Sensorless Monitoring of Cutting Force Variation With Fractured Tool Under Heavy Cutting Condition

2016 ◽  
Author(s):  
Yuki Yamada ◽  
Yasuhiro Kakinuma ◽  
Takamichi Ito ◽  
Jun Fujita ◽  
Hirohiko Matsuzaki
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Moving Average ◽  
Cutting Condition ◽  
Force Estimation ◽  
Signal Processing Technique ◽  
Tool Condition ◽  
Force Variation ◽  
Monitoring Performance ◽  
Peak Value

Cutting force is widely regarded as being the one of the most valuable information for tool condition monitoring. Considering sustainability, sensorless cutting force monitoring technique using inner information of machine tool attracts attention. Cutting force estimation based on motor current is one of the example, and it is applicable to detection of tool breakage with some signal processing technique. However, current signal could not capture fast variation of cutting force. By improving monitoring performance of cutting force, the hidden tool condition information is more accessible. In this study, monitoring performance of cutting force variation due to tool fracture was enhanced by using multi-encoder-based disturbance observer (MEDOB) and simple moving average. Friction force and torque which deteriorate monitoring performance was eliminated by moving average. First, monitoring accuracy of cutting force was verified through end milling test. Next, local peak value of estimated cutting force was extracted and the ratio of neighboring peak value was calculated to capture the tool fracture. Estimated value using MEDOB could capture the variation resulting from tool fracture.

Precise Cutting Force Estimation by Hybrid Estimation of DC/AC Components

2020 ◽  
Author(s):  
Taiki Sato ◽  
Shuntaro Yamato ◽  
Yasuhiro Imabeppu ◽  
Naruhiro Irino ◽  
Yasuhiro Kakinuma
Keyword(s):  
Cutting Force ◽  
Thrust Force ◽  
End Milling ◽  
Moving Average ◽  
Low Frequency ◽  
Friction Model ◽  
Ball Screw ◽  
Estimation Accuracy ◽  
Force Estimation ◽  
Feed Direction

Abstract External sensor-less cutting force estimation using a load-side disturbance observer (LDOB) has potential to estimate the cutting force with high accuracy in both feed and cross-feed directions. However, the accuracy of its low frequency components in feed direction decrease due to effect of the friction and heat of a ball-screw-driven stage. In this study, DC and AC components of the cutting force is estimated by different methods; friction-compensated motor thrust force and LDOB, and the cutting force was estimated in real time by hybridizing them. In particular, regarding the friction model, the dynamic and static characteristics of the friction force in each axis (X, Y, Z) were identified from the idling test results. In addition to the model that depends on the velocity, the characteristics of the friction that depend on the position was also identified and considered when compensating for the motor thrust force. Then, a simple moving average filter with an appropriate window length is applied to the cutting force by LDOB and motor thrust force, and the DC component error of LDOB is corrected by that of motor thrust force. The validity of the proposed method was evaluated through end-milling tests. The experimental results showed that estimation accuracy of cutting force using the proposed method can be greatly improved in feed directions. On the other hand, in cross-feed direction, the cutting estimation was performed using the conventional LDOB.

Monitoring of Cutting State in End-Milling Based on Measurement of Tool Behavior Using CCD Image

2019 ◽  
Vol 13 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Shinichi Yoshimitsu ◽  
◽  
Daiki Iwashita ◽  
Kenji Shimana ◽  
Yuya Kobaru ◽  
...  
Keyword(s):  
Cutting Force ◽  
Process Monitoring ◽  
High Speed ◽  
End Milling ◽  
Small Diameter ◽  
Ccd Camera ◽  
Cutting Conditions ◽  
Cutting Condition ◽  
Tool Deflection ◽  
Spindle Power

To date, various in-process monitoring and measuring techniques for milling have been proposed; these are based on factors such as spindle power, cutting force, and vibration. However, the spindle power and cutting force in small-diameter milling processes are too small, thereby rendering these methods ineffective. This study aims to develop an in-process monitoring system of the cutting state, and thus, prevent tool breakage in milling when using a small-diameter tool. Our previous study showed that this monitoring technique is based on the analysis of the tool projection image by a CCD camera. It enables a precise measurement of tool deflection during high-speed milling. In this study, we apply this system to the measurement of tool deflection in end milling under different cutting conditions, including tool type, machining shape, workpiece, and feed rate. Moreover, we examine the relationship between tool deflection and cutting conditions. The results clarify that this system enables in-process monitoring of tool deflection. The measured tool deflection with this system is influenced by the cutting condition. In addition, the tool deflection shows a periodical change in one turn, which seems to be related to the number of tool edges.

Interrelationships between cutting force variation and tool wear in end-milling

2001 ◽  
Vol 109 (3) ◽  
pp. 229-235 ◽  
Author(s):  
A Sarhan ◽  
R Sayed ◽  
A.A Nassr ◽  
R.M El-Zahry
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
End Milling ◽  
Force Variation

The Importance of Including Size Effect When Modeling Slot Milling

1998 ◽  
Vol 120 (1) ◽  
pp. 68-75 ◽  
Author(s):  
S. N. Melkote ◽  
W. J. Endres
Keyword(s):  
Size Effect ◽  
Cutting Force ◽  
End Milling ◽  
Helix Angle ◽  
Milling Process ◽  
Depth Of Cut ◽  
Slot Milling ◽  
Milling Operations ◽  
Force Variation ◽  
Axial Depth

This paper presents a detailed mechanistic force analysis that includes size effect for slot milling operations. Existing studies of the milling process have modeled the slot end milling operation as a simple geometric extension of peripheral end milling models with constant values for the specific energies used to predict forces for a given cutter geometry and cutting conditions. This paper addresses the limitations of this approach for accurate predictions of the instantaneous cutting force variation, particularly for steady-state slotting with four-flute cutters. It is shown through a comparison of model simulations and experimental results that significantly improved predictions of the cutting force variation are obtained by properly accounting for the size effect in slotting. The dependence of the cutting force variation on axial depth of cut and helix angle is demonstrated. Practical implications of selecting helix angle and axial depth of cut based on the improved slot end milling model are also discussed. Modeling approaches other than the mechanistic approach considered here are also noted in this light.

Monitoring and Prediction of Surface Roughness in Ball End Milling with Air Blow Application

2012 ◽  
Vol 538-541 ◽  
pp. 1332-1337 ◽  
Author(s):  
Somkiat Tangjitsitcharoen ◽  
Suthas Ratanakuakangwan
Keyword(s):  
Surface Roughness ◽  
Regression Analysis ◽  
Cutting Force ◽  
Multiple Regression Analysis ◽  
Prediction Accuracy ◽  
Prediction Interval ◽  
End Milling ◽  
Cutting Condition ◽  
Ball End Milling ◽  
Roughness Model

This paper presents the additional work of the previous research in order to investigate the relations of the cutting conditions and the various air blow applications which affect the surface roughness. The suitable cutting condition is determined for the aluminum (Al6063) with the ball end milling by utilizing the response surface analysis referring to the minimum surface roughness. The cutting force is monitored during the cutting to analyze the surface roughness. The dynamometer is employed and installed on the table of 5-axis CNC maching center to measure the in-process cutting force. The models of surface roughness and cutting force are calculated by using the multiple regression analysis with the least squared method at 95% significant level. The experimentally obtained results showed that the surface roughness can be well explained by the in-process cutting force. The prediction accuracy and the prediction interval have been presented to verify the obtained surface roughness model at 95% confident level.

Surface Roughness Prediction in Ball-End Milling Process for Aluminum by Using Air Blow Cutting

2011 ◽  
Vol 418-420 ◽  
pp. 1428-1434 ◽  
Author(s):  
Keerati Karunasawat ◽  
Somkiat Tangjitsitcharoen
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
End Milling ◽  
Cutting Speed ◽  
Milling Process ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Ball End Milling ◽  
Tool Diameter ◽  
End Milling Process

The objective of this research is to develop the surface roughness and cutting force models by using the air blow cutting of the aluminum in the ball-end milling process. The air blow cutting proposed in order to reduce the use of the cutting fluid. The surface roughness and cuttting force models are proposed in the exponential forms which consist of the cutting speed, the feed rate, the depth of cut, the tool diameter, and the air blow pressure. The coefficients of the surface roughness and cutting force models are calculated by utilizing the multiple regression with the least squared method at 95% significant level. The effects of cutting parameters on the cutting force are investigated and measured to analyze the relation between the surface roughness and the cutting conditions. The experimentally obtained results showed that the cutting force has the same trend with the surface roughness. The surface plots are constructed to determine the optimum cutting condition referring to the minimum surface roughness.

Investigation of Dry Cutting and Applications of Cutting Fluid in Ball-End Milling Process

2011 ◽  
Vol 291-294 ◽  
pp. 3013-3023 ◽  
Author(s):  
Somkiat Tangjitsitcharoen ◽  
Channarong Rungruang
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
End Milling ◽  
Cutting Parameters ◽  
Milling Process ◽  
Cutting Fluid ◽  
Cutting Condition ◽  
Dry Cutting ◽  
Ball End Milling ◽  
End Milling Process

In order to realize the environmental hazard, this paper presents the investigation of the machinability of ball-end milling process with the dry cutting, the wet cutting, and the mist cutting for aluminum. The relations of the surface roughness, the cutting force, and the cutting parameters are examined based on the experimental results by using the Response Surface Analysis with the Box-Behnken design. The in-process cutting force is monitored to analyze the relations of the surface roughness and the cutting parameters. The proper cutting condition can be determined easily referring to the minimum use of cutting fluid, and the minimum surface roughness and cutting force of the surface plot. The effectiveness of the obtained surface roughness and cutting force models have been proved by utilizing the analysis of variance at 95% confident level.

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