Manufacture Of Electronic Assemblies Research Articles

Study on the Optimization of the Material Distribution Path in an Electronic Assembly Manufacturing Company Workshop Based on a Genetic Algorithm Considering Carbon Emissions

In order to solve the problems of high carbon emissions, low distribution efficiency and high costs related to the process of material distribution in manufacturing workshops, a multi-objective workshop material distribution path optimization problem model is established, and the model is solved using an improved genetic algorithm. The problem is processed using Gray code and crossover and variation operations with a genetic algorithm. To improve the search accuracy and convergence speed of the algorithm, an adaptive mutation method is proposed to enhance the diversity of the population and to achieve global optimal path objective finding. The improved algorithm is applied to workshop path multi-station logistics path planning, which effectively solves the transport path optimization and station solving problems in workshop logistics distribution, and the convergence speed and convergence accuracy of the algorithm are significantly improved. Finally, a simulation analysis is carried out on the optimization of the production material distribution of a smart gas meter workshop owned by K Company, which is an electronic assembly manufacturing company. We used MATLAB software for the case company logistics distribution route model for data analysis and solving. Due to the consideration of carbon emissions, we did not consider two kinds of experiments, which were two different cases of the optimal path. The experimental results verify that the distribution optimization scheduling model can meet the demands for immediate material distribution in the production workshop, which is conducive to improving material distribution efficiency, reducing logistics costs and achieving the goal of lowering carbon emissions. This optimization model has a certain utility in that in the current context of aiming for carbon neutral and carbon peaking, early low carbon distribution layout can reduce the environmental cost of the enterprise, making material distribution a more environmental economic path.

A joint chance constrained optimization algorithm with robust reconstruction for multi-echelon and multi-period closed-loop manufacturing adjustable system design under multi-source uncertainty

The complex electronic assembly scheduling problem under uncertainty poses a new challenge. The joint chance constraint programming method based on robust reconstruction is used to hedge the endogenous and external uncertainty in the closed-loop manufacturing scheduling model of multi-echelon and multi-product electronic assembly process under multi-source uncertainty in this study. The numerical cases of electronic factory in assembly and closed-loop manufacturing mode are studied, the sensitivity of cost to different types of uncertain parameters is analyzed. The results show that different types of uncertainty have different effects on economic benefits, and endogenous uncertainty has a greater impact on manufacturing costs. Decision makers can adjust the adjustable parameters according to external policies and economic situation to control the conservatism and economic benefits of the scheme, and at the same time reduce the demand for uncertain data and improve the efficiency of solution. The model provides a new sustainable production method for electronic assembly manufacturing practitioners, and makes the best production decision when weighing economic benefits and risks.

Low Back Pain (LBP) Incidence, Ergonomics Risk and Workers' Characteristics in Relations to LBP in Electronics Assembly Manufacturing.

Aims:Electronics industry workers might have increased the risk of low back pain (LPB). This cohort study aimed to investigate LBP incidence and provide a baseline of ergonomic factors and workers’ characteristics associated with LBP.Methods:A six-month monitoring phase was designed using 196 electronic workers to identify LBP incidence. Baseline data were collected for ergonomic risk by RULA and lighting intensity measurement. Personal factors and work stress were surveyed by job content questionnaires (JCQ).Results:Ergonomic risk related to sitting posture was indicated at inspection with lamp (66.7%; change needed). High risk was shown among standing workers at punching and E-check processes. The lighting intensity did not meet the recommended standard in the arm range zone 2 of inspection and E-check stations. Dissatisfaction was reported due to work stress, workload, work rhythm, and job control. The six-month LBP incidence was 52.5%. Work experience less than three years (RR = 1.41; 95% CI: 1.031.90) and chronic diseases (RR = 1.41; 95% CI: 1.091.82) were significantly correlated with LBP incidence.Conclusions:Ergonomic and lighting conditions at E-check and inspection should be improved, and the promotion of short break exercise during shiftwork period is suggested. LBP should be closely surveilled in workers who had less job experience and underlying diseases.

FAILURE ANALYSIS OF DISCOLORED ENIG PADS IN THE MANUFACTURING ENVIRONMENT

Manufacturing of electronic assemblies using printed circuit boards (PCBs) with electroless nickel/immersion gold (ENIG) surface finishes requires front-end PCB evaluation that will guarantee that good quality product enters the assembly line. The most common is an IPC-4552 mandated plating thicknesses verification of 3-6μm and a minimum of 0.05μm for nickel and gold, respectively. Coupled with visual examination, this verification method suffices for general PCB acceptance but may not be robust enough in cases where ENIG plating in PCBs is compromised. That poses challenges in the manufacturing environment, where resulting latent defects are detected in downstream processes but not at upfront incoming inspection. Manifestation of such latent anomaly was observed in the form of ENIG pad discoloration with variations from yellow, red or grey discolored surfaces to a more pronounced plating degradation, such as corrosive pitting. The launched failure analysis involved evaluation of manufacturing processes suspected to contribute to the cause of the condition. Effects of thermal processes, cleaning methods, soldering, parylene deposition and factory cleanliness were examined thoroughly. Concurrently, metallurgical analysis of ENIG pads was performed, where samples were subjected to scanning electron microscopic/energy dispersive x-ray spectroscopic (SEM/EDX) cross section analysis, Auger electron spectroscopy (AES) and gold (Au) and electroless nickel (Ni) surface examination. The resulting analysis revealed a highly porous electroless nickel coating with deep crevasses and fissures penetrating down to the base copper (Cu) layer. These open nickel boundaries were attributed to the corrosive environment within ENIG plating, which resulted in the pad surface discoloration. The root cause of ENIG pad discoloration and pitting was traced back to poor ENIG line process controls. Subsequent introduction of a nickel controller into the ENIG line were the implemented countermeasures. To mitigate the effects of discoloration at the electronic assembly level, a tinning process was implemented to prevent nickel plating oxidation and to ensure that good wettability for reliable solder joints was maintained.

A field investigation of manual forces associated with trigger and push to start electric screwdrivers

AbstractThis study investigated manual forces associated with trigger start (TS) and push to start (PTS) activation in‐line electric screwdriver designs. The vertically directed axial screwdriver force transmitted with the driver to the fastener and the grip/finger forces on the driver handle were measured from 13 employees in an electronics assembly manufacturing facility. The PTS driver was associated with significantly ( p < .01) higher axial force than the TS driver at two of the four workstations, where the difference was as high as a 184% increase (36.5 vs. 103.8 N). Total finger force on the screwdriver handle was also higher for the PTS screwdriver ( p < .01). The PTS screwdriver may reduce instances of fastener head damage (“cam out”) by requiring a minimum level of axial force to ensure better contact between the screwdriver bit and the fastener. However, this appears to come at the expense of greater manual forces exerted by the operator. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 367–382, 2007.

Orbotech introduces new AOI series for electronics assembly manufacturing

Orbotech introduces new AOI series for electronics assembly manufacturing

Analysis in Manufacturing Systems Simulation: A Case Study

A case study of the transition of an electronics assembly manufacturing system from a traditional push production control system to a just in time (pull control system) is presented. Emphasis is on the unique simulation analysis aspects of the case study. The experimental design follows a dynamic programming formulation, representing the system transition through stages with the states at each stage representing combinations of stage-specific improvement possibilities and process control parameter values. Relationships between the primary performance measure, run time for a batch, and other performance measures are developed to identify process control variables and opportunities for system improvement. Actual production control data is employed for validation of system standard values, estimation of model input parameter values, and comparison with simulation results for validation purposes.

Solderability Changes of Printed Wiring Board Surfaces during Electronic Assembly Operations

Today's electronic assembly manufacturing operations can be complex combinations of process steps such as IR reflow, wave soldering, special soldering of connectors or sensitive components, cleaning, rework, etc. Such multiple exposures to elevated temperatures and/or oxidising environments (e.g., aqueous cleaning) can have a negative effect on the solderability of printed wiring board (PWB) surfaces. This in turn may limit the effectiveness of subsequent soldering operations, such as wave soldering following an IR reflow step. The purpose of this study is to assess the impact of individual assembly process steps on the solderability of PWB surfaces. The PWB surfaces are initially treated with protective coatings of benzotriazole (BTA). The process steps investigated include: IR reflow in air and in nitrogen; vapour phase reflow; aqueous cleaning; adhesive cure; and wave soldering as a function of solder temperature and flux type. Meniscograph wettability testing is used to measure relative solderability changes, and Auger electron spectroscopy (AES) is used to monitor surface chemical changes, particularly oxide formation. The overall result is a body of fundamental information providing insight into optimisations of process flows, equipment operating specifications, process temperatures and selection of flux types.

A Comparison of Control Paradigms for Adhesive Dispensing

Summary This paper compares implementation styles for elements of the solution of a control problem encountered in the manufacture of electronic assemblies. The implementation studies include the application of rule based control within an object oriented environment, a neural network based system equivalent to elements of the rule based process controller and a design study for a control system implemented in a conventional procedural language. The control task IS the control of the accurate dispensing of the small quantities of adhesive used to secure surface mount components to mixed technology printed circuit boards and therefore allow the assemblies to be wave soldered.

Ensuring Reliability of Avionics Systems

THE reliability of ICs and other semi‐conductors is a subject which continues to challenge both manufacturers and users. “High specification” markets such as the Avionics Sector, lead the user demand for a greater degree of assurance that the products they install demonstrate a longer and more effective life. The percentage of DOA (dead on arrival) components has become less but, nevertheless, Burn‐in of standard devices, or even re‐screening of those supplied as “high rel”, remain important activities in the manufacture of electronic assemblies — and a benefit to the user of the final product. Early failures, also known as “infant mortalities” and the concern for extended life in components, creates an element of worry in the minds of those companies whose products are required to provide high MBTFs, extended operational life and minimum risk of failure.

New Developments in the Technology of Automation-Related Joining Processes

This paper compares implementation styles for elements of the solution of a control problem encountered in the manufacture of electronic assemblies. The implementation studies include the application of rule based control within an object oriented environment, a neural network based system equivalent to elements of the rule based process controller and a design study for a control system implemented in a conventional procedural language. The control task IS the control of the accurate dispensing of the small quantities of adhesive used to secure surface mount components to mixed technology printed circuit boards and therefore allow the assemblies to be wave soldered.