Influence of milling toolpaths in machining of the turbine blade

2019 ◽  
Vol 91 (10) ◽  
pp. 1327-1339
Author(s):  
Seyedamin Jarolmasjed ◽  
Behnam Davoodi ◽  
Babak Pourebrahim Alamdari

Purpose The purpose of this paper is to machine the pressure surface of the turbine blade made of A286 iron-based superalloy by using four directions of raster strategy, including horizontal upward, horizontal downward, vertical upward and vertical downward, to achieve appropriate surface roughness and to investigate the tool wear in each strategy. Design/methodology/approach In this study, all cutting tests were performed by DAHLIH-MCV 1020 BA vertical 3-axis machining center with ball nose end mill. After milling by each strategy, according to the surface slope, the surface was divided into 27 meshes, and roughness of surface was studied and compared. Roughness measuring after machining was implemented by using portable Mahr ps1 roughness tester, and surface texture was photographed by CCD 100× optical zoom camera. Also, to measure tool flank wear in each strategy as an indication of tool life, the surface of workpiece was divided into four equal areas. The wear of the inserts was measured by ARCS vertical non-contact measuring system at the end of each area. Findings The results indicate that cutting directions and toolpath strategies have significant influence on tool wear and surface roughness in machining processes and that they can be taken into consideration individually as determinative parameters. In this case, the most uniform surface texture and the lowest surface roughness are obtained by using horizontal downward direction; in addition, abrasion is a dominant tool wear mechanism in all experiments, and tool wear in the horizontal downward is lower than other strategies. Practical implications Machining of turbine blades or other airfoil-shaped workpieces is quite common in manufacturing aerospace and aircraft products. The results of this research contribute to increasing quality of machined surface and tool life in machining of turbine blade. Originality/value This work proves the significance of milling strategies in machining of the turbine blade made of A286 superalloy and, consequently, exhibits the proper strategy in terms of surface roughness and tool life. Also, this work explains and elaborates the behavior of A286 superalloy in machining processes, which has not been studied much in recent research works.

2018 ◽  
Vol 16 (6) ◽  
pp. 828-836
Author(s):  
Razika Aouad ◽  
Idriss Amara

PurposeThe purpose of this paper is to study the influence of the cutting conditions (cutting speed, feed rate and cutting depth) on the roughness (Ra) and on the flank wear (Vb) of the steel AISI 4140.Design/methodology/approachMixed ceramic (CC650) and polycrystalline cubic boron nitride (PCBN) have been used to carry out straight turning tests under dry conditions.FindingsThe results indicate that PCBN is more efficient than mixed ceramic (Al2O3+TiC) used in terms of wear resistance regardless of the aggressiveness of the AISI 4140 at 50 hardness rockwell (HRC). Consequently, it is the most powerful. Surface quality attained with PCBN tool considerably compares with that of grinding. Even when the tool wear VB reached 0.3 mm, the majority of the recorded Ra values did not exceed 1 m at the various speeds tested. The correlation of tool wear Vb and surface roughness Ra established allows obtaining experimental empirical data on the cutting tool wear from measured surface roughness for practical use in industry. The values of constants and the coefficient of determinationR2of this mathematical model will be calculated. Mathematical models expressing the relation between the elements of the cutting regime and technological parameters (tool life and roughness) are proposed.Originality/valueMany works have been already made in the similar manner, but this study of CC650 and PCBN wear is the first. Through this study, we propose a mathematical model expressing the relation between the elements of the cutting regime, tool life and roughness.


2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110112
Author(s):  
Li Xun ◽  
Wang Ziming ◽  
Yang Shenliang ◽  
Guo Zhiyuan ◽  
Zhou Yongxin ◽  
...  

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.


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.).


2021 ◽  
Vol 2021 (4) ◽  
pp. 4836-4840
Author(s):  
ROBERT STRAKA ◽  
◽  
JOZEF PETERKA ◽  
TOMAS VOPAT ◽  
◽  
...  

The article compares two cutting edge preparation methods and their influence on the machined surface roughness of the difficult to cut nickel alloy Inconel 718 and the tool wear of cutting inserts made of cemented carbide. The manufacturing and preparation process of cutting inserts used in the experiment were made by Dormer Pramet. The preparation methods used in the experiment were drag finishing and brushing. Cutting parameters did not change during the whole turning process to maintain the same conditions in each step of the process and were determined based on tests for a semi-finishing operation of the turning process. To obtain durability of 25 to 30 minutes with controlled development of the tool wear the cutting parameters were determined with cooperation with the cutting inserts manufacturer.


2017 ◽  
Author(s):  
Mayur A. Makhesana ◽  
Kaushik M. Patel

Machining is the manufacturing process, capable of producing required shape and size by material removal. In recent times industries are striving to enhance the performance of machining processes. One of the problem associated with machining is the amount of heat generation as a result of friction between tool and workpiece. Heat generated may affect the quality of machined surface and tool wear. In order to control it, cutting fluid is applied in large quantity. The problem arises with the use of cutting fluid is its effect on worker’s health and environment. The present investigation is an attempt to explore the use the solid lubricants in machining as an alternative to cutting fluid. The work involves development of minimum quantity solid lubrication set up. Turning experiments has been performed by applying solid lubricants mixed with cutting fluid in minimum quantity. The performance of minimum quantity solid lubrication has been assessed in form of obtained surface finish, power consumption and tool wear during turning. Experimental findings discovered the superiority of minimum quantity solid lubrication over conventional cutting fluid and can be considered as cost effective and sustainable lubrication method.


2019 ◽  
Vol 3 (2) ◽  
pp. 131-141
Author(s):  
Evan Hanks ◽  
Anthony Palazotto ◽  
David Liu

Purpose Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of electron beam melted (EBM) additively manufactured Ti-6Al-4V. Additive manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include aircraft battle damage repair (ABDR), small batch manufacturing to fill supply gaps and replacement for obsolete parts. This paper aims to assess the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM-manufactured Ti-6Al-4V. Additively manufactured EBM products have a high surface roughness in “as-manufactured” condition which is an artifact of the manufacturing process. The surface roughness is known to affect the results of ultrasonic inspections. Experimental data from this research demonstrate the ability of ultrasonic inspections to identify imbedded flaws as small as 0.51 mm at frequencies of 2.25, 5 and 10 MHz through a machined surface. Detection of flaws in higher surface roughness samples was increased at a frequency of 10 MHz opposed to both lower frequencies tested. Design/methodology/approach The approach is to incorporate ultrasonic waves to identify flaws in an additive manufactured specimen Findings A wave frequency of 10 MHz gave good results in finding flaws even with surface roughness present. Originality/value To the best of the authors’ knowledge, this was the first attempt that was able to identify small flaws using ultrasonic sound waves in which surface roughness was present.


Author(s):  
Ferial Hakami ◽  
Alokesh Pramanik ◽  
Animesh K Basak

Higher tool wear and inferior surface quality of the specimens during machining restrict metal matrix composites’ application in many areas in spite of their excellent properties. The researches in this field are not well organized, and knowledge is not properly linked to give a complete overview. Thus, it is hard to implement it in practical fields. To address this issue, this article reviews tool wear and surface generation and latest developments in machining of metal matrix composites. This will provide an insight and scientific overview in this field which will facilitate the implementation of the obtained knowledge in the practical fields. It was noted that the hard reinforcements initially start abrasive wear on the cutting tool. The abrasion exposes new cutting tool surface, which initiates adhesion of matrix material to the cutting tool and thus causes adhesion wear. Built-up edges also generate at lower cutting speeds. Although different types of coating improve tool life, only diamond cutting tools show considerably longer tool life. The application of the coolants improves tool life reasonably at higher cutting speed. Pits, voids, microcracks and fractured reinforcements are common in the machined metal matrix composite surface. These are due to ploughing, indentation and dislodgement of particles from the matrix due to tool–particle interactions. Furthermore, compressive residual stress is caused by the particles’ indentation in the machined surface. At high feeds, the feed rate controls the surface roughness of the metal matrix composite; although at low feeds, it was controlled by the particle fracture or pull out. The coarser reinforced particles and lower volume fraction enhance microhardness variations beneath the machined surface.


Author(s):  
Aaron Beal ◽  
Dave Dae-Wook Kim ◽  
Kyung-Hee Park ◽  
Patrick Kwon

A comparative study was conducted to investigate drilling of a titanium (Ti) plate stacked on a carbon fiber reinforced plastic panel. The effects on tool wear and hole quality in drilling using micrograin tungsten carbide (WC) tools were analyzed. The experiments were designed to first drill CFRP alone to create 20 holes. Then CFRP-Ti stacks were drilled for the next 20 holes with the same drill bit. This process was repeated until drill failure. The drilling was done with tungsten carbide (WC) twist drills at two different speeds (high and low). The feed rate was kept the same for each test, but differs for each material drilled. A Scanning Electron Microscope (SEM), and a Confocal Laser Scanning Microscope (CLSM), were used for tool wear analysis. Hole size and profile, surface roughness, and Ti burrs were analyzed using a coordinate measuring system, profilometer, and an optical microscope with a digital measuring device. The experimental results indicate that the Ti drilling accelerated WC flank wear while CFRP drilling deteriorated the cutting edge. Entry delamination, hole diameter errors, and surface roughness of the CFRP plate became more pronounced during drilling of CFRP-Ti stacks, when compared with the results from CFRP only drilling. Damage to CFRP holes during CFRP-Ti stack drilling may be caused by Ti chips, Ti adhesion on the tool outer edge, and increased instability as the drill bits wear.


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