The International Journal of Advanced Manufacturing Technology

Yu, K.; Sheu, S.; Chen, K.

doi: 10.1007/s00170-006-0598-zpmid: N/A

Recently, studies associated with testing the quality and performance of each process for a product with multi-characteristics are proposed more often. However, most studies are limited to discussing one single type of quality characteristic. Practically, a multi-characteristic product is potentially composed of three types: smaller-the-better, larger-the-better, and nominal-the-best. In this paper, we propose an integrated product capability index which considers these three different types of quality characteristics. According to the theory of testing hypothesis, we develop a testing procedure for the product capability index to judge whether the process capabilities of total quality characteristics meet the customers’ demands. In addition, the relationship between the product capability index and the yield of the entire product will be introduced. Finally, an example is provided as a practical application.

Katz, Reuven

doi: 10.1007/s00170-006-0615-2pmid: N/A

Reconfigurable machines form a new class of machines that are designed around a specific part family of products and allow rapid change in their structure. They are designed to allow changes in machine configuration according to changes in production requirements. The reconfiguration may be related to changes in machine functionality or its scalability, i.e., the change in production volumes or speed of operation. Reconfigurable machines represent a new class of machines that bridges the gap between the high flexibility and high cost of totally flexible machines and the low flexibility and low cost of fully dedicated machines. The design principles of reconfigurable machines follow a similar philosophy, which was derived for reconfigurable manufacturing systems, and present an approach for the design of machines to be used mainly in high-volume production lines. This paper introduces design principles for reconfigurable machines, which may be applied in different fields of manufacturing. Based on these design principles, three types of reconfigurable machines were designed for various types of production operations such as: machining, inspection and assembly. This paper shows how the suggested design principles were utilized in the design of several full-scale machine prototypes and tested experimentally.

Ching-Kao, Chang; Lu, H.

doi: 10.1007/s00170-006-0630-3pmid: N/A

This paper presents an optimal cutting-parameter design of heavy cutting in side milling for SUS304 stainless steel. The orthogonal array with grey-fuzzy logics isapplied to optimize the side milling process with multiple performance characteristics. A grey-fuzzy reasoning grade obtained from the grey-fuzzylogics analysis is used as a performance index to determine the optimal cutting parameters. The selected cutting parameters are spindle speed, feed per tooth,axial depth of cut and radial depth of cut, while the considered performance characteristics are tool life and metal removal rate. The results ofconfirmation experiments reveal that grey-fuzzy logics can effectively acquire an optimal combination of the cutting parameters. Hence, performance in theside milling process for heavy cutting can be significantly improved through this approach.

Shabtay, Dvir; Kaspi, Moshe

doi: 10.1007/s00170-006-0617-0pmid: N/A

This paper presents models for calculating the optimal cutting feed rate and spindle speed at each stage in a multistage transfer machine. The optimal cutting conditions are determined by taking into account the cutting constraints for three objective functions, which are: minimum expected cycle time, minimum expected cost per unit, and maximum expected profit rate, using a one-dimensional search procedure. The efficiency range in which the optimal solutions for the three objective functions can be found is also analyzed. In addition, the optimal cutting conditions at each stage are compared to those of a stand-alone cutting machine.

Cao, Jun; Lai, Xinmin; Jin, Sun; Lin, Zhongqin

doi: 10.1007/s00170-006-0624-1pmid: N/A

In sheet metal assembly, not only the component variations and tool errors, but also the component structure (joint type) and assembly process (assembly sequence) affect the final dimensional quality. In this paper, a systematic method for adaptive joint design considering different assembly sequence is proposed to meet the in-process dimensional adjustability of KCs (key characteristics). First, the adaptive characteristic of the sheet metal joint is depicted. Then, the mathematical model in order for concurrently optimizing both joint type and different assembly sequence is presented. How to evaluate the combination of joint type and assembly sequence is carried out according to two conditions: (1) for single KC, and (2) for multiple KCs. The KC confliction is considered to ensure the important KCs. Genetic algorithm is used to resolve the optimization of joint design. An example is chosen to demonstrate our method finally, and various joint designs are acquired according to different assembly sequences by this means. The proposed methods make it possible for us to improve the dimensional quality of product in the design stage.

Mahadevan, P.; Dixit, U.; Robi, P.

doi: 10.1007/s00170-006-0633-0pmid: N/A

In the present work, an axi-symmetric cold forging problem is analyzed using radial basis function collocation method. The material is assumed to be rigid-plastic strain hardening. At each increment of the punch displacement, the problem is solved using an Eulerian control volume approach. The mixed pressure-velocity formulation is adopted, in which the hydrostatic stress and velocities are approximated by linear combinations of multiquadrics radial basis functions, the coefficients of which are obtained by satisfying the continuity and equilibrium equations at certain points called collocation points. The resulting non-linear equations are solved using a trust region method available in MATLAB, which is based on interior-reflective Newton method. Because of the nature of the equations, hydrostatic stress values contain spurious terms. To eliminate them, boundary conditions on hydrostatic stress are required, which are not known initially. Therefore the problem is solved in two stages. In the first stage, the problem is solved without any boundary condition for the hydrostatic stress and the forging load is computed by dividing the total power by the punch velocity. The hydrostatic stress at the punch-workpiece interface is obtained from the known forging load. In the second stage, the problem is solved again by putting the additional hydrostatic stress boundary conditions. Computational performance of the proposed method is studied by carrying out parametric study.

Alagumurthi, N.; Palaniradja, K.; Soundararajan, V.

doi: 10.1007/s00170-006-0619-ypmid: N/A

Grinding is the most common abrasive machining process and in many cases the last of the series of machining operations. Compared to other machining processes grinding requires very high-energy input per unit of volume of material removal. The chip removal process consists of rubbing, plowing and metal removal. The frictional resistance encountered between work material, the tool, and the chip tool interface and the resistance to deformation during shearing of chips contributes to a rise in temperature and the cutting zone. The temperature generated is not only quite high but the temperature gradients are also severe. Under abusive grinding conditions, the formation of the heat-affected zone was observed which damages the ground surfaces of the workpieces. The present work aims at optimizing the amount of heat generation and modeling the temperature rise between wheel and work contact zone in a cylindrical grinding process so as to achieve better surface integrity in AISI 3310, AISI 6150, and AISI 52100 steel materials. Taguchi’s methodology a powerful tool in design of experiments for quality is used for optimization process.

Tam, Hon-Yuen; Hua, Meng; Zhang, Lei

doi: 10.1007/s00170-006-0625-0pmid: N/A

This paper presents a method for the finishing of aspheric surfaces using fixed abrasives. The strategy is to remove a specified amount of material from the surface. The method assumes concentric tool paths perpendicular to the axis of the surface. The key parts of the method are: (1) efficient computation of the material removal profile for each tool path and (2) optimisation of the feed rate for the tool paths. Simulation results are included to illustrate the proposed method, which suggest that the method is potentially useful for aspheric surface finishing.

Ding, W.; Xu, J.; Shen, M.; Fu, Y.; Xiao, B.; Su, H.; Xu, H.

doi: 10.1007/s00170-006-0626-zpmid: N/A

CBN grinding tools have been broadly utilized in machining difficult-to-cut materials in recent years. Grains of the conventional grinding tools, however, are held in the tool matrix just through the mechanical incrustation effect induced by the electroplated or sintered metal, which results in the stochastic grain distribution and limited grain protrusion, in addition to the easy grain pullout and premature tool failure by the strong impact forces generated during machining. These properties and shortcomings of the electroplated or sintered tools have restricted the potential of CBN superabrasive grains. Therefore, a new technology has been developed and introduced in this paper to fabricate successfully monolayer CBN grinding tools, in which the highly protruding grains could be planted in the required uniform pattern through the brazing effect among CBN grains, filler alloy and tool substrate at elevated temperature. Finally, comparative grinding tests performed with the conventional electroplated and newly-developed brazed CBN tools have indicated that highly increased efficiency and prolonged tool lives, as well as low fabrication and use cost could be achieved by applying the brazed CBN grinding tools.

Au, K.; Yu, K.

doi: 10.1007/s00170-006-0628-xpmid: N/A

Cooling design of plastic injection mould is important because it not only affects part quality but also the injection moulding cycle time. Traditional injection mould cooling layout is based on a conventional machining process. As the conventional drilling method limits the geometric complexity of the cooling layout, the mobility of cooling fluid within the injection mould is confined. Advanced rapid tooling technologies based on solid freeform fabrications have been exploited to provide a time-effective solution for low-volume production. In addition, research has made attempts to incorporate conformal cooling channel in different rapid tooling technologies. However, the cooling performance does not meet the mould engineer’s expectations. This paper proposes a novel scaffold cooling for the design of a more conformal and hence more uniform cooling channel. CAD model for constructing the scaffolding structure is examined and cooling performances are validated by computer-aided engineering (CAE) and computer fluid dynamics (CFD) analysis.