Assessment of Hole Quality and Thrust Force when Drilling CFRP/Al Stack Using Carbide Tools

2012 ◽  
Vol 234 ◽  
pp. 28-33 ◽  
Author(s):  
Sina Alizadeh Ashrafi ◽  
Safian Sharif ◽  
Yahya Mohd Yazid ◽  
Ali Davoudinejad

Drilling composite materials is challenging due to the anisotropic and non-homogenous structure of composites. In fabrication works, metals are joined to composites to form a hybrid strengthened structures, and this posed a great problem during drilling, due to the dissimilar drilling conditions for each material and also sharp metal chips effect on the quality of hole on composite plates. This paper evaluates the experimental results on the machining performance of coated and uncoated 4 facet carbide drills when dry drilling stack of carbon fiber reinforced plastic (CFRP) and aluminum. Drilling trials were carried out on CFRP/Al2024/CFRP stack at constant cutting speed of 37 m/min with three feed rates within 0.03-0.25 mm/rev. Results revealed that 4 facet coated drills performed better than uncoated drills in terms of delamination. It was found that hole entry delamination increases with increasing feed rate, however uncut fibers which were dominant at low feeds on hole exit, disappears with increasing feed rate. It was also found that thrust force for coated tools were quite higher than uncoated tools.

Author(s):  
Eshetu D. Eneyew ◽  
M. Ramulu

In this study, an experimental investigation on the drilling of unidirectional carbon fiber reinforced plastic (UD-CFRP) composite was conducted using polycrystalline diamond (PCD) tipped eight facet drill. The quality of the drilled hole surface was examined through surface roughness measurements and surface damage by scanning electron microscopy (SEM). It was found that, fiber pullout occurred in two specific sectors relative to the angle between the cutting direction and the fiber orientation. The thrust force was highly influenced by the feed rate than the cutting speed and it shows a significant variation throughout the rotation of the drill.


2020 ◽  
Vol 17 (5) ◽  
pp. 661-674 ◽  
Author(s):  
Sathiyamoorthy Margabandu ◽  
Senthilkumar Subramaniam

Purpose This paper aims to deal with the influence of cutting parameters on drill thrust force, delamination and surface roughness in the drilling of laminated jute/carbon hybrid composites. Design/methodology/approach The hybrid composites were fabricated with four layers of fabrics, which are arranged in different sequences using the hand-layup technique. Drilling experiments involved drilling of 6 mm diameter holes on the prepared composite plates using high-speed steel and solid carbide drill materials. Analysis of variance was used to find the influence, percentage contribution and significance of drilling parameters on drilling-induced damages. Scanning electron microscopy analysis was also conducted to understand the fracture behavior and surface morphology of the drilled holes. Findings The experimental study reveals that the most significant effect was the feed rate influenced the drill thrust force and the drill speed influenced both delamination factor and surface roughness of hybrid fiber-reinforced composites. From observations, the suggested combination for drilling jute/carbon hybrid composites is carbide drill, spindle speed of 1,750 rpm and feed of 0.03 mm/rev. Originality/value The new lightweight and low-cost hybrid composites were developed by hybridizing jute with carbon fabrics in the epoxy matrix with interplay arrangements. The influence of cutting speed and feed rate on delamination damage and surface roughness in the drilling of hybrid composites have been experimentally evaluated.


Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 289 ◽  
Author(s):  
Antonio Rubio-Mateos ◽  
Asuncion Rivero ◽  
Eneko Ukar ◽  
Aitzol Lamikiz

In finishing processes, the quality of aluminum parts is mostly influenced by static and dynamic phenomena. Different solutions have been studied toward a stable milling process attainment. However, the improvements obtained with the tuning of process parameters are limited by the system stiffness and external dampers devices interfere with the machining process. To deal with this challenge, this work analyzes the suitability of elastomer layers as passive damping elements directly located under the part to be machined. Thus, exploiting the sealing properties of nitrile butadiene rubber (NBR), a suitable flexible vacuum fixture is developed, enabling a proper implementation in the manufacturing process. Two different compounds are characterized under axial compression and under finishing operations. The compression tests present the effect of the feed rate and the strain accumulative effect in the fixture compressive behavior. Despite the higher strain variability of the softer rubber, different milling process parameters, such as the tool feed rate, can lead to a similar compressive behavior of the fixture regardless the elastomer hardness. On the other hand, the characterization of these flexible fixtures is completed over AA2024 floor milling of rigid parts and compared with the use of a rigid part clamping. These results show that, as the cutting speed and the feed rate increases, due to the strain evolution of the rubber, the part quality obtained tend to equalize between the flexible and the rigid clamping of the workpiece. Due to the versatility of the NBR for clamping different part geometries without new fixture redesigns, this leads to a competitive advantage of these flexible solutions against the classic rigid vacuum fixtures. Finally, a model to predict the grooving forces with a bull-nose end mill regardless of the stiffness of the part support is proposed and validated for the working range.


2012 ◽  
Vol 217-219 ◽  
pp. 1912-1916
Author(s):  
Ji Hua Wu

Surface roughness plays a critical role in evaluating and measuring the surface quality of a machined product. Two workpiece materials have been investigated by experimental approach in order to gain a better understanding of their influence on the obtained surface roughness in the micro-milling processes. The experimental results show that: surface topography is completely different for different materials at the same cutting speed and feed rate; surface roughness increases with an increase of material grain size. Surface roughness decreases to a lowest value, and then increases with an increase of the feed rate. A new surface model to illustrate the influence of material and uncut chip thickness was developed. The model has been experimentally validated and shows more promising results than Weule’s model.


Author(s):  
Tarakeswar Barik ◽  
Kamal Pal ◽  
Smruti Parimita ◽  
Priyabrata Sahoo ◽  
Karali Patra

Fiber-reinforced plastic is one of the top priorities lightweight materials with excellent mechanical properties for the aerospace industries in recent years. However, it is difficult to machine despite having unique properties due to its non-homogeneous and abrasive nature in alternate fiber and matrix layers. Thus, it is found to be a challenging task to drill hole on such hard-to-machine materials, which is highly essential for the development of most of the engineering structural components. The present work addresses various drilling-induced defects such as delamination, circularity error, and roughness variations in the hole surface during drilling of quasi-isotropic cross-fiber oriented bi-directional woven-type carbon fiber reinforced plastic laminate using a full factorial design of experiments for different drill geometry. The response surface methodology was considered for the regression model development, which was found to be highly significant. The machining forces with associated torque have also been acquired during drilling, which was divided and further analyzed in time domain to correlate with drilling flaws. The drilling-induced delamination was found to be higher at a high feed rate using a higher drill point angle due to substantial thrust force generation at the initial stages in the drilling cycle. However, the internal surface finish with associated circularity error was reduced for higher spindle speed with less feed rate using a low drill point angle because of low torque fluctuation at the final drilling phases. The axial thrust force was found to be a prime indicator of drilled hole surface delamination, whereas drilling torque precisely indicated internal surface roughness as well as circularity error. The global root mean square, along with a local peak of thrust and torque, both were highly essential to completely characterize the drilled hole quality.


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.


2010 ◽  
Vol 09 (01) ◽  
pp. 63-72 ◽  
Author(s):  
M. SENTHIL KUMAR

The paper discusses the study on thrust force and torque while drilling GFRP composites with SiC fillers. The input parameters such as cutting speed, feed rate and point angle were varied and influencing parameters such as thrust force and torque were studied. The experimental investigation was made during the drilling of GFRP with SiC fillers using four standard twist drills of point angles 90°, 100°, 110° and 120°.


2011 ◽  
Vol 188 ◽  
pp. 372-375
Author(s):  
H.L. Zhang ◽  
Jin Chen

Drilling is one of the complex machining processes, which has been widely applied in the manufacturing area. In this paper, a 3D coupled thermo-mechanical finite element model was used for simulating the thrust force, torque and von Mises equivalent stress at different cutting conditions. The J-C damage model (shear failure) was used in conjunction with the J-C plasticity model, as well as the continuous adaptive remeshing technical. The results show that the thrust force and torque increase with the increasing of the cutting speed and feed rate, and the influence of the feed rate is more obviously.


2019 ◽  
Vol 26 (02) ◽  
pp. 1850139 ◽  
Author(s):  
A. PALANISAMY ◽  
T. SELVARAJ

In this work, an attempt has been made to optimize the process parameters on turning operation of INCOLOY 800H, with the aid of cryogenically treated (24[Formula: see text]h, 12[Formula: see text]h and untreated) multi-layer chemical vapor deposition (CVD) coated tools. The influencing factors like cutting speed, feed rate, depth of cut and cryogenic treatment were selected as input parameters. Surface roughness, microhardness and material removal rate (MRR) were considered as output responses. The experimentation was planned and conducted based on Taguchi L27 standard orthogonal array (OA) with three levels and four factors. Multi-criteria decision making (MCDM) methods like grey relational analysis (GRA) and technique for order preference by similarity to ideal solution (TOPSIS) have been used to optimize the turning parameters in this work. Similar results were obtained from these MCDM techniques. Analysis of variance (ANOVA) was employed to identify the significance of the process parameters on the responses. Experimental research proved that machining performance could be improved efficiently at cutting speed is 55[Formula: see text]m/min, feed rate is 0.06[Formula: see text]mm/rev, depth of cut is 1[Formula: see text]mm and 24[Formula: see text]h cryogenically treated tool. Tool wear was analyzed for the cutting tool machined at the optimum cutting condition with the help of scanning electron microscope (SEM) and energy dispersion spectroscopy (EDS). Dry sliding wear test was also conducted for the optimal condition. The percentage improvement in machining performances is 12.70%.


2013 ◽  
Vol 652-654 ◽  
pp. 2105-2108
Author(s):  
Xu Xing Jin

Mar-M247 is widely used in industry for its excellent mechanical properties at high temperatures, but it has the shortcoming of difficulty manufactured. In order to obtain the cutting characteristics of Mar-M247, firstly, an end milling experiment was set up accordingly, where three types of cutting tools coated respectively by TiN, TiCN and TiAlN were employed. Then the parameters of cutting speed and feed rate were defined as the tool cutting variables. Finally, based on different cutting variables, the performance of tool wear, tool life, and workpiece surface roughness were analyzed and discussed. The results indicate when the tool coated by TiAlN, cutting speed of range 1600 ~ 3200 rpm and feed rate of range 0.06 ~ 0.08 mm / tooth are chosen together, the integrated states manufactured of the tool and the workpiece would be best, the method of this research can provide some references for studying others Nickel-based superalloys.


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