate on cutting force

Test and measurement

In order to study the influence of the change of feed rate on the ultrasonic vibration cutting force, in the cutting test, the machine speed is kept n=90r/min, the depth of cut a p =0.3mm, only the feed amount f is changed, and the feed is measured separately. The cutting force F c of ultrasonic vibration cutting and ordinary cutting when the quantity f=0.08mm, 0.12mm, 0.20mm, the test result is shown in Table 2.

results and analysis

The relationship between the feed amount obtained by the test and the cutting force is shown in Fig. 3. It can be seen from the figure that as the feed rate increases, the cutting resistance increases, and the normal cutting force and the vibration cutting force increase, but the vibration cutting force increases faster. The reason is that with the feed rate and As the feed resistance increases, the amplitude of the vibration cutting decreases, resulting in a faster increase in cutting force. Since the large feed amount during vibration cutting may cause low-frequency vibration of the tool holder, the feed amount used in this test is small to ensure the machining accuracy and the surface quality.

Table 3 Relationship between cutting force F c and depth of cut a p
Cutting depth a p (mm) 0.1 0.3 0.5
Vibration cutting force F c (N) 3.60 14.80 39.72
Ordinary cutting force F c (N) 15.30 45.50 64.50

Figure 4 Relationship between depth of cut and cutting force
Influence of cutting depth on cutting force

Test and measurement

In order to study the influence of the change of cutting depth on the ultrasonic vibration cutting force, in the cutting test, the machine speed n=90r/min and the feed rate f=0.08mm/r are kept unchanged, and only the depth of cut a p is changed. The cutting force F c of the ultrasonic vibration cutting and the ordinary cutting at the depths of cut a p = 0.1 mm, 0.3 mm, and 0.5 mm were measured, and the test results are shown in Table 3.

results and analysis

The relationship between the depth of cut obtained by the test and the cutting force is shown in Fig. 4. As can be seen from the figure, the cutting force is quite sensitive to changes in depth of cut. When the depth of cut a p <0.3mm, the vibration cutting force is only 1/3 of the ordinary cutting force; when the depth of cut reaches 0.5mm, the vibration cutting force and the ordinary cutting force gradually approach, indicating that the tool depth increases with the depth of cut The cutting load per unit area increases, the tool amplitude decreases, and the pulse cutting effect of the vibration cutting is weakened, so that the average cutting force during vibration cutting increases.

A comprehensive analysis of the single-factor relationship between cutting force and cutting parameters during normal cutting and ultrasonic vibration cutting shows that:

Compared with ordinary turning, the average main cutting force F c of ultrasonic vibration turning is significantly reduced. The reduction in F c is particularly significant at smaller cutting applications.

Under the condition of ultrasonic vibration turning, the cutting force increases steadily with the increase of the cutting amount. The cutting force of ultrasonic vibration turning—the cutting speed characteristic is significantly different from the cutting force-cutting speed characteristic exhibited by the influence of built-up edge during normal cutting. Microscopic observations show that ultrasonic vibration turning does not produce built-up edge in the corresponding cutting speed range.

When the cutting speed v is greater than the critical cutting speed, ultrasonic vibration turning still has the above characteristics; when v increases to a certain value, the increase of the cutting force tends to be gentle.

4 Multi-factor orthogonal test and analysis of cutting force and cutting parameters during vibration cutting
Table 4 Test factor level table
Test factor Speed ​​(m/min) Feed rate (mm/r) Cutting depth (mm)
Level 1 4.24 0.08 0.10
Level 2 8.48 0.10 0.30
Level 3 12.72 0.15 0.50
Multi-factor orthogonal test scheme

The orthogonal test of cutting force for ultrasonic vibration turning of SiC p /Al metal matrix composites was carried out. The relationship between cutting force and cutting parameters was discussed by regression orthogonal analysis, and the most suitable vibration cutting parameters were selected. The rotational speed, feed rate and depth of cut are the three most important and essentially independent parameters in the turning process. Therefore, the above three parameters are selected as orthogonal test factors. Using the L 9 (2 3 ) orthogonal table as a three-factor, three-level orthogonal test (regardless of interaction), the test factor level table shown in Table 4 was established.

Test results and analysis

According to the cutting conditions listed in Table 4, using the L 9 (2 3 ) orthogonal table, the cutting force test data shown in Table 5 can be obtained.

Table 5 Cutting force test data
Test number Rotating speed
(m/min) 		Feed rate
(mm/r) 		Cut depth
(mm) 		Radial cutting force
(N) 		Main cutting force
(N)
1 4.24 0.08 0.10 4.18 2.58
2 4.24 0.10 0.30 10.30 7.03
3 4.24 0.15 0.50 24.30 36.14
4 8.48 0.08 0.30 13.76 8.14
5 8.48 0.10 0.50 23.00 30.00
6 8.48 0.15 0.10 10.18 3.12
7 12.72 0.08 0.50 27.47 33.30
8 12.72 0.10 0.10 6.29 4.00
9 12.72 0.15 0.30 10.56 8.00
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