Drilling Quality Research Articles

Evaluation of different drilling quality and fatigue life prediction of nickel-based superalloy using equivalent initial flaw size

The initial quality assessment and total fatigue life prediction of film cooling holes under different drilling processes have great impact on key structural components. In this paper, the initial fatigue quality of nickel-based superalloys with different drilling processes were evaluated and the fatigue life was predicted based on the equivalent initial flaw size (EIFS) theory. We raised the modified K-T diagram method based on intrinsic stress intensity factor threshold considering the small crack data. The fatigue crack growth test at room temperature is carried out on the single edge notched specimens made of nickel-based superalloy GH4169 under two different drilling processes (HEDM and FEDM) to quantitatively evaluate EIFS values. Then, a new expression of fatigue crack growth rate is proposed based on EIFS. Finally, the total fatigue life within 2 times error band is predicted by combining EIFS and fatigue crack growth rate, which confirms the validity of fatigue models and tests.

Influence of fiber direction and processing parameters on drilling temperature of CFRP

Drilling high quality holes is a necessary prerequisite to ensure efficient and accurate connection and assembly of CFRP components. In addition to cutting force, cutting heat is another important factor affecting the quality of CFRP drilling. In this paper, a drilling experiment of CFRP laminate is carried out, and the method of prefabricating thermocouple holes on the edge of the test-hole is used to study the influence of fiber direction and processing parameters on the drilling temperature. Results show that when drilling along the fiber direction of 0°, the heat conduction in the edge area of test-hole wall is better than that of drilling along the fiber direction of 90°. Accordingly, the drilling temperature is obviously higher. Under this experimental condition, the temperature difference of the edge area of test-hole caused by the fiber direction is as high as 44 °C. At the feed rate of 0.04 mm/rev, when the speed increases from 1500 rpm to 4500 rpm, the axial force decreases by 13.9 %, and the peak temperature at p1 and v1 increase by 63.2 % and 22.2 %, respectively. At the spindle speed of 3000 rpm, when the feed rate increases from 0.02 mm/rev to 0.06 mm/rev, the drilling axial force increases by 35.0 %, and the peak temperature at p1 and v1 decreases by 31.1 % and 30.0 %, respectively.

Performance of fan chips on drilling aluminium process

The metal fabrication process, especially in the metal drilling process, one of the parameters that affect the quality of metal drilling results is cooling media, because it affects the life of the tool used. This paper aims to determine the performance of using fan chips as an alternative to cooling media in the metal drilling process area. The method used with flow simulation and drilling process experiments on workpiece made from aluminum alloy 5086 in experimental testing uses a variation of the spindle rotation of a metal drilling machine with the aid of taking test data with an anemometer and infrared thermometer in the drilling process of the aluminum alloy 5086 workpiece. After experimenting with chips through spindle rotation variations, cooling of the process area occurs when the engine spindle rotation rotates above 1000 rpm and the temperature decreases at the end of the tool area by 5°C compared to without using fan chips. A decrease in the temperature of the work area of the drilling workpiece aluminum alloy 5086 compared without using fan chips has an impact on increasing the tool life limit by 12% or increasing tool life by 5 minutes.

Effect of processing of dental drill noise on subjective impression

The sound produced by a dental air turbine handpiece (dental drill) can markedly influence the sound environment in a dental clinic, and many patients have reported that the sound of a dental drill elicits unpleasant feelings. A comfortable sound environment for patients is desirable in medical care. To identify approaches for improving the sound quality of dental drills, we need to determine systematically the effects of the physical properties of the sounds of dental drills on their impressions. We, therefore, prepared 40 sound stimuli by processing different sound levels or frequency components comprising the sounds emitted by four kinds of dental drills. This study is designed to use psychoacoustic experiments to determine the effects of dental drill sounds on subjective impressions. The analysis resulted in the following findings: the overall attenuation of each original sound stimulus by 5 dB or 10 dB had statistically significant effects and improved the unpleasant impression. Attenuation of the frequency components above 9 kHz by 10 dB also improved the impressions, relative to those for the original sound stimuli. When the prominent frequency components at approximately 6 kHz were attenuated by 10 dB, no statistically significant differences were observed between the impressions corresponding to the original and processed stimuli. The Comfort Index (CI), which consists of the equivalent continuous A-weighted sound pressure level (LAeq) and calculated sharpness, showed a good correlation with unpleasant impressions. The present findings suggest that the consideration of acoustical characteristics based on the CI is useful in reducing the sound pressure level and refining the frequency characteristics of sounds emitted by dental drills, and this can aid in the development of new dental devices to create a comfortable sound environment in dental clinics.

Study on delamination inhibition and chip breakage mechanism in drilling metal laminated materials with double cone drill

Abstract With the continuous deepening of material research, laminated materials have been widely used in the aerospace field. The most common metal laminated material is aluminum/titanium (Al/Ti) stacks. Drilling is one of the most common methods of assembly. Due to the difference in material characteristics, problems such as delamination damage and chips winding around the drill are easy to occur when drilling metal laminated materials, which affect the drilling quality. The purpose of this study is to inhibit the delamination of Al/Ti laminated materials and improve the fracture ability of chips by changing the second point angle of the double cone drill. In this paper, the mechanical analysis of the drill structure is firstly carried out to obtain the torque models, and the drilling force is mainly analyzed based on torque. The combination of experiments and finite element method (FEM) is used to verify the correctness and feasibility of the mechanical models. The results show that, compared with the ordinary twist drill, the double cone drill can reduce the drilling force. Then, the effects of drilling force on delamination damage, chip morphology, and chip breakage during twist drilling and double cone drilling are analyzed and compared using simulation. The study found that compared with the twist drill, the use of the double cone drill to drill Al/Ti laminated materials will reduce the drilling force, resulting in less delamination damage. In addition, the second point angle makes the chip thickness produced by the double cone drill smaller than that of the twist drill, making it easier to break chips. Delamination damage and chip thickness decrease with the decrease of the second point angle.

Water-jet guided laser drilling of thermal barrier coated aerospace alloy

Drilling using quasi-continuous wave (QCW) millisecond pulse fibre laser is the state-of-the-art for producing film-cooling holes over uncoated aero-engine components. Laser drilling of coated components, including thermal barrier coated (TBC) components, is still a challenging task due to the risk of coating delamination. Water-jet guided (WJG) laser is nowadays increasingly used for machining of advanced materials such as ceramics and composites. This paper aims to study the basic fundamental characteristics of WJG lasers drilling of acute angular holes over TBC coated nickel superalloy and compare it with the state-of-the-art QCW millisecond fibre laser. Experiments were performed to investigate the characteristics of both QCW and WJG laser drilling in terms of TBC delamination, recast layer formation, hole surface topology and cycle time. Finite element analysis based numerical model was developed and used, to understand and confirm the mechanism of heat propagation and the subsequent material removal characteristics for both WJG and QCW laser. Experimental results show that the WJG laser drilling quality (in terms of thermal damages) is very similar to the process of cold-ablation (i.e. machining without inducing any thermal defects within the substrate material). The numerical model confirms the hypothesis that the high-temperature zone of WJG laser machining process is wholly confined within the small laser irradiation zone, which helps to avoid the TBC delamination typically observed with long pulse acute angle laser drilling process. The material removal mechanism of WJG laser machining seems to be the combination of melt ejection by vapour pressure, melt ejection by impulse shock pressure and by the action of water-jet pressure.

Saringan Cangkang Telur Bebek Efektif Memperbaiki Kualitas pH Dan Kadar Besi Air Sumur Bor

Water well drill that is in the Pondok Pesantren Hidayatullah Banjarbaru seen physically yellowish and smelly. Preliminary test result obtained pH 4.9 and Fe 2.5 mg/L. Based on the quality of clean water standards have not fulfilled the requirements of 1.0 mg/L and pH 6.5-8.5. It needs to be done research test of duck egg filter making in improving the quality of pH and Fe water well drill. The goal of this research is to know the effectiveness of duck egg filter in improving the quality of pH and Fe water wells drill. Types of research are experiments with pretest-posttest with control group. The population in the research is the whole water well drill in the Pondok Pesantren Hidayatullah Banjarbaru. A research sample is a water well drill that is partially taken for trial. Analysis of the influence thickness of the sieve using Anova asymp Test < œ (0.000 < 0.05) means there is a difference between the filter thickness of duck egg, 0 cm, 20 cm, 40 cm, 60 cm. Then done test Posh Hoc Tests can be concluded that there is a meaningful difference between the thickness of the filter of ducks egg shells 0 cm, 20 cm, 40 cm, 60 Based on the research results of the sieve 40 cm with a weight of 291 gram is an effective sieve in lowering the water level of the well drill.

Influence of hole quality on fatigue life of drilled CFRP with the different ply orientation angle

In this study, the effect of drilling quality on fatigue life of UD, 0/90, and ± 45 fiber angle carbon fiber reinforced plastics (CFRP) was investigated. CFRPs were drilled using WC, HSS, and Brad Spur tool types that have different geometries and materials at different feed rates of 0.05, 0.10, and 0.15 mm/rev, and at the different spindle speeds of 1000, 3000 and 5000 rev/min. Thrust forces were measured during the drilling of CFRPs, and surface roughnesses, deformation factors, and maximum tensile forces were measured after drilling operations. Thrust force, surface roughness, and deformation factor were evaluated in terms of drilling quality. The drilling parameters that cause the best, average, and worst drilling quality were determined. Then, fatigue behaviors of CFRPs drilled in these drilling parameters were investigated. Fatigue tests were carried out at %75, %80, %85, and %90 load ratios based on the lowest tensile force of the drilled samples. As a result of the study, it was determined that the thrust force, the deformation factor, and the surface roughness increased as the feed rate increased. However, the thrust force, the deformation factor, and the surface roughness decreased as the spindle speed increased. Besides, the best drilling quality was obtained from the drilling operation performed using WC tool type, at a spindle speed of 5000 rev/min and a feed rate of 0.05 mm/rev. The worst drilling quality was obtained from the drilling operation performed using Brad Spur tool type, at a spindle speed of 1000 rev/min and a feed rate of 0.15 mm/rev. With the decreasing drilling quality, a significant decrease occurred in the tensile force and fatigue life of CFRPs. The tensile load and fatigue life of CFRPs drilled in optimum drilling parameters were obtained higher. In the case of selecting the correct drilling parameters, it was observed that the reduction in fatigue life of CFRPs could be prevented ratios of %22–49.

Annular drilling process and quality control neural network model of stainless steel micro-hole with femtosecond laser

Annular drilling process and quality control neural network model of stainless steel micro-hole with femtosecond laser

Assessing the quality of drilling-and-blasting operations at the open pit limiting contour

Purpose. To develop a methodology for assessing the quality of drilling-and-blasting operations when setting the side to the final position. In this regard, it is necessary to study the nature of deformations in the near-side masses of the design open-pit contours and to assess the seismic impact of blast waves in accordance with damage in the near and far zones from the open-pit boundary, as well as the level of generated seismic vibrations. Methodology.A methodology for assessing the quality of drilling-and-blasting operations at the limiting contour of open pits is developed using the analysis of the mining-and-geological conditions of the rocks constituting the field, in-situ surveying of the state of the open-pit sides, analysis of the physical-mechanical properties of the host rocks, analytical studies and instrumental measurements of the blasting effect. Findings.Based on the analytical methods, the calculation and analysis of the seismicity coefficient of the rocks at the field have been performed. By means of instrumental measurement of the blasting effect in open pit, data have been obtained on the seismic impact of blasting operations on the near-side mass. Based on the results of these works, a methodology for assessing drilling-and-blasting operations at the limiting contour of the open pit has been developed. Originality.In this work, to assess the blasting effect, the seismicity coefficient of the rock mass is used, which characterizes the degree of elastic response to external dynamic influence and is a parameter that determines the elastic seismic wave intensity with distance from the site of blasting operations. Based on the calculation, a map of the seismicity coefficient distribution in the open-pit area has been compiled. Using the method of instrumental measurements, which serves to determine the seismic impact of blasting on a rock mass, the degree of blasting effect on a near-side mass has been revealed. This made it possible to develop a method for assessing the blasting quality, based on determining the percentage of permissible deviations in the face drilling quality. Practical value.The results of the work will be used to calculate the safe parameters of conducting the blasting operations when setting the side to the final position. This method for assessing the quality of drilling-and-blasting operations can be applied at any mining enterprise conducting open-cut mining of minerals.

Study on dedicated drill bit design for carbon fiber reinforced polymer drilling with improved cutting mechanism

Carbon fiber reinforced polymer (CFRP) has significant applications in the aerospace and automobile industries. However, the relatively high thermomechanical loads generated when drilling CFRP is considerably detrimental to the cutting tool. To address this issue, in this work, a step-change in the performance of CFRP drilling was conducted by switching the cutting model from crushing/compression fracture to the shear cutting of the composite workpiece to suppress the thermomechanical loads using a novel web thinning design. To evaluate the performance of the proposed drill bit, a comprehensive comparison was carried out between the dedicated and conventional drill bit designs from thermal, mechanical, and chip formation points of view. The results show that the dedicated drill bit outperformed the conventional drill bit in terms of thrust force, temperature elevation, burr, and exit-delamination. An in-depth observation revealed that the shear cutting became dominant in the drilling with the proposed drill bit while the crushing/compression was dominant with the conventional drill bit. The transition of the phenomena was induced by the properly designed rake angle. The mechanism of material removal in CFRP drilling using the dedicated drill bit design provides a new design direction to modifying the rake angle for improving the efficiency and quality of composite material drilling.

Impact of blast zone on mining processes in fractured rock mass

Generalization of the abundant experimental and theoretical research accomplished by Russian and foreign scientists in the 20th–21st centuries enables distinguishing between a few action zones of blasting, namely, crushing zone (fine grain crushing), radiating cracking zone, induced-fracture zone, shaking zone (residual stress after blasting), and blast-induced load zone. In the crushing zone, overgrinding takes place, which has an adverse influence on efficiency of processing of uranium, for instance, or granular quartz. The radiating cracking zone size in blasting in fractured rock masses governs the quality of drilling and blasting. The induced-fracture zone determines stability of rock mass and, consequently, safety of production processes both in surface and underground mines. In the shattering zone, fractured rock mass experiences residual stresses, which induces new fractures and rock falls, or dynamic events due to lithostatic pressure in rockburst-hazardous rock mass. This article aims at the experimental and theoretical determination of geometrics of blast-induced impact zones in different geological and geotechnical conditions with a view to developing appropriate actions toward abatement of the adverse effect exerted by these zones on geomechanical and technological processes in the course of mining. The theoretical formulas are given for the radii of the crushing, radiating cracking, induced fracturing and residual stress zones. Reliable applicability of the formulas in actual mining is proved by comparison of the calculations with the full-scale testing data. To mitigate the crushing zone impact, it is possible to charge the wellhead interval with a radial air gap, which decreases density of charging. Arrangements toward reduction of the zones of induced-fractures and residual stresses are proposed. Energy of the man-mane zone of residual stresses after blasting can be targeted at activation of raise driving with raise borer 2KV.

THE UTILIZATION OF DRILL CUTTING WASTE FOR BRICK MANUFACTURING

Chevron Geothermal Salak, Ltd (CGS) as one of the Geothermal Power Plants, to increase geothermal reserves, CGS conducts drilling and as is well known this activity produces a lot of drill cutting waste material so that it can quickly fill the temporary storage area. To overcome this, efforts should be made to reduce and / or utilize the waste. The effort is to use the material as a mixture of brick manufacturing. The purpose of this study is to be able to know the use of drill cutting waste as a raw material for brick manufacturing, to know the properties or characteristics and quality of drill cutting waste, and to be able to know the composition of the drill cutting waste mixture for brick manufacturing. The compositions used is drill cutting waste, soil stabilizer, and cement. In this study the compressive strength test was carried out at a maximum age of 28 days. It aims to find out the best mixture composition in the brick manufacturing, so that it gets high quality and can be used in the field. The results of this study can be concluded that by utilizing drill cutting waste as a material for making concrete blocks, it has achieved a compressive strength of 21.74 MPa that meets the quality requirements of concrete bricks in the quality level category IV. The brick products produced from the use of drill cutting can be used for drainage channels, trash container, pond walls, and retaining wall.

Study and analysis of various inclination pathway electrode tool in electrical discharge drilling

Abstract The response characteristics of Electrical Discharge Drilling (EDD) such as Material Removal Rate (MRR), critical drill depth, aspect ratio, taper angle, corner radius, drill quality are dependent upon the electrode design, fabrication mode, input variables, elimination of debris from machining area and working conditions. The present study aims to improve the response characteristics by modifying the design of a hollow cylindrical electrode. The modification consists of new angular pathway in the electrode with various angles (60°, 63°, and 66°) along with linear pathways. The response characteristics improvement noticed the nature of the Material Removable Rate (MRR), aspect ratio, and critical drill depth with the profile of proposed electrode. The proposed electrode has effectively removed the debris from machining area at an inclined pathway angle of 66° and presented a significant improvement in the average machining taper angle and corner. The overall quality of drilling improved with the proposed electrode design.

Characterization of machinability of sintered steel foams having different porosities during drilling operations

Steel foams are a new class of engineering materials with exceptional structure and properties. Foams produced by powder metallurgy generally have a near-net shape, however, sometimes machining operations may be required. The presence of porosity in steel foams significantly affects the cutting process and causes poor machinability. This study deals with the evaluation of the machinability of Cu-Ni-Mo-based steel foams having different porosity produced by powder metallurgy. High speed steel and carbide-tipped drills were used for the drilling. All tests were performed in dry condition with drill diameter of 3 mm. The drilling characteristics were evaluated in terms of the surface roughness, chip formation, drilling force, tool wear, microstructure and hardness change after drilling. The machinability was also evaluated by measuring average width of breakout and skewness values of the hole drilled. The results indicated that the increase of porosity negatively affected the drilling quality of high porous steels. Both drills broke the chips in powder form and produced discontinuous chips. High porous parts exhibited higher hardness change as compared to lower ones. The carbide drill showed acceptable drilling forces and surface quality. HSS drill is not suitable for drilling due to poor hole quality and high drill wear. Highlights Steel foams exhibit poor machinability due to highly porous structure. Porosity and tool type significantly affect the surface integrity of steel foams. Surface roughness and drill wear increased with increasing porosity; however, feed force decreased. Intense presence of pores decreases the tool life remarkably. The skewness values of hole are positive in all porosities. Carbide-tipped drill produced the finest hole quality. The larger damage was observed at the exit of the drilled holes with HSS drill.

Laser drilling process of Fe78Si9B13 amorphous alloy foil

The research on laser drilling of amorphous foils can promote the application of amorphous alloy in micro-machining. In this article, the effects of current, pulse width and defocusing amount on the quality of machined hole on Fe78Si9B13 amorphous alloy foils were analyzed by controlling the laser parameters. The experimental results showed that the hole diameter, remelting area (RMA) thickness and heat affected zone (HAZ) thickness increased obviously with the increase of current and pulse width. But high current caused serious erosion near the entrance of the hole and the taper of the machined holes increased with increasing pulse width. When the defocusing amount was 0, the hole diameter was the smallest and the forming quality of the machined hole was the best. Every parameter needs to be adjusted and coordinated to improve the quality of laser drilling.

Torsional model of the drill string, and real-time prediction of the bit rotational speed and the torque on bit, in an oil well drilling tower

In an oil well drilling tower, the Bottom Hole Assembly (BHA) data is needed to optimize the controllable variables such as weight on bit and bit rotational speed for obtaining the optimum drilling rate. In order to acquire the data of the BHA, a simple and low-cost method, can be predicting of these parameters. In this study, first the torsional modelling of the drill string is implemented by dividing its length to some equal sections, then the effects of dividing on the estimation accuracy are evaluated. Using an ADRC (Active Disturbance Rejection Controller) in the vertical and rotational motions dynamics, some proper observers to predict the bit rotational speed, rock stiffness and torque on bit, in real-time are designed and presented. Dividing the drill string length to more sections, leads to design high order observer, so the performance of the designed observers with different orders, are compared and analysed. Employing the integral square error analysis, it is revealed, dividing the drill string length to more sections, leads more accurate in the prediction of bit rotational speed, but not more effect on the estimated rock stiffness, and torque on bit. Also it is shown that increasing of the observer bandwidth, leads to more accurate in the estimation, but concludes the estimation be more sensitive to the sensor noise. Employing the presented observers in this study to estimate the BHA data, in addition to enhance the drill quality and safety, the controllable variables are optimized, and consequently the whole drilling process can be robustly controlled, with no needs to the expensive measurement systems at the BHA.

Novel orbital drilling and reaming tool for machining holes in carbon fiber–reinforced plastic (CFRP) composite laminates

Carbon fiber–reinforced plastics (CFRPs) have excellent mechanical and physical properties and are widely used to manufacture structural components and skins in aviation and aerospace. Industrial applications impose high requirements on the quality and efficiency of CFRP drilling. However, it is difficult to meet these requirements with conventional methods, such as drilling and orbital drilling. To improve hole processing quality, a novel cutting tool for orbital drilling was proposed in this research. Replacing the end mill in conventional orbital drilling (COD) with this novel cutting tool can enable an orbital drilling and reaming (ODR) machining process, which can suppress defects and reduce the thrust force when machining CFRP composite laminates. The thrust forces, tool wear, cutting temperatures, and hole quality in the ODR process presented in this paper were studied experimentally. The results indicated that machining with the novel ODR tool effectively reduced the thrust force and cutting temperature observed when machining with the general end mill. Moreover, the hole quality and tool life during ODR were exceedingly better than those during COD. The experimental results showed that processing with the novel tool has immense potential to replace existing processing methods for machining holes in CFRP composite laminates.

Design and field test of hydraulic thruster

With the increase of inclination and friction in the process of drilling deep wells or highly deviated wells, the horizontal component of the gravity of drilling strings decreases continuously, causing difficulty in applying weight on bit and slow penetration, which cannot meet the urgent demand of improving the quality and efficiency of drilling. Therefore, a single-stroke two-stage hydraulic thruster has been proposed, which changes the traditional way of applying WOB by pushing the piston rod down by differential pressure between the annulus and the tool tube. The performance parameters of the tool have been obtained through the ground test, the sealing performance and structural strength are reliable, and the stretching motion is stable. The field application of hydraulic thruster has been carried out in well Tao-2-4-18A, and the results showed that the drilling rate increased by about 50% compared with that of adjacent wells in both the Zhifang formation and the Heshanggou formation. In addition, the flexible pressurized propulsion function of this tool could effectively protect the bit and reduce times of trips.

APPLICATION OF MULTI CRITERIA DECISION MAKING OF SETTING INPUT PROCESS PARAMETERS FOR DRILLED PRODUCT QUALITY OF Al Si7 Cu4

Apparently, the drilling geometry and treatment influence the drill operation and its performance. Factually, the performance given by the drill bit is powerfully associative with efficiency, hence with economical fabrication. As a further matter, typical performance indicator, that is deviation from diameter, Cylindricity, tool wear, surface roughness is have been changed by drilling geometry. This fact that stress needed for novelty in drill design with further performance indicator optimization for quality of hole. In that prospect, here new drilling geometries were used. Various Drilling trials stayed directed utilizing the L9 orthogonal array. Various treatment processes like heat treatment, cryogenic or untreated (just as received) were carried out. Various tool nomenclature involving changing of helix angle were considered. The investigation performed on AlSi7Cu4 alloy with standard cutting tool, utilized all by trial made under dry cutting conditions. Later, drills were used to obtain hole on AlSi7Cu4, and their performance were examined and optimized to suggest optimum constraints of best attention. To estimate the performance of the drills, the drill quality of the hole stayed studied in terms of deviation of diameter, Cylindricity, and tool wear, surface roughness by the parameter optimization and the percentage of contribution were carried out by VIKOR methodology. As a result, geometry was developed by consideration of these negativities, and was found to show up superiority in performance when compared to other geometries in terms of quality of hole.