Technical Library | 2016-08-18 15:38:09.0
The Selective Reflow Rework Process is an approach to improving the high volume rework process, increasing process capabilities and process repeatability by using a standard reflow oven of 12 zones, pick and place machinery, semi-automated printing gear and Solder Paste Inspection (SPI) implementations. This approach was able to reduce the amount of rework equipment by more than half. Our human resource requirements (indirect and direct labor) were cut by more than 50% and our rolled throughput yield increased from 68.9% to 84.14%. The Selective Reflow Rework Process is less reliant upon operators and has become a repeatable, stable rework process.
Technical Library | 2021-04-21 19:28:30.0
Voids affect the thermal characteristics and mechanical properties of a solder joint, thereby affecting the reliability of the solder interconnect. The automotive sector in particular is requiring the mitigation of solder voids in various electronic control modules to the minimum possible level. Earlier research efforts performed to decrease voids involved varying the reflow profile, paste deposit, paste alloy composition, stencil aperture, and thickness.
Technical Library | 2016-02-11 18:26:43.0
Although reflow ovens may not have been dramatically changed during the last decade the reflow process changes step by step. With the introduction of lead-free soldering not only operation temperatures increased, but also the chemistry of the solder paste was modified to meet the higher thermal requirements. Miniaturization is a second factor that impacts the reflow process. The density on the assembly is increasing where solder paste deposit volumes decreases due to smaller pad and component dimensions. Pick and place machines can handle more components and to meet this high through put some SMD lines are equipped with dual lane conveyors, doubling solder paste consumption. With the introduction of pin in paste to solder through hole components contamination of the oven increased due to dripping of the paste.
Technical Library | 2020-11-24 23:12:27.0
In a lead-free reflow process, temperatures are higher, and materials use outgasses more than in a leaded reflow process. The trends toward higher density populated boards and more pin-in-paste technology also increase solder paste use. More components and more solder paste result in more outgassing of chemistry during the reflow process. Some assemblies report condensation of vapors when the cold printed circuit board enters the oven. Little is known about the interaction between these condensed materials in terms of the interaction between these condensed materials and the reliability of the assembly. Apart from the question of reliability, a printed circuit board contaminated with a small film of residues after reflow soldering is not desirable.
Technical Library | 2021-12-16 01:52:32.0
Package on Packages (PoP) find use in applications that require high performance with increased memory density. One of the greatest benefits of PoP technology is the elimination of the expensive and challenging task of routing high-speed memory lines from under the processor chip out to memory chip in separate packages. Instead, the memory sits on top of the processor and the connections are automatically made during assembly. For this reason PoP technology has gained wide acceptance in cell phones and other mobile applications. PoP technology can be assembled using one-pass and two-pass assembly processes. In the one-pass technique the processor is first mounted to the board, the memory is mounted to the processor and the finished board is then run through the reflow oven in a single pass. The two-pass technique has an intermediate step in which the memory is first mounted onto the processor.
Technical Library | 2016-09-19 20:26:36.0
This white paper seeks to set out the value of a ‘smarter’ approach to the reflow process and how a more intelligent oven can offer real added value and performance to the entire line. It also lays out some of the criteria that is important when selecting smart equipment for a smart process, that conforms to, and is ready for, IoM or Industry 4.0
Technical Library | 2021-08-04 18:46:25.0
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.
Technical Library | 2020-07-29 19:58:48.0
The majority of flexible circuits are made by patterning copper metal that is laminated to a flexible substrate, which is usually polyimide film of varying thickness. An increasingly popular method to meet the need for lower cost circuitry is the use of aluminum on Polyester (Al-PET) substrates. This material is gaining popularity and has found wide use in RFID tags, low cost LED lighting and other single-layer circuits. However, both aluminum and PET have their own constraints and require special processing to make finished circuits. Aluminum is not easy to solder components to at low temperatures and PET cannot withstand high temperatures. Soldering to these materials requires either an additional surface treatment or the use of conductive epoxy to attach components. Surface treatment of aluminum includes the likes of Electroless Nickel Immersion Gold plating (ENIG), which is extensive wet-chemistry and cost-prohibitive for mass adoption. Conductive adhesives, including Anisotropic Conductive Paste (ACP), are another alternate to soldering components. These result in component substrate interfaces that are inferior to conventional solders in terms of performance and reliability. An advanced surface treatment technology will be presented that addresses all these constraints. Once applied on Aluminum surfaces using conventional printing techniques such as screen, stencil, etc., it is cured thermally in a convection oven at low temperatures. This surface treatment is non-conductive. To attach a component, a solder bump on the component or solder printed on the treated pad is needed before placing the component. The Aluminum circuit will pass through a reflow oven, as is commonly done in PCB manufacturing. This allows for the formation of a true metal to metal bond between the solder and the aluminum on the pads. This process paves the way for large scale, low cost manufacturing of Al-PET circuits. We will also discuss details of the process used to make functional aluminum circuits, study the resultant solder-aluminum bond, shear results and SEM/ EDS analysis.
Technical Library | 2009-12-23 16:55:08.0
Leading up to the development of lead-free soldering alloys, Horizontal Convection* was developed for the reflow process. Getting the correct temperature profile, with the narrow process window in lead-free applications, is now more important than ever. In each chamber or zone, air is circulated toward one side of the oven above the PCB and toward the opposite side of the oven below the PCB, forming a cyclone around the board. The forced air circulation results in a uniform temperature profile along the entire circuit board assembly. This technology is ideal for the precise profiles needed for lead free soldering.
Technical Library | 2013-03-27 23:43:40.0
Vapor phase, once cast to the annals’ of history is making a comeback. Why? Reflow technology is well developed and has served the industry for many years, it is simple and it is consistent. All points are true – when dealing with the centre section of the bell curve. Today’s PCB manufacturers are faced with many designs which no longer fall into that polite category but rather test the process engineering groups with heavier and larger panels, large ground planes located in tricky places, component mass densities which are poorly distributed, ever changing Pb Free alloys and higher process temperatures. All the time the costs for the panels increase, availability of “process trial” boards diminishes and yields are expected to be extremely high with zero scrap rates. The final process in the assembly line has the capacity to secure all the value of the assembly or destroy it. If a panel is poorly soldered due to poor Oven setup or incorrect programming of the profile the recovery of the panel is at best expensive, at worst a loss. For these challenges people are turning to Vapor Phase.
Reflow ovens for automated SMT PCB assembly, specializing in lead free processing and nitrogen reflow. The best convection reflow ovens on the market.
4 Vreeland Rd.
Florham Park, NJ USA
Phone: 973-377-6800
