Printed circuit boards manufacturability

For sensor applications, printed circuit boards are manufactured and assembled in larger sized batches. If possible, testing and trimming are also done in the same way. Finally, the PCB is devided into individual sensor modules. This approach is key to minimizing cost. 

Optimization is an activity carried out in almost every aspect of our life, from planning the best route in our way back home from woik to more sophisticated approximations at the stock market, or the parameter optimization for a wave solder process used in a printed circuit board assembly manufacturer optimization theory has gained importance over the last decades. From science to applied engineering (to name a few), there is always something to optimize and of course, more than one way to do it. 

As the fundamental building block for printed circuits, base materials must meet the needs of the printed circuit board (PCB) manufacturer, the circuit assembler, and the original equipment manufacturer (OEM). A balance of properties must be achieved that satisfies each member of the supply chain. In some cases, the desires of one member of the supply chain conflict with another. For example, the need for improved electrical performance by the OEM, or improved thermal performance by the assembler, may necessitate the use of resin systems that require longer multilayer press cycles or less productive drilling processes, or both. 

MIL-PRF-31032 Printed Circuit Board/Printed Wiring Board Manufacturing, General... 

For the DWEP printed circuit board, a final physical size of 3 by 4 inches was achieved. In addition, to the small physical size, the routed printed circuit board was also composed of four layers of conductive copper. After post router verification of the board artwork design, five four-layered prototype printed circuit boards were manufactured and electrically and thermally tested by the fabrication shop (Sovereign Electronics, Youngstown, OH) prior to shipping. The total cost for these five prototype printed circuit boards was approximately 1800. 

THERMLfilm HT is a new advanced line of high-temperature polyimide films reportedly able to withstand the fluctuating temperatures, abrasion and chemicals inherent in the printed circuit board (PCB) manufacturing process. The new product line will be available worldwide to manufacturers that need high-density barcode and alphanumeric PCB labels, including military contractors and manufacturers of electronics, aerospace, and automotive goods. Web www.flexcon.com... 

Printed wiring boards consist of a substrate, typically a glass fiber-reinforced epoxy laminate, copper foils as conducting layers, and electronic components mounted on the laminate surface. For the majority of printed circuit boards the manufacturing process comprises these process steps ... 

Printed circuit boards manufacture is aided by the use of KMnO. Alkaline permanganate solution is used to remove resin smeared on the interior hole wall of multilayered printed circuit boards. Additionally the hole wall is etched, resulting in a surface with excellent adhesion characteristics, for electrodeless copper (250). The alkaline permanganate etchback system containing >60 g/L KMnO and 40-80 g/L NaOH at 70—80°C, is effective for difunctional, tetrafiinctional, and polyimide resin substrates, where the level of etchback is direcdy proportional to the immersion time (10—20 min) (251). 

Most of the laminates used for rigid printed circuit boards have been classified, by the National Electrical Manufacturers Association (NEMA), according to the combination of properties that determine the suitabiHty of a laminate for a particular use. Eiber reinforcements make laminate-effective properties orthotropic. 

Electrical Laminates. A significant use for epoxy resins is in the manufacture of copper-clad epoxy-glass printed circuit boards. Systems are available that meet the National Electrical Manufacturers Association (NEMA), GIO, Gil, FR3, FR4, FR5 specifications. Currently the majority of boards are manufactured to the fiame-retardant FR4 specification. The flame retardance is achieved by the use of a soHd epoxy resin based on... 

Flame retardants in printed circuit boards partnership. Circuit boards are commonly used in electronics in consumer and industrial products, including computers and cell phones. In order to ensure fire safety, manufacturers commonly produce circuit boards with flame-retardant chemicals. While serving an important performance function, some flame-retardant chemicals can be harmful if released into the environment. To better understand the issues and the full range of options for flame-retarding circuit boards, DfE is engaging with the electronics industry and other stakeholders in a partnership. 

In the manufacture of printed circuit boards, the unwanted copper is etched away by acid solutions of cupric chloride (Equation 1.1). As the copper dissolves, the effectiveness of the solution tails and it must be regenerated. The traditional way of doing this is to oxidize the cuprous ion produced with acidified hydrogen peroxide. During the process the volume of solution increases steadily and the copper in the surplus liquor is precipitated as copper oxide and usually landfilled. 

The 40 CFR part 433 does not apply to (a) metallic platemaking and gravure cylinder preparation conducted within or for printing and publishing facilities and (b) existing indirect discharging job shops and independent printed circuit board manufacturers which are covered by 40 CFR part 413. 

U.S. PSES for All Metal Finishing Plants Except Job Shops and Independent Printed Circuit Board Manufacturers... 

The term independent printed circuit board manufacturer shall mean a facility that manufactures printed circuit boards principally for sale to other companies. 

Manufacture of Printed Wiring Boards. Printed wiring boards, or printed circuit boards, are usually thin flat panels than contain one or multiple layers of thin copper patterns that interconnect the various electronic components (e.g. integrated circuit chips, connectors, resistors) that are attached to the boards. These panels are present in almost every consumer electronic product and automobile sold today. The various photopolymer products used to manufacture the printed wiring boards include film resists, electroless plating resists (23), liquid resists, electrodeposited resists (24), solder masks (25), laser exposed photoresists (26), flexible photoimageable permanent coatings (27) and polyimide interlayer insulator films (28). Another new use of photopolymer chemistry is the selective formation of conductive patterns in polymers (29). 

Fabrication of Devices and Materials. Many of the previously discussed applications of photopolymer technology have utilized photopolymer materials to manufacture a part that is then incorporated into commercial products (e.g. film resists used to manufacture printed circuit boards). One area that has been increasing very rapidly in the past 5-6 years has been the use of photopolymer chemistry to fabricate devices and materials that are used directly in the final product. This development has been made possible, in part, by the design of new photopolymer chemistry that can produce polymerized materials with enhanced physical properties. 

Printed circuit board materials, 17 843 Printed circuit board manufacture,... 

D-glass with high dielectric properties, transparent to electromagnetic waves. The principal applications relate to the manufacture of radomes, electromagnetic windows and high-tech printed circuit boards. 

TBBA, a brominated flame retardant, is used in the epoxy resin laminate in printed circuit boards in most manufacturers products. In 1997, a phosphorus-based alternative to TBBA was developed by the German engineering giant, Siemens,... 

Uses. Solvent jet fuel anti-icing additive in the semiconductor industry in manufacture of printed circuit boards... 

Maryland Supeifund Site Natural attenuation enabled new development at 70-acre Superfund site approximately 20 miles northwest of Baltimore, Maryland. This property had been contaminated by a printed circuit board manufacturing company. According to a manager, the pump-and-treat remediation system failed to meet groundwater treatment goals, though it cost over 1 million to construct and more than 200,000 a year to operate. It was estimated that this approach could cost as much as 5 million over 10 years and would still not achieve the cleanup objectives of the Maryland Department of Environment (D17452R). 

Pressure sensors that give temperature-corrected, linear, analog voltage output are available from Motorola and other manufacturers. In such sensors, the on-chip electronics correct any temperature effects and nonlinearities in the output of the piezoresistors. The on-chip electronics replace a shoebox-size collection of printed circuit boards. The price of this kind of smart sensor is considerably less than 100. The integration of a large amount of circuitry on the chip allows functions like amplification, offset correction, self-testing, autocalibration, interference reduction, and compensation of cross-sensitivities (6). 

Larger 3- and 4-m.e.v. Dynamitron electron beam accelerators are likewise available commercially. Service capabilities increase with the m.e.v. level of the electron beam accelerator. A 3.0-m.e.v. Dynamitron electron beam accelerator furnishes radiation capable of penetrating a maximum 370 mils of a unit density material or 185 mils of 2.0-density material other performance capabilities are doubled as well. The overwhelming majority of polyolefin plastic products now being manufactured have section thicknesses which can be penetrated safely even by a 1.5-m.e.v. electron beam accelerator. Two possible exceptions would be printed circuit board and thick-walled pipe. A 3-m.e.v. accelerator could readily meet such requirements. The performance capabilities of the 3-m.e.v. accelerator (12-ma. power supply) are increased not only with respect to maximum depth of penetration but also processing capability, which amounts to 14,000 megarad-pounds per hour at 50% absorption efficiency. 

MSA and other lower alkanesulfonic acids are useful for plating of lead, nickel, cadmium, silver, and zinc (409). MSA also finds use in plating of tin, copper, lead, and other metals. It is also used in printed circuit board manufacture. In metal finishing the metal coating can be stripped chemically or electrolytically with MSA. MSA also finds use in polymers and as a polymer solvent and as a catalyst for polymerization of monomers such as acrylonitrile. MSA also finds use in ion-exchange resin regeneration because of the high solubility of many metal salts in aqueous solutions. 

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