Pcb specifications

When you give a PCB for fabrication, you need to specify details on PCB materials, impedance controls, finish, copper thickness and so on.

Most of the details are so common that they are always assumed. However still it is better to know them. Below is a screenshot of quotation submitted by a fabricator for a PCB design of size 9. The layers may be either routing layer or plane layer. The commonly used no. The PCB materials used for 3 or 4 layers would almost be same. Routing layers contains tracks while plane layer are generally used to connect power or ground.

Plane layers have plane of copper from which connections are drawn up or down wherever needed. Islands can be formed on plane layers and each island may have different signal. Suppose some sets of chips on one board use 3. It is a commonly used PCB material. The reasons for its ubiquity as a PCB material are its high dielectric strength, high mechanical strength, light weight, resistance to moisture and other properties conducive for PCB manufacturing.

Go for higher thickness if you have heavy components on board to get better strength. Keep an eye on thickness even when you have high voltages on board. Another popular way to express is in grams or Oz. Ounces per square foot of copper per unit area. X Oz would mean that X Ounces were spread on the Board material and it was distributed uniformly over an area of 1 square foot. Go for higher copper thickness if the current density on board is greater than in average digital circuits.

In normal boards 35 microns is good. Up till a current of 1A and copper thickness of 1 Oz, track width of 10 mils is safe. If unchecked, such tracks may cause significant power loss. For maximum power to be transferred to other end of track, length and geometry of the track should be carefully laid taking care of transmission line equations. As a rule of thumb, if the board is of FR4 PCB material with copper tracks and signal rise time is 1 nanosecond then 2 inches is a safe distance.

If the track length exceeds this and signal integrity is important then consider the transmission line effects also. There are lot of free programs and excel sheet available on net that calculate impedances for prevalent geometries.

If impedance control has been mentioned to the fabricator then an extra test is done on the completed PCB to check the required impedances. However, they can be filled for various reasons. One need arises when vias are to be protected from solutions, dust etc. Vias can also be filled with conducting materials to increase the current carrying capacity of via. One more reason is to level the board. Example is a rubber pushbutton which has contacts printed on the board. An example is the kind of buttons used in calculator.

This wearing out also happens when daughter card slot are provided on main board.

NCAB Group PCB Specification Qualification & Release Process

The contacts on this slot are rubbed when card is pushed in or out.FR-4 is a composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant self-extinguishing. FR-4 glass epoxy is a popular and versatile high-pressure thermoset plastic laminate grade with good strength to weight ratios. With near zero water absorption, FR-4 is most commonly used as an electrical insulator possessing considerable mechanical strength.

pcb specifications

The material is known to retain its high mechanical values and electrical insulating qualities in both dry and humid conditions. These attributes, along with good fabrication characteristics, lend utility to this grade for a wide variety of electrical and mechanical applications. Of these, FR-4 is the grade most widely in use today. G, the predecessor to FR-4, lacks FR-4's self-extinguishing flammability characteristics. Hence, FR-4 has since [ when?

FR-4 epoxy resin systems typically employ brominea halogen, to facilitate flame-resistant properties in FR-4 glass epoxy laminates. Some applications where thermal destruction of the material is a desirable trait will still use G non flame resistant. Typical physical and electrical properties of FR-4 are as follows.

The abbreviations LW lengthwise, warp yarn direction and CW crosswise, fill yarn direction refer to the conventional perpendicular fiber orientations in the XY plane of the board in-plane. In terms of Cartesian coordinateslengthwise is along the x-axis, crosswise is along the y-axis, and the z-axis is referred to as the through-plane direction.

Keep in mind that the values for the parameters listed below are an example for a certain manufacturer's material. Each manufacturer will have slightly different values for the parameters listed below. It's better to check the datasheet of the specific material being used. Verifying the actual values is very important for high frequency designs. FR-4 is a common material for printed circuit boards PCBs. A thin layer of copper foil is laminated to one or both sides of an FR-4 glass epoxy panel.

These are commonly referred to as copperclad laminates. When ordering a copper clad laminate board, the FR-4 and copper thickness can both vary and so are specified separately. These work out to thicknesses of FR-4 is also used in the construction of relaysswitchesstandoffsbusbarswashersarc shields, transformers and screw terminal strips. From Wikipedia, the free encyclopedia. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources.

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Understanding Printed Circuit Board Assembly Cleanliness Specifications

Poole; P. Witting Journal of Electronic Materials. Categories : Printed circuit board manufacturing Fibre-reinforced polymers. Hidden categories: Articles needing additional references from September All articles needing additional references All articles with vague or ambiguous time Vague or ambiguous time from August Namespaces Article Talk.As manufacturers of printed circuit boards, or PCBs, know, ensuring quality throughout the manufacturing process is critical and requires careful attention at all phases.

Adhering to standards from the trade association IPC can help. IPC is the trade association for the electronic interconnection industry. It provides standards for the assembly and protection of electronic equipment, as well as training, market research and public policy advocacy. IPC is a member-driven organization and has more than 4, member companies around the world.

Its members include companies in all aspects of the global electronics industry, including designers, suppliers, board manufacturers, assembly companies and original equipment manufacturers. The organization got its start in as the Institute for Printed Circuits. It later changed its name to the Institute for Interconnecting and Packaging Electronic Circuits due to the expansion to packaging and electronic assemblies from bare boards.

IPC has its headquarters in Bannockburn, Ill.

pcb specifications

What are the IPC standards? They are the most widely recognized acceptability codes in the electronics industry. The organization publishes standards for nearly every phase of the electronic product development cycle, including design, purchasing, assembly, packaging and more. IPC currently has more than active standards and more than 1, standards in its resource library. Committees of volunteers from across the electronics industry draft, edit and vote on IPC standards.

More than 3, industry professionals across the globe participate in this process. Committees can include people from around the world, as members can participate via in-person meetings, teleconference and email. The association provides validation services programs, including a standards gap analysis that helps organizations address manufacturing issues and determine what they need to do to reach compliance with standards.

It maintains a qualified manufacturers list and qualified products to help you determine if a product complies with IPC standards. There are more than IPC-licensed training centers around the world. The organization also offers online and multimedia education and training resources.

Additionally, the organization conducts market research and does work in government relations and environmental policy. IPC advocates for the electronics industry, with regulators around the world. Producing safe, reliable, high-performing PCB products requires persistent attention to detail and commitment to quality throughout the production process. Adhering to IPC standards throughout the process can help companies achieve that.

You can implement an IPC standard for nearly every phase of production. Complying with IPC standards can help a company improve its processes and products in numerous ways.

Here are four of the leading benefits. Adhering to IPC standards throughout the manufacturing process can help companies improve the quality and reliability of their products.

Creating products that perform better and last longer will help make a company more competitive and more profitable, as well as improve customer satisfaction. IPC standards can help improve processes and also increase consistency in products. Adhering to IPC standards helps improve communication both internally and externally by ensuring everyone is using the same terminology and agrees on expectations.

Internally, employees who speak the same language can collaborate and more easily make the changes needed to make improvements. IPC standards also improve communication with customers, supplier vendors, regulators and others. Using the same terminology can prevent miscommunication that can lead to production delays and inconsistencies and, potentially, unhappy customers. The improvements that result from using IPC standards can help reduce costs. Improving quality and minimizing miscommunications diminishes the likelihood of delays and reworks.

IPC standards can also allow companies to minimize resource use and increase efficiency. Adhering to internationally recognized standards like those from IPC gives a company instant credibility. Even if someone knows nothing about your business, when they see you follow IPC standards, they can rest assured of your commitment to quality.Powered by QuikWeb Developer.

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Understanding PCB Materials and Specifications

Same Day - 5 Day. Same Day - 4 Weeks. Quantity Req. Plating Finish. IPC Class 2 - A Board Thickness. Full Range Available. Down to 2. Solder Mask LPI. Various Color Options. Hole Size. Hole Tolerance. Rout Tolerance. Non-Plated Only. Plated Holes. Lead-Free Markings. Gold Fingers.

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pcb specifications

Controlled Dielectric.We remember the wonderful meals that we cook and serve, but do we remember what happened next? We remember the creative works of art that our children bring home to us from school, but do you know what the teacher did after those projects were finished?

Cleaned up. Cleaning up after a job is such an integral part of our lives that it is easy to dismiss its importance. But without taking the time to do it, we would quickly be in a lot of trouble. This is also true in the manufacturing of circuit boards. You may not even have realized it, but cleaning a circuit board while it is in production is critically important. A PCBA can collect different contaminants during the manufacturing process that, if not properly taken care of, could impact its ability to function correctly.

The important thing is that your contract manufacturer should have processes in place for inspection and cleanup of assembled boards.

A circuit board goes through many different processes while it is being manufactured, from the etching of the metals during fabrication to the application of solder during the assembly. All of these processes have the potential of leaving various residues and contaminants on the finished board. These residues can cause short-term and long-term problems with the board.

In the short term, any visible residues and contaminants on the board will be very obvious and could cause concern, even in cases in which it may not actually be a problem. No-clean flux residue is an example of this. They may also cause intermittent functional problems in the board that are difficult to find or reproduce. The long-term problems of inadequate cleaning, however, pose a much larger threat. By not thoroughly cleaning the finished PCBA, residues and contaminants can compromise the reliability of the finished board.

An example of this is ionic contamination. When ionic residues remain on a finished PCB, they contain molecules that could become conductive when exposed to moisture. This can result in accelerated corrosion or dendritic growth of conductive metal slivers that cause unintended shorts between nets.

Some of the ionic residues that can collect on a PCB during manufacturing include:. Additional long-term problems from inadequate cleaning include poor adhesion of conformal coatings, functional problems with board mounted relays and switches, and poor contact with interconnects such as cables, edge connector fingers, and sockets. You can see why PCB cleaning is such a vital part of the entire manufacturing process. The water pressure will be set according to the guidelines set by the solder and equipment manufacturers.

There may also be additional cleaning processes, including IPA isopropanol alcohol wipedowns, removal of no-clean flux residues, and ultrasonic cleaning. These specialized cleanings are typically done only when there are documented requests for them.

The CM will submit a sample for regular testing, usually to an outside service provider. The CM will also visually inspect the finished PCBA to make sure that it passes their internal standard of cleanliness. To make sure that your circuit board is fully cleaned by your CM, you should get answers to the following:. At the end of the day, your CM should put quality firstand that includes ensuring circuit boards are properly cleaned.

PCB Placement and Routing

The CM should be fully versed in cleanliness standards and have cleaning processes and equipment that are fully documented and top of the line. You must be logged in to post a comment. Skip to content. May 21 Some of the ionic residues that can collect on a PCB during manufacturing include: Salts Flux activators Plating chemistries Acids Perspiration Additional long-term problems from inadequate cleaning include poor adhesion of conformal coatings, functional problems with board mounted relays and switches, and poor contact with interconnects such as cables, edge connector fingers, and sockets.

Are they fully versed in PCB manufacturing cleanliness standards? Do they have the equipment and processes in place to adequately clean your circuit board? Are they able to respond to any specialized cleaning requests that you might have?

At VSEour company facilities and culture are focused on meeting the highest standards of quality possible for our customers, and that means ensuring your circuit boards are properly cleaned. Contact us today to learn more about partnering with us for your next project.This is guaranteed through a product specification and quality control that is far more stringent than other suppliers, and ensures that the product delivers what it promises. At first sight, PCBs differ little in appearance, irrespective of their inherent quality.

Customers cannot always see the difference, but they can rest assured that NCAB puts a great deal of effort into ensuring that in turn, their customers are also supplied with PCBs that meet the most stringent quality standards.

pcb specifications

It is vital that PCBs function reliably both during the manufacturing assembly process and, out in the field. Apart from the costs involved, faults during assembly can end up being built into the final product via the PCBs, with possible failure in the field resulting in compensation claims.

Relative to that, in our opinion, the cost of a premium quality PCB is negligible. In all market sectors, particularly those producing products with critical applications, the consequences of such failures could be devastating.

Such aspects must be considered when comparing PCB prices. Reliability and a guaranteed long life cycle involve an initially higher outlay, but will pay for themselves in the long run. Blow holes or outgassing, electrical continuity problems inner layer separation, barrel cracking during assembly or risk of field failures under load conditions. Poor repair can actually lead to open circuits being supplied. Reduced electrical characteristics can lead to poor impedance performance.

Tighter control of dielectric spacing provides less deviation in electrical performance expectations. Poor inks can lead to problems with adhesion, resistance to solvents and hardness — all of which can see soldermask coming away from the board ultimately leading to corrosion of the copper circuitry. Tighter tolerances means improved dimensional quality of the product — better fit, form and function.

Also problems with assembly into any housing due to increased deviation in dimensions. Better electrical insulation, less risk of flaking or loss adhesion and greater resilient to mechanical impact — wherever that may happen!

Thin deposits of soldermask can lead to problems with adhesion, resistance to solvents and hardness — all of which can see soldermask coming away from the board ultimately leading to corrosion of copper circuitry. Multiple scratches, minor damage, touch ups and repairs — a functional but perhaps unsightly board.

If concerned over what can be seen, then what risks are involved with what cannot be seen, and the potential impact on assembly or risk when in the field? Half filled via holes may trap chemical residues from the ENIG process which can cause problems such as solderability.

Such via holes can also trap solderballs within the hole which can escape and cause short circuits either during assembly or in the field. Security in knowing that through the release process, all of the specifications have been verified. Risk that the product received will not be validated adequately and that any deviations to specification may not be spotted until assembly or final box build…. Special set-ups are necessary for each panel with a defect, and if the x-outs are not clearly marked or not segregated from the main delivery, there is a risk of assembling a known bad board; waste of components and time.

Specific requirements of depth of via fill Benefits A good quality filled via hole will provide less risk of rejection during the assembly process.

NCAB Group specific qualification and release process for every purchase order Benefits Security in knowing that through the release process, all of the specifications have been verified.All team members can work with the entire database in real time without any need to partition and re-assemble.

Xpedition Enterprise design creation tools help engineers capture schematics, integrate ICs onto the PCB, and communicate electrical and physical rules to all design teams. Electronic Design Automation. Connectivity Electrification Autonomous Architecture. Contact PCB Design. Service Bureaus. Overview Technical Specifications Resources Services. Technical Specifications Common constraint definition environment is shared between schematic capture and layout, allowing the evaluation of critical signals at any design stage Capabilities produces a single, powerful and easy-to-use design environment Database and user interfaces and rules increase productivity The RF module integrates RF and PCB design; the PCB layout environment understands RF circuitry and interfaces directly with Agilent and AWR RF simulation tools Area fills automatically around traces, vias, and pads as the board is edited Rules-by-area greatly improves routing Functionality allows you to simultaneously route multiple nets, including differential pairs Enables the creation of multiple product configurations from a single design database.


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