Increase In Feed Rate Research Articles

Predator‐scale spatial analysis of intra‐patch prey distribution reveals the energetic drivers of rorqual whale super‐group formation

Abstract Animals are distributed relative to the resources they rely upon, often scaling in abundance relative to available resources. Yet, in heterogeneously distributed environments, describing resource availability at relevant spatial scales remains a challenge in ecology, inhibiting understanding of predator distribution and foraging decisions. We investigated the foraging behaviour of two species of rorqual whales within spatially limited and numerically extraordinary super‐aggregations in two oceans. We additionally described the lognormal distribution of prey data at species‐specific spatial scales that matched the predator's unique lunge‐feeding strategy. Here we show that both humpback whales off South Africa's west coast and blue whales off the US west coast perform more lunges per unit time within these aggregations than when foraging individually, and that the biomass within gulp‐sized parcels was on average higher and more tightly distributed within super‐group‐associated prey patches, facilitating greater energy intake per feeding event as well as increased feeding rates. Prey analysis at predator‐specific spatial scales revealed a stronger association of super‐groups with patches containing relatively high geometric mean biomass and low geometric standard deviations than with arithmetic mean biomass, suggesting that the foraging decisions of rorqual whales may be more influenced by the distribution of high‐biomass portions of a patch than total biomass. The hierarchical distribution of prey in spatially restricted, temporally transient, super‐group‐associated patches demonstrated high biomass and less variable distributions that facilitated what are likely near‐minimum intervals between feeding events. Combining increased biomass with increased foraging rates implied that overall intake rates of whales foraging within super‐groups were approximately double those of whales foraging in other environments. Locating large, high‐quality prey patches via the detection of aggregation hotspots may be an important aspect of rorqual whale foraging, one that may have been suppressed when population sizes were anthropogenically reduced in the 20th century to critical lows. A free Plain Language Summary can be found within the Supporting Information of this article.

Fuzzy Logic-Based Prediction of Drilling-Induced Temperatures at Varying Cutting Conditions along with Analysis of Chips Morphology and Burrs Formation

Friction and plastic deformation at the tool–chips interaction during a dry drilling process results in temperature rise and promotes tool wear and surface roughness. In most of the components produced in industries, a drilling process is used to make a hole for final assembly. Therefore, knowledge of temperatures produced during drilling operation at various machining input parameters is required for the best quality product. A fuzzy logic-based algorithm is developed to predict the temperature generated in the drilling process of AISI 1018 mild steel. The algorithm used speed and feed rate of the drill bit as input parameters to the fuzzy domain. A set of rules was used in the fuzzy domain to predict maximum temperature produced in the drilling process. The developed algorithm is simulated for various input speed and feed rate parameters and was verified through the maximum temperature measured during drilling of the studied material at selected speed–feed combinations. Experiments were conducted to validate the results of developed fuzzy logic-based algorithm by using non-contact infrared pyrometer for drilling of AISI 1018 steel. A good agreement between the predicted and experimentally measured maximum temperature was observed with an error less than 6%. It is found that temperature increases with increase in cutting speed and feed rate. Size of roll back burr formation at the hole perimeter significantly increases with increase in drill speed and feed rate. Segmental continuity in spiral or helix chips morphology is more at low feed and high cutting speed. Chip radius increases with increase in feed rate and results in damaging of the machined surface and causes burr formation while the radius decreases with cutting speed along with improved hole surface finish.

Eco-friendly manufacturing towards the industry of the future with a focus on less cutting fluid and high workpiece quality applied to the grinding process

The global effort in order to reduce impacts to the environment and people produces the need for new technologies as an eco-friendly alternative to replace the cutting fluids, which directly affects the grinding process. In this sense, grinding uses a large amount of cutting fluid to mitigate high temperatures and their consequences. Thus, alternatives to the cutting fluid should reduce the use of fluid combined with the maintenance of production, like minimum quantity lubricant (MQL). The MQL with pure oil tends to produce results close to the cutting fluid method, but improvements in its cooling capacity are still mainly needed. Therefore, this work studies the MQL with oil-water dilution (1:1, 1:3, and 1:5) varying the feed rate in the external cylindrical grinding of AISI 4340 steel, comparing it with pure MQL and the conventional method with abundant cutting fluid. The results of applying MQL 1:5 produced workpieces with similar quality to that obtained with the conventional cutting fluid. In addition, the MQL method resulted in less variation with the increase of feed rate when compared to other lubri-refrigerant methods applied.

Effect of microstructure on high-speed cutting modified anti-fatigue performance of Incoloy A286 and titanium alloy TC17

Anti-fatigue performance is vital for components used in aerospace industry, and cutting processes were widely considered to modify the workpiece anti-fatigue performance. However, most of the existing researches only associated the anti-fatigue performance to the cutting condition and surface integrity, without revealing the effect of material microstructure. In this work, the Incoloy A286 and titanium alloy TC17, two kinds of commonly used material in aerospace industry, were adopted as samples to reveal the influence mechanism of material microstructure on the high-speed cutting modified anti-fatigue performance. It was found that, due to the different microstructure, especially the grain structure and size, the effects of cutting process on the machined surface integrity and anti-fatigue performance of these two materials were different. For Incoloy A286, the large size and cubic structure increased the difficulty in deformation and breaking of grains, making the cutting parameters have limited effect on grain refinement. Hence, the fracture toughness of machined surfaces decreased on the whole with an increased feed rate and depth of cut, which reduced the fatigue life. For titanium alloy TC17, the small lath-shaped grains were easy to deform and break, resulting in the notably grain refinement of machined surfaces, which contributed to the prolonged fatigue life when the feed rate and depth of cut increased. All in all, the material microstructure may change the effect rule of cutting process on the machined workpiece anti-fatigue performance, and thus the cutting condition should be designed by considering the material microstructure.

Dynamic characteristics and research on the dual-drive feed mechanism

The dual-drive feed mechanism (DDFM) based on the drive at the center of gravity (DCG) principle has been widely adopted in computer numerical control (CNC) machines and industrial robots that require high precision and high stability. The friction force affected by feed rates and moving parts positions can change the contact stiffness of kinematic joints, which can further impact on dynamic characteristics of the DDFM and cause dual axes difference. Considering the contact stiffness of kinematic joints, this paper adopts the lumped parameter method to establish the general dynamic model of the DDFM. The equivalent axial stiffness of kinematic joint and feed system transmission stiffness are all derived regarding the influence of feed rates and moving parts positions. The dynamic experiments on the DDFM with different feed rates and moving parts positions are carried out to verify the proposed model. The results suggest that in the motion stage, the DDFM’s natural frequency is greater than that in the static stage, and behaves differently in different feed rates and moving parts positions. The axial contact stiffness value of the ball-screw and nut B can reach 0 when the feed rate increases. When the moving parts are in the middle position of the crossbeam, the DDFM is the most stable and the dynamic performance is the best.

A new geometric model of serrated chip formation in high-speed machining

• The serrated chip geometry can be predicted effectively with average value. • The serrated chip formation can be modeled effectively in time domain without measurement of chip geometry. • The critical shear strain rate for the disappear of crack in machining of cast aluminum alloy are presented. The geometry of serrated chip is of paramount importance to the analysis of physical and thermal phenomena in chip formation process, and it can affect tool fatigue life, surface finish and geometric accuracy of the machining part. This paper presents a novel geometry model of serrated chip segment based on chip formation and cutting force in metal cutting by considering the difference between deformation of shear band and primary shear zone. Where, focusing on the high-speed machining, it key points about the geometry of chip segment, shear band angle, secondary shear angle, third shear angle (curvature angle of second shear band), the strain and its rate, and their evolutions in chip formation process are developed, respectively. Finally, the experimental and simulated instances can verify the proposed method. The results can show that this proposed model having a high accuracy can effectively reflect the evolution of chip segment. The shear angle is silent increased with increase of feed rate, while the difference between shear angles is decreasing with increase of feed rate. While the shear strain is increasing with the increasing feed rate and decreasing with increase of cutting depth, the cutting velocity can enlarge the difference. The critical shear strain rate and cutting velocity for the disappear of crack in chip for feed rate of 0.117mm, 0.14mm and 0.187mm are 1.566e 5 1/s and 32.71m/s, 1.486e 5 1/s and 35.98m/s, 1.279e 5 1/s and 39.25m/s, respectively, which decreased with increased of feed rate.

Experimental investigation into tool wear, cutting forces, and resulting surface finish during dry and flood coolant slot milling of Inconel 718

Inconel 718 superalloy is a widely used material in aerospace due to its high strength, corrosion resistance, and high resistance to thermal fatigue. Excellent mechanical and thermal properties also make Inconel 718 one of the most difficult-to-machine alloys. This study aims to take a different approach of analyzing tool wear during machining of Inconel 718 by measuring worn-out area on each flute from three different faces of flute. This paper also includes analysis of cumulative tool wear, cutting forces, surface roughness, topography, burr formation, and chip morphology at various machining parameters and cooling conditions. The cutting speed was kept constant at 60 m/min due to the goal of machining at highest possible speed and the limitation in maximum spindle speed of the machine tool. Experiments were carried out in dry and flood coolant machining using uncoated carbide tools by varying depth of cut and feed rate for four different settings each. It was found that the amount of tool wear varied for different flutes when measured from top, rake, and back faces of each flute, even for the same tool. The back and rake faces exhibit more chipping wear when machining is carried out at higher depth of cut, irrespective of the cooling conditions. At the same machining conditions for the range of parameters selected in this study, flood coolant machining resulted in slightly higher tool wear at the back and rake faces of cutting flutes and generated higher cutting speed, which may be interrelated. The gradual increase in tool wear over time resulted in an increase in surface roughness from entry to exit of a 76.2 mm machined slot. Flood coolant machining resulted in slightly smoother surface finish at the lower settings of depth of cut and feed rate, while the burr formation was marginally higher in flood coolant machining during machining at higher feed rate and depth of cut. The amount of serration was found to increase specifically with the increase of feed rate and was found to be higher for dry machining compared to flood coolant machining at the same parameter settings. Finally, the new approach of tool wear analysis from different faces of individual cutting flute could provide important guidelines for predicting tool life or potential catastrophic tool failure during machining of Inconel 718.

Investigation of Surface Roughness and Tool wear during turning of Titanium Alloy Grade 5 (Ti-6Al-4V) by using coated carbide tool and optimization of process parameters

The paper presents an experimental investigation to analyze the effects of process parameters on the surface roughness & tool wear in dry machining of Ti-6Al-4V. The process variable used are tool noise radius, feed rate & cutting speed to study their effect on surface roughness and tool wear using coated carbide as cutting tool. The surface roughness of the specimen has been measured with the help stylus-type Profilometer, Surfcom Flex 50A. The tool wear of cutting inserts is analysis by SEM analysis. The results show that the feed rate and nose radius are the significant variable for surface roughness. Surface roughness increases considerably with the increase in feed rate & tool wear and as the nose radius of cutting tool increases, the value of tool wear decreases. The process parameters are optimized for surface roughness.

Phytodetrital quality (C:N ratio) and temperature changes affect C and N cycling of the intertidal mixotrophic foraminifer Haynesina germanica

The combination of lower diet quality and increased metabolic rates is assumed to cause cascading effects on organismic C cycling. Future changes in CO2 levels or terrestrial nutrient discharges in marine ecosystems can lead to increased phytoplankton C:N ratios relative to consumer C:N ratios, lowering the quality of the food source. In this study, we compared the single and interactive effects of diet quality and temperature on the feeding behavior and C and N intake and release of a common and abundant intertidal mixotrophic protist, the foraminifer Haynesina germanica. Two batches of artificially produced and dual isotope-labeled (13C/15N) chlorophyte detritus with different C:N ratios (5.6 and 7.1) were fed to the foraminifer at 3 different temperatures (15, 20, 25°C). We observed a strong interactive effect of temperature and diet. A very strong increase in feeding rates was observed at 20°C for the low-quality food source. Respiration rates of carbon derived from the low-quality diet (C:N ratio of 7.1) were lower than those of the high-quality diets and increased at 25°C. This indicates that a high C content of the diet might be of advantage in calcifying mixotrophs, since respired excess C could be advantageous for test calcification. Additionally, respired excess C could be a useful resource of CO2 for kleptoplast photosynthesis and functionality in the mixotrophic lifestyle of H. germanica. Further, the observed effects of diet and temperature could impact nutrient fluxes in the habitat of H. germanica, possibly leading to food-web shifts in the future.

Ocena performansi mašine sa motorom za ljuštanje ginger korena

A 5kg motorized Ginger rhizome (Zingiber Officinale Roscoe) peeling machine was designed, developed and tested. Three moisture contents (70%, 75% and 80% wb), three feed rates (54 kg/h, 68 kg/h and 73 kg/h) and three peeling speeds (230 rpm, 270 rpm and 300 rpm) were used for the performance evaluation of the machine. A 3 × 3 × 3 factorial experiment in a randomized complete block design (RCBD); replicated two times was used to study the effects and interactions of the three factors (moisture content, feed rates and peeling speed) on the performance parameters (peeling efficiency, peeling capacity and percent damage). Relationship between performance parameters and the influencing factors were determined using multilevel factorial design and response surface methodology for the graphical analyses. The study showed that peeling efficiency increased from 82.3% to 88.5% with an increase in moisture content from 70% to 80%, a decrease in feed rate from 73 kg/h to 54 kg/h and an increase in peeling speed from 230 rpm to 300 rpm. Peeling capacity increased from 2.4 kg/h to 11.64 kg/h with an increase in moisture content from 70% to 80%, a decrease in feed rate from 73 kg/h to 54 kg/h and an increase in peeling speed from 230 rpmto300 rpm. Percent damage increased from 6.3% to 14.4% with a decrease in moisture content from 80% to 70%, an increase in feed rate from 54 kg/h to 73 kg/h and an increase in peeling speed from 230 rpm to 300 rpm. The analysis of variance (ANOVA) result showed that the interaction of moisture content, feed rate and peeling speed had significant effect on peeling efficiency, peeling capacity and percent damage at p<0.05 level. For a maximum peeling efficiency, peeling capacity and minimum percent damage, an optimum moisture content of 75%, feed rate of 68 kg/h and peeling speed of 270 rpm were recommended for use.

Analysis of optimized turning parameters of Hastelloy C-276 using PVD coated carbide inserts in CNC lathe under dry condition

The major problem regarding machining of nickel-based superalloy such as Hastelloy C-276 is high tool wear for prolonged operation due to work hardening effect and the surface roughness which directly affects the performance of machined component during its application. In this study, the Design of Experiments (DOE) has been used to study the effect of main turning parameters (Cutting speed (V), Feed rate (F) and Depth of Cut (D)) to obtain minimum Cutting force (Fz), Surface Roughness (Ra) and tool wear of carbide inserts with the turning of Hastelloy C-276 under different cutting conditions. Dry machining of the workpiece was performed, and tests were designed according to Taguchi Analysis L16 orthogonal array. ANOVA analysis was performed to determine the importance of machining parameters on Fz, Ra, Tool wear. The results were analysed using Mean plots, signal -to -noise S/N ratio and 3D surface graphs. Optimal operating parameters were determined using the S/N ratio and desirability function analysis. Mathematical models were created for Fz, Ra and tool wear using Response Surface Methodology (RSM). The results indicate that Fz is significantly dependent on V, F and D and is minimum for higher cutting speed and lower feed and depth of cut. Ra is significantly dependent on feed rate and increases with increasing feed rate. Tool wear is significantly dependent on Cutting speed and has a parabolic variation with the same. The composite desirability of the output parameters is acceptable and tool life study is done for the optimized parameters. Chip morphology study and Tool life study was done to understand the nature of chip formed and the deformation of cutting insert.

Fabrication of ECM and study of its parameters in NaCl electrolyte

Electrochemical machining (ECM) is a process based on principle of Faraday’s to remove metal from the work piece. Faraday laws of electrolysis states that weight of substance produced during electrolysis is proportional to current passing, length of time the process used and the equivalent weight of material which is deposited. In ECM, a high current is passed between tool (cathode) and work piece (anode), through a conductive fluid. This non contact process produces the cavity which is the replica of the tool. This process is not affected by strength, hardness or toughness of the work piece. The major components are feed control system, electrolyte supply system, power supply unit, and work piece holding device. Experiments are carried out to note the change in M.R.R with respect to the process parameters: voltage, feed rate, flow of electrolyte and concentration of electrolyte. The M.R.R increases with an increase of electrolyte concentration and feed rate. The results obtained from the series of experiments carried out are tabulated and also represented graphically.

Modeling and Numerical Study of Ceramic Paste Extrusion

The extrusion processes of ceramic pastes, including 3D printing, are used for the production of high-value products. Ceramic paste extrusion is a complex process which depends on the paste rheological properties, die and extruder geometries, and operational parameters. Modeling and quantitative analysis of paste molding are important to design proper extrusion process for the production of high-value extrudates of desired strength, shape, and morphology. In this paper, the mathematical model of ram extrusion of ceramic materials is established, and the paste continuity and momentum equations for non-Newtonian fluid based on the modified Herschel-Bulkley viscous model were solved numerically. The effects of die geometry and paste feed rate on the distributions of paste velocity and pressure in the extruder and die were investigated numerically. As a result, the steeper radial profile of longitudinal velocity and higher value of longitudinal velocity were obtained in the narrow die. The pressure significantly increases in the die at a high feed rate, and the pressure profile is almost flat in the barrel. The rate of increase of the maximum pressure decreases with an increase of paste feed rate. The pressure steeply increases in the die of small diameter. The maximum pressure linearly increases with the ratio of die length to diameter.

Prediction of Temperature During Machinability of Al2O3 Reinforced Al7075

Metal matrix composite Al2O3 particle reinforced Al have become useful engineering materials due to their properties such as low cost, wear-resistant, heat-resistant and low weight. The present study focused on prediction of temperature produced during machining of Al2O3 reinforced with Al7075. In this investigation the percentage of Al2O3 (mesh size of 100-300)was varied 1%, 3%, 5%, 7% and 9% to the base material of Al7075. The temperature was measured using thermal gun at machining tip of the tool at which maximum temperature were measured by varying operational parameters such as depth of cut (0.25, 0.5, 0.75, 1 and 1.25mm), spindle speed (80, 112, 140, 200 and 355rpm) and feed rate (0.10, 0.12, 0.16, 0.2 and 0.25mm/sec). Experimental results revels that the temperature increases with increase in feed rate and depth, whereas, in case of spindle speed there is a fluctuation in temperature for all the combinations considered. The percentage contribution of operational parameters on temperature was determined using ANOVA analysis. Overall analyses for all the combination considered shows that feed rate (45.07%), depth (33.75%) and spindle speed (5.2%) on temperature. The developed models with a P-value are less than 0.05 were considered to be a statistically significant with 95% of confidence interval. A good agreement between experimental and statistical modeling were achieved and comparison of experimental and statistical analysis were drawn.

Drilling Speed and Bone Temperature of a Robot-assisted Ultrasonic Osteotome Applied to Vertebral Cancellous Bone.

An experimental investigation of a robot-assisted ultrasonic osteotome applied to vertebral cancellous bone. The aim of this study was to investigate the effect of various ultrasonic parameter settings on temperature in the drilling site and penetration time and determine the most suitable parameters for efficient and safe robot-based ultrasonically assisted bone drilling in spinal surgery. A robot-assisted ultrasonic osteotome device may be safe and effective for spinal drilling. Sixty specimens of bovine vertebral cancellous were randomly assigned to one of six groups, which varied by mode of ultrasonic vibration (L-T and L) and feed rate (one percent [0.8 mm/s], two percent [1.6 mm/s], and three pecent [2.4 mm/s]). Maximum temperature in the drilling site and penetration time was recorded. Maximum temperature in the drilling site decreased as output power increased for L-T and L modes, was significantly lower for L-T compared to L mode at each feed rate and power setting, was significantly different at feed rates of 1.6 mm/s versus 0.8 mm/s and 2.4 mm/s versus 0.8 mm/s for L-T mode at an output power of 60 W and 84 W, but was not influenced by feed rate for L mode. Penetration time did not significantly improve as output power increased for both L-T and L modes, was significantly decreased with increased feed rates, but was not significantly different between L-T and L modes. The optimal parameters for applying a robot-assisted ultrasonic osteotome to vertebral cancellous bone are L-T mode, maximum output power of 120 W, and maximum feed rate of 2.4 mm/s.Level of Evidence: 4.

Cellular automaton modeling of dynamic recrystallization in Al-Mg alloy coating fabricated using the friction surfacing process

In this study, the dynamic recrystallized microstructure of the friction-surfaced Al-Mg alloy coating was predicted using a cellular automaton model. To realize this objective, using the temperature and strain rate results obtained from a 3D thermo-mechanical finite element model combined with a cellular automaton model, the microstructure of the coating was predicted by taking into account the effects of the secondary phase particles during the coating process. Based on the results, it was observed that the percentage of error in estimating the grain size when considering the effects of secondary phase particles was much lower than the case where the effects of secondary phase particles were not considered. In addition, by considering a rotational speed in the range of 600–3000 rpm, a traverse speed in the range of 50–750 mm/min, and an axial feeding rate in the range of 100–820 mm/min, it is observed that with a simultaneous increase in the rotational and traverse speeds as well as a simultaneous increase in the axial feeding rate and the traverse speed, the grain size of the coating decreases; however, it bounces back up after reaching the minimum value. Based on the results predicted by the microstructural model, the minimum grain size of the coating (1.8 μm) was obtained at the rotational speed of 1400 rpm, the axial feed rate of 400 mm/min, and the traverse speed of 400 mm/min.

Analysis of flow behavior of size distributed spherical particles in screw feeder

A screw feeder is mainly used in industries for conveying and elevating granular materials. Despite having a simplistic design, the mechanics of conveying the material is quite complex. The flow behavior of particles in a screw feeder is influenced by its geometric and operating parameters. In this study, the authors focus on the change in flow behavior by changing these parameters, using the discrete element method (DEM) simulations software LIGGGHTS. The mass flow rate measurement and visual examination of the particle fill level in our experimental studies served as model validation. The simulations were conducted with monosized spherical particles, and a mass-based uniform distribution of particles, with diameters between 2 and 5 mm. A mass based uniform size distribution was considered to represent multisized biomass particles, with particle properties of a representative biomass being used. The simulations quantify the screw feeder performance in terms of mass flow rate, average particle speeds (axial, radial, and swirl), and average contact forces (normal and tangential). The average particle axial and radial speed increased and swirl speed decreased with increasing rotational speed. The increase in feed rate and flight pitch ratio enhances the average radial and swirl speed of particles. The swirl and radial speeds are highest for smallest particle diameter for all three varying parameters. The average normal and tangential contact forces increased with increasing rotational speed, particle feed rate and pitch flight ratio and was found highest for biggest particle diameter.

Experimental Investigations and Modeling of Tool Wear in Gun-Drilling Process of 37Cr4 Forge Steel, Using Artificial Neural Network with Taguchi Method

In this study, the tool wear in gun-drilling process of 37Cr4 forge steel was studied. So, the Taguchi method of design of experiments was used to investigate the effects of inputs (tool tip angles (internal and exterior cutting edge angles, free angle of inner and outer cutting edge) and feed rate) on tool wear as output, experimentally. Also, the feedforward backpropagation neural network was used to predict the tool wear in gun-drilling process considering internal and exterior cutting edge angles, free angle of inner and outer cutting edge and feed rate as input parameters of the neural network. In order to select the best performance network with minimum mean squared error in predicting the tool wear in gun-drilling process, the Taguchi method of design of experiments was used. Once again, the input parameters of this design were the number of neurons in hidden layer, type of training function and transfer function of hidden layer of neural network, and mean squared error obtained from neural network run was the output parameter. According to the results, increasing internal and exterior cutting edge angles leads to higher tool wear, while increasing free angle of inner and outer cutting edge decreases tool wear. The tool wear increases by increasing tool feed rate at the first steps, but it decreases by further increase in feed rate. Also, the mean squared error of the neural network with the best performance to predict the tool wear was 0.000433, the most differences of the network and experimental results were 0.096 µm and the regression R value of the network with the best performance was 0.98468.

Fatigue Life Enhancement of Carbon Steel By Ball Burnishing Process (Dept.M)

Burnishing, a plastic deformation process, becomes more popular in satisfying the increasing demands of machine component performance and reliability. Thus, investigating the burnishing parameters in order to improve the product quality is especially crucial. The objective of this research is 10 studies on the effect of the burnishing process on fatigue life. Experimental work was carried out on a CNC lathe to study the effect of burnishing parameters, such as, burnishing feed and burnishing force, on some surface characteristics such as; surface roughness, microhardness, and reduction in diameter. Then the effects of the burnishing parameters on the fatigue life are investigated through a fatigue test. Burnishing force and burnishing feed play an important role in controlling the values of all surface characteristics and fatigue life. Optimum burnishing parameters are established to minimize roughness and/or maximize surface hardening and fatigue life. It is found that it is possible to get longer fatigue life for machined parts than the virgin material by setting the proper burnishing conditions. Longer fatigue life is achieved using burnishing force of 210 N and feed rate of 0.12inm/rev. In general the microhardness at the burnished surface increases as the force and feed rate increase. The distribution of microhardness along the depth below the burnished surface and its affected depth are directly proportional with the burnishing force. It is also clearly shown that the fatigue life of burnished materials cannot be determined or explained solely by surface roughness or microhardness.

Preliminary Investigation of Delamination Factor for Drilling Wood Plastic Composites (WPC)

This study examines the effect of the delamination factor on wood composite drilling. Drilling is one of the most important machining operations in the manufacturing process, operating in a variety of ways to make life better every day. The preliminary experiment focuses on the implementation of three drilling strategies to determine the most appropriate for drilling composite and to identify the effect of the machining parameters of wood plastic composite (WPC) drilling. The CNC machining centre is used at the factory of the local company to assist them in the provision of certain production inputs. It is observed that the single step drill peck is the best suited strategy for drill WPC with less delamination at the entrance and exit holes compared to the other two methods, 2-peck and 4-peck drills. Hole tends to create a peel-up and to force the delamination down heavily along the hole edge when using the 4-peck process while the least peel-up pattern happens when using a single-step method. The findings also show a large amount of peel-up delamination as the feed rate increases. Therefore, the final results are also useful in understanding the relationship between the drilling parameters and the cutting experiments.