On-line application of microprocessors in quality control

A system is described that collects data and computes and plots control charts and sampling plans automatically. An inspection device is connected with a microcomputer to measure a physical characteristics of a product, transmit data to the computer and process and store summary statistics. The software accepts preliminary measurements, computes control limits, accepts further measurements, plots them on a CRT or plotter and stops the process when an out-of-control measurement is detected. The software will also determine a single-sampling plan which meets specified producer's and consumer's risks, measures products to determine if acceptable and will report decisions on lot acceptance.     

Automated inspection in robotic additive manufacturing using deep learning for layer deformation detection

Journal of Intelligent Manufacturing - In this paper, an automated layer defect detection system for construction 3D printing is proposed. Initially, a step-by-step procedure is implemented to...     

Study of connection detailing on SMRF seismic behavior for unequal beam depths

This study investigates the differences in the seismic behavior of Special Moment Resisting Frames (SMRF) with unequal beam depths, which can be affected by connection detailing arrangements. The studied connection detailing arrangements consist of continuity plate arrangements, such as straight or inclined continuity plates, coverplate, flange plate connections, and the haunch connection system on the shallow beam side, which can create some alternatives for the connection of the shallow beam and the deep beam to the column. In spite of the occurrence of this special case in everyday engineering practice, the codes do not take these special cases into consideration. Six full-scale experiments were performed in order to improve the understanding of the seismic behavior associated with this special case. Companion analyses were then conducted in order to consider the effects of the above-mentioned connection detailing arrangements on the analytical rupture indices. The results of the experiments and analyses have shown that the described connection detailing arrangements can achieve performance corresponding to story drift ratios of at least 4% to 6% before experiencing 20% strength degradation. By the use of a specific combination of a flange plate connection with a haunch connection system, crack propagation on the deep beam's bottom flange, which is observed in most connection detailing arrangements for this special case, can be eliminated.     

A linearized polynomial mixed integer programming model for the integration of process planning and scheduling

This paper presents a linearized polynomial mixed-integer programming model (PMIPM) for the integration of process planning and scheduling problem. First, the integration problem is modeled as a PMIPM in which some of the terms are of products of up to three variables, of both binary and continuous in nature. Then, an equivalent linearized model is derived from the polynomial model by applying certain linearization techniques. Although the linearized models have more variables and constraints than their polynomial counterparts, they are potentially solvable to the optimum in comparison to their equivalent polynomial models. Experiments show that the linearized model possesses certain characteristics that are absent from other models in the literature, and provides a fundamental framework for further research in this area.     

Development of a Rapid Prototyping System using Response Surface Methodology

This case study presents an investigation of the relationships between eight process operating variables (factors) and five part performance measures (responses) in a rapid prototyping system. The use of fractional factorial, single‐factor foldover, and central composite designs is demonstrated. Polynomial regression models are constructed for each response, followed by a desirability function model. Canonical and ridge analyses are used to identify a group of factor settings that simultaneously produce improved performance for all responses. Copyright © 2006 John Wiley & Sons, Ltd.     

Integration of process planning and scheduling functions

Automated process planning (APP) has received a considerable amount of attention in recent years. This has mainly been due to APP allowing for the bridging of the gap between design and manufacturing, and for its automation of the related tedious human task. While there have been several efforts in developing interfaces between computer-aided design (CAD) and APP, little attention has been given to the integration of APP and scheduling, which is likely to be of even higher importance. This paper addresses the basic issues involved in the integration of the two functions, demonstrates a methodology and the potential benefits of the integrated approach by an example, and presents directions for future research.     

Evaluation of Ayrton-Perry formula to predict the compressive strength of batten columns

This research was performed to evaluate two analytical methods for predicting the compressive strength of batten columns. Batten columns were subjected to pure axial compression, and the compressive strength was measured. The analytical methods used included the well-known Ayrton-Perry and ultimate strength curve methods to calculate the compressive strength of imperfect solid web columns, but their validity has not yet been studied experimentally on built-up columns. The geometrical parameters considered included the batten plate spacing and dimensions and the distance between the two longitudinal chords. The results show that the analytical methods were generally valid for the prediction of the compressive strength in batten columns and solid web columns. Using the average results of the Ayrton-Perry and ultimate strength curve methods leads to the best prediction of the column compressive strength. It was also shown that the initial imperfections in the batten columns could have a more important effect than the geometrical specifications on the value of compressive strength.     

The influence of build strategies in selective inhibition sintering (SIS)

Selective Inhibition Sintering of metal alloys (SIS-metal) has been proven effective in the additive manufacture (AM) of low resolution bronze parts. Recent advancements in the use of a high-precision inkjet print head represented an order of magnitude improvement in SIS-metal resolution. However, the fabrication of complex three-dimensional metallic parts required new SIS-metal compatible, cross-sectional image generation based on the part boundary profile. In the proposed study, five candidate layer-processing approaches were identified and validated for basic geometries. These approaches were chosen from previous research as well as preliminary investigations and were applied to a modified SIS-metal process for validation. The validation criteria were based upon the amount of powder waste produced, the ability to handle complex geometries, printing speed, extraction (post-processing) speed, and part integrity. Results are discussed for implementation of the five candidate layer processing approaches in the fabrication of basic shapes. A preliminary evaluation is presented for their use on more complex geometries. Two approaches were then chosen for the construction of more complex geometries, the results of which are presented.     

Generation of alternative process plans in integrated manufacturing systems

The availability of alternative process plans is a key factor for integration of design, process planning, and scheduling functions. The availability of alternative process plans can speed up the process of incremental process plan generation which can help in providing real time cost feed back to the designer after each design modification. Also alternative process plans relax the constraints in the optimization of production schedules, which in turn results in more efficient use of production resources and better delivery schedules. This paper describes a methodology for generation of alternative process plans in the integrated manufacturing environment. The procedure consists of: selection of alternative machining processes, clustering and sequencing of machining processes, and generation of a process plan network. Each of these steps is explained in detail. The result of the procedure is the process plan network that provides all alternative process plans for the given part. Methods for the selection of an optimal process plan are also described. Computational complexity of the procedure is discussed and experimental results on several realistic examples are shown.