Theses supervised by Prof. Dr. Necdet Geren
20 theses · Çukurova University
Alternative proposals for automating rework of advanced surface mount components
ABSTRACT M.Sc. THESIS ALTERNATIVE PROPOSALS FOR AUTOMATING REWORK OF ADVANCED SURFACE MOUNT COMPONENTS Murat ÇAKIRCA DEPARTMENT OF MECHANICAL ENGINEERING INSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OF ÇUKUROVA Supervisor : Prof. Dr. Necdet GEREN Year: 2004, Pages: 205 Jury : Prof. Dr. Necdet GEREN : Prof. Dr. Melih BAYRAMO?LU : Assist. Prof. Dr. Murat AKSOY Owing to the inevitably increasing complexity in the printed circuit board assemblies (PCBAs), continuing improvements in current state of art technology remain elusive to achieve 100 percent manufacturing yields. Hence, rework and repair of complex, high value PCBAs is inevitable process during their service life. Additionally, due to the complicated natural structure of advanced surface mount components (SMCs) coupled with the novel technological requirements, there is a significantly growing need for a fully automated robotic rework system that can carry out the whole rework process of the advanced SMCs on the basis of a batch size of one. Thus, this study substantially aims to investigate and find out viable alternative proposals for fully automated, robotic rework of advanced type SMCs by effectively scmtinizing existing manual rework procedures, methods, tools and currently available technology on automation including industrial robots, sensory devices, inspection and control equipments etc. Development of such an automated robotic rework cell system was found to be technically and economically possible. Keywords: Automated PCBA Rework, Advanced SMCs, Robotic Rework, Automated Advanced SMCs Rework.
The design of the water-jet cutting machine, intensifier unit
Some of the advantages that the water-jet cutting systems provide in industrial area are: wide scale of cutting materials, any form can be cut easily, no tool change or wear, no thermal distortion. For these advantages water-jet cutting technology is getting spread in the industrial usage. The main part to intensify the water to the high pressures is the intensifier unit. Intensifier can be single layered as they can be double- layered or multi-layered. As 180 MPa is the upper pressure limit for the single layer intensifier due to the material properties based on material strength, the multi-layered intensifiers can withstand ultra high pressures. A single-layer prototype was produced in Mechanical Engineering Department Laboratory in The University of Çukurova which has the operating pressure of 180 MPa. Later a double-layer intensifier was produced to increase the operating pressure up to the 300 MPa. In this study, the design limits of the last prototype of intensifier was investigated according to the material, and optimum design criteria was found. Optimum design parameters and stress distributions along the radial axis were shown in graphs by using mathematical tools like Mathematica®. And the optimization method was explained briefly.
Design of a fully automated flexible PCBA rework system using systematic design techniques
Many various electronic products having different sizes are currently produced by the use of printed circuit board assemblies (PCBAs) that are assembled using surface mount IC packages and printed circuit boards. As with bigger products which are assembled with the use of PCBAs with bigger IC packages and printed circuit boards, the rework process that is carried out manually or with the use of semi-automated devices can be successful. Smaller electronic products such as mobile phones, computers, watch modules, smart cards, etc which involve PCBA with miniaturized advanced type surface mount components (SMCs) and high density boards, the rework process is not easily carried out manually or with the use of semi-automated devices and is prone to unsuccess. The rework of such SMCs can only be possible with fully automated flexible rework system. The design of such a system must be achieved by the systematic design methods or tools, taking into account all phases of a design process.Development of such a fully automated flexible PCBA rework system using systematic design techniques was found to be technically and economically possible.
Optimization of process parameters of drilling using the Taguchi method
In this study, optimization of process parameters of drilling operation in an horizontal machining center with C35 Mod BY workpiece material with TiCN coated indexable drilling inserts has been targeted. Surface roughness, perpendicularity and cylindiricity were selected as performance characteristics. Controlled factors were selected as hole diameter, hole depth, feed-rate and peripheral cutting speed. A L9 (34) orthogonal array has been employed and experimental runs have been planned. The performance characteristics were measured and various signal to noise ratios were calculated. Analysis of Variance has been carried out and effect levels of the controlled factors has been analyzed. From the analyzed data confirmation experiments have been carried out and the results were analyzed.
Redesign of high pressure pipes and connections for water-jet cutting system
Some of the advantages that the water-jet cutting systems provide in industrial area are: wide scale of cutting materials, any form can be cut easily, no tool change or wear, no thermal distortion. For these advantages water-jet cutting technology is getting spread in the industrial usage. A singlelayer prototype was produced in Mechanical Engineering Department Laboratory in the University of Çukurova which has the operating pressure of 180 MPa. Later a double-layer intensifier was produced to increase the operating pressure up to the 300 MPa. In this study, the high pressure connection parts which works under 300 Mpa is redesigned using reverse engineering and redesign methodology, a program is written for conical shrink-fit parts and using this program the conical form parts? optimum parameters are found in the water-jet system. Beside this, basic control parameters and some other parameters relationship was investigated.
Systematic design of carton separating machine
Corrugated cardboards (carton boards) are used for making containers to protect goods. Containers are made by cutting and folding a flat sheet of corrugated cardboard to obtain a desired pattern for one-piece package with fold-down corner. Undesired portions of the flat sheet cardboard are separated from the desired one-piece pattern. This may be called as ?the separation of the undesired pattern?. All of the steps are carried out using mass productions machines except ?the separation of the undesired pattern? that is usually the last production step before shipping the patterns to customers. The last step is usually performed manually using an employee who uses tools such as pneumatic saw or an adze to separate the unwanted portion form the desired one-piece pattern. This manual process slows down the production and creates damages on the edges of the cardboard such as buckling of flute structures, tears, and etc. This thesis aims to design an automated machine for ?the separation of the undesired pattern?. It uses systematic machine design methodology, which consists of conceptual design, embodiment design, and detail design stages. It also provides the steps of each phase including the results obtained.
A comparison of approaches to involute spur gear design
This thesis meets a need of selecting and using appropriate involute spur gear design approaches for all designers including the expert designers and novice learners who are practicing a spur gear design. Five design approaches with different level of difficulty, including the most commonly used machine elements textbooks, national and international standards were selected for comparison of design results. The results of each approach were analyzed by using a finite element method, ANSYS. And the loss or gain obtained from each of the approach was determined and results were given comparatively considering the gear failures criteria, speed ratios and power transmission ranges. Useful outputs, practical curves and charts were introduced to select the appropriate design approach. In addition to this, the study provides conversion factors which may be used to multiply the results of simple gear design approaches to ANSI/AGMA standards or in any of the five selected one. It also offers the best approach for students and designers who aim to optimize the gear design.
Parametric design of automotive ball joint using computer assisted 3d modeling
Ball joints which are used in steering system of vehicles have hundreds of different types and configurations. In this study, a platform called as "parametric design platform" has been developed for the parametric design of automotive ball joint using 3D modelling to reduce design time and cost. The developed platform can be used for part and assembly design with top-down design approach. In the development of the platform original "flow diagram" and "decomposition technique" has been used. The major advantage of the proposed system is that the system can parametrically change assembly, part, part material, feature, geometry and dimensions in a programmable environment. This provides a wide range of alternative solutions to design every parts of ball joints systematically. Whereas parametric systems, which is not programmable, provide change in dimensions only. After completing the development of "parametric design platform" tests have been applied to validate design and the results demonstrate the practicability and validity of the parametric system. Key Words: Parametric Design, Ball Joint, CAD Modeling, Automotive Steering System
Investigating the success of a new systematic product design approach on example designs
Morphological design methodology is one of the most useful methods to use during concept generation stage. Best design solution can be reached between the options which are offered. However, there has been considerable criticism of this design process model. Because, many possible combinations and different solutions can be obtain by multiplying of all function alternatives with one another. Only one or two of these design alternatives is practicable for production stage. Hence, concept design stage which is most important step of machine design stage does not complete easily during product design stage. In this study, we applied some modifications to morphological product design to achieve a new and different systematic product design methodology. Three different products will be used for performance measurement of a new approach to systematic product design and comparison with morphological design methodology. All of these methodologies will be apply to three products and the success of new approach will be obtain comparatively
The effect of additives on the low velocity impact properties of low density fiber sandwich panels
Sandwich structures with carbon fiber-epoxy face sheets and polyvinyl chloride foam core material are known for their high strength and flexural stiffness despite their low weight. However, poor impact characteristics make it difficult to operate these materials under impact load without failure. In this thesis work, it is aimed to increase the impact resistance of low weight composite sandwich structures. The focus is on the epoxy matrix, which has a brittle structure, because the improvement in impact properties is intended to be achieved without significant weight gain. Graphene, boron carbide and kaolin were used as additives in this study for the application of matrix toughening method. 2%, 5% and 10% by weight additives were mixed into epoxy matrix and sandwich structures were produced by hand lay-up and vacuum bagging method. All configurations were subjected to a low velocity drop weight impact test at three different energy levels (10 J, 17.5 J and 25 J). The results obtained from the experiments and the images of the post-impact damage of the sandwich structures are presented comparatively. According to the test results, configurations containing boron carbide additive were the most resistant to impact load. It has been observed that graphene additive increases impact resistance at low additive ratios, while kaolin additive has no significant effect on impact resistance.
A comparison of approaches to involute helical gear design
In this thesis, helical gears are designed according to different design approaches. The analytical iterations were made using MATLAB tool and the design results, module (m) and face width (F) were obtained for each design approach. Afterwards, three dimensional solid modeling was created using CATIA with the aid of design result of analytical calculations. The results obtained from the analytical method were confirmed by "Finite Element Analysis" using ANSYS. The design results of each design approach used in this study are compared with each other. Useful graphs, outputs, tables and charts are presented. In addition, the conversion factors of four different design approaches with respect to ANSI / AGMA Standard were obtained.
A comparison of approaches to involute bevel gear design
This thesis meets a need of selecting and using appropriate involute bevel gear design approaches for all designers from the expert to novice learners who are practicing a straight bevel gear design. Four straight bevel gear design approaches with different level of difficulty, including the ones available in the most commonly used machine elements textbooks, national and international standards were selected for comparison of design results. The results of each approach were analysed by using a finite element method, ANSYS. And the variations on the design results of each of the approach were determined, and the results were given comparatively considering the gear failures criteria, speed ratios and power transmission ranges. The outputs, practical curves and charts were introduced to select the appropriate design approach. In addition to this, the study provides conversion factors which may be used to translate the results of simple gear design approaches into ANSI/AGMA international standards or in any of the four selected one by multiplying with the appropriate conversion factors. It also offers the best approach for students and designers who aim to optimize the bevel gear design.
Ratings of various gear design approaches and a translation technique for spiral bevel gear design
In this thesis, spiral bevel gear design under bending fatigue stress has been designed according to various national and international standards and machine element textbooks. Numerical analysis was performed using the analytical results (module(m) and face width(F)) obtained from the design made for each approach. Numerical analysis was done using Ansys software. The dimensionless gear rating numbers (GRi) is obtained for each approach and then the derived correlation equations are used to generate the dimensionless conversion factors (CFs). CFs allow designers and engineering students to easily conversion from one approach to ANSI/AGMA Standard. In addition, it allows the designer to optimization of gear tooth volume using GRi values.
Developing and testing of polymer foam core sandwich structures with hybrid carbon fiber/wire mesh sheet facings
In this study, flexural characteristics of sandwich structures consist of carbon fiber/epoxy facings hybridized with fine wire mesh sheets and extremely low-density PVC foam core were investigated. A comprehensive work was conducted considering the following parameters: core thickness, wire mesh size, stacking sequences of wire mesh sheets, and support span length in flexural tests. During the evaluation of bending properties, both analytical and experimental approaches were utilized. To test the effect of design parameters on experimental results, two-way ANOVA was also applied. Failure mode analysis was made based on analytical collapse force mechanisms and primary failure modes were addressed. Significant improvements in flexural characteristics of sandwich structures were obtained. Besides improving bending behavior and the increased load-carrying capacity even at the same deflection values, the sandwiches with wire mesh sheets also prevented catastrophic sudden failure. The developed sandwiches can be good candidates in applications where both high stiffness-to-weight ratio and resistance to sudden failure are desired.
Development of a new sheet metal forming technique using low melting alloy 3D printers
The objective of this study is to produce a sheet metal forming mold made from the low melting point Bi58Sn42 alloy which proved to have sufficient strength in sheet metal forming operations by using open-source desktop type fused deposition modelling (FDM) 3-Dimensional (3D) printer and to evaluate the performance of the 3D printed mold for low volume sheet metal parts production. Thus, it was aimed to develop fast and inexpensive tooling methodology for small sized batch production. In this context, initially the 3D printing experiments were performed to produce the sheet metal forming mold. The encountered problems during the performed 3D printing experiments were analyzed. Accordingly, both tunings in print settings (extrusion temperature, extrusion multiplier, printing speed, infill rate, and etc.) and customizations on the extruder of the available FDM type 3D printer were made to print the Bi58Sn42 alloy properly. Subsequently, the performance of the 3D printed mold was evaluated according to the dimensional change on it during the performed pressing operations. Results showed that the 3D printed mold was rigid enough for low volume sheet metal parts production. Key Words: Bi58Sn42 alloy, customization on extruder, FDM, sheet metal forming mold, small sized batch production
Parametric modelling and validation for ball joint in Matlab partial differential equation module
The ball joint is exposed to variable loads and has a very critical importance in terms of safety in the automotive industry. Ball joints, which have hundreds of different variations, need to be analyzed under many different load conditions at the design stage. In this study, a parametric analysis study was carried out for the ball joint component. As an alternative to the parametric analysis performed with Excel, CAD software and Finite Element Analysis software, parametric analysis was performed in the Matlab Partial Differential Equation module. Simple geometries were also solved using the Manual Solution Method and softwares to ensure validation of the results. It has been observed that the results are generally compatible with each other, and many limitations of the Matlab software have emerged. If these limitations are removed, Matlab software will be used more widely for parametric analysis. Thus, time and cost will be reduced during the design phase.
Çeşitli mikro kanal kesit geometrilerine sahip karbon elyaf takviyeli kompozitlerin darbe ve eğilme davranışlarının belirlenmesi
In this thesis study, the effect of embedded microchannels serving functions such as thermal management, self-healing and damage detection in smart/multi-functional composite applications on the mechanical performance of carbon fiber reinforced polymer (CFRP) laminates has been investigated in terms of channel cross-section geometry. Reference test specimens without channels (NC) were compared with reference test specimens which have circular (CC), square (SC), hexagonal (HC), and star-shaped (StC) channels; behaviour under bending load was evaluated using a three-point bending test according to ASTM D790, while behaviour under impact load was evaluated using a 30 J low-velocity drop weight test according to ASTM D7136. In order to quantitatively relate geometry to the mechanical results, cross-sections of reference specimens were scanned using a coordinate measuring machine (CMM) and modelled in CAD software to calculate section properties. The results indicate that microchannel integration does not completely compromise performance under suitable production conditions; however, the damage initiation threshold and propagation characteristics change significantly as the cross-section becomes angled or complex. In terms of equivalent bending rigidity (SB), the highest increase compared to the NC (non-channelled) reference sample was observed in the circular-channelled (CC) reference sample (+68.1%). The absence of sharp corners in the circular cross-section limits stress concentrations, ensuring a more homogeneous load transfer and explaining the observed trend. In addition, circular geometry can offer advantages in terms of preserving fiber continuity, as it can cause lower local fiber deviation compared to sharp-edged channel geometries during manufacturing. While peak forces followed a similar pattern in impact tests, the absorbed energy was found to be lower in all channelled groups compared to NC (non-channelled test specimens). However, post-impact visual examinations have shown that the discontinuities created by micro-channels can divert the path of damage propagation, thereby limiting damage propagation in the thickness direction to a certain extent and contributing to the damage remaining more localised. Keywords: Smart composites, Embedded micro-channels, CFRP composites, Bending test, Impact test
The effect of wire mesh sheets on the fatigue properties of CFRP/PVC foam sandwich panels
Sandwich structures are frequently preferred in engineering applications requiring bending strength due to their low weight and high flexural stiffness. These sandwich structures can be subjected not only to static bending loads but also to variable bending loads in many engineering applications. In this study, stainless-steel wire mesh sheet hybridization was applied on very low-density polymeric sandwich structures and their fatigue performance under variable loading conditions was investigated. Plain woven carbon fiber and stainless-steel wire mesh sheet hybrid structure, epoxy resin, and closed cell polyvinyl chloride (PVC) foam with a density of 48 kg/m3 were used in the face sheets, binding matrix, and the core of the sandwiches, respectively. Sandwich production was carried out by hand lay-up and vacuum bagging methods. There are a total of 15 different sandwich configurations within the scope of this study. Sandwich structures were first subjected to a static three-point bending test at a speed of 2 mm/min and load and displacement data were recorded. The maximum load values obtained from the static three-point bending test were used to determine the maximum and minimum loads applied in the fatigue tests. The test configurations were subjected to a three-point bending fatigue test at 80% load level, 0.1 load ratio, and 5 Hz frequency in load-controlled mode. It was found that the hybridized stainless-steel wire mesh sheet thickness and hybridization position significantly affected the fatigue life. It was also observed that the effect of hybridization became more pronounced as the core thickness increased. SN curves of four different configurations were obtained for a more in-depth fatigue analysis. Two of these configurations were M100.F1.C10 and M100.F1.C30 configurations containing stainless-steel wire mesh sheet, and the other two were REF.C10 and REF.C30 configurations tested to reveal the effect of hybridization. It was observed that the hybridization of stainless-steel wire mesh sheet made in 10 mm core sandwiches was effective at high load levels but not at low load levels. On the other hand, it was observed that the hybridization made in 30 mm core sandwiches was effective at all load levels.
Impact and bending behaviours of composites with various channel diameters
Fiber-reinforced polymer composites (FRPCs) with micro-vascular/vascular channels are used for different purposes in various applications, such as self-healing ability, thermal management and damage detection. Understanding the behavior of these types of composites under mechanical loads is crucial, as their applications continue to expand day by day. Therefore, the current MSc thesis study examines the impact and bending behavior of carbon fiber reinforced polymer composites with microvascular/vascular channels of different diameters. All specimens were manufactured to maintain all parameters except for the vascular channel diameters. This allows the effects of various channel diameters on material behavior to be directly observed. Bending tests revealed that increased vascular channel diameters significantly increased the stiffness (rigidity) of the material. In particular, a 41.26% increase in stiffness values was reported in CFRP specimens with a 5 mm vascular channel diameter compared to reference specimens without channels. In drop weight impact (DWI) tests, it was observed that various channel diameters particularly altered the fracture mechanism. As the channel diameter increased, the fractures became less catastrophic in the same energy levels. However, in DWI tests, behaviors that could affect the test result in largediameter specimens are reported, and it was observed that the test fixtures or specimen placements needed to be revised for future studies.
Parametric design of a ball bushing using Rhino 3D Grasshopper and artificial intelligence
This study investigates how Rhino 3D Grasshopper, a visual programming-based CAD tool, can be utilized for the parametric modeling of ball bushings, which are critical components in mechanical design. The aim of this research is to develop a customizable and adaptable design framework using Rhino 3D Grasshopper and Artificial Intelligence (AI)-based optimization techniques. Traditional parametric design methods often require advanced programming knowledge, which limits accessibility for engineers without coding skills. Grasshopper's node-based graphical interface simplifies the parametric modeling process by enabling the visual definition of geometry, constraints, and design rules. The study begins with a literature review, examining current parametric design methodologies and CAD tools. Following this, a comprehensive ball bushing model will be developed, incorporating design parameters such as geometric variations, material properties, and mechanical constraints. Additionally, the flexibility and efficiency of the model will be enhanced using Grasshopper's Python interface. Finally a comparison will be made with traditional CAD modeling techniques, particularly PTC Creo-based ball bushing designs. The comparison process will focus on design flexibility, time efficiency, and optimization capabilities. The findings reveal that Rhino 3D Grasshopper offers a robust parametric design platform for mechanical engineering, providing significant advantages in terms of modularity, real-time modifications, and computational efficiency.