Infrared vision techniques in quality control of surface-mount circuit board solder paste printing

1995 ◽  
Author(s):  
Jarmo T. Alander ◽  
Mikko Huusko ◽  
Aimo Karonen ◽  
Jari Kuusrainen ◽  
Lars Unonius
Keyword(s):  
Quality Control ◽  
Circuit Board ◽  
Solder Paste ◽  
Surface Mount ◽  
Solder Paste Printing ◽  
Infrared Vision

The behaviour of solder pastes in stencil printing with electropolishing process

2013 ◽  
Vol 25 (3) ◽  
pp. 164-174 ◽  
Author(s):  
Yong‐Won Lee ◽  
Keun‐Soo Kim ◽  
Katsuaki Suganuma
Keyword(s):  
Circuit Board ◽  
Surface Finishing ◽  
Design Parameters ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Content Type ◽  
Solder Paste Printing ◽  
Solder Mask

PurposeThe purpose of this paper is to study the effect of the electropolishing time of stencil manufacturing parameters and solder‐mask definition methods of PCB pad design parameters on the performance of solder paste stencil printing process for the assembly of 01005 chip components.Design/methodology/approachDuring the study, two types of stencils were manufactured for the evaluations: electroformed stencils and electropolished laser‐cut stencils. The electroformed stencils were manufactured using the standard electroforming process and their use in the paste printing process was compared against the use of an electropolished laser‐cut stencil. The electropolishing performance of the laser‐cut stencil was evaluated twice at the following intervals: 100 s and 200 s. The performance of the laser‐cut stencil was also evaluated without electropolishing. An optimized process was established after the polished stencil apertures of the laser‐cut stencil were inspected. The performance evaluations were made by visually inspecting the quality of the post‐surface finishing for the aperture wall and the quality of that post‐surface finishing was further checked using a scanning electron microscope. A test board was used in a series of designed experiments to evaluate the solder paste printing process.FindingsThe results demonstrated that the length of the electropolishing time had a significant effect on the small stencil's aperture quality and the solder paste's stencil printing performance. In this study, the most effective electropolishing time was 100 s for a stencil thickness of 0.08 mm. The deposited solder paste thickness was significantly better for the enhanced laser‐cut stencil with electropolishing compared to the conventional electroformed stencils. In this printing‐focused work, print paste thickness measurements were also found to vary across different solder‐mask definition methods of printed circuit board pad designs with no change in the size of the stencil aperture. The highest paste value transfer consistently occurred with solder‐mask‐defined pads, when an electropolished laser‐cut stencil was used.Originality/valueDue to important improvements in the quality of the electropolished laser‐cut stencil, and based on the results of this experiment, the electropolished laser‐cut stencil is strongly recommended for the solder paste printing of fine‐pitch and miniature components, especially in comparison to the typical laser‐cut stencil. The advantages of implementing a 01005 chip component mass production assembly process include excellent solder paste release, increased solder volume, good manufacture‐ability, fast turnaround time, and greater cost saving opportunities.

scholarly journals An intelligent approach for improving printed circuit board assembly process performance in smart manufacturing

2020 ◽  
Vol 12 ◽  
pp. 184797902094618
Author(s):  
Vincent WC Fung ◽  
Kam Chuen Yung
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Smart Manufacturing ◽  
Process Performance ◽  
Solder Paste ◽  
Assembly Process ◽  
Printed Circuit Board Assembly ◽  
Printed Circuit ◽  
Circuit Board Assembly ◽  
Solder Paste Printing

The process of printed circuit board assembly (PCBA) involves several machines, such as a stencil printer, placement machine and reflow oven, to solder and assemble electronic components onto printed circuit boards (PCBs). In the production flow, some failure prevention mechanisms are deployed to ensure the designated quality of PCBA, including solder paste inspection (SPI), automated optical inspection (AOI) and in-circuit testing (ICT). However, such methods to locate the failures are reactive in nature, which may create waste and require additional effort to be spent re-manufacturing and inspecting the PCBs. Worse still, the process performance of the assembly process cannot be guaranteed at a high level. Therefore, there is a need to improve the performance of the PCBA process. To address the aforementioned challenges in the PCBA process, an intelligent assembly process improvement system (IAPIS) is proposed, which integrates the k-means clustering method and multi-response Taguchi method to formulate a pro-active approach to investigate and manage the process performance. The critical process parameters are first identified by means of k-means clustering and the selected parameters are then used to formulate a set of experimental studies by using the multi-response Taguchi method to optimize the performance of the assembly process. To validate the proposed system, a case study of an electronics manufacturer in the solder paste printing process was conducted. The contributions of this study are two-fold: (i) pressure, blade angle and speed are identified as the critical factors in the solder paste printing process; and (ii) a significant improvement in the yield performance of PCBA can be achieved as a component in the smart manufacturing.

Fundamental Analyses of Smart Tooling for Assembly of Thin Flexible Circuit and Board Systems

1999 ◽  
Author(s):  
Ruijun Chen ◽  
Daniel F. Baldwin
Keyword(s):  
Form Solution ◽  
Circuit Board ◽  
Flexible Substrates ◽  
Solder Paste ◽  
Assembly Process ◽  
Design Data ◽  
Solder Paste Printing ◽  
Bond Pads ◽  
Close Form ◽  
The Impact

Abstract Flexible nature of flexible circuits/boards poses new fixture tooling challenges for standard surface mount assembly equipment. The flexible substrates experience significant transverse displacements under perpendicular assembly forces during solder paste printing and component placement processes. The displacements result in misregistration of the component leads and substrate bond pads, leading to assembly process defects. Solder reflow process further complicates the issue due to the thermo-mechanical warpage induced. Reengineered and specialized dedicated tooling for fixturing flexible substrates in standard assembly equipment is becoming extremely important. This paper focuses on developing analysis methodologies and theories for implementing Smart Tooling. The primary goals being to determine the impact of fixturing on assembly process quality and to determine optimum fixturing configurations for thin flexible circuit board assemblies based on circuit board design data. A mathematical model to describe both transverse and perpendicular displacements of flex substrates is developed, and its close-form solution for transverse displacements is obtained. Using a “near” optimum fixturing configuration to minimize transverse displacements is verified.

scholarly journals Integrating the TRIZ and Taguchi's Method in the Optimization of Processes Parameters for SMT

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yung-Tsan Jou ◽  
Wen-Tsann Lin ◽  
Wei-Cheng Lee ◽  
Tsu-Ming Yeh
Keyword(s):  
Optimal Parameter ◽  
Circuit Board ◽  
Solder Paste ◽  
Taguchi’S Method ◽  
Key Factors ◽  
Factors Affecting ◽  
Assembly Technology ◽  
Ejection Speed ◽  
Solder Paste Printing

SMT is an assembly technology for core circuit board parts. Unless process parameters are effectively controlled, poor solderability may result in a decline in product quality. This study looks at an SMT manufacturing process in a multinational company. First, the TRIZ contradiction matrix is revised to investigate the association between the 39 parameters in the contradiction matrix and 13 parameters that influence the unevenness of solder paste in the solder paste printing process. Expert verification is then used to screen the key factors affecting the quality of SMT, which are then combined with Taguchi's method to identify the optimal parameter set influencing the thickness of SMT solder paste.Results. TRIZ identifies squeegee pressure, ejection speed, squeegee speed, and squeegee angle as the four parameters with the greatest influence on SMT solder paste thickness. Taguchi's method is used to identify the optimum levels set for the experimental factors and carry out confirmation experiments. TheS/Nratio improved from 21.732 db to 26.632 db, while the mean also improved from the current 0.163 mm to 0.155 mm, close to the target value of 0.15 mm. The results show that applying TRIZ and Taguchi's method for the purpose of product improvement is feasible.

scholarly journals Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3353
Author(s):  
Marina Makrygianni ◽  
Filimon Zacharatos ◽  
Kostas Andritsos ◽  
Ioannis Theodorakos ◽  
Dimitris Reppas ◽  
...  
Keyword(s):  
High Resolution ◽  
Form Factors ◽  
Circuit Board ◽  
Lead Free ◽  
Process Conditions ◽  
Solder Paste ◽  
Electronic Components ◽  
Successful Operation ◽  
Fine Pitch ◽  
Forward Transfer

Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.

A Study of the Aperture Filling Process in Solder Paste Stencil Printing

1999 ◽  
Author(s):  
Jianbiao Pan ◽  
Gregory L. Tonkay
Keyword(s):  
Flip Chip ◽  
Deposition Process ◽  
Area Ratio ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Surface Mount ◽  
Fine Pitch ◽  
Main Indicator ◽  
Advanced Packaging

Abstract Stencil printing has been the dominant method of solder deposition in surface mount assembly. With the development of advanced packaging technologies such as ball grid array (BGA) and flip chip on board (FCOB), stencil printing will continue to play an important role. However, the stencil printing process is not completely understood because 52–71 percent of fine and ultra-fine pitch surface mount assembly defects are printing process related (Clouthier, 1999). This paper proposes an analytical model of the solder paste deposition process during stencil printing. The model derives the relationship between the transfer ratio and the area ratio. The area ratio is recommended as a main indicator for determining the maximum stencil thickness. This model explains two experimental phenomena. One is that increasing stencil thickness does not necessarily lead to thicker deposits. The other is that perpendicular apertures print thicker than parallel apertures.

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