Topical meeting on optical interference coatings (OIC'2001): design contest results

A gain-flattening filter (GFF) for minimum manufacturing errors (12 designs submitted) and dense wavelength-division multiplex (DWDM) filters for low group-delay (GD) variation (9 designs submitted) was the subject of a design contest held in conjunction with the Optical Interference Coatings 2001 topical meeting of the Optical Society of America. Results of the contest are given and evaluated. It turned out that the parameter space for GFFs with optimum performance when manufacturing errors are not considered is much different from that when manufacturing errors are considered. DWDM filter solutions with low GD variation are possible.     

A new tolerance design method for a secondary rechargeable battery using design of experiments with mixture

Mixing errors in the manufacturing process of a mixture may cause a sizeable variation in the performance of the product, leading to the need for the tolerance design. Even though a variety of procedures have been proposed for the optimal tolerance design based on quality loss and manufacturing costs, there are no available tolerance design methods when mixing errors exist in the manufacturing process of a mixture. In this article, we propose a new tolerance design method for the case where mixing errors are involved in massive manufacturing process of a secondary rechargeable battery. Using an approximation method, we derive quality loss function, reflecting the effects of mixing errors on the product performances. Statistical design of mixture experiments is applied to build empirical models of performances as functions of component proportions in the corresponding quality loss function. A real‐life case study on the tolerance design of a secondary battery is provided for the illustration of the proposed method. The results show the efficiency of the proposed method in designing the tolerances to minimize the quality loss and manufacturing costs. Copyright © 2008 John Wiley & Sons, Ltd.     

Process Yield Analysis for Nonlinear Profiles in the Presence of Gauge Measurement Errors

Process yield plays an important role in many manufacturing industries for measuring process performance. However, gauge measurement errors have significant effect on process capability analysis. In this study, we present a method based on the yield index to evaluate the process yield of nonlinear profiles in the presence of gauge measurement errors. The results indicate that the presence of gauge measurement errors in the data leads to different behaviors of the yield index estimator according to the existence of the gauge variability. Our proposed test procedure can be easily used to determine whether or not manufacturing processes meet the quality requirements when gauge measurement errors are considered. A real example from a manufacturing process is used to demonstrate the applications of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.     

Product data quality validation system for product development processes in high-tech industry

Among various product data, 3D CAD data plays a key role in current product design and manufacturing processes including industrial design, detail design, CAE, inspection, mould-making, production, and so on. If 3D CAD data has geometrical or topological errors by user mistakes or modelling software bugs and those errors are not cleaned by the data creator in an early stage, the data will be transferred to the downstream operators and they have to fix the errors before starting their own work. Because 3D data is quite complex, it is very difficult to recognise the data errors manually in a modelling system before a big problem is encountered which blocks the next operation. In this case, it generally causes time delay and high cost for data correction and the effect will be bigger when the process is close to the back-end. In this research, we develop a fully automated product data quality validation and management system to support the product development processes of high-tech products like televisions, camcorders, mobile telephones, home appliances, etc. The system automatically validates the 3D data in real time and gives 3D error reports to the creator to correct modelling failures in their steps. Also, project managers can check or control the data delivery based on the data quality for each step.     

A study of improving overlay accuracy by applying a new outlier handling method in FPD manufacturing

As the pixel size of display devices has been reduced, overlay accuracy between layers needs to be more improved in flat panel display (FPD) manufacturing. However, because of large substrate size and non-uniform processes in FPD manufacturing, an improvement of overlay accuracy has been a challenging work. As an effort to improve overlay accuracy, overlay error correction, which is a kind of feedback control similar to one in semiconductor manufacturing, has also been applied in the photo lithography processes for FPD. However, its characteristics and problems were not technically well investigated as much as in semiconductor manufacturing. This paper investigates one of the problems encountered in the practice of the overlay error correction: outliers in the measurement of overlay errors. Such outliers can cause undesirable effects on overlay accuracy, if used for the overlay error correction. In order to systematically cope with such outliers, a new framework is proposed for detecting and handling outliers as well as for verifying the result. In the consideration of the proposed framework, a new outlier detecting and handling method is also proposed. This method is based on a robust regression technique and is compared with others through simulation to confirm its better performance.     

Robust shape and topology optimization considering geometric uncertainties with stochastic level set perturbation

When geometric uncertainties arising from manufacturing errors are comparable with the characteristic length or the product responses are sensitive to such uncertainties, the products of deterministic design cannot perform robustly. This paper presents a new level set‐based framework for robust shape and topology optimization against geometric uncertainties. We first propose a stochastic level set perturbation model of uncertain topology/shape to characterize manufacturing errors in conjunction with Karhunen–Loève (K–L) expansion. We then utilize polynomial chaos expansion to implement the stochastic response analysis. In this context, the mathematical formulation of the considered robust shape and topology optimization problem is developed, and the adjoint‐variable shape sensitivity scheme is derived. An advantage of this method is that relatively large shape variations and even topological changes can be accounted for with desired accuracy and efficiency. Numerical examples are given to demonstrate the validity of the present formulation and numerical techniques. In particular, this method is justified by the observations in minimum compliance problems, where slender bars vanish when the manufacturing errors become comparable with the characteristic length of the structures. Copyright © 2016 John Wiley & Sons, Ltd.     

Dove prism with increased throughput for implementation in a rotational-shearing interferometer

An analytical expression is derived for the tilt introduced into a wave front by a Dove prism with manufacturing errors in the prism's base angles and pyramidal angle. We found that the tilt decreases when the base angles are increased above the values of traditional design. The increase in the length-aperture ratio of a prism is detrimental to the prism's performance. However, a Dove prism with a widened aperture increases throughput and maintains a manageable prism weight for implementation in a rotational shearing interferometer. Thus we propose a Dove prism designed with a widened aperture to increase throughput in a rotational shearing interferometer and with larger base angles to minimize the wave-front tilt introduced by manufacturing errors. Experimental results implemented in a rotational shearing interferometer demonstrate the feasibility of this design.     

A method of identifying latent human errors in work systems

Work system improvements are implemented in various manufacturing processes to prevent problems caused by human errors. However, they are almost always applied to problems which have already occurred. This paper examines a method of identifying latent human errors existing within the work systems beforehand. A procedure for applying failure mode and effect analysis to this identification problem was defined based on over 1000 empirical errors: a work system decomposition criterion and fundamental error modes for listing latent human errors, and then applied to three practical manufacturing processes in order to evaluate its effectiveness.     

Effects of manufacturing errors on diffraction efficiency for multilayer diffractive optical elements

The effect of manufacturing errors on diffraction efficiency for multilayer diffractive optical elements (MLDOEs) used in imaging optical systems is discussed in this paper. The relationship of diffraction efficiency and depth-scaling errors are analyzed for two different cases: the two relative depth-scaling errors change in the same sign and in the opposite sign. For the first condition, the corresponding diffraction efficiency decreases more slowly. The effect of periodic width errors on diffraction efficiency is also evaluated. When the two major manufacturing errors coexist, the magnitude of the decrease of diffraction efficiency is analyzed for MLDOEs. The result can be used for analyzing the effects of the manufacturing errors on diffraction efficiency for MLDOEs.     

The future role of DNC in metalworking SMEs

This paper provides a framework to describe the current status, and many configurations of DNC that can be encountered today. Major research issues relating to the design and implementation of future DNC are highlighted, in view of new manufacturing paradigms such as the Holonic and Fractal Factory. The characteristics, techniques, beliefs and values that compose these paradigms are already present to a limited degree in the small to medium sized companies. This paper will present a novel view of DNC, and how the latest advancement in PC based controller technology in combination with the manufacturing paradigms, will create a new role for DNC on the manufacturing shop floor.     

Applying GMP to Computerization in a Solid-Oral-Dosage-form-Factory

Quality Assurance and Pharmaceutical security as well must be given a particular consideration both for hardware and software when computerized pharmaceutical industrial operations are concerned

Hardware: The preparation of validation should begin with the design of a computerized system and rely upon specifications and upon defined operational limits

It is suitable to prepare documentation as from the development of the system in order to obtain a fruitful communication between all those concerned with design, implementation, maintenance, validation and auditing

A revalidation procedure should be prepared and maintained updated, in the event of a change in one or several operating conditions

Software: As with hardware, validation of software should be envisioned as early as the development phase. Preparation of test procedures and documentation should start at this very stage. Qualification and validation will be designed to find errors in the program and not to prove that no errors exist. They will be carried out at the operational boundaries of the software and will aim at testing the critical decision paths of the program. Verifications must be repeated a sufficient number of times to demonstrate that the results are repeatable

As with other pharmaceutical manufacturing systems, a formal procedure should exist to support changes made to the software. Vendor supplied software should be verified and documented with the same rigour and details that in-house developed software. Manual back-up systems must be provided for and regularly tested in the event of failure of the automated process. Computerized systems and good manufacturing practices applied to manufacturing of solid oral dosage forms: An application of the above-stated principles is given and illustrated     

Dove棱镜的加工误差对耦合损耗的影响

平行光束经过有加工误差的Dove棱镜后,在出射面往往会发生角度倾斜和离轴偏差,从而导致利用Dove棱镜制成的光纤旋转连接器的传输耦合损耗增大。对于Dove棱镜的加工误差在耦合损耗方面的影响,本文利用光线追迹的方法对其进行了理论及模拟分析。分析结果显示,由于加工误差带来的耦合损耗随着Dove棱镜的底角误差及其锥体角误差的增加而增大。而后依据理论结果及光纤旋转连接器的需求,设计加工了5块Dove棱镜,测量了其耦合损耗,并对实验测量值进行了修正,进一步验证了理论的正确性。     

Functional tolerancing: A design for manufacturing methodology

The problem addressed in this paper is the development of a physico-mathematical basis for mechanical tolerances. The lack of such a basis has fostered a decoupling of design (function) and manufacturing. The groundwork for a tolerancing methodology is laid by a model of profile errors, whose components are justified by physical reasoning and estimated using mathematical tools. The methodology is then presented as an evolutionary procedure that harnesses the various tools, as required, toanalyze profiles in terms of a minimum set of profile parameters and tore-generate them from the parameters. This equips the designer with a rational means for estimating performance prior to manufacturing, hence integrating design and manufacturing. The utility of thefunctional tolerancing methodology is demonstrated with performance simulations of a lathe-head-stock design, focusing on gear transmission with synthesized errors.     

Uncertainty analysis and allocation of joint tolerances in robot manipulators based on interval analysis

Many uncertain factors influence the accuracy and repeatability of robots. These factors include manufacturing and assembly tolerances and deviations in actuators and controllers. The effects of these uncertain factors must be carefully analyzed to obtain a clear insight into the manipulator performance. In order to ensure the position and orientation accuracy of a robot end effector as well as to reduce the manufacturing cost of the robot, it is necessary to quantify the influence of the uncertain factors and optimally allocate the tolerances. This involves a study of the direct and inverse kinematics of robot end effectors in the presence of uncertain factors. This paper focuses on the optimal allocation of joint tolerances with consideration of the positional and directional errors of the robot end effector and the manufacturing cost. The interval analysis is used for predicting errors in the performance of robot manipulators. The Stanford manipulator is considered for illustration. The unknown joint variables are modeled as interval parameters due to the inherent uncertainty. The cost-tolerance model is assumed to be of an exponential form during optimization. The effects of the upper bounds on the minimum cost and relative deviations of the directional and positional errors of the end effector are also studied.     

Microwave noise measurement errors caused by frequencydiscrepancies and nonzero bandwidth

We develop analytical expressions for two frequency-related errors encountered in noise parameter measurements of devices with high-reflection coefficients such as GaAs FET's and HEMT's. The first error is caused by a discrepancy between the measurement frequency of the noise-measuring receiver and the frequency of the reflection coefficient-measuring apparatus. The second is caused by variation of the noise power spectral density across the bandwidth of the noise-measuring receiver. A noise power measurement on a cooled GaAs FET is presented as a demonstration, in which the noise power level exhibits narrow peaks which rise about 10 dB above the general level at regular frequency intervals. It is shown that the severity of both of the frequency-related errors is related to the shape of these peaks. Simple expressions are derived which allow the severity of these two types of errors to be estimated when values are available for the reflection coefficient magnitudes and transmission line lengths in a system. Expressions are also derived which give the variation with frequency of the measured noise power and also of the two error terms, if the noise parameters of the device under test are also available. This analysis accounts successfully for the main features of the experimental noise power observation     

Online control using integrated moving average model for manufacturing errors

We propose a protocol for online control using an Integrated Moving Average (IMA) model for manufacturing errors. This model is suitable for manufacturing processes that are mildly to moderately non-stationary. The protocol is similar to that of the Shewhart X-bar chart. After some number N of the units of product have been manufactured, the ( N + 1)th unit is sampled and its error relative to the target value is checked and recorded. At each check, the observed absolute error is compared against a benchmark, called the correction limit denoted by D to assess the state of errors. When errors are excessive, the system is stopped for correction. Our objective is to determine the ideal settings for N and D from engineering economic and statistical viewpoints. We use root expected mean square error (REMSE) as a measure of the dispersion of errors subject to online control. We use the IMA model to approximate REMSE as a simple function of N and D . Next, we use the approximate REMSE to define a loss function due to manufacturing error. We then determine explicit expressions for N and D that minimize the loss function. The expressions for N and D are simple functions of the engineering economic parameters (manufacturer's cost per unit of product due to errors, cost of checking, cost of correction, and product tolerance) and the two statistical parameters of IMA. We discuss estimation of these parameters and propose how this approach may be used for multiple product characteristics.     

A method of obtaining the radiation modulation function in an optoelectronic digital angle converter using a radon transform

A method of obtaining the radiation modulation function in the optical channel of practical optoelectronic digital angle converters using the apparatus of analytical geometry together with a local radial Radon transform is considered. The majority of the instrumental errors that arise when manufacturing and assembling the optomechanical unit are taken into account. The method can be extended to a wide class of optical coding devices and has practical applications.     

Simple Estimates for the Effects of Mid-spatial-Frequency Surface Errors on Image Quality

Mid-spatial-frequency surface errors can be introduced by various manufacturing processes. These errors bridge the gap between traditional figure and finish errors. Although the effects of mid-spatial-frequency errors on the imagery of an optical system can be modeled with a ray-based approach, simply tracing rays provides little insight. We present an alternative method that treats surface errors as perturbations to the nominal surface profile. This approach, combined with standard statistical methods, allows one to make simple back-of-the-envelope predictions of the effects of mid-spatial-frequency errors for various measures of optical performance. Two examples illustrating the effectiveness of this approach are presented.     

熔体发泡法制备工艺的发展与展望

论述了国内外泡沫金属生产中熔体发泡法制备工艺的发展形势，并对熔体发泡法中不同种发泡工艺在生产中的应用情况进行了全面的概述。介绍了国内外对采用熔体发泡法生产泡沫金属所做的各种试探性研究，总结了其应用于生产实践中所存在的不足，对不同种发泡工艺的优缺点以及关键技术作了进一步的探讨。最后对熔体发泡法生产泡沫金属的发展前景做了前瞻性展望。