scholarly journals Failure and Control of PCBN Tools in the Process of Milling Hardened Steel

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 885
Author(s):  
Guangyue Wang ◽  
Xianliang Zhou ◽  
Xuefeng Wu ◽  
Jing Ma

The polycrystalline cubic boron nitride (PCBN) milling tool can be used in the mold industry to replace cemented carbide tools to improve machining efficiency and quality. It is necessary to study the tool wear and failure mechanism to increase machining efficiency and extend tool life. Cr12MoV is used to analyze the failure form of PCBN tools in the interrupted cutting of hardened steels at low and high speed conditions in milling experiments. Experimental results show that the failure forms of PCBN tools include chipping and flank wear at low speed, and the failure modes at high speed are flank wear, the surface spalling of the rake face, and the fatigue failure on the flank face. The failure mechanism of different failure forms is analyzed by observing the surface morphology of the tool and using the theory of fracture mechanics. The results show that a high cutting speed should be selected to avoid the early damage of low speed and achieve better application of PCBN tools. At high cutting speed, tool failure is mainly caused by mechanical wear, diffusion wear, and oxidation wear. Moreover, a fatigue crack will occur at the cutting edge on the chamfered tool under thermal–mechanical coupling because of the intergranular fracture of the CBN grain and binder. A large area of accumulated fatigue damage may appear due to the influence of alternating mechanical stress and thermal stress. Finally, the control method to avoid tool failure is presented.

2018 ◽  
Vol 16 (2) ◽  
pp. 51
Author(s):  
Sunarto Sunarto ◽  
Sri Mawarni

AbstrakPemesinan laju tinggi yang diindikasikan dengan kecepatan potong tinggi pada proses pembubutan keadaan kering menjadi bahasan utama pada penelitian ini. Kecepatan potong (Vc) merupakan salah satu penyebab meningkatnya temperatur pemotongan dan akan mempengaruhi daya tahan alat potong. Akibat temperatur pemotongan yang tinggi pahat akan mengalami kerusakan salah satunya berupa Aus Sisi (VB). VB akan tumbuh secara terus menerus seiring dengan waktu pemotongan. Tujuan penelitian ini adalah untuk mengetahui pengaruh pemesinan laju tinggi terhadap laju pertumbuhan VB selama proses pembubutan paduan Aluminium 6061. Metode yang digunakan dalam penelitian ini adalah dengan menggunakan pahat karbida (Wc+Co) yang dilapisi dengan bahan pelapis Titanium Aluminium Nitrida dan Titanium Nitrida (TiAlN/TiN) menggunakan mesin bubut CNC serta membagi tiga kondisi pemotongan yaitu pada kecepatan potong 800 m/menit, 1000 m/menit dan 1200 m/menit. Hasil yang dicapai dari kondisi pemotongan tersebut adalah pada kecepatan potong 1200 m/menit menghasilkan ukuran VB yang lebih besar jika dibandingkan dengan kecepaatan potong 800 m/menit dan 1000 m/menit dengan waktu pemotongan masing-masing selama enam menit.Kata Kunci: Kecepatan Potong (Vc), Aus Sisi (VB), Alat PotongAbstractHigh speed machining which is indicated by high cutting speed in the dry lathe process becomes the main discussion in this study. The cutting speed (Vc) is one of the causes of increasing the cutting temperature and will affect the durability of the cutting tool. Due to high cutting temperature the cutting tool will suffer damage one of them is Flank Wear (VB). VB will grow continuously along with the cutting time. The purpose of this research is to know the effect of high speed machining to growth rate of VB during the process of Aluminum 6061 alloy. The method used in this research is by using  cutting tool (Wc + Co) coated with Titanium Aluminum Nitride and Titanium Nitride coating materials (TiAlN / TiN) using CNC lathe and dividing the three cutting conditions ie at cutting speed of 800 m / min, 1000 m / min and 1200 m / min. The result of the cutting condition is at a cutting speed of 1200 m / min resulting in a larger VB size when compared to 800 m / min cutting speed and 1000 m / min with each cutting time of six minutes.Keywords: Cutting Speed (Vc), Flank Wear (VB), Cutting Tool


2021 ◽  
Vol 5 (2) ◽  
pp. 34
Author(s):  
Guangxian Li ◽  
Ge Wu ◽  
Wencheng Pan ◽  
Rizwan Abdul Rahman Rashid ◽  
Suresh Palanisamy ◽  
...  

Polycrystalline diamond (PCD) tools are widely used in industry due to their outstanding physical properties. However, the ultra-high hardness of PCD significantly limits the machining efficiency of conventional abrasive grinding processes, which are utilized to manufacture PCD tools. In contrast, electrical discharge grinding (EDG) has significantly higher machining efficiency because of its unique material removal mechanism. In this study, the quality and performance of PCD tools machined by abrasive grinding and EDG were investigated. The performance of cutting tools consisted of different PCD materials was tested by high-speed turning of titanium alloy Ti6Al4V. Flank wear and crater wear were investigated by analyzing the worn profile, micro morphology, chemical decomposition, and cutting forces. The results showed that an adhesive-abrasive process dominated the processes of flank wear and crater wear. Tool material loss in the wear process was caused by the development of thermal cracks. The development of PCD tools’ wear made of small-sized diamond grains was a steady adhesion-abrasion process without any catastrophic damage. In contrast, a large-scale fracture happened in the wear process of PCD tools made of large-sized diamond grains. Adhesive wear was more severe on the PCD tools machined by EDG.


Author(s):  
Muataz Al Hazza ◽  
Khadijah Muhammad

High speed machining has many advantages in reducing time to the market by increasing the material removal rate. However, final surface quality is one of the main challenges for manufacturers in high speed machining due to the increasing of flank wear rate. In high speed machining, the cutting zone is under high pressure associated with high temperature that lead to increasing of the flank wear rate in which affect the final quality of the machined surface. Therefore, one of the main concerns to the manufacturer is to predict the flank wear to estimate and predict the surface roughness as one of the main outputs of the machining processes. The aim of this study is to determine experimentally the optimum cutting parameters: depth of cut, cutting speed (Vc) and feed rate (f) that maintaining low flank wear (Vb). Taguchi method has been applied in this experiment. The Taguchi method has been universally used in engineering analysis.  JMP statistical analysis software is used to analyse statically the development of flank wear rate during high speed milling of hardened steel AISI D2 to 60 HRD. The experiment was conducted in the following boundaries: cutting speed 200-400 m/min, feed rate of 0.01-0.05 mm/tooth and depth of cut of 0.1-0.2 mm. Analysis of variance ANOVA was conducted as one of important tool for statistical analysis. The result showed that cutting speed is the most influential input factors with 70.04% contribution on flank wear.


2014 ◽  
Vol 941-944 ◽  
pp. 1917-1921
Author(s):  
Qi Fen Zhou ◽  
Peng Zhou ◽  
Hai Ying Zhang

In this paper, the oxide nanometer composite cutting performance of ceramic tools cutting cast iron were studied. And the tool failure modes were mainly analyzed. Through the study found that, with the increase of tool wear with cutting speed, failure forms mainly adhesion wear. When the cutting speed is low, the knife before the crater wear become the main form of ceramic cutting tool wear, boundary wear and the surface of the knife after wear is also very serious. And in the process of cutting, the collapse edge can also occur now; With the increase of cutting speed, collapse become the main failure forms of cutter blade.


2010 ◽  
Vol 447-448 ◽  
pp. 806-810 ◽  
Author(s):  
Hiromasa Yamamoto ◽  
Kentaro Satake ◽  
Hiroyuki Sasahara ◽  
Toru Narita ◽  
Masaomi Tsutsumi ◽  
...  

In rotary cutting difficult-to-cut materials, less tool wear is observed at higher cutting speeds, contrary to the case of conventional single-point turning. In order to examine this characteristic feature of rotary cutting, this study focuses on the effects of cutting speed and tool peripheral speed on tool failure. Dry rotary cutting tests of stainless steel SUS304 were carried out using coated carbide tools. Cutting speeds were set at 100 m/min, the speed typically recommended for conventional turning, and 500 m/min. At 100 m/min, adhesions and subsequent chippings were observed on the cutting edges. Meanwhile, at 500 m/min the higher average temperature at the tool-workpiece contact area caused small wear spots, rather than adhesions at the optimized tool speed. Hence, for rotary cutting, a higher cutting speed is more effective in terms of both achieving several-times-higher productivity and reducing the amount of tool failure due to the difference of tool failure modes.


Author(s):  
Shoujin Sun ◽  
Milan Brandt ◽  
Matthew S Dargusch

Variation in the geometric and surface features of segmented chips with an increase in the volume of material removed and tool wear has been investigated at cutting speeds of 150 and 220 m/min at which the cutting tools fail due to gradual flank wear and plastic deformation of the cutting edge, respectively. Among the investigated geometric variables of the segmented chips, slipping angle, undeformed surface length, segment spacing, degree of segmentation and chip width showed the different variation trends with an increase in the volume of material removed or flank wear width, and achieved different values when tool failed at different cutting speeds. However, the chip geometric ratio showed a similar variation trend with an increase in the volume of material removed and flank wear width, and achieved the similar value at the end of tool lives at cutting speeds of both 150 and 220 m/min regardless of the different tool failure modes. Plastic deformation of the tool cutting edge results in severe damage on the machined surface of the chip and significant compression deformation on the undeformed surface of the chip.


2010 ◽  
Vol 34-35 ◽  
pp. 1816-1821 ◽  
Author(s):  
Yu Su ◽  
Ning He ◽  
Liang Li

Cryogenic minimum quantity lubrication (CMQL) is a kind of green cooling/lubrication technique, which consists of the application of a small amount of lubricant (6-100 ml/h), delivered in a refrigerated compressed gas stream to the cutting zone. This paper experimentally investigates the effect of CMQL on cutting temperature and tool wear in high-speed end milling of titanium alloys. Comparative experiments were conducted under different cooling/lubrication conditions, i.e. dry milling, refrigerated air cutting, and CMQL. The refrigerated gas equipment was manufactured based on composite refrigeration method to provide the refrigerated air. The experimental results show that application of CMQL resulted in drastic reduction in cutting temperature and tool wear especially when machining titanium alloys at a high cutting speed.


2013 ◽  
Vol 483 ◽  
pp. 3-8 ◽  
Author(s):  
Rui Dong Shen ◽  
Xiu Mei Wang ◽  
Chun Hui Yang

In this study, to simulate the grinding process for rolled homogeneous armor steel (RHA) 4043, a single-grain cutting process is modeled using a three-dimensional (3-D) numerical model, which is developed using a coupled finite element (FE) - smoothed-particle hydrodynamics (SPH) approach. The proposed numerical model is then employed to investigate the influences of grain negative rake angle (-22°, -31°, and-45°) as well as high and super-high cutting speed ranged from 100 m/s to 260 m/s in the cutting processes. The numerical results show the cutting forces are much lower and the maximum chip thickness is much larger when using a smaller grain negative rake angle.


2013 ◽  
Vol 589-590 ◽  
pp. 232-237 ◽  
Author(s):  
Guo Sheng Su ◽  
Zhan Qiang Liu

For most of materials, a chip transformation from continuous to serrated takes place at a relative high cutting speed which is called the critical cutting speed (CCS). Serrated chips at CCS have different characteristics from those at higher cutting speeds. In this paper, the chip transformation is analytically investigated. The deformation in the primary shear zone (PSZ) during the transformation is analyzed. The critical shear strain at CCS for chip transformation is proposed. Cutting Experiments are carried out with four metals, and metallographical and morphological investigations on the chip transformation are conducted. The results show that serrated chips can be produced if the shear localization along a shear plane occurs before the shear plane reaches to the middle of PSZ. At CCS, the flow stress of the shear plane passing through the PSZ reaches maximum at the middle of PSZ and then decreases with further straining. The high thickness of localized shear bands makes the serrated chip at CCS look as a wave. At CCS, the shear strain of chip segments is approximately equal to the critical shear strain for chip transformation. Influences of material hardess (brittleness) on chip transformation are also discussed.


1964 ◽  
Vol 86 (2) ◽  
pp. 134-140 ◽  
Author(s):  
K. L. Chandiramani ◽  
N. H. Cook

An attempt has been made to investigate the nature and cause of the variation of surface finish with cutting speed during orthogonal cutting operations. It is found that the variation of cutting speed alone is sufficient to give rise to the three different mechanisms of chip formation, conventionally known as discontinuous, continuous without “bue” (built-up-edge) and continuous with bue. The transition from low-speed, nonbue cutting to high-speed, bue cutting is found to greatly influence the surface finish and in fact the entire cutting mechanism. Photomicrographs of the cutting zones, the chips, and the profiles of the finished surfaces have been taken to observe these changes closely. Tests have also been carried out to determine the relative importance of cutting speed and cutting temperature in affecting the surface finish of the workpiece being machined.


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