Performance of Reground Tools in Drilling

Author(s):  
Jose Aecio Gomes de Sousa ◽  
Marcelo do Nascimento Sousa ◽  
Alisson Rocha Machado

The present work evaluates the performance of step drills, new and after regrinding. The tools were made of P20 cemented carbide coated with TiAlN. The routine of re-coating them after regrinding were varied (no recoating, recoating over the previous coating and recoating after removing the previous coating). The output parameters considered for determining the machining performance were: tool life, thrust force, torque, form errors (roundness and cylindricity) and surface roughness (Ra and Rz parameters). The results generated with the resharpened tools were compared to those obtained with a new tool (first time used). The results showed that in general the reground tools showed worse performance than the new tools, regardless the parameter considered. Only the tools that have undergone the process of cleanness of the previous coating and then reground and recoated (with the same type of coating) showed results similar to the new tools. The tools with no recoating and those that received the recoating over the previous showed, practically in all tests, higher thrust force and torque, larger form errors and worse surface roughness than the new tools.

2014 ◽  
Vol 800-801 ◽  
pp. 191-196
Author(s):  
Bin Zhao ◽  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Hong Tao Zhu

The nickel-based superalloy GH4033 is one of the difficult-to-cut materials. In order to investigate the machinability of GH4033, the tool cutting performance, tool failure modes, tool life and the relationships between surface roughness and tool flank wear were studied by using different coated cemented carbide cutting tools under dry cutting. Aiming at the amount of metal removal combining with the tool life and surface quality, the better cutting tool coating type and optimal cutting parameters were obtained through the orthogonal experiments. The results showed that the cutting performance of TiCN coated tool (GC4235) was better than that of TiAlN coated tool (JC450V). With these two kinds of tools, the machined surface roughness decreased to a minimum value and then increased with the increase of flank wear. When cutting GH4033, the main wear mechanism for both of the two types of tools included adhesive wear, diffusive wear, abrasive wear, edge wear and coating peeling.


2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771061 ◽  
Author(s):  
Duc Tran Minh ◽  
Long Tran The ◽  
Ngoc Tran Bao

In this article, an attempt has been made to explore the potential performance of Al2O3 nanoparticle–based cutting fluid in hard milling of hardened 60Si2Mn steel (50-52 HRC) under different minimum quantity lubrication conditions. The comparison of hard milling under minimum quantity lubrication conditions is done between pure cutting fluids and nanofluids (in terms of surface roughness, cutting force, tool wear, and tool life). Hard milling under minimum quantity lubrication conditions with nanofluid Al2O3 of 0.5% volume has shown superior results. The improvement in tool life almost 177%–230% (depending on the type of nanofluid) and the reduction in surface roughness and cutting forces almost 35%–60% have been observed under minimum quantity lubrication with Al2O3 nanofluids due to better tribological behavior as well as cooling and lubricating effects. The most outstanding result is that the uncoated cemented carbide insert can be effectively used in machining high-hardness steels (>50 HRC) while maintaining long tool life and good surface integrity (Ra = 0.08–0.35 µm; Rz = 0.5–2.0 µm, equivalent to finish grinding) rather than using the costlier tools like coated carbide, ceramic, and (P)CBN. Therefore, using hard nanoparticle–reinforced cutting fluid under minimum quantity lubrication conditions in practical manufacturing becomes very promising.


Author(s):  
Chaiya Dumkum ◽  
Pakin Jaritngam ◽  
Viboon Tangwarodomnukun

This article presents a comprehensive analysis of surface characteristics and drilling performance of uncoated and coated tungsten carbide drills. The single- and double-layer coatings of TiN, TiAlN and AlCrN were examined in terms of surface roughness, microhardness and crack resistance. In addition, drilling torque and thrust force were experimentally measured and compared to the developed models based on the drilling mechanics and drill geometries. Tool wear and hole surface roughness were also considered to assess the machining performance of different coated tools. The results revealed that all coated drills can offer better cut surface quality, 28% lower cutting loads and longer tool life than the uncoated drills. Although AlCrN was found to be the hardest coating material among the others, it caused large wear on the cutting edges and poor surface roughness of produced holes. The lowest torque and thrust force were achievable using TiN-coated drill, while the use of TiAlN coating resulted in the lowest surface roughness and smallest tool wear. Furthermore, the drilling torque and thrust force model developed in this study were found to correspond to the experimental measures with the average error of 8.4%. The findings of this work could facilitate the selection of coating materials to advance the machining performance.


2016 ◽  
Vol 10 (4) ◽  
pp. 533-539 ◽  
Author(s):  
Katsushi Furutani ◽  
◽  
Eiji Kagami ◽  

Future lunar, planetary, and asteroid exploration will strongly demandin situanalysis of rock samples to obtain data related to various aspects. For precise composition analysis, a sample surface should be smoothed. In this paper, a surface shaver with a piezoelectric actuator is proposed and its machining performance in air is investigated. Shaving teeth are mounted at the ends of a pair of lever mechanisms. The device is pressed through four springs onto the workpiece with a linear actuator. When a sinusoidal voltage of 50 Vp-pand an offset voltage of 25 V were applied, the resonance frequency was 556 Hz and the unloaded amplitude of the shaving teeth was 0.77 mmp-p. Basalt workpieces were machined for 10 min in air. Increasing the thrust force reduced the surface roughness, although the amount removed diminished with a further increase in the thrust force. The surface roughness varied widely not only due to the amount removed but also due to containing the pores.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 850 ◽  
Author(s):  
Zhaojun Ren ◽  
Shengguan Qu ◽  
Yalong Zhang ◽  
Xiaoqiang Li ◽  
Chao Yang

In this paper, TiAlN-coated cemented carbide tools with chip groove were used to machine titanium alloy Ti-6Al-0.6Cr-0.4Fe-0.4Si-0.01B under dry conditions in order to investigate the machining performance of this cutting tool. Wear mechanisms of TiAlN-coated cemented carbide tools with chip groove were studied and compared to the uncoated cemented carbide tools (K20) with a scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The effects of the cutting parameters (cutting speed, feed rate and depth of cut) on tool life and workpiece surface roughness of TiAlN-coated cemented carbide tools with chip groove were studied with a 3D super-depth-of-field instrument and a surface profile instrument, respectively. The results showed that the TiAlN-coated cemented carbide tools with chip groove were more suitable for machining TC7. The adhesive wear, diffusion wear, crater wear, and stripping occurred during machining, and the large built-up edge formed on the rake face. The optimal cutting parameters of TiAlN-coated cemented carbide tools were acquired. The surface roughness Ra decreased with the increase of the cutting speed, while it increased with the increase of the feed rate.


2012 ◽  
Vol 174-177 ◽  
pp. 425-428
Author(s):  
Nian Suo Xie ◽  
Jin Wang

SiC/Cu composite materials were fabricated by powder metallurgy, and microstructure of composite was analyzed by means of metallographic microscope. The high speed steel tool and cemented carbide tool are used as cutters, and machining performance of SiC/Cu Composites were studied by cutting lathe and wire-electro discharge machine. The relationship between wire-electro discharge machining cutting speed and pulse interval were studied by wire-electro discharge machine. The results show that the composite cutting surface roughness increases with increasing of the content of SiC particles when the size of SiC is 40μm, while composite cutting surface roughness decreases with increasing of the content of SiC particles when the size of SiC is 20μm, the cemented carbide tolls have longer life than high-speed steel tools. The surface roughness of composite increases with the increasing of source voltage, but it decreases with increasing of pulse interval in the wire-electro discharge machining cutting conditions.


2021 ◽  
Author(s):  
He Sui ◽  
Lifeng Zhang ◽  
Shuang Wang ◽  
Zhaojun Gu

Abstract Axial ultrasonic vibration-assisted cutting (AUVC) has proved to have better machining performance compared with conventional cutting methods; however, the effect of numerous and complex influencing factors on machining performance has not been clearly revealed and a recommended combination of cutting conditions has not been proposed yet, especially for difficult-to-machine material such as Ti6Al4V alloy. This paper focuses on experimental and theoretical investigation into machining performance when cutting Ti6Al4V with the AUVC method. First, a retrospective of the separation characteristics of AUVC is provided and the variable parameter cutting characteristics are demonstrated. We classify the influencing factors on machining performance into four categories: machining parameters, vibration parameters, tool choice, and cooling conditions. The relationship between these factors in terms of their effect on machining performance is established theoretically. Then, it describes experiments to determine the influence of these factors on cutting force, tool life, and surface roughness. For absolute influence, the orders for cutting force, tool life, and surface roughness are respectively cutting depth > amplitude > feed rate > rotation speed, rotation speed > feed rate > amplitude > cutting depth, and feed rate > amplitude > cutting depth > rotation speed. However, for relative influence, the order is unified as: amplitude > feed rate > rotation speed > cutting depth. Finally, it suggests a smaller feed rate, larger amplitude, moderate rotation speed, and smaller cutting depth in addition to a WC tool coated with TiAlN and used under HPC cooling condition for optimal performance of AUVC. This recommendation is based on the theoretical analysis and experimental results of cutting force, surface roughness, and tool life.


2013 ◽  
Vol 766 ◽  
pp. 123-141 ◽  
Author(s):  
S.R. Karnik ◽  
V.N. Gaitonde ◽  
S. Basavarajappa ◽  
J. Paulo Davim

The glass epoxy polymer composites are broadly used in various engineering fields because of outstanding properties. Even if, these composites are produced as near net shapes, the machining has to be carried out in the last stage of manufacture. Drilling is used to install the fasteners for assembly of laminates, but drilling of composites is somewhat complex task owing to exceedingly abrasive nature of reinforcement. Hence the choice of optimal process parameters is essential for successful machining performance. This paper illustrates the application of simulated annealing (SA) approach for simultaneous minimization of various machinability aspects such as thrust force, hole surface roughness and specific cutting coefficient during drilling of glass epoxy polymer composites. The experiments were performed as per full factorial design (FFD) for glass epoxy composites (without filler) and silicon carbide (SiC) filled glass epoxy composites materials. The mathematical models of proposed machinability characteristics were constructed using response surface methodology (RSM) with spindle speed and feed as controllable factors. The experimental investigation indicates that the SiC filled glass epoxy composite provides better machinability compared to glass epoxy composite without the addition of filler. The proposed machinability models were then utilized with SA to select the optimal parameters such as spindle speed and feed, which results in minimal thrust force, hole surface roughness and specific cutting coefficient.


Author(s):  
Salman Pervaiz ◽  
Ibrahim Deiab ◽  
Amir Rashid ◽  
Mihai Nicolescu

Titanium alloys generally show low machinability ratings. They are referred as difficult-to-cut materials due to their inherent properties such as low thermal conductivity, high chemical reactivity and high strength at elevated temperatures. Cooling strategies play an important role to improve the machining performance of the cutting process. In order to facilitate the heat dissipation from the cutting zone, generous amount of coolant is used when machining highly reactive metals such as titanium alloys. Generally, cutting coolants are nominated as pollutants due to their non-biodegradable nature. This article presents experimental evaluation of a minimal quantity cooling lubrication system. The study investigates a combination of sub-zero-temperature air and vegetable oil–based mist as possible environmentally benign alternative to conventional cooling methods. The results are compared with the dry and flood cutting environments as well. Machinability was evaluated experimentally by considering the surface finish, cutting forces, tool life and their associated tool wear mechanisms. It was concluded from the results obtained from the surface roughness, cutting force and tool life investigation that minimal quantity cooling lubrication (internal) cooling strategy has encouraging potential to replace the conventional flood cooling method.


2021 ◽  
Vol 1206 (1) ◽  
pp. 012007
Author(s):  
Avez Shaikh ◽  
Ajinkya Shinde ◽  
Satish Chinchanikar ◽  
Guruprasad Zagade ◽  
Sonia Pardeshi

Abstract Hard turning with CBN and ceramic inserts is commonly regarded as a cost-effective alternative to grinding. However, there have been few studies comparing hard turning with low-cost carbide tools to high-cost CBN and ceramic cutting tools. However, when it comes to the usage of cutting coolant during severe turning, there are mixed outcomes. In this study, a PVD-coated TiSiN-TiAlN carbide tool was used to hard turn AISI 52100 steel in a dry and MQL environment. Through multi-objective optimization, a comparative assessment in terms of surface roughness, cutting force, and tool life under various cutting settings is provided. In terms of three components of cutting force, surface roughness, and tool life, mathematical models were constructed to forecast and improve machining performance. Under both dry and MQL conditions, the study discovered an optimal cutting speed of 108 m/min, a feed value of 0.09 mm/rev, and a depth of cut of 0.16 mm. Under MQL, hard turning produced optimal surface roughness and tool life of 0.88 m and 64 minutes, respectively. In comparison to hard turning under dry cutting, the optimal surface roughness was 1.07 m and the tool life was 49 minutes. Under MQL, tool life increased by over 31%, according to the findings of the experiments. Under dry and MQL conditions, however, no significant differences in cutting forces and surface roughness were identified.


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