barcode scanner programming asp.net SOLDERING TECHNIQUES in Software

Creation QR in Software SOLDERING TECHNIQUES

SOLDERING TECHNIQUES
QR Reader In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Making Quick Response Code In None
Using Barcode generation for Software Control to generate, create QR Code image in Software applications.
47.3.1.4 Venting. Oven venting is required to remove harmful fumes from the oven tunnel. If there is too little venting, fumes will not be removed effectively. Too much exhaust will pull in room air through the tunnel entrance, tunnel exit, or both, which can disturb thermal performance. If nitrogen is being introduced to lower oxygen levels, too strong an exhaust draw will negate the effect of the nitrogen or make it difficult to control the oxygen level within the oven. For a more detailed look at venting, see Sec. 47.3.2. 47.3.1.5 Cooling. Just as important as heating the solder, the solder must be brought back to solid state before the board is handled. Otherwise, components sitting in liquid solder could move. Also, as a material such as solder solidifies and crystallizes, mechanical motion can perturb the lattice structure. The resultant solder joints may be of poorer quality and lesser reliability. Some ovens rely upon passive cooling, whereas others have active cooling elements such as fans or even chillers (fans blowing over chilled radiators).
Reading QR-Code In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
Create QR Code 2d Barcode In C#.NET
Using Barcode drawer for Visual Studio .NET Control to generate, create Denso QR Bar Code image in .NET applications.
47.3.2 Forced-Convection Reflow Oven This is the preferred tool for controlled and reliable reflow soldering dependent on heated air recirculated at high velocity in the oven tunnel. The only direct irradiation of the PCBs is by the longest IR wavelengths emitted by the hot surfaces within the tunnel. 47.3.2.1 Forced-Convection Reflow Module. Heating is accomplished primarily through heated air streams directed at the PWB s top and bottom surfaces. This method imparts greater thermal uniformity and controllability of the reflow process than any other reflow oven heating methods. It precludes overheating of the circuit board and/or components caused by preferential absorption common to direct IR heating methods. Although the combination IR-convective method has helped in this regard, it is no substitute for the hot-air forced-convection technology. Top-of-the-line forced-air-convection ovens have heating modules mounted above and below the board conveyor. They accomplish heating by passing a high-velocity air stream drawn from the tunnel ambient over resistance heaters, through perforated platens. The heating elements are typically shielded from the board to mitigate the effects of any direct or indirect IR impingement on the circuit board. The high-velocity air flows are baffled and regulated to impart a uniform temperature across the tunnel width. Each module is quickly heated and highly controllable. Several heating modules are set side by side along the length of the oven. It is typical to duplicate the forced-convection module array on the bottom of the oven tunnel to impart controllability of the reflow time-temperature profile and to help in even heating of the board from both sides simultaneously. Fig. 47.6 depicts this arrangement. 47.3.2.2 Cooling. Some ovens rely upon passive cooling to lower the temperature of the PCB assembly below the solder liquidus point. In this case, the board traverses a region of the oven devoid of heaters cooling along the way.This is generally adequate for thin, low-thermalmass boards. But the reality of multilayer, densely packed circuit boards necessitates some means of cooling to ensure that solder joints are solid prior to exiting the oven and before handling the board.To accomplish this, many ovens incorporate an area of active cooling after the last heating zone within the oven (see Fig. 47.7). Active cooling comes in many forms. Forced-air cooling by fans is the most common. Fans can be deployed on top, on the bottom, or in combination for board cooling. Among the most exotic but the most efficient is the water-to-gas heat exchanger found in some ovens. This provides a stream of temperature-controlled cool air at the exit end of the oven for board cooldown and has distinct advantages in nitrogen atmosphere reflow systems. This method uses whatever process gas is in the oven, cooling it and redirecting it onto the circuit board. Thus, this method does not require additional nitrogen for cooling, does not draw any additional air into the oven that might degrade the nitrogen atmosphere, and precludes the need
QR-Code Drawer In VS .NET
Using Barcode generation for ASP.NET Control to generate, create Denso QR Bar Code image in ASP.NET applications.
Create Quick Response Code In .NET
Using Barcode creation for VS .NET Control to generate, create QR-Code image in .NET applications.
Print QR-Code In Visual Basic .NET
Using Barcode printer for .NET Control to generate, create Quick Response Code image in .NET applications.
Bar Code Printer In None
Using Barcode generator for Software Control to generate, create bar code image in Software applications.
Painting Code 128A In None
Using Barcode generation for Software Control to generate, create Code-128 image in Software applications.
Draw UPC A In None
Using Barcode encoder for Software Control to generate, create UPC Symbol image in Software applications.
EAN / UCC - 13 Maker In None
Using Barcode printer for Software Control to generate, create EAN / UCC - 13 image in Software applications.
Bar Code Printer In None
Using Barcode generation for Software Control to generate, create barcode image in Software applications.
2 Of 5 Standard Creation In None
Using Barcode printer for Software Control to generate, create 2 of 5 Industrial image in Software applications.
EAN 13 Encoder In None
Using Barcode creation for Online Control to generate, create EAN-13 Supplement 5 image in Online applications.
Data Matrix Creator In None
Using Barcode creation for Online Control to generate, create DataMatrix image in Online applications.
EAN13 Creation In VS .NET
Using Barcode encoder for .NET framework Control to generate, create GS1 - 13 image in .NET framework applications.
Make EAN13 In Java
Using Barcode generation for BIRT reports Control to generate, create EAN 13 image in BIRT applications.
Print EAN-13 In .NET
Using Barcode creation for Reporting Service Control to generate, create GTIN - 13 image in Reporting Service applications.
USS Code 39 Maker In .NET
Using Barcode creation for .NET Control to generate, create Code 39 image in VS .NET applications.
Data Matrix Generation In Java
Using Barcode generation for Java Control to generate, create DataMatrix image in Java applications.
Copyright © OnBarcode.com . All rights reserved.