An HDP-HMM based approach for tool wear estimation and tool life prediction

2020 ◽  
pp. 1-13
Author(s):  
Danyang Han ◽  
Jinsong Yu ◽  
Diyin Tang
2018 ◽  
Vol 1 (4) ◽  
pp. 218-225 ◽  
Author(s):  
Amin Dadgari ◽  
Dehong Huo ◽  
David Swailes

Author(s):  
D D Zhang

Accurate prediction of tool life is essential to guarantee surface quality and economics of cutting operations in face milling. This article presents a procedure for tool life prediction through in-process adaptation of tool wear rate based on indirect measures. The procedure effectively accounts for the uncertainty of tool wear progress owing to the complexity of the machining process. First, sensor fusion of spindle motor current AC and DC portions is taken to estimate the actual tool wear through relevance vector machine. Then, a tool life prediction model relating flank wear with cutting time is proposed for tracking the progress of tool wear under certain cutting settings. Further, a recursive least square algorithm is developed to update the parameters of the tool life prediction model by considering the error between the predicted tool wear and the estimated tool wear. Finally, the updated model capturing the uncertainty of tool wear progress is used to predict tool life in face milling. Tool life experiments validate that the adaptive procedure can quickly track the progress of tool wear, and make more accurate prediction of tool life compared with the procedure with constant model parameters.


2020 ◽  
Author(s):  
Qilin Xiang ◽  
Aibo Xu ◽  
Ling Yuan ◽  
Xiang Hu ◽  
Liwei Luo ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5011
Author(s):  
Cécile Escaich ◽  
Zhongde Shi ◽  
Luc Baron ◽  
Marek Balazinski

The TiC particles in titanium metal matrix composites (TiMMCs) make them difficult to machine. As a specific MMC, it is legitimate to wonder if the cutting mechanisms of TiMMCs are the same as or similar to those of MMCs. For this purpose, the tool wear mechanisms for turning, milling, and grinding are reviewed in this paper and compared with those for other MMCs. In addition, the chip formation and morphology, the material removal mechanism and surface quality are discussed for the different machining processes and examined thoroughly. Comparisons of the machining mechanisms between the TiMMCs and MMCs indicate that the findings for other MMCs should not be taken for granted for TiMMCs for the machining processes reviewed. The increase in cutting speed leads to a decrease in roughness value during grinding and an increase of the tool life during turning. Unconventional machining such as laser-assisted turning is effective to increase tool life. Under certain conditions, a “wear shield” was observed during the early stages of tool wear during turning, thereby increasing tool life considerably. The studies carried out on milling showed that the cutting parameters affecting surface roughness and tool wear are dependent on the tool material. The high temperatures and high shears that occur during machining lead to microstructural changes in the workpiece during grinding, and in the chips during turning. The adiabatic shear band (ASB) of the chips is the seat of the sub-grains’ formation. Finally, the cutting speed and lubrication influenced dust emission during turning but more studies are needed to validate this finding. For the milling or grinding, there are major areas to be considered for thoroughly understanding the machining behavior of TiMMCs (tool wear mechanisms, chip formation, dust emission, etc.).


Author(s):  
Andres F. Clarens ◽  
Ye-Eun Park ◽  
Jacob Temme ◽  
Kim Hayes ◽  
Fu Zhao ◽  
...  

Carbon Dioxide is an industrial byproduct that has been proposed as an alternative metalworking fluid (MWF) carrier with lower environmental impacts and better cooling potential than existing MWFs. This paper investigates the heat removal and tool life effects of rapidly expanding supercritical CO2 (scCO2)-based MWFs relative to MWFs delivered as a flood of semi-synthetic emulsion or as minimum quantity lubrication (MQL) sprays. When cutting both compacted graphite iron (CGI) and titanium, tool wear was most effectively controlled using the scCO2-based MWF compared with the other MWFs. Analysis in this paper suggests that the performance benefit imparted by rapidly expanding scCO2 appears to be related to both the cooling potential and penetration of the sprays into the cutting zone. High-pressure gas sprays have lower viscosity and higher velocity than conventional MWFs. An experiment in which the spray direction was varied clearly demonstrated the importance of spray penetration in tool wear suppression. The type of gas spray is also a significant factor in tool wear suppression. For instance, a spray of N2 delivered under similar conditions to CO2 effectively reduced tool wear relative to water based fluids, but not as much as CO2. This result is particularly relevant for MQL sprays which are shown to not cool nearly as effectively as scCO2 MWFs. These results inform development of scCO2-based MWFs in other machining operations, and provide insight into the optimization of scCO2 MWF delivery.


2013 ◽  
Vol 554-557 ◽  
pp. 1961-1966 ◽  
Author(s):  
Yessine Ayed ◽  
Guenael Germain ◽  
Amine Ammar ◽  
Benoit Furet

Titanium alloys are known for their excellent mechanical properties, especially at high temperature. But this specificity of titanium alloys can cause high cutting forces as well as a significant release of heat that may entail a rapid wear of the cutting tool. To cope with these problems, research has been taken in several directions. One of these is the development of assistances for machining. In this study, we investigate the high pressure coolant assisted machining of titanium alloy Ti17. High pressure coolant consists of projecting a jet of water between the rake face of the tool and the chip. The efficiency of the process depends on the choice of the operating parameters of machining and the parameters of the water jet such as its pressure and its diameter. The use of this type of assistance improves chip breaking and increases tool life. Indeed, the machining of titanium alloys is generally accompanied by rapid wear of cutting tools, especially in rough machining. The work done focuses on the wear of uncoated tungsten carbide tools during machining of Ti17. Rough and finish machining in conventional and in high pressure coolant assistance conditions were tested. Different techniques were used in order to explain the mechanisms of wear. These tests are accompanied by measurement of cutting forces, surface roughness and tool wear. The Energy-dispersive X-ray spectroscopy (EDS) analysis technique made it possible to draw the distribution maps of alloying elements on the tool rake face. An area of material deposition on the rake face, characterized by a high concentration of titanium, was noticed. The width of this area and the concentration of titanium decreases in proportion with the increasing pressure of the coolant. The study showed that the wear mechanisms with and without high pressure coolant assistance are different. In fact, in the condition of conventional machining, temperature in the cutting zone becomes very high and, with lack of lubrication, the cutting edge deforms plastically and eventually collapses quickly. By contrast, in high pressure coolant assisted machining, this problem disappears and flank wear (VB) is stabilized at high pressure. The sudden rupture of the cutting edge observed under these conditions is due to the propagation of a notch and to the crater wear that appears at high pressure. Moreover, in rough condition, high pressure assistance made it possible to increase tool life by up to 400%.


2018 ◽  
Author(s):  
Kai Guo ◽  
Bin Yang ◽  
Jie Sun ◽  
Vinothkumar Sivalingam

Titanium alloys are widely utilized in aerospace thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is thus of great importance to understand and quantitatively predict tool life. In this study, the wear of coated carbide tool in milling Ti-6Al-4V alloy was assessed by characterization of the worn tool cutting edge. Furthermore, a tool wear model for end milling cutter is established with considering the joint effect of cutting speed and feed rate for characterizing tool wear process and predicting tool wear. Based on the proposed tool wear model equivalent tool life is put forward to evaluate cutting tool life under different cutting conditions. The modelling process of tool wear is given and discussed according to the specific conditions. Experimental work and validation are performed for coated carbide tool milling Ti-6Al-4V alloy.


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