An Experimental Study of the Drilling of Aramid Composites

1995 ◽  
Vol 117 (4) ◽  
pp. 271-278 ◽  
Author(s):  
F. Veniali ◽  
A. Di Ilio ◽  
V. Tagliaferri

Major drilling characteristics of Aramid fiber-reinforced plastics are experimentally investigated. The chip appears highly deformed and tends to smear on the tool. Forces and, mainly, torque are more influenced by the tool diameter than by the feed rate and cutting speed. On the contrary, the specific cutting energy strongly depends upon the feed rate due to size effects of the tool tip. The damage in the work, i.e., delamination at entry and exit side, can be controlled by taking into account the relationships between machining parameters and forces and torque. Generally, the tool fails by gross brittle failure at the periphery rather than by generalized land wear.

CERNE ◽  
2011 ◽  
Vol 17 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Erica Moraes de Souza ◽  
José Reinaldo Moreira da Silva ◽  
José Tarcísio Lima ◽  
Alfredo Napoli ◽  
Túlio Jardim Raad ◽  
...  

Modern technologies for continuous carbonization of Eucalyptus sp. require special care in wood cutting procedures. Choosing the right tool, cutting speeds and feed rates is important to manage time and energy consumption, both of which being critical factors in optimizing production. The objective of this work is to examine the influence of machining parameters on the specific cutting energy consumption of Eucalyptus sp. stands MN 463 and VM 01, owned by V&M Florestal. Tests were performed at the Wood Machining Laboratory of the Federal University of Lavras (DCF/UFLA). Moist logs 1.70m in length were used. The experiment was set up using a 3 x 3 x 4 x 2 factorial design (cutting speed x feed rate x number of teeth x tree stand). Results were subjected to analysis of variance and means were compared by the Tukey test at the 5% significance level. Greater cutting speeds, lower feed rates and the 40 teeth circular saw consumed more specific energy. Stand MN 463 consumed more specific energy. The combination of cutting speed 46 m.s-1, feed rate 17 m.min-1 and 24 teeth circular saw produced better specific energy consumption results for stand MN 463. As for stand VM 01, the combination of cutting speed 46 m.s-1, feed rate 17 m.min-1 and 20 teeth circular saw resulted in lower specific energy consumption.


2016 ◽  
Vol 23 (5) ◽  
pp. 543-550 ◽  
Author(s):  
Seyedbehzad Ghafarizadeh ◽  
Jean-François Chatelain ◽  
Gilbert Lebrun

AbstractMachining is one of the most practical processes for finishing operations of composite components, allowing high-quality surface and controlled tolerances. The high-precision surface milling of carbon fiber-reinforced plastics (CFRP) is particularly applicable in the assembly of complex components requiring accurate mating surfaces as well as for surface repair or mold finishing. CFRP surface milling is a challenging operation because of the heterogeneity and anisotropy of these materials, which are the source of several types of damage, such as delamination, fiber pullout, and fiber fragmentation. To minimize the machining problems of CFRP milling and improve the surface quality, this research focuses on the effect of multiaxis machining parameters, such as the feed rate, cutting speed, and lead angle, on cutting forces and surface roughness. The results show that the surface roughness and cutting forces increase with the feed rate, whereas their variations are not uniform when changing the cutting speed. Generally, a lower surface roughness was achieved by using a lower cutting feed rate (0.063 mm/rev) and higher cutting speeds (250–500 m/min). It was also found that the cutting forces and surface roughness vary significantly and nonlinearly with the lead angle of the cutting tool with respect to the surface.


2018 ◽  
Vol 37 (15) ◽  
pp. 993-1003 ◽  
Author(s):  
Jun Hu ◽  
Dezhi Zhu

An experimental investigation of carbon fiber-reinforced plastics cutting with an Nd:YVO4 picosecond pulsed system was presented. One-factor experimental design was used in order to explain the influence of cutting parameters including laser power, hatch distance and cutting speed on the pulsed laser–material interaction. The process parameters were optimized by using central composite design of response surface methodology. The results in kerf width, taper angle, material removal rate, and heat-affected zones were discussed through the micrographs observed with optical microscope. Specimens were cut with three different tools: picosecond pulsed laser, nanosecond pulsed laser, and conventional cutting, and the tensile strength and bending strength tests were conducted. Furthermore, the effect of the heat-affected zones on the static strength was also analyzed.


2019 ◽  
Vol 29 (3) ◽  
pp. 454-466
Author(s):  
P Ghabezi ◽  
M Farahani ◽  
A Shahmirzaloo ◽  
H Ghorbani ◽  
NM Harrison

In this paper, a comprehensive experimental investigation was carried out to precisely characterize the delamination and uncut fiber in the drilling process. A digital imaging procedure was developed in order to calculate the damage resulted from the drilling process. A novel method is proposed in this article based on image intensity to verify the obtained results. A full factorial experimental design was performed to evaluate the importance of the drilling parameters. Among other process parameters, feed rate, cutting speed, and tool diameter are the principal factors responsible for the delamination damage size during the drilling. The drilling process was assessed based on two proposed incurred damage factors, specifically the delamination factor and uncut fiber factor. Experimental results demonstrated that the feed rate was the paramount parameter for both delamination and uncut fiber factors. It was observed that both factors increased with an increase in the feed rate. Additionally, by increasing the tool diameter, the delamination and uncut fiber factors significantly increase. The effects of the cutting speed on damage factors were not linear. The minimum delamination factor and uncut fiber factor were obtained at the cutting speed of 1500 and 2500 r/min, respectively.


Author(s):  
Brian Boswell ◽  
Mohammad Nazrul Islam ◽  
Ian J Davies ◽  
Alokesh Pramanik

The machining of aerospace materials, such as metal matrix composites, introduces an additional challenge compared with traditional machining operations because of the presence of a reinforcement phase (e.g. ceramic particles or whiskers). This reinforcement phase decreases the thermal conductivity of the workpiece, thus, increasing the tool interface temperature and, consequently, reducing the tool life. Determining the optimum machining parameters is vital to maximising tool life and producing parts with the desired quality. By measuring the surface finish, the authors investigated the influence that the three major cutting parameters (cutting speed (50–150 m/min), feed rate (0.10–0.30 mm/rev) and depth of cut (1.0–2.0 mm)) have on tool life. End milling of a boron carbide particle-reinforced aluminium alloy was conducted under dry cutting conditions. The main result showed that contrary to the expectations for traditional machined alloys, the surface finish of the metal matrix composite examined in this work generally improved with increasing feed rate. The resulting surface roughness (arithmetic average) varied between 1.15 and 5.64 μm, with the minimum surface roughness achieved with the machining conditions of a cutting speed of 100 m/min, feed rate of 0.30 mm/rev and depth of cut of 1.0 mm. Another important result was the presence of surface microcracks in all specimens examined by electron microscopy irrespective of the machining condition or surface roughness.


2020 ◽  
pp. 089270572093916
Author(s):  
Nafiz Yaşar ◽  
Mustafa Günay ◽  
Erol Kılık ◽  
Hüseyin Ünal

In this study, the mechanical and machinability characteristics of chitosan (Cts)-filled polypropylene (PP) composites produced by injection molding method were analyzed. Uniaxial tensile, impact, hardness, and three-point flexural tests were used to observe the influence of Cts filler on the mechanical behavior of PP. For the machinability analysis of these materials, drilling experiments based on Taguchi’s L27 orthogonal array were performed using different drill qualities and machining parameters. Then, machining conditions are optimized through grey relational analysis methodology for machinability characteristics such as thrust force and surface roughness obtained from drilling tests. The results showed that tensile, flexural strength, and percentage elongation decreased while impact strength increased with adding the Cts filler to PP. Moreover, it was determined that the tensile and flexural modulus of elasticity increased significantly and there was a slight increase in hardness. Thrust forces decreased while surface roughness values increased when the Cts filler ratio and feed rate was increased. The optimal machining conditions for minimizing thrust force and surface roughness was obtained as PP/10 wt% Cts material, uncoated tungsten carbide drill, feed rate of 0.05 mm/rev, and cutting speed of 40 m/min. In this regard, PP composite reinforced by 10 wt% Cts is recommended for industrial applications in terms of both the mechanical and machinability characteristics.


2018 ◽  
Vol 12 (2) ◽  
pp. 104-108 ◽  
Author(s):  
Yusuf Fedai ◽  
Hediye Kirli Akin

In this research, the effect of machining parameters on the various surface roughness characteristics (arithmetic average roughness (Ra), root mean square average roughness (Rq) and average maximum height of the profile (Rz)) in the milling of AISI 4140 steel were experimentally investigated. Depth of cut, feed rate, cutting speed and the number of insert were considered as control factors; Ra, Rz and Rq were considered as response factors. Experiments were designed considering Taguchi L9 orthogonal array. Multi signal-to-noise ratio was calculated for the response variables simultaneously. Analysis of variance was conducted to detect the significance of control factors on responses. Moreover, the percent contributions of the control factors on the surface roughness were obtained to be the number of insert (71.89 %), feed (19.74 %), cutting speed (5.08%) and depth of cut (3.29 %). Minimum surface roughness values for Ra, Rz and Rq were obtained at 325 m/min cutting speed, 0.08 mm/rev feed rate, 1 number of insert and 1 mm depth of cut by using multi-objective Taguchi technique.


2013 ◽  
Vol 465-466 ◽  
pp. 1075-1079 ◽  
Author(s):  
Erween Abdul Rahim ◽  
Z. Mohid ◽  
M.R. Hamzah ◽  
A.F. Yusuf ◽  
N.A. Rahman

Hole making process is not strictly to the drilling technique where others machining could also influence to the quality in CFRP hole.Therefore, helical milling process becomes as an alternative method to produces bore on CFRP plate thus minimizing the defects. The common defects on CFRP are delamination, splintering and cracking. Meanwhile, if the CFRP stacking together with aluminum plate, burr at exit hole of aluminium plate is produced. Therefore, it is essential to control the critical machining parameters to assure a good quality of the hole. The main objective of this project is to improve the hole quality of CFRP/AL stack in terms of surface roughness using helical milling technique. In addition the cutting force and temperature will be measured as well. There are three levels of cutting speeds; two levels of feed rate and depth per helical path are made accordingly to helical milling characteristics. It was found that all tool design exhibit comparable performance for helical milling process on CFRP/Al stack.


2016 ◽  
Vol 16 (2) ◽  
pp. 75-88 ◽  
Author(s):  
Munish Kumar Gupta ◽  
P. K. Sood ◽  
Vishal S. Sharma

AbstractIn the present work, an attempt has been made to establish the accurate surface roughness (Ra, Rq and Rz) prediction model using response surface methodology with Box–Cox transformation in turning of Titanium (Grade-II) under minimum quantity lubrication (MQL) conditions. This surface roughness model has been developed in terms of machining parameters such as cutting speed, feed rate and approach angle. Firstly, some experiments are designed and conducted to determine the optimal MQL parameters of lubricant flow rate, input pressure and compressed air flow rate. After analyzing the MQL parameter, the final experiments are performed with cubic boron nitride (CBN) tool to optimize the machining parameters for surface roughness values i. e., Ra, Rq and Rz using desirability analysis. The outcomes demonstrate that the feed rate is the most influencing factor in the surface roughness values as compared to cutting speed and approach angle. The predicted results are fairly close to experimental values and hence, the developed models using Box-Cox transformation can be used for prediction satisfactorily.


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