Value Stream Mapping of Rope Manufacturing: A Case Study

In today’s competitive market place, manufacturing companies must apply continuous process improvement in order to maintain a returning customer base. One way of achieving constant process improvement is through value stream mapping. Value stream mapping is used to visualize the current processes for easier understanding and problem identification. A well-defined problem statement will ensure a successful outcome of a project improvement process. This research provides a case study performed on a rope manufacturing process. A current state value stream map is created, and the possible improvements are suggested. The implemented results are shown in the form of future state map. The results show that, after waste elimination and structural revision, a manufacturing process becomes more efficient, enabling the customer to receive an order significantly faster.

Designing a Test Fixture with DFSS Methodology

This paper addresses the application of Design for Six Sigma (DFSS) methodology to the design of a marine riser joint hydraulic line test fixture. The original test fixture was evaluated using Value Steam Mapping (VSM) and appropriate Lean design tools such as 3D Modeling and Finite Element Analysis (FEA). A new test fixture was developed which resulted in improving the process cycle efficiency for the test from 25% to 50% percent, leading to a 50% reduction in test cost. Handling of the new test fixture is greatly improved as compared to the original fixture.

Supply Chain Inventories of Engineered Shipping Containers

Manufacturing operations that assemble parts often receive components in expensive highly engineered shipping containers. As these containers circulate among suppliers, assembly operations, and logistic providers, they require inspections and repairs. This paper presents mathematical models that predict the number of available containers as functions of damage, repair times, and scheduled daily production. The models allow making complex decisions with a few basic parameters. Results not only show a minimal investment in the number of containers and safety stock but also quantify the dependence on damage rates and repair times for ordering additional containers.

Multiattribute Assessment of Consumables for TIG Welding of Aluminum Alloys

Consumable materials for welding processes such as filler alloy, electrode, and shielding gas have major implications in welding technology. Selecting the appropriate set of consumable materials for welding aluminum alloys from various available alternates gives rise to a significant decision making problem. This study proposes a strategic justification tool based on integrated analytical hierarchy process, technique for order preference by similarity to ideal solution (AHP-TOPSIS), to screen and select the best possible combination of filler alloy, electrode, and shielding gas for TIG welding. Based on qualitative analysis of available alternates, ER5356 filler alloys and 0.8% zirconiated electrode are selected as suitable consumable in combination with pure argon as shielding gas. The proposed result is experimentally validated using mechanical property testing.

Impacts of Wear and Geometry Response of the Cutting Tool on Machinability of Super Austenitic Stainless Steel

This paper presents a study of tool wear and geometry response when machinability tests were applied under milling operations on the Super Austenitic Stainless Steel alloy AL-6XN. Eight milling trials were executed under two cutting speeds, two feed rates, and two depths of cuts. Cutting edge profile measurements were performed to reveal response of cutting edge geometry to the cutting parameters and wear. A scanning electron microscope (SEM) was used to inspect the cutting edges. Results showed the presence of various types of wear such as adhesion wear and abrasion wear on the tool rake and flank faces. Adhesion wear represents the formation of the built-up edge, crater wear, and chipping, whereas abrasion wear represents flank wear. The commonly formed wear was crater wear. Therefore, the optimum tool life among the executed cutting trails was identified according to minimum length and depth of the crater wear. The profile measurements showed the formation of new geometries for the worn cutting edges due to adhesion and abrasion wear and the cutting parameters. The formation of the built-up edge was observed on the rake face of the cutting tool. The microstructure of the built-up edge was investigated using SEM. The built-up edge was found to have the austenite shear lamellar structure which is identical to the formed shear lamellae of the produced chip.

An Architecture for Hybrid Manufacturing Combining 3D Printing and CNC Machining

Additive manufacturing is one of the key technologies of the 21st century. Additive manufacturing processes are often combined with subtractive manufacturing processes to create hybrid manufacturing because it is useful for manufacturing complex parts, for example, 3D printed sensor systems. Currently, several CNC machines are required for hybrid manufacturing: one machine is required for additive manufacturing and one is required for subtractive manufacturing. Disadvantages of conventional hybrid manufacturing methods are presented. Hybrid manufacturing with one CNC machine offers many advantages. It enables manufacturing of parts with higher accuracy, less production time, and lower costs. Using the example of fused layer modeling (FLM), we present a general approach for the integration of additive manufacturing processes into a numerical control for machine tools. The resulting CNC architecture is presented and its functionality is demonstrated. Its application is beyond the scope of this paper.

Pervasive Investigations of Critical Speed over Weight and Deflection Factors of Shaft Assembly in CNC Ball Screw System

The demand for higher productivity requires machine tools to work on the adequate critical speed to have faster and more accurate ball screw system. Ball screw affects severely over the higher rotation speed of the shaft in computer numeric control (CNC) machining centers. This paper deals with an approach to calculate the initial critical speed of the shaft. Critical speed requires significant attention due to its major use in the manufacturing sectors. The impacts of weight on the critical speed of shaft assembly have been analyzed from theoretical as well as analytical investigations. Additionally, we evaluated the impact of weight on the deflection of the shafts along with failure analysis of shafts with respect to critical speed. Further, we computed the results for critical speed based factor to enhance the accuracy of CNC machining centers. Finally, the analytical estimations have been carried out to prove the validity of our proposal.

Dynamic Interaction between Machine, Tool, and Substrate in Bobbin Friction Stir Welding

The bobbin friction stir welding (BFSW) process has benefits for welding aluminium alloy 6082-T6 in the boat-building industry. However this alloy is difficult to weld in the thin state. There are a large number of process variables and covert situational factors that affect weld quality. This paper investigates how tool holder and machine-type affect BFSW weld quality of 4 mm Al6082-T6. The variables were tool features (three types), machine-controller type (two types), and tool holder (fixed versus floating). Fourier analysis was performed on motor spindle current to determine the frequency response of the machine. An interaction was found between the computer numerical control (CNC), the degrees of freedom of the tool holder, and the substrate (workpiece). The conventional idea that the welding tool has a semisteady interaction with the substrate is not supported. Instead the interaction is highly dynamic, and this materially affects the weld quality. Specific vibrational interactions are associated with poor welding. The CNC machine-type also emerges as a neglected variable that needs to be given attention in the selection of process parameters. Although compliance in the tool holder might seem useful, it is shown to have negative consequences as it introduces tool positioning problems.

Analyzing the Effect of Machining Parameters Setting to the Surface Roughness during End Milling of CFRP-Aluminium Composite Laminates

The quality of the machining is measured from surface finished and it is considered as the most important aspect in composite machining. An appropriate and optimum machining parameters setting is crucial during machining operation in order to enhance the surface quality. The objective of this research is to analyze the effect of machining parameters on the surface quality of CFRP-Aluminium in CNC end milling operation with PCD tool. The milling parameters evaluated are spindle speed, feed rate, and depth of cut. The L9 Taguchi orthogonal arrays, signal-to-noise (S/N) ratio, and analysis of variance (ANOVA) are employed to analyze the effect of these cutting parameters. The analysis of the results indicates that the optimal cutting parameters combination for good surface finish is high cutting speed, low feed rate, and low depth of cut.

Implementation of Computer Aided Engineering for Francis Turbine Development in Nepal

The expansion of the existing industries involved in the production of components of hydropower to the Francis turbine manufacturer up to 5 MW unit size has been recognized as one of the most promising business models in Nepal. Given the current fact that the development of Francis turbines with the manufacturers of Nepal has not been done yet, due to lack of designing expertise and limitations in the available technology, this paper presents the use of different available manufacturing technologies, which is suitable in the Nepalese hydropower market. This is an experience based paper, in which the advanced manufacturing process implementing Computer Aided Simulation (CAS), Computer Aided Design (CAD), and Computer Aided Manufacturing (CAM) is introduced for turbine manufacturing. Moreover, CAD from Solidworks, 3D printing from Rapid Prototyping Machine (RPM), and manufacturing of three designs by three different methods, dye casting, lost wax casting, and forging in a local workshop, have been described. The outcome of this work is the identification of suitable Francis turbine development methodologies in context of Nepal, incorporating industrial revolution through research based products.