Technical Library | 2007-01-31 12:08:36.0
Air-powered dispensing systems use controlled pulses of air pressure to dispense solder paste from syringe reservoirs in uniform amounts. In this paper, EFD explains the most critical variables affecting air-powered dispensing of solder pastes and shows how to manage those variables to your advantage.
Technical Library | 2018-12-19 21:23:59.0
With the rapid trend towards miniaturization in surface mount and MEMs lid-attach technology, it is becoming increasingly challenging to dispense solder paste in ultra-fine dot applications such as those involving chip capacitors or BGA packages, as well as dispensing ultra-fine lines in MEMs lid-attach applications. In order to achieve ultra-fine dots and fine line widths while dispensing solder paste, both the solder material and dispensing equipment need to be optimized. Optimizing the equipment can be very challenging, as there are many input variables that can affect the dispense quality of the solder paste. In this paper we will evaluate the many equipment variables involved in the solder paste dispensing process, and the impact these variables have on the dispense quality of the solder paste.
Technical Library | 2018-11-06 12:42:25.0
Solder paste is a homogeneous, stable suspension of solder powder particles suspended in a flux binder, and is one of the most important process materials today in surface mount technology (SMT). By varying the solder particle size, distribution and shape, as well as the other constituent materials, the rheology and printing performance of solder pastes can be controlled. Paste flow behavior is very important in defining the printing performance of any paste.The purpose of this paper is to study the rheological behavior of SAC (Sn-Ag-Cu) solder paste used for surface mount applications in the electronic industry. The reason why the rheological tests are presented in this paper are two critical sub-processes: aperture filling and paste withdraw. In this paper, we report on the investigation of the rheological profiles, the serrated cone-to-plate system was found as effective in parameter minimizing the wall-slip effect
Technical Library | 2015-10-01 16:12:51.0
Solder paste printing is known to be one of the most difficult processes to quality assure in electronic manufacturing. The challenge increases as the technology development moves toward a mix between large modules and small chip components on large and densely populated printed circuit boards. Having a process for quality assurance of the solder paste print is fast becoming a necessity.This article describes a method to ensure quality secured data from both solder paste printers and inspection machines in electronic assembly manufacturing. This information should be used as feedback in order to improve the solder paste printing process.
Technical Library | 2007-01-31 14:10:17.0
This white paper is suitable for both new and experienced users. It is a practical education in the use and misuse of auger valves for solder paste dispensing.
Technical Library | 2008-03-03 19:43:53.0
Solder pastes are key materials in surface mount technology (SMT) for assembly of printed circuit boards (PCBs). Introduction of lead-free has placed new demands on materials and processes in SMT, requiring materials and process engineers to adopt to lead free whilst ensuring process yields stay at the highest possible levels. Key is the solder paste, a material of great complexity involving engineering sciences, metallurgy, chemistry and physics. This article helps those working with solder pastes improve their understanding of this key material.
Technical Library | 2014-03-13 15:25:01.0
A student competition paper at Budapest University of Technology And Economics, Department of Electronics Technology gives background, covers stencil design and discusses stencils intended for pin in paste application. The stencil applied for depositing the solder paste is a thin, 75–200 µm thick metal foil, on which apertures are formed according to the solder pads on the printed circuit board. Stencil printing provides a fast, mass solder paste deposition process; relatively expensive, appropriate and recommended for mass production.
Technical Library | 2007-01-03 16:36:58.0
Solder paste dispensing is not a new process. However, today's microelectronics present a daunting array of technical challenges to meet deposit size requirements. The need for better paste formulations, more precise equipment, and more tightly controlled processes is driving paste suppliers and equipment suppliers to develop new methods and materials. The most challenging solder paste deposits are those smaller than 0.25mm in diameter and today’s electronics demand such deposits. This paper addresses the process requirements for solder paste micro-deposits in terms of material, equipment and process variable control required for success in producing 0.25mm and smaller deposits.
Technical Library | 2013-03-12 13:25:18.0
High density and miniaturized circuit assemblies challenge the solder paste printing process. The use of small components such as 0201, 01005 and μBGA devices require good paste release to prevent solder paste bridging and misalignment. When placing these miniaturized components, taller paste deposits are often required. To improve solder paste deposition, a nano-coating is applied to laser cut stencils to improve transfer efficiency. One concern is the compatibility of the nano-coating with cleaning agents used in understencil wipe and stencil cleaning. The purpose of this research is to test the chemical compatibility of common cleaning agents used in understencil wipe and stencil cleaning processes.Compatibility of Cleaning Agents With Nano-Coated Stencils
Technical Library | 2023-09-26 19:14:44.0
The transition from tin-lead to lead free soldering in the electronics manufacturing industry has been in progress for the past 10 years. In the interim period before lead free assemblies are uniformly accepted, mixed formulation solder joints are becoming commonplace in electronic assemblies. For example, area array components (BGA/CSP) are frequently available only with lead free Sn-Ag-Cu (SAC) solder balls. Such parts are often assembled to printed circuit boards using traditional 63Sn-37Pb solder paste. The resulting solder joints contain unusual quaternary alloys of Sn, Ag, Cu, and Pb. In addition, the alloy composition can vary across the solder joint based on the paste to ball solder volumes and the reflow profile utilized. The mechanical and physical properties of such Sn-Ag-Cu-Pb alloys have not been explored extensively in the literature. In addition, the reliability of mixed formulation solder joints is poorly understood.
