scholarly journals Understanding the Effect of Reflow Profile on the Metallurgical Properties of Tin–Bismuth Solders

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 121
Author(s):  
Karel Dušek ◽  
David Bušek ◽  
Petr Veselý ◽  
Anna Pražanová ◽  
Martin Plaček ◽  
...  

Sn–Bi alloys are desirable candidates for soldering components on printed circuit boards (PCBs) because of their low melting point and reduced cost. While certain tin–bismuth solders are well characterized many new alloys in this family have been developed which need proper characterization. The following study looks at the behavior of four different Sn–Bi alloys—traditional 42Sn58Bi and 42Sn57Bi1Ag and two new tin–bismuth alloys—in solder paste during the reflow soldering process. Each alloy was processed using different reflow profiles that had varying times above liquidus (TALs) and peak temperatures. The PCBs were then analyzed to see how the processing variables influenced wetting, voiding, microstructure, intermetallic layer composition, and thickness. After analysis, the PCBs were then subjected to thermal cycling experiments to see how reflow profile impacted microstructure evolution. The results demonstrated that reflow profile affects properties such as metal wetting and voiding. It does not however, greatly impact key metallurgical properties such as intermetallic layer thickness.

2014 ◽  
Vol 655 ◽  
pp. 95-100 ◽  
Author(s):  
Alireza Esfandyari ◽  
Aarief Syed-Khaja ◽  
Tallal Javied ◽  
Jörg Franke

One of the key factors in efficient and defect-free electronics manufacturing is the soldering of electronic components to the printed circuit boards. The deciding factor in the reliability and lifetime of the product is the quality of the soldered interconnections. The setting up of the reflow soldering profile plays a crucial role in the electrical functionality and robustness of the product. Especially the miniaturization of the assemblies and the development of new materials make it inevitable for the definition of new processes, optimization and implementation. In this paper, the combination of over-pressure and convection reflow soldering to minimize the defect rate and the related energy analysis for energy efficiency will be discussed and presented. A statistical analysis with variations in solder time, cost, energy, quality trade-off in the over-pressure reflow soldering process for classical printed circuit boards (PCBs) has been demonstrated.


2013 ◽  
Vol 60 (6) ◽  
pp. 2318-2331 ◽  
Author(s):  
Csaba Benedek ◽  
Olivér Krammer ◽  
Mihály Janoczki ◽  
László Jakab

2019 ◽  
Vol 1 (7) ◽  
pp. 35-41
Author(s):  
G. I. Korshunov ◽  
A. A. Petrushevskaya ◽  
P. S. Zaitsev

The article discusses the application principles of the industry 4.0 concept to improve the basic technological processes of electronics production. The problems of quality assurance in the automatic installation of printed circuit boards. Examples of the introduction optical inspections and fluoroscopy to reduce the marriage are given. The features of screen printing processes and their control using 2D and 3D inspections are considered. The location structure of the automatic optical inspection installations in the automatic line of printed wiring and communication of the automatic screen printing printer and 3D solder paste inspection is presented. A process model for the automatic installation of printed circuit boards using the elements of Industry 4.0 is presented. The organization of machine-to-machine interaction increases the automation of the system and eliminates the «human factor», as a result of which the production process is accelerated and the probability of occurrence erroneous actions resulting in nonconformities of products with standards is reduced. The tasks of organizing and certification of 3D fluoroscopy electronics, as well as the actual improving tasks the typical automatic assembly line of printed circuit boards, are considered.


2021 ◽  
Author(s):  
Ala Al Robiaee

As the global marketplaces consider mandating lead-free equipments, many questions arise about the impact and feasibility of replacing lead in printed circuit boards soldering applications. In this project, the results presented of a study on comparing the process of screening lead paste versus lead free paste parameters for regular stencil printing using standard manufacturing methods. The key process parameters studies were: squeegee speed, squeegee pressure, and screening yield for both types of pastes. Two solder paste formulations (lead paste and lead-free paste) were evaluated in this study. The analysis of the pastes deposit volumes showed that for normal manufacturing range of printer (screener) settings (speed and pressure) tested the two pastes performed the same. The results also showed that the squeegee speed has a greater effect on the printing process than the squeegee pressure. The tests clearly showed that the lead paste was affected more by setting changes compared to the lead free paste. Varying the print speed and pressure for type of pastes by observing the resulting printed paste volumes optimized screening parameters. This study confirms that a new stencil or stencil design is not needed for the lead free paste. However, this study recommends a change to the sitting of the screening print process. Stencil cleaning frequency is one of the main factors that impact the production rate in an SMT line. The project highlights new results that lead free paste throughput will be less compared to lead paste at the screening step. The number of rejected boards screened with lead free-paste exceeded normal manufacturing standards. As stencil cleaning is a must function, it was recommended to increase stencil wiping frequency when lead free paste [is] in use in order to obtain a consistent volume with less screening defect.


Author(s):  
Riky Tri Yunardi ◽  
Moh. Zakky Zulfiar ◽  
Rr. Wanda Auruma Putri ◽  
Deny Arifianto

In the technology to create prototypes for electronic hardware is usually constructed using surface mount device printed circuit board (SMD PCB). In this paper introduces the design and implementation of low-cost electrical solder paste dispenser that supports the PCB solder process. The design consists of a nozzle and linear drive systems based on stepper motors operating with electric power to push the plunger down to drop the solder paste on the board. To test the performance of solder paste that has been designed verified by experiment. Solder paste dispenser design was tested using SMD resistor with the solder pads of different sizes for R0603, R0805, and R1206 on PCB. The results showed that the design of the prototype was able to put the pasta in various field pads between 0.54 mm2, 0.91 mm2 and 1.44 mm2 for standard solder pads with an error in the 2% - 5%. Based on the results, the device has been shown to potentially be used to attach electronic components to printed circuit boards.


Author(s):  
A. De Luca-Pennacchia ◽  
M. Á. Sánchez-Martí­nez

Solder paste deposit on printed circuit boards (PCB) is a critical stage. It is known that about 60% of functionality defects in this type of boards are due to poor solder paste printing. These defects can be diminished by means of automatic optical inspection of this printing. Actually, this process is implemented by image processing software with its inherent high computational time cost. In this paper we propose to implement a high parallel degree image comparison algorithm suitable to be implemented on FPGA, which could be incorporated to an automatic inspection system. The hardware implementation of the algorithm allows us to fulfill time requirements demanded by industry.


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