barcode scanner asp.net mvc PRINTED CIRCUITS HANDBOOK in Software

Paint QR Code 2d barcode in Software PRINTED CIRCUITS HANDBOOK

PRINTED CIRCUITS HANDBOOK
Scan QR Code JIS X 0510 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
QR-Code Drawer In None
Using Barcode maker for Software Control to generate, create QR Code image in Software applications.
environmental regulations. Preheaters are added to reduce the thermal shock when parts entered the working fluid, thereby providing a more controlled time-temperature profile. Lower capital cost and properties of the condensation heat source previously noted cause condensation or vapor phase reflow to be well suited for prototype development programs and small production volumes. 40.3.3.7 Hand Soldering. As noted earlier, in the highly automated surface-mount assembly line having automated paste printing and component placement capabilities, hand soldering would not be particularly advantageous in terms of maximizing production volumes. However, in some applications, the assembly process includes a hand-soldering operation. For example, often odd-form components cannot be incorporated in a pick-and-place machine, or temperature-sensitive devices cannot be exposed to the reflow furnace environment. Under these circumstances, the hand-soldering step is performed after mass soldering (reflow, wave, etc.). The implication is that hand soldering is now being performed on what is potentially a very-high-valued circuit board. Therefore, factors such as handling damage, electrostatic discharge (ESD) damage, and thermal damage to nearby components by the soldering iron tip, as well as flux residue contamination, must be thoroughly addressed at the development stage of the hand-soldering process. The use of Pb-free solders has not impacted the hand-soldering process itself. There is a slight lengthening of the soldering time, typically from 3 to 4 sec. to 5 to 7 sec., due to the higher melting temperatures of the Pb-free solders. The same soldering iron equipment can provide the necessary tip temperatures. The high-Sn solder compositions, coupled with their higher melting temperatures, can more quickly degrade the tip. Lastly, the operator should not mistake a duller appearance to the fillet surface for a cold solder joint. 40.3.3.8 Conduction (Sikama) Soldering. Conduction soldering is the process in which heat arrives to the solder paste by means of conduction through the substrate. The process, which is illustrated in Fig. 40.24, is also termed Sikama soldering, being named after the primary
QR Recognizer In None
Using Barcode decoder for Software Control to read, scan read, scan image in Software applications.
QR Code Generation In Visual C#.NET
Using Barcode printer for VS .NET Control to generate, create QR Code JIS X 0510 image in .NET applications.
FIGURE 40.24 Schematic diagram depicting conduction soldering. The pusher bar presses the circuit board along the surface of platen. Heaters under the platen determine the time-temperature profile.
QR Code Generation In .NET Framework
Using Barcode generator for ASP.NET Control to generate, create QR Code image in ASP.NET applications.
QR-Code Maker In Visual Studio .NET
Using Barcode printer for VS .NET Control to generate, create QR-Code image in .NET applications.
ASSEMBLY PROCESSES
Generating QR Code In Visual Basic .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Denso QR Bar Code image in .NET framework applications.
EAN 128 Maker In None
Using Barcode creation for Software Control to generate, create UCC - 12 image in Software applications.
equipment manufacturer. The equipment is set up to accommodate an inline process, although it can be used in batch mode as well. The circuit board is pushed along on top of the heated platen by rods attached to a conveyor. Different sets of heating elements under the platen heat the latter locally to different temperatures along its length, creating heat zones such as those in a reflow furnace. The soldering process can be performed in air or using an inert atmosphere. The fact that the substrate is fully supported along its entire footprint (which is needed to maximize heat input) precludes excessive warpage. The conduction heating process has been used almost exclusively for ceramic substrate because these materials do not degrade when exposed to the high platen temperatures. Thermal degradation would be more likely for organic laminates. Best results are realized when this process is used with relatively thin substrates (<1.0 mm). 40.3.3.9 Cleaning. Cleaning is typically the final step in the circuit board assembly process. There is a variety of cleaning equipment, from hand-loaded, batch-type dishwasher machines for smaller production volumes, up to larger inline units that are integrated into the back end of the assembly line for large production volumes. In response to environmental regulations, cleaning solutions have moved away from the once popular organic solvents to aqueous and semi-aqueous cleaners based on water- and water-alcohol-based compositions. Similarly, the handling of the waste stream is also important. Closed-loop systems are preferable to oncethrough cleaning process because of regulations governing the disposal of the waste stream. In the case of assemblies requiring multiple soldering steps, the cleaning portion of the prior soldering step does not leave a residue on the surface that degrades the solderability required for the follow-on process. The use of a Pb-free process does not necessarily have a significant impact on the cleanability of circuit boards. At one time, it was believed that flux residues from Pb-free processes would be more difficult to remove, due to the higher soldering temperatures. Subsequently, it has been determined that thermal degradation of those residues is not as severe, so current cleaning processes appear to perform adequately. 40.3.3.10 Pb-Free Solders. The equipment types described in the preceding sections are often combined to form an electronics assembly line.The term line implies that the equipment is physically located end to end, thereby allowing for the movement of circuit boards between the different functions or stations.Although this scenario is, in fact, typically the case, it need not always be so. Under some circumstances, it may be advantageous to locate some stations a distance away others on the shop floor, thus requiring operators to move product between the two sites on wheeled racks. This is usually the case with inspection and repair/rework functions as well as for some cleaning processes due to health or safety concerns. The setup and hence the flow of a product assembly process are referred to as the (assembly) line architecture. Numerous variables are considered when developing any assembly line architecture. The underlying consideration is optimizing the level of automation. Some of these variables include the following:
Making Code 128 In None
Using Barcode generator for Software Control to generate, create Code 128C image in Software applications.
Drawing Barcode In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
Available floor space and facilities (electricity, exhaust, computer networks, etc.) Equipment footprint and cost of ownership or lease Labor costs Production volumes and product changeover flexibility Circuit board technology (through-hole, surface-mount, or mixed) Soldering technology: Sn-Pb versus Pb-free Inspection and quality requirements
ECC200 Maker In None
Using Barcode generation for Software Control to generate, create ECC200 image in Software applications.
Encoding ANSI/AIM Code 39 In None
Using Barcode drawer for Software Control to generate, create Code39 image in Software applications.
It is important for the manufacturing engineer to consider not only each of these points individually, but to also apply the proper weighting factors of their importance when integrating them together to develop a process for the product(s).
Code 2 Of 5 Encoder In None
Using Barcode encoder for Software Control to generate, create 2/5 Industrial image in Software applications.
UPC Symbol Generator In Objective-C
Using Barcode maker for iPad Control to generate, create GTIN - 12 image in iPad applications.
Linear 1D Barcode Generation In VB.NET
Using Barcode printer for .NET framework Control to generate, create 1D Barcode image in Visual Studio .NET applications.
Barcode Encoder In Visual Studio .NET
Using Barcode creator for .NET framework Control to generate, create barcode image in .NET applications.
GS1 128 Creator In None
Using Barcode drawer for Excel Control to generate, create EAN 128 image in Microsoft Excel applications.
EAN / UCC - 13 Printer In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create EAN / UCC - 14 image in Eclipse BIRT applications.
Create Bar Code In VS .NET
Using Barcode generation for ASP.NET Control to generate, create bar code image in ASP.NET applications.
Making Barcode In Java
Using Barcode creator for Java Control to generate, create barcode image in Java applications.
Copyright © OnBarcode.com . All rights reserved.