Tool Face Temperatures in High Speed Milling

1990 ◽  
Vol 112 (2) ◽  
pp. 132-135 ◽  
Author(s):  
P. Lezanski ◽  
M. C. Shaw

While it is now generally understood that in continuous chip forming processes such as turning, there is no magic high speed above which tool temperature decreases and tool life increases with increased cutting speed. However, it has been suggested that this may not be the case in intermittent cutting operations such as face milling. It is argued that in such an operation, the tool temperature oscillates between an ambient value at the beginning of a cut and a maximum value at the end of a cut. As cutting speed is increased, the cutting time per cut will decrease and hence the fractional approach to the equilibrium value. Thus, even though the equilibrium temperature will increase with cutting speed, it is conceivable that the maximum temperature at the end of a cut will decrease. This possibility has been tested experimentally using the chip-tool thermocouple technique to record temperature vs time curves for a variety of cutting conditions. In no case was the exit temperature found to decrease with increase in cutting speed.

2015 ◽  
Vol 656-657 ◽  
pp. 237-242
Author(s):  
Kenji Yamaguchi ◽  
Tsuyoshi Fujita ◽  
Yasuo Kondo ◽  
Satoshi Sakamoto ◽  
Mitsugu Yamaguchi ◽  
...  

It is well known that a series of cracks running perpendicular to the cutting edge are sometimes formed on the rake face of brittle cutting tools during intermittent cutting. The cutting tool is exposed to elevated temperatures during the periods of cutting and is cooled quickly during noncutting times. It has been suggested that repeated thermal shocks to the tool during intermittent cutting generate thermal fatigue and result in the observed thermal cracks. Recently, a high speed machining technique has attracted attention. The tool temperature during the period of cutting corresponds to the cutting speed. In addition, the cooling and lubricating conditions affect the tool temperature during noncutting times. The thermal shock applied to the tool increases with increasing cutting speed and cooling conditions. Therefore, to achieve high-speed cutting, the evaluation of the thermal shock and thermal crack resistance of the cutting tool is important. In this study, as a basis for improving the thermal shock resistance of brittle cutting tools during high-speed intermittent cutting from the viewpoint of cutting conditions, we focused on the cooling conditions of the cutting operation. An experimental study was conducted to examine the effects of noncutting time on thermal crack initiation. Thermal crack initiation was found to be restrained by reducing the noncutting time. In the turning experiments, when the noncutting time was less than 10 ms, thermal crack initiation was remarkably decreased even for a cutting speed of 500 m/min. In the milling operation, the number of cutting cycles before thermal crack initiation decreased with increasing cutting speed under conditions where the cutting speed was less than 500 m/min. However, when the cutting speed was greater than 600 m/min, thermal crack initiation was restrained. We applied the minimal quantity lubrication (MQL) coolant supply to the intermittent cutting operation. The experimental results showed that the MQL diminished tool wear compared with that under the dry cutting condition and inhibited thermal crack initiation compared with that under the wet cutting condition.


2014 ◽  
Vol 1017 ◽  
pp. 747-752
Author(s):  
Hiromi Isobe ◽  
Keisuke Hara

This paper reports the stress distribution inside the workpiece under ultrasonic vibration cutting (UVC) condition. Many researchers have reported the improvement of tool wear, burr generation and surface integrity by reduction of time-averaged cutting force under UVC condition. However general dynamometers have an insufficient frequency band to observe the processing phenomena caused by UVC. In this paper, stress distribution inside the workpiece during UVC was observed by combining the flash light emission synchronized with ultrasonically vibrating cutting tool and the photoelastic method. Instantaneous stress distribution during UVC condition was observed. Because UVC induced an intermittent cutting condition, the stress distribution changed periodically and disappeared when the tool leaved from the workpiece. It was found that instantaneous maximum cutting force during UVC condition was smaller than quasi-static cutting force during conventional cutting when the cutting speed was less than 500 mm/min.


2008 ◽  
Vol 392-394 ◽  
pp. 793-797
Author(s):  
Bin Jiang ◽  
Min Li Zheng ◽  
Fang Xu

Based on analyses of cutting heat and temperature in high speed milling, to construct a model of critical cutting speed for high speed milling cutter, find out influencing factor of critical cutting speed, and put forward optimization method of high speed milling cutter based on critical cutting speed. The results indicate that chip conducts a majority of cutting heat along with increase of cutting speed, feed speed and the rake of cutter. Cutting heat which workpiece conducts gradually diminishes when heat source accelerates. When cutting performance of cutter satisfies requirements of high speed milling, the proportion of cutting heat which workpiece conducts approaches its maximum as cutting speed comes to critical cutting speed. To optimize high speed face milling cutter for machining aluminum alloy according to critical cutting speed, the cutter takes on better cutting performance when cutting speed is 2040m/min~2350m/min.


2011 ◽  
Vol 117-119 ◽  
pp. 594-597 ◽  
Author(s):  
Mu Lan Wang ◽  
Yong Feng ◽  
Xiao Xia Li ◽  
Bao Sheng Wang

An experimental system used for temperature measurement is designed by the K-type thermocouple thermometry to achieve a direct measurement of cutting temperature in high speed orthogonal turning. The general regularity of temperature distribution is concluded, and the corresponding influences of cutting speed and cutting depth on the maximum temperature value are discussed in detail. Experimental data and simulating results are comparative analyzed to demonstrate the feasibility and correctness of Finite Element Method (FEM) model simulation and analytical solution. The verified model of temperature field can be applied to develop an effective non-contact soft-sensing method for high speed cutting temperature.


2004 ◽  
Vol 126 (6) ◽  
pp. 931-936 ◽  
Author(s):  
N. Ranc ◽  
V. Pina ◽  
G. Sutter ◽  
S. Philippon

The working processes of metallic materials at high strain rate like forging, stamping and machining often induce high temperatures that are difficult to quantify precisely. In this work we, developed a high-speed broad band visible pyrometer using an intensified CCD camera (spectral range: 0.4 μm–0.9 μm). The advantage of the visible pyrometry technique is to limit the temperature error due to the uncertainties on the emissivity value and to have a good spatial resolution (3.6 μm) and a large observation area. This pyrometer was validated in the case of high speed machining and more precisely in the orthogonal cutting of a low carbon steel XC18. The cutting speed varies between 22 ms−1 and 60 ms−1. The experimental device allows one to visualize the evolution of the temperature field in the chip according to the cutting speed. The maximum temperature in the chip can reach 730°C and minimal temperature which can be detected is around 550°C.


Author(s):  
M. Salahshoor ◽  
Y. B. Guo

Biodegradable magnesium-calcium (Mg-Ca) implants have the ability to gradually dissolve and absorb into the human body after implantation. The critical issue that hinders the application of Mg-Ca implants is its poor corrosion resistance to human body fluids. A promising approach to tackle this issue is tailoring the surface integrity characteristics of the orthopedic implants to get an appropriate corrosion kinetic. High speed face milling of biodegradable Mg-Ca alloy is used in this study as a possible way to achieve that goal. Polycrystalline diamond inserts are used to avoid material adhesion and likely fire hazards. All the cutting tests are performed without using coolant to keep the manufacturing process ecological. High cutting speed of 40 m/s and 200 μm depth of cut are applied in a broad range of feed values to cover finish and rough cutting regimes. The effect of feed as a key machining parameter which defines the amount and duration of thermo-mechanical load and ultimately provides higher chances for surface integrity changes are investigated.


Author(s):  
Nhu-Tung Nguyen ◽  
Dung Hoang Tien ◽  
Nguyen Tien Tung ◽  
Nguyen Duc Luan

In this study, the influence of cutting parameters and machining time on the tool wear and surface roughness was investigated in high-speed milling process of Al6061 using face carbide inserts. Taguchi experimental matrix (L9) was chosen to design and conduct the experimental research with three input parameters (feed rate, cutting speed, and axial depth of cut). Tool wear (VB) and surface roughness (Ra) after different machining strokes (after 10, 30, and 50 machining strokes) were selected as the output parameters. In almost cases of high-speed face milling process, the most significant factor that influenced on the tool wear was cutting speed (84.94 % after 10 machining strokes, 52.13 % after 30 machining strokes, and 68.58 % after 50 machining strokes), and the most significant factors that influenced on the surface roughness were depth of cut and feed rate (70.54 % after 10 machining strokes, 43.28 % after 30 machining strokes, and 30.97 % after 50 machining strokes for depth of cut. And 22.01 % after 10 machining strokes, 44.39 % after 30 machining strokes, and 66.58 % after 50 machining strokes for feed rate). Linear regression was the most suitable regression of VB and Ra with the determination coefficients (R2) from 88.00 % to 91.99 % for VB, and from 90.24 % to 96.84 % for Ra. These regression models were successfully verified by comparison between predicted and measured results of VB and Ra. Besides, the relationship of VB, Ra, and different machining strokes was also investigated and evaluated. Tool wear, surface roughness models, and their relationship that were found in this study can be used to improve the surface quality and reduce the tool wear in the high-speed face milling of aluminum alloy Al6061


2005 ◽  
Vol 128 (2) ◽  
pp. 606-610 ◽  
Author(s):  
Rachid M’Saoubi ◽  
Hariharan Chandrasekaran

Cutting tool temperature distribution was mapped using the infrared-charge-coupled device technique during machining of carbon steel SS2511 (∼AISI 3115) and stainless steel AISI 316L under oblique cutting conditions with chip breaker geometry inserts. Results indicated that the temperature on the rake surface was not uniform. Local maximum temperature points are present on the tool face at different locations, i.e., land, groove, backwall, and at the end of tool chip contact. Further investigation of the effect of cutting parameters on the tool temperature indicated that a suitable combination of cutting speed and feed resulted in a lower tool temperature for conditions of comparable material removal rate.


2008 ◽  
Vol 375-376 ◽  
pp. 663-666
Author(s):  
Min Li Zheng ◽  
Bin Jiang ◽  
Jia Liu ◽  
Chong Yu He

According to the characteristics of high speed face milling process, the models of dynamic cutting forces and frequency spectrum were established. By means of frequency spectrum analysis for dynamic cutting forces of high speed face milling cutter, the law of influence of cutter’s structure and parameters on dynamic cutting performance of cutter was acquired, high speed face milling cutter for machining aluminum alloy was developed, and evaluation for dynamic cutting performance of cutter was processed based on experiment. The results indicate that more teeth of cutter and greater cutting contact angle can make the energy more dispersible, higher cutting speed and greater rake of cutter can depress dynamic cutting forces, and improve effectively dynamic cutting performance of cutter. High speed face milling cutter with five teeth takes on better dynamic high speed cutting performance for machining aluminum alloy, as cutting contact angle exceeds ninety degrees but it is less than one hundred eighty degrees, and cutting speed exceeds 2260m/min.


2008 ◽  
Vol 375-376 ◽  
pp. 593-597
Author(s):  
Bin Jiang ◽  
Min Li Zheng ◽  
Fang Xu ◽  
Ya Guang Li

Based on loads analysis and failure analysis for high speed face milling cutter with indexable inserts, the failure criterion of cutter was propounded, and the finite element model of cutter was established. By means of modal analysis and stress field analysis, the law of influence of the structure and elements of cutter on the safety of cutter was acquired, high speed face milling cutter for machining aluminum alloy was developed. According to ISO15641 international standard, safety prediction of cutter and experiments were completed. The results indicate that rigidity failure rotational speed is higher strength failure rotational speed of high speed face milling cutter, connection strength between cutter body and screw bolt affects directly the safety rotational speed of cutter. High speed face milling cutter for machining aluminum alloy possesses higher safety and better dynamic milling performance as cutting speed is less than 2820m/min.


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