Optimization of Solder Paste Printing Parameters Using Design of Experiments (DOE) (original) (raw)
Related papers
The International Journal of Advanced Manufacturing Technology, 2019
The present study examines the effect of squeegee load, squeegee speed, and separation speed on the printing performance of lead-free solder paste, and solder printing was carried out to evaluate the effect of the filled volume of the solder paste during stencil printing. Application of pressure on the squeegee affects the filled volume of the solder paste in the stencil aperture, and the incorrect pressure setting could cause incomplete filling. Herein, an experiment was conducted on a printing machine employing surface mount technology. The solder paste used in the study was Sn/Ag/Cu (SAC305), and four components, namely, 0603, small outline transistor (SOT), 1210, and tantalum-D, were tested. The filled volume and height of the solder paste under different squeegee loads, squeegee speeds, and separation speeds were determined, and the solder volume was found to vary with the squeegee load and component type. Response surface method (RSM) optimization is conducted to obtain optimum filled volume and solder paste height and area during the printing process. The method showed squeegee load, squeegee speed, and separation speed have considerable effects on filled volume, solder paste height, and solder paste area.
Soldering & Surface Mount Technology, 2019
Purpose The purpose of this paper is to investigate and minimize the printing-related defects in the surface mount assembly (SMA) process. Design/methodology/approach This paper uses an experimental approach to explore process parameter and printing defects during the SMA process. Increasing printing performance, various practices of solder paste (Ag3.0/Cu0.5/Sn) storage and handling are suggested. Lopsided paste problem is studied by varying squeegee pressure and the results are presented. Unfilled pads problems are observed for ball grid array (BGA) and quad flat package (QFP) which is mitigated by proper force tuning. In this paper, a comparative study is conducted which evaluates the manifestation of printing offset due to low-grade stencil. The input/output (I/O) boards were oxidized when the relative humidity was maintained beyond 70 per cent for more than 8 h. This pad oxidation problem is overcome by proper printed circuit board (PCB) handling procedures. When the unoptimize...
Effect Of Squeegee Blade On Solder Paste Print Quality
2010
The solder paste deposition process is viewed by many in the industry as the leading contributor of defects in the Surface Mount Technology (SMT) assembly process. As with all manufacturing processes, solder paste printing is subject to both special and common cause variation. Just like using graduated cylinders from distinctly different manufacturing processes to measure a volume of liquid, using different blades types can contribute significant special cause variation to a process. Understanding the significant differences in print performance between blade types is an important first step to establishing a standard blade for an SMT process. Over the last 30 years, the SMT assembly process has become increasingly more sophisticated. There are two primary methods of applying solder paste to a circuit board using a stencil printer: squeegee blade printing and enclosed head printing. While each method has its advantages and disadvantages, this study focuses on the squeegee blade prin...
Effect of Temperature on Solder Paste During Surface Mount Technology Printing
2020
There are lots of companies manufacturing electronic components that have commonly used the Surface Mount Technology printing process. However, the temperature of solder paste printing on the Printed Circuit Board can influence the presence of defects in Surface Mount Technology. In this paper, the experiment called Surface Mount Technology printing is built and tested to characterize the temperature of solder pastes in order to prevent the electronic waste and rejection rate of the malfunctioning electronics due to poor soldering. The microstructures of solder paste on printed circuit board and copper substrate are inspected under Scanning Electron Microscopy. It is focused on two parameters that affect the performance of a printed circuit board, which includes the filling areas of solder paste and the distance between ball grid arrays. From the experiment and analysis results, the filling area decreases as the temperature increases during the Surface Mount Technology printing process. In short, when the temperature of SAC305 increases, the viscosity and filling areas decreases. In fact, SAC305 gave the second rank of smallest area (18.86%) and distance (43.43%) after SAC307. The average area and distance are fair enough for the solder to hold the component placement, unlike SAC307 which likely causes tombstone.
As the density of board design increasing fast, the distance between the adjacent components becomes much smaller. When the miniature chip components and the fine pitch components which require smaller volumes of solder paste are close to the castle-like components, connectors with poor pin co-planarity and CCGAs which require more solder paste, only one single thickness stencil could not satisfy all of the components at the same printing process. At present, the step stencil is the cheapest and most popular solution, but the layout density could not increase more because of the keep-out distances. The objective of this iNEMI Solder Paste Deposition Project is to understand the major factors to step stencil printing quality and where are the limitations.
Characterization of printed solder paste excess and bridge related defects
2008 2nd Electronics Systemintegration Technology Conference, 2008
Surface Mount Technology (SMT) involves the printing of solder paste on to printed circuit board (PCB) interconnection pads prior to component placement and reflow soldering. This paper focuses on the solder paste deposition process. With an approximated cause ratio of 50-70% of post assembly defects, solder paste deposition represents the most significant cause initiator of the three sub-processes. Paradigmatic cause models, and associated design rules and effects data are extrapolated from academic and industrial literature and formulated into physical models that identify and integrate the process into three discrete solder paste deposition events-i.e. (i) stencil / PCB alignment, (ii) print stroke / aperture filling and (iii) stencil separation / paste transfer. The project's industrial partners are producers of safety-critical products and have recognised the in-service reliability benefits of electro-mechanical interface elimination when multiple smaller circuit designs are assimilated into one larger Printed Circuit Assembly (PCA). However, increased solder paste deposition related defect rates have been reported with larger PCAs and therefore, print process physical models need to account for size related phenomena.
The Optimization of the Soldering Process Through Experiment Design
The purpose of this paper is to improve the wave soldering process of electronic component, which usually results in a great number of defects, such as insufficient soldering and short-circuits. The wave solder machine has several control factors (parameters), including solder temperature, preheat temperature, conveyor speed, flux type, flux pressure, solder wave depth, and conveyor board angle on conveyor. In addition, however, there are several other factors (noises factors) that cannot be controlled. Designing an experiment with so many control factors implies a big number of the runs. To decrease the number of runs, the authors have identified from previous experience the factors that bear the greatest influence on soldering defects: flux-pressure, conveyor speed, and board angle on conveyor. In the first stage of the experiments, a screening experiment 2 3 with 3 replicates was designed. After analyzing the data, a control factor was eliminated and in the second stage a central composite design with 2 control factors was designed. Analysis of the experiment data showed that the wave soldering process was optimized by minimizing the soldering defects .
2009 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference, 2009
The widely recognized industry standard IPC-7525 has been used as the starting point for an experimental program that explores the effect of varying the keep out distance for 0201 and 0402 chip components, CSP and SOP with pitches down to 0.4mm, and larger components represented by CCGA. Other variables that were included in the experimental program to determine if they had an effect on the sensitivity of paste transfer to keep-out distance included stencil type, step height and solder type. In the first stage of the project the printing to each pad was measured with automated 3D SPI systems and optimum combinations of parameters identified by statistical analysis. In this paper the authors will explain the methodology chosen to achieve the project objectives and indicate the direction of likely future work. Early results indicate that a key objective of the project, to provide evidence to support the case for a reduction in the keep out distances below the current industry standard, might be achievable.
Leaded and Lead-Free Solder Paste Evaluation Screening Procedure
2007
Numerous studies have shown that greater than 60% of end of line defects in SMT assembly can be traced to solder paste and the printing process. Reflowing adds another 15% or so. In light of this fact, it is surprising that no simplified procedure for solder paste evaluation has been documented. This paper is about such a procedure. By using designed experiments and the measurement of critical solder paste related process metrics, we were able to develop a solder paste evaluation procedure that maximizes information about the solder paste and its processability while minimizing experimentation. While using only 12 stencil printed PWBs, we were able to generate statistically significant results that enabled us to rank solder pastes according to their performance. Response metrics that were investigated were print volume and definition before and after pause, squeegee hang up, slump, tack, release from aperture, and solder joint quality. In addition, we found such variation in solder ...
Flow processes in solder paste during stencil printing for SMT assembly
Journal of Materials Science: Materials in Electronics, 1995
Solder paste is used for reflow soldering of Surface Mount Devices (SMDs). In this paper we discuss how the various stages of the stencil printing cycle affect the rheological properties of the solder paste. First the heat generated in the paste roll is examined to see what effect it has on solder paste rheology, then we analyse in detail the process of paste withdrawal from a metal mask stencil and discuss those properties of solder paste that lead to a good print in terms of the size and shape of the solder paste particles, and their packing. In order to do this, we review some of the experiments and phenomena that have been shown to occur in dense suspensions, and see what aspects of that work are applicable to solder paste printing.