WEDM microdrilling of 316 L stainless steel orthopedic implant

2020 ◽  
Vol 234 (17) ◽  
pp. 3416-3435
Author(s):  
AK Sahu ◽  
S Pattanayak ◽  
S Panda
Keyword(s):  
Feed Rate ◽  
Side Wall ◽  
Orthopedic Implants ◽  
Quality Characteristics ◽  
Recast Layer ◽  
Entry And Exit ◽  
Response Characteristics ◽  
316 L Stainless Steel ◽  
Drilling Condition

The development in manufacturing has insisted upon the fabrication of microdrilled holes on orthopedic implants, with finished side wall (devoid of cracks and burr), thin recast layer, low taper, and improved circularity at entry and exit of the hole. In this study, therefore, a multiobjective optimization of wire electric discharge machining microdrilling response characteristics is addressed in order to improve the hole quality characteristics and viability of implants. To improve the quality characteristics of the hole, a hybrid statistical analysis is developed based on grey relational analysis and coefficient of variation. It identifies the key process parameters that are responsible for improving the quality of the hole. The parametric study also reveals that wire feed rate and servo feed rate have a striking effect on the quality of the hole. An important implication of this study is that a thin recast layer, improved entry and exit circularity, adequate taper were observed under optimum drilling condition.

Design of Double Cone Twist Drill Geometry to Improve the Holes Quality While Drilling in Multi-Stack Made of CFRP/Al

2014 ◽  
Author(s):  
Redouane Zitoune ◽  
Sofiane Alma Bouacif ◽  
Krishnaraj Vijayan ◽  
Collombet Francis
Keyword(s):  
Feed Rate ◽  
Thrust Force ◽  
Double Cone ◽  
Twist Drill ◽  
Entry And Exit ◽  
Composite Part ◽  
Numerical Studies ◽  
Aluminum Part ◽  
Cone Drill

In this paper, experimental and numerical studies on drilling of multi-material made of CFRP laminate sandwiched with aluminum part have been carried out. These tests have been conducted using carbide drills (K20) to study the influence of spindle speed, feed rate and lip length of the double cone drill on cutting forces and holes quality. From the experimental study it was found that the double cone drills used for the experimental analysis encountered less thrust force compared to the standard twist drill. In addition the quality of the holes after drilling was evaluated, and found that no delamination (entry and exit of the hole of the composite part) even at higher feed rate (> to 0.1 mm/rev). By numerical modeling, it was noticed that, after machining with standard twist drill at higher feed rates, the thrust force generated induces a small opening at the CFRP/Al interface.

Experimental Investigation on Prediction of Hole Quality Characteristics of Aluminum Matrix Composite (AMC225xe)

2012 ◽  
Vol 622-623 ◽  
pp. 1305-1309 ◽  
Author(s):  
Sureshkumar Manickam Shanmugasundaram ◽  
Lakshmanan Damodhiran ◽  
Murugarajan Angamuthu
Keyword(s):  
Experimental Investigation ◽  
Matrix Composite ◽  
Process Parameters ◽  
Feed Rate ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composite ◽  
Quality Characteristics ◽  
Hole Quality ◽  
Machining Properties

Wide spread applications of composite materials have been significantly growing in aerospace, naval, space, and automotive industries. Drilling of such materials is a challenging task because of differential machining properties and checking the quality of hole is significantly a great attention. In this paper, experimental investigation on prediction of hole quality characteristics of aluminum matrix composite (AMC225xe) during drilling process. The influence of process parameters such as speed, feed rate and coolant flow rate on the surface finish and circularity were investigated during the experimentation. The experiments were conducted according to the Taguchi’s L9 array design using process parameters. The quality of the hole characteristics were measured using roughness tester and CMM. Regression analysis has been carried out for prediction of hole quality characteristics from the experimentation. It is observed that the predicted results are good correlation with measured values. Also, the results indicate that the feed rate is the most influencing parameter for drilling of AMC225xe.

Beech sapling architecture following small and medium gap disturbances in silver fir-beech old-growth forests in Slovenia

2005 ◽  
Vol 156 (12) ◽  
pp. 481-486 ◽  
Author(s):  
Jurij Diaci ◽  
Lahorka Kozjek
Keyword(s):  
Light Intensity ◽  
Quality Characteristics ◽  
Stem Length ◽  
Silver Fir ◽  
Beech Forests ◽  
Vertical Growth ◽  
Relative Light Intensity ◽  
Stem Bending ◽  
Negative Effect

The objective of our research was to examine the effect of canopy shading on beech sapling architecture in the oldgrowth silver fir-beech forests of Pecka and Rajhenavski Rog. In August 2003 we sampled one plot (352 m2) in a large gap in Pecka, which was a result of a strong windstorm in 1983, and eight small gaps (26–78 m2) with similar sapling heights (3.8–8 m). A ground view of each gap was drawn including the characteristics of gap border trees and the density of separate sapling layers was recorded. The height and diameter were measured for each sapling, as well as the following quality characteristics on selected dominant saplings: width of the crown,number of larger branches and knots (>1/3 DBH), intensity of stem bending, deviation from vertical growth, number of terminal shoots, and the type of damage. The results show a negative effect of high canopy shading (estimated relative light intensity was below 5%) on the architectural quality of saplings. A lower overall density of saplings, greater intensity of bending and deviation from vertical growth, a shorter stem length without branches, a larger number of saplings with two terminal shoots, and a larger number of damaged saplings were observed in small gaps.

scholarly journals Effect of Tool Geometry Parameters on the Formability of a Camera Cover in the Deep Drawing Process

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3993
Author(s):  
Thanh Trung Do ◽  
Pham Son Minh ◽  
Nhan Le
Keyword(s):  
Deep Drawing ◽  
Thickness Distribution ◽  
Metal Flow ◽  
Sheet Thickness ◽  
Side Wall ◽  
Tool Geometry ◽  
Drawing Process ◽  
Nose Radius ◽  
Deep Drawing Process

The formability of the drawn part in the deep drawing process depends not only on the material properties, but also on the equipment used, metal flow control and tool parameters. The most common defects can be the thickening, stretching and splitting. However, the optimization of tools including the die and punch parameters leads to a reduction of the defects and improves the quality of the products. In this paper, the formability of the camera cover by aluminum alloy A1050 in the deep drawing process was examined relating to the tool geometry parameters based on numerical and experimental analyses. The results showed that the thickness was the smallest and the stress was the highest at one of the bottom corners where the biaxial stretching was the predominant mode of deformation. The problems of the thickening at the flange area, the stretching at the side wall and the splitting at the bottom corners could be prevented when the tool parameters were optimized that related to the thickness and stress. It was clear that the optimal thickness distribution of the camera cover was obtained by the design of tools with the best values—with the die edge radius 10 times, the pocket radius on the bottom of the die 5 times, and the punch nose radius 2.5 times the sheet thickness. Additionally, the quality of the camera cover was improved with a maximum thinning of 25% experimentally, and it was within the suggested maximum allowable thickness reduction of 45% for various industrial applications after optimizing the tool geometry parameters in the deep drawing process.

scholarly journals Quality Characteristics of Semi-Moist Apricot-Cornflakes: Effect of Different Composite Coating Application and Storage Time

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 516
Author(s):  
Roghieh Sakooei-Vayghan ◽  
Seyed Hadi Peighambardoust ◽  
Rubén Domínguez ◽  
Mirian Pateiro ◽  
José M. Lorenzo
Keyword(s):  
Storage Time ◽  
Composite Coatings ◽  
Protein Isolate ◽  
Quality Characteristics ◽  
Moisture Loss ◽  
Coating Application ◽  
Hot Air ◽  
And Storage ◽  
Β Carotene

The effect of different composite coatings on quality of semi-moist apricot cubes mixed with cornflakes was investigated during 180 days of storage. The apricot cubes were osmotically dehydrated (OD) and coated before hot-air drying (HAD) at 60 °C. Chitosan-bees wax (CBW) and whey protein isolate-bees wax-oleic acid (WPI-BW-OA) coatings were applied after HAD and the samples were added to cornflakes. Application of OD and pectin-ascorbic acid (Pec-AA) coating (prior to HAD) and WPI-BW-OA coating (after HAD) led to significant retention of total phenol compounds, β-carotene and antioxidant activity in apricot cubes compared to uncoated and CBW-coated samples. WPI-BW-OA-coated samples gave significantly higher L* values (lighter color) and b* values (more creamy or yellowish color) and lower a* values (less reddish color) and browning values than control followed by CBW-coated apricots at any time of storage (p < 0.05). The rate of apricot moisture loss and cornflakes moisture gain was higher in uncoated apricot cubes, followed by CBW- and WPI-BW-OA-coated samples. Application of WPI-BW-OA coating was effective in retaining the crispness measured by lower firmness (Fmax) values in cornflakes upon storage. Based on the obtained results, WPI-BW-OA coating allowed effectively preserving the quality characteristics of semi-moist apricot cubes and cornflakes components in the mixed state.

scholarly journals Effect of Humidity-Controlled Dehydration on Microbial Growth and Quality Characteristics of Fresh Wet Noodles

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 844
Author(s):  
Jun-Jie Xing ◽  
Dong-Hui Jiang ◽  
Zhen Yang ◽  
Xiao-Na Guo ◽  
Ke-Xue Zhu
Keyword(s):  
Shelf Life ◽  
Microbial Growth ◽  
Treatment Time ◽  
Positive Influence ◽  
Quality Characteristics ◽  
Plate Count ◽  
Cooking Properties ◽  
Total Plate Count ◽  
Different Temperatures

Humidity-controlled dehydration (HCD) was innovatively applied in this paper to control the growth of microorganisms in fresh wet noodles (FWN). Effects of HCD treatment with different temperatures (40, 60 or 80 °C), relative humidity (RH, 50%, 70% or 90%) and treatment time (5–32 min) on the total plate count (TPC), the shelf-life, and qualities of FWN were investigated. The results showed that HCD reduced the initial microbial load on the fresh noodles and extended the shelf-life up to 14–15 days under refrigeration temperature (10 °C). A 1.39 log10 CFU/g reduction for the initial TPC was achieved after HCD treatment at the temperature of 60 °C and RH of 90%. HCD with higher RH had a more positive influence on quality improvement. The L* values, the apparent stickiness, and the cooking properties of the noodle body were improved by HCD while good sensory and texture quality of noodles were still maintained after the dehydration process.

STUDY ON THE PROCESS OF RAPESEED HULLING BY THE IMPACT

2019 ◽  
Author(s):  
А.О. РЕНЗЯЕВ ◽  
О.П. РЕНЗЯЕВ ◽  
С.Н. КРАВЧЕНКО ◽  
Р.В. КРЮК
Keyword(s):  
Rotational Speed ◽  
Calculated Data ◽  
Quality Characteristics ◽  
Complete Separation ◽  
Edible Oil ◽  
Siberian Region ◽  
The Core ◽  
The Cost ◽  
The Impact

Исследованы прочностные и физико-механические свойства оболочки рапса с точки зрения ее разрушения и удаления. Установлено, что наиболее рациональным является двухстадийный способ обрушивания: 1-я стадия – на вальцовых мельницах, 2-я – на центробежной обрушивающей машине. Определены параметры центробежной обрушивающей машины для обеспечения минимальной необходимой линейной скорости 10,81 м/с: угол наклона отбойной пластины (90 ± 2)°, частота вращения барабана (2400 ± 150) об/мин. Установлено, что правильно подобранные условия и угол, под которым происходит удар, позволяют значительно снизить количество не до конца обрушенного семени и содержание расколотого ядра. При этом при свободном ударе об отбойную пластину под углом, отличным от 88–91°, или подаче недостаточно равномерного потока семян значительно увеличивается содержание необрушенных семян. На разрушение 1 кг семян необходимо затратить 58,45 Дж. Таким образом, по расчетным данным, для семян рапса диаметром 1,5 мм частота вращения барабана должна находиться в диапазоне от 2221 до 2565 об/мин при ударе семени под углом 90°. Диаметр семян рапса, выращиваемого в Сибирском регионе, составляет от 0,8 до 1,8 мм. Установлено, что подсушивание семян рапса в течение 30–40 с при температуре 100°С позволяет увеличить эффективность разрушения оболочки до полного ее отделения от ядра рапса. Представленные результаты позволяют повысить качество очистки семян рапса от оболочки и улучшить качественные характеристики получаемого масла, облегчить последующие технологические процессы получения пищевого масла, снизить затраты на рафинацию и дезодорацию на 2%. The strength and physico-mechanical properties of the shell of rapeseed in terms of its destruction and removal are investigated. It is established that the most rational is a two-stage method of seed hulling: the 1st stage – on roller mills, the 2nd – on a centrifugal hulling machine. The parameters of the centrifugal hulling machine to provide the minimum required linear speed of 10,81 m/s are defined: the angle of inclination of the turnback plate (90 ± 2)°, the rotational speed of drum (2400 ± 150) RPM. It is established that the correctly selected conditions and the angle at which the impact occurs, can significantly reduce the amount is not completely hulling seed and the substance of the split nucleus. At the same time, with a free impact on the turnback plate at an angle different from 88–91°, or the supply of an insufficiently uniform flow of seeds, the content is not completely hulling seed increases significantly. On hulling of 1 kg of seeds it is necessary to spend 58,45 J. Thus, according to the calculated data, for rape seeds with a diameter of 1,5 mm, the rotational speed of drum should be in the range from 2221 to 2565 RPM when the seed is struck at an angle of 90°. The diameter of rapeseed grown in the Siberian region ranges from 0,8 to 1,8 mm. It was found that drying of rapeseed for 30–40 s at a temperature of 100°C, can increase the efficiency of destruction of the shell to its complete separation from the core of rapeseed. The presented results make it possible to improve the quality of cleaning of rape seeds from the shell and improve the quality characteristics of the obtained oil, facilitate the subsequent technological processes of obtaining edible oil, reduce the cost of refining and deodorization by 2%.

Water quality of the Beli Lom river

1999 ◽  
Vol 39 (8) ◽  
pp. 55-62 ◽  
Author(s):  
Anastasios I. Stamou ◽  
Bogdana Koumanova ◽  
Stoyan Stoyanov ◽  
Georgy Atanasov ◽  
Konstantinos Pipilis
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Finite Difference ◽  
Treatment Plant ◽  
Quality Characteristics ◽  
Order Model ◽  
The Third ◽  
Do Concentration

A general methodology for the study of water quality in rivers is presented. The paper consists of four parts. In the first part the general characteristics of the area of study, which is the Beli Lom river, and its major pollution sources are presented. The effluent of the Razgrad Wastewater Treatment Plant (RWWTP) has been identified as the most significant pollution point source, due to the inadequate performance of the plant. The second part deals with data collection and processing. Four series of data have been collected, including physical, flow and water quality characteristics. In the third part a 1-d, finite-difference, second-order model is presented. In the fourth part, the model is calibrated, for the determination of its main coefficients, and is successfully verified by predicting the BOD and DO concentrations in the Beli Lom river for all series of data. Finally, the model has been applied to determine the maximum BOD and minimum DO effluent concentrations of the RWWTP, so that a minimum DO concentration is maintained throughout the river.

scholarly journals Quality characteristics of spatial furniture

2009 ◽  
pp. 135-145 ◽  
Author(s):  
Dusan Skakic ◽  
Igor Dzincic
Keyword(s):  
Quality Control ◽  
Quality Characteristics ◽  
High Quality ◽  
Production Economy ◽  
Production Practice ◽  
Basic Quality ◽  
Quality Of Products ◽  
Quality Production

The quality of products represents one of the key aims of any modern organized production. In the production practice, it is essential to establish the optimal relationship between quality, production economy and delivery deadlines. Furniture quality is evaluated by three levels and they are: basic quality, high quality and especially high quality. The results presented in this paper are based on the sample measurements of chairs and tables during 2007 and 2008 at the Institute for Furniture Quality Control.

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