A.O. Akii Ibhadode

Development of Asbestos-Free Friction Lining Material from Palm Kernel Shell

Friction materials are applicable for braking and transmission in various machines and equipment. Their composition keeps changing to keep pace with technological development and environmental/legal requirements. For more than 80 years asbestos has been used as a friction material because of its good physical and chemical properties. However, due to the health hazard associated with its handling, it has lost favour and several alternative materials are being increasingly used. Thus, in this work, a non - asbestos friction material was developed using an agro-waste material base - palm kernel shell (PKS)- along with other constituents. Among the agro-waste shells investigated the PKS exhibited more favourable properties. Taguchi optimization technique was used to achieve optimal friction material formulation and manufacturing parameters. The derived friction material was used to produce automobile disk brake pads. The laboratory brake pads were tested for wear and effectiveness on a car. When compared with a premium asbestos-based commercial brake pad they were found to have performed satisfactorily. However, more pad wear was observed on the PKS pad at high vehicular speeds beyond 80km/hour. The results suggest that palm kernel shell could be a possible replacement for asbestos in friction lining materials.

Numerical Investigation of Thermo-Mechanical Behaviour of Ball Grid Array Solder Joint at High Temperature Excursion

The solder joints of surface mount components (SMCs) experience thermal degradation culminating in creep and plastic shear strain deformation when subjected to cyclic temperature load over time. Degradation at the joints is due to thermal stress induced by the incompatible, differential and nonlinear expansion mismatch of the different bonded materials in the assembly. The stress magnitude influences the strain behaviour. Plastic strain response of solder joint is critical at the materials interface at the lower part of the joint due to the occurrence of wider variation in the coefficient of thermal expansion of the bonded materials and this may lead to static structural failure. The life expectancy of electronic components reduces exponentially as the operating temperature increases thus making reliability a key concern for electronic systems operating at high temperatures and in harsh environments. This paper reports on the numerical investigation of thermo-mechanical response of a critical BGA joint especially the character of plastic deformation of SnPb solder used in forming the joint as well as the joint’s high temperature reliability. The analysis uses a 3-D models to predict the effect of the transient thermal load on the static structural integrity of a single BGA joint. In this study, the base diameter of solder ball (interface between the PCB, copper pad and the solder) experienced higher damage than the top diameter interconnects. The paper provides a simplified methodology to study the reliability of BGA solder joint at high temperatures excursion.

On a method for die container design in completely closed die forging

Relatively simple design equations are derived for selecting container external diameter in completely closed die forging, using die expansion as a basis. The method imposes a theoretical lower limit on the tolerance than can be specified on the maximum diameter of a forging. The method can be used for axisymmetric shapes such as solid and hollow cylinders, +-, U-, H-, and T-shapes.

Technical Properties of Some Plant Fibres Compared with Glass Fibre

The tensile strength, specific tensile strength, breaking force, tenacity and percent elongation of some fibres extracted from eight fibrous plants found in Northern Nigeria were determined with a view to ascertaining their suitability for the replacement of glass fibre in plastic composites. Also the crimp properties and work of rupture with the specific work of rupture for all the plant fibres were analysed. The fibrous plants were Sisal (Agave Sisalana) (ASA), Lalloh (Corchorus Triden L.) (CCR), Dargaza (Grewia Mollis Juss) (GRW), Kenaf (Hibiscus Cannabinus L.) (HCB), Goruba (Hyphaene Thebaica)(HYP), Sukuwa (Sida Acuta) (SDA), Karlgo (Piliostigma Thoningii) (PTA) and Shikuri Tuggah (Urena Lobata) (ULB). Their properties were compared with E-Glass. The results show that whereas the highest tensile strength of the plant fibre (ASB) was about one-third that of the glass fibre, the highest specific tensile strength of the plant fibre (HCB) was about 5 times that of the glass fibre. The percent elongation of the plant fibres except HYB and SDA were at least 5.6 times that of the glass fibre. The specific work of rupture for the plant fibre were also found to be upto 31% higher compared with that of glass. Three of the plant fibres, (HCB, ASA and ULB) were observed to be possible replacements for the classic glass fibre.

Development of a New Flux for Aluminium Gas Welding

A new flux based on NaCl – CaCl2 – CaF2 – Na3AlF6 was developed for the gas welding of aluminium and its alloys. The flux was generated by the application of the Hadamard multivariate chemical composition model. The model uses a 8 x 8 matrix and a full factorial analysis to generate several compositions within given ranges of the constituent flux elements. Mechanical and field tests were carried out on weldments made with the flux. The tensile strength, Izod impact strength and hardness of the all – weld metal were 310MPa, 5.35J and 100BHN. The weld deposition efficiency was 90.3%.The new flux and two popular commercial fluxes were given to five expert aluminium welders to use for three months, and were requested to rate the performances. The results showed that there was an agreement between the responses of the welders that the new flux performed better than the commercial versions available in Nigeria.

Design and Development of an Integrated Small-Scale Oil Palm Fruit Processing Mill

The oil palm (elaeis guneensis) is a very important economic crop in West Africa where it is native. The fruit bunch contains 23 to 30% oil and is the highest yielding of all vegetable oil crops. Palm oil is the second most important vegetable oil in world consumption and the first to be commercialized internationally. Africa and indeed Nigerian was the world’s highest producer of palm oil prior to 1961. Today, Nigeria is the fourth largest producer after Indonesia, Malaysia and Thailand. One of the main reasons given for this fall is lack of efficient mechanized processing equipment for the small-scale producers who produce over 80% of the country’s palm oil. Their methods of production are labour intensive, batch, tedious, inefficient, and produce poor quality oil, have low throughput, unable to extract palm kernel alongside palm oil and so productivity is low and products (palm oil and palm kernel) lack competitiveness. This work has developed a mechanized oil palm fruit processing mill with six fully integrated systems for extracting good quality palm oil and palm kernel, while utilizing process wastes as the main source of heat energy. Each system/unit is expected to operate at the best quoted system efficiency. Tests are ongoing to determine and confirm these efficiencies.

The Impact of 3D Printing Technology to the Nigerian Manufacturing GDP

3D printing can spur manufacturing rebirth in Nigeria and the World in general. There are many areas where 3D printing is creating significant change, particularly in designing and prototyping of new products, in the arts, and in visualizing abstract concepts. This is a step change from conventional manufacturing processes to rapid prototyping and layer manufacturing. This report has defined rapid prototyping, rapid manufacturing and the current technologies available to fabricate 3D components. In addition to this, it provides a brief overview of the current contributions of the Edo University Iyamho (EUI) in collaboration with the Federal University of Petroleum Resources, to sustain manufacturing research initiatives towards the development of locally fabricated 3D printer and the possible future Additive Manufacturing in Nigeria. It is anticipated that this work will benefit the Nigerian academic, research institutes, industries, thus, enhance the GDP contribution of the manufacturing sector in Nigeria.

Computerised Design Approach to a Sub-Press Mould for Composite Materials Manufacture

This paper focuses on the design of a sub-press mould mounted on a 100-Tonne hydraulic press during compression moulding of composite materials manufacturing process. The sub-press consisting of platens, punch and mould, and guide columns were designed using Microsoft Visual Basic software to minimize time wastages in trail-and-error procedures and mould modifications resulting after the mould is manufactured. Graphical representations of variables which were used in the design such as: platen thickness, guide pin dimensions, clamping force, heat supply, heat losses, and heating element were obtained. The program developed was tested on a solved example in a standard textbook and the result obtained compared well with the result in the book.

Risering of a Four-Cavity Die Production Mould by Convectional Method

This paper demonstrates the possibility of developing skill in producing sound metal casting from a four-cavity die production mould by assessing the riser design criteria and the castings. The assessment takes into account the location of the casting’s hot spots, casting modulus, liquid metal mass in the risers and the principle of directional solidification. The mould flask is oriented in such a way that a riser is placed directly on top of the casting’s hot spots for proper feeding during solidification. The assessment result of casting modulus shows that the feeder modulus Mf = 5.85 x 10-3 M and the casting hot spot modulus Mh = 1.88 x 10-3 M .The assessment result of castings solidification time shows that the castings solidify within 12 seconds while the feeders solidify within 30 seconds. From the assessment results it is observed that the risers hold liquid metal, feed the castings to full solidification and solidify later than the castings which they feed. Examinations at the cross sections of the finished castings revealed the absence of void formation which is a clear indication of effective and functional risers. Thus, the risers have achieved the desired requirement.

Punch and Counterpunch Design by the Die Expansion Method in Completely Closed Die Forging

Design equations based on die expansion are derived for selecting punch and counterpunch dimensions in completely closed die forging. The method imposes lower limits on the punch (counterpunch) – container radial clearance and forging height tolerance that may be specified.