Empirical model for estimating the surface roughness of machined components under various cutting speed

The increasing importance of turning operations is gaining new dimensions in the present industrial age, in which the growing competition calls for all the efforts to be directed towards the economical manufacture of machined parts as well as surface finish is one of the most critical quality measure in mechanical products. In the present work, empirical models for estimating the surface roughness of machined components under various cutting speed have been developed using regression analysis software. The centre lathe was used to turn the components (stainless steel, mild steel and aluminum cast) at different cutting speed ranging between 76 rev/min to 600 rev/ min at a constant depth of cut of 1 mm/pass and feed rate of 0.5 mm/rev. and surface roughness of machined components measured with a digital portable surface roughness tester (TR100 Model) using centre line average method. The values obtained from the empirical models were found to compare favourably with the experimental values. The Mean Absolute Percent Deviation (MAPD) which measures absolute error as a percentage was found to be 1.46% (stainless steel), 4.55 %( mild steel) and 4.76% (aluminum cast) respectively. These values were insignificant and below the maximum recommended value of 10%. These model performances were therefore found to be satisfactory and show good predictability. @JASEMKeywords: cutting speed, centre lathe, empirical model, surface roughness, Mean absolute percentage deviatio

Effects of Process Parameters in the Production of High Density Polyethylene-Grass Composite

This study investigates the effects of process parameters in the production of high density polyethylene-grass composite; the process parameters and their interaction on the mechanical properties of the produced high density polyethylene-grass composite were investigated using split-split plot design. The results of the calculated Fisher’s Ratio (Fcal) at significant value of 0.05 for the process parameters such as percentage by volume of material, barrel temperature, material type and their interactions ranges from -80.11 to 29.95, and were presented on ANOVA Table. The results obtained shows that these process parameters contribute significantly to the production of high density polyethylene-grass composite in polymeric industries.Keywords: High density polyethylene-Grass composite, mechanical properties, Process parameters, Split-Split Plot Desig

Barrel Temperature Effects on the Mechanical Properties of Injection Moulded Plastic Products

The study of the effect of barrel temperatures on the tensile strength, proof stress, percentage elongation and flexural modulus of injected moulded plastic products of polyvinyl chloride (PVC), polypropylene (PP) and high density polyethylene (HDPE) have been carried out. An existing mould was used for the production of tension and deflection test specimen. Then a plunger type of injection machine was used to mould test specimens at various barrel temperatures ranging from 1600C to 2800C, keeping all other process variables constant. The tensile and deflection test carried out on the specimen, The results obtained showed that the maximum tensile strength for PVC, PP, and HDPE are 6.10N/mm2, 21.67N/mm2, and 12.94N/mm2 at barrel temperature of 2700C, 2700C, 2100C; Maximum proof stress was 3.44N/mm2, 20.63N/mm2, and 13.65N/mm2 at barrel temperature of 2400C, 2500C and 1600C; Maximum percentage elongation was 281% , 172%, and 313% at barrel temperature of 2700C, 2700C, and 2300C and Maximum flexual modulus was 19.56 X102 N/mm2, 29.03 X102 N/mm2 and 27.88 X102 N/mm2 at barrel temperatures of 2400C, 2800C, and 1600C respectively.http://dx.doi.org/10.4314/njt.v34i2.1

Effect of Cutting Fluids on the Flank Wear of High Speed and Carbide Tipped Cutting Tools

The major needs in machining are high material removal rate, good work surface finish and low tool wear. These objectives can be achieved by reducing tool wear using proper cutting fluid during machining. The effect of some cutting fluids namely: Mentholated spirit, paraffin, and soluble oil on the flank wear of High-speed steel and carbide tipped tools by orthogonal cutting has been studied. Cente lathe was used for cylindrical turning operated at a speed of 370rpm and depth of cut of 1mm to machine aluminum, brass, mild steel and medium carbon steel workpiece. It was observed that soluble oil with 20% water concentration gave minimum flank wear among the cutting fluids used. The flank wear were 0.002mm, 0.008mm, 0.009mm and 0.012mm for soluble oils, mentholated spirit, paraffin and dry machining respectively cutting fluid using high speed Steel cutting tool and Aluminum workpiece. For the workpiece, aluminum gave minimum tool flank wear, followed by brass. mild Steel and Medium Carbon Steel respectively. Carbide tipped tool also exhibited better flank wear resistance than High speed steel. Soluble oil gave the minimum flank wear and best surface finish for all workplace and so have the capacity to give a longer tool life when compared with other cutting fluid studied

MODELLING OF RESPONSES FROM ORTHOGONAL METAL CUTTING OF MILD STEEL USING CARBIDE INSERT TOOL

The purpose of this research was to develop models for the prediction of responses from orthogonal metal cutting process that are responsible for the machinability ratings of this technological system. Mild steel work-piece material that is representative sample for various industrial applications was machined. The various industrial applications of this representative sample range from mechanical shafts to fasteners, screws and hydraulic jack. These machine elements require high degree of surface finish. A fifteen-run based Box-Behnken response surface design was created using widely established machining parameters, namely cutting speed, feed rate and depth of cut. The optimum predicted responses from the orthogonal cutting process for the optimal process parameters are 0.1742 micron, 0.4933 micron, 0.1845 micron, 0.3673 micron, 794.6839 seconds and 19.642 seconds for the Ra, Rz, Rq, Rt, TL and M/C time respectively. The associated desirabilities for these optimum responses are 1.000000, 1.000000, 1.000000, 1.000000, 0.524122, and 0.361858 respectively.   http://dx.doi.org/10.4314/njt.v36i1.1

Performance Evaluation of Refractory Bricks produced from locally sourced Clay Materials

The performance evaluation of refractory bricks produced from some local clay deposits in Delta State, Nigeria was investigated. Four major sites in Delta State renowned for abundant clay deposits were selected, namely; Oghara, Ekpan, Ubeji and Jeddo. The clay samples were crushed, milled (pulverised) and sieved to produce very fine grains of less than 250 \u3bcm particle size distribution for all samples. They were then tested for shrinkage, bulk density, Loss on ignition, cold compression strength, apparent porosity, and thermal shock resistance. Also, their mineralogical composition and fusion temperatures were examined. The results shows that kaolin deposit at Oghara was found to be the best material suitable for the lining of the walls of most high thermally operated equipment as the expected operational temperatures of most of them are below 1200\ub0C. It had a bulk density, porosity,cold compressive strength, shrinkage, loss of ignition, slag resisance of 1.74g/cm3, 31.44%,100kg/cm2, 5% and 12.18% respectively. Oghara clay was found to be less dense, contains more porosity, and possesses low iron content and higher refractoriness with fusion temperature above 1200\ub0C. Ekpan clay is also suitable for medium thermal application in furnaces, kilns and stoves, while the rest could be beneficiated to improve on their insulating properties

Manufacture of Power Hacksaw Blades From Locally Available Medium Carbon Steel

The manufacture of power hacksaw blades using worn out sawmill blades made of medium carbon steel has bean achieved. They were produced through carburization, hardening and tempering processes. The produced power hacksaw blade when compared with the imported one showed the former having a slightly higher wear rate than the latter. The result also showed that the tool life of the produced power hacksaw having a hardness value of 459BHN and the imported one of hardness value 575 BHN was 922.3mins and 1140mins respectively. Although, the imported hacksaw blade has a slightly higher tool life than the produced one, which may due to a higher hardness value, the produced power hacksaw blade compares favourably well with the imported hacksaw blade.Keywords: Power hacksaw blade, bone charcoal, tooth wear, tooth life, hardness valueJournal of the Nigerian Association of Mathematical Physics, Volume 20 (March, 2012), pp 443 – 44

Manufacture of Power Hacksaw Blades From Locally Available Medium Carbon Steel

The manufacture of power hacksaw blades using worn out sawmill blades made of medium carbon steel has bean achieved. They were produced through carburization, hardening and tempering processes. The produced power hacksaw blade when compared with the imported one showed the former having a slightly higher wear rate than the latter. The result also showed that the tool life of the produced power hacksaw having a hardness value of 459BHN and the imported one of hardness value 575 BHN was 922.3mins and 1140mins respectively. Although, the imported hacksaw blade has a slightly higher tool life than the produced one, which may due to a higher hardness value, the produced power hacksaw blade compares favourably well with the imported hacksaw blade.Keywords: Power hacksaw blade, bone charcoal, tooth wear, tooth life, hardness value

Design and Fabrication of a Foundry Sand Mixer Using Locally Available Materials

Most small foundry shops mix their sand manually which is not efficient since homogenous mix cannot be guaranteed and even when foundry mixer are available most of them are imported costing the nation huge foriegn exchange. A foundry sand mixer capable of mixing foundry sand has been designed and fabricated using locally available material. The sand mixer components machine frame, mixing pan, motor support, gear box speed reducer, Shaft, discharge door and Mixing blades were designed ,produced and assembled together to produce the mixer. A step-turned shaft of diameters 23mm and 33mm attached to a 2hp, 3 phase electric motor to transmit the torque required to effectively turn and mix the sand in the pan. The mixer test results show that the average mixing time of the sand mixer to mix 20kg of sand was 14minutes and the mixer efficiency was 52%.The fabricated mixer compare favourably with the the imported existing one which has an efficiency of 59%.The application of this sand mixer by foundry shops will eliminate the use manual effort which is cumbersome, time wasting and inefficient.It will also save the the country of huge foreign exchange used in the importation of foundry sand mixershttp://dx.doi.org/10.4314/njt.v33i4.2