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PCB Populating,electronics circuit board populating,components PCBA soldering and populate,high quality low cost shenzhen,cn china
PCB manufacturing process:
--------------------------------------------------------------------------------


Printed circuit boards (PCBs) are used in electronics to support and connect electrical components. Connections are made using conductive pathways, also called traces, etched from copper sheets laminated onto a non-conductive substrate. The PCB manufacturing process requires much effort, which is why most companies choose to outsource it instead.

About PCBs

PCBs were invented in 1936 by Austrian engineer Paul Eisler. Eisler first used PCBs in his radio sets. Later on, PCBs evolved and were used to make rugged radio transmitters used by the US in World War II. After the war, PCBs were re-manufactured for commercial use.

Design

Generally, PCBs are composed of 24 conductive layers separated and supported by layers of insulating material (substrates) laminated together with heat, pressure and sometimes vacuum. The most typical substrate used in single-sided PCBs is the FR-2 (synthetic resin bonded paper). The FR-2 type is cheap and easy to drill, but is prone to cracking and is not good for making plated through hole boards. Meanwhile, double sided and multilayer boards use the FR-4 type, made from fiberglass-type of material.

1. Silk screen printing – uses etch-resistant inks to protect the copper foil. Subsequent etching removes the unwanted copper.
2. Photoengraving – uses a photo mask and chemical etching to remove the copper foil from the substrate.
3. PCB milling – uses a two- or three-axis mechanical milling system to mill away the copper foil from the substrate.

Lamination and drilling

Multi-layer PCBs are formed by bonding together separately etched thin boards. After this, holes (vias) are normally drilled through the PCB using drill bits made from solid tungsten carbide. The holes are then plated to form plated-through holes that electrically connect the conducting layers of the PCB.

Exposed conductor plating, coating, and soldering

Exposed pads and lands to which components will be mounted are typically plated, because bare copper oxidizes quickly and can be difficult to solder. The solder is usually a tin-lead alloy, but new solder compounds are now used to comply with the Restriction of Hazardous Substances (RoHS) directive, which restricts the use of lead.

Screen printing

Text and picture labels may be printed on the surface of the PCB using screen printing. Screen print is also known as the silk screen, or, in one sided PCBs, the red print. Creating a PCB
All components are in the upper left corner
Set up line styles this way: Style name Line width [mil] Via hole [mil] Via size [mil] Clearance [mil]
Signal 20 24 56 14
Power 40 35 65 14
Fat 80 50 80 14
Skinny 12 24 48 14

DRC constants
It is necessary to set (overwrite) several values in /usr/local/share/pcb/Pcb or /usr/share/pcb/Pcb config file to get the DRC parameters right for the chosen process:

For PCB versions pcb-20040215 and earlier:

Pcb.Bloat: 1378
Pcb.minWid: 1182
Pcb.Shrink: 400
For PCB versions pcb-20040530 and later:

Pcb.Bloat: 1378
Pcb.minWid: 1182
Pcb.Shrink: 400
Pcb.minSlk: 787
If you are running GTK PCB, then enable milimeter grid units in Screen -> Enable milimeter grid units and then go into File -> Preferences -> Sizes -> Design Rule checking and enter Minimum copper spacing 0.35
Create ground planes and lock them
Pins (not pads!) that are on ground:
Green them using "f"
Select -> Select all connected objects
SetFlag(SelectedPins, thermal)
Manually add thermal to locked pins (green)
Send SMD components which have a green end to the solder side.
Disable the ground and power in the netlist
Green the ground and place components so that ratnests become as short as possible (working in the solder view) according to schematic. Prevent high concentration of ratnests in one spot - in such case, move affected components a little apart, to accomodate for future numerous traces, so that critical traces are as short as possible. You can flip SMD parts between the sides of the board to make the ratnest shorter.
Enable the power in the netlist
Place bypass capacitors to chips according to the schematic. Pathfinder-tagged User-tagged Both

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All about nuts and bolts...
D. Murali

Printed circuit boards, and `populating' them, form the crux of the issue in this interesting case.

THE recent issue of Excise Law Times reports the case of Jolly Electrical Industries that came up before the Customs, Excise and Service Tax Appellate Tribunal (CESTAT), Mumbai.

Jolly had imported parts of photocopiers, microfilm reader printers, microfilm cameras and paper shredders.

But the Customs Department confiscated all these saying that the import was of `complete machines in SKD condition', not `parts' as the company had claimed in the import documents.

Jolly submitted that it manufactured electronic products in Vadodara; that it used the imported parts for manufacture of finished goods after adding components sourced from domestic sources; and that it paid Excise Duty when the assembled machines were cleared.

For the Department, however, there was a guidance from a conference of the Collectors of Customs: "When all the packages are imported in the very same consignments and the assembling of the machine involves only sample operations like fixing devices (screws, nuts, bolts, and so on) or by riveting or welding, the goods so imported should be classifiable as a complete machine."

Jolly protested by pointing out that PCBs (or, printed circuit boards) were `incomplete' and that these were critical components.

The Commissioner said that the PCBs were `populated'. The company said that the PCBs were `indeed populated' but added that it had to "further populate the PCBs before these could be fixed together with other parts, to make a functional machine."

Therefore, the Department was of the view that the imported PCBs were already populated and that whatever Jolly did in its factory was of `minor' nature.

For its part, Jolly claimed that it had the necessary machinery for populating the PCBs, and that the value of domestic components came to 30 to 35 per cent of the assembled machines, as verified by the Central Excise officials.
MeshNetics - 802.15.4 / ZigBee Wireless RF Modules
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overview
Practical Electronics/PCB Layout
The efficient laying out of traces on is a complex skill, and requires much patience. This task has been made vastly easier with the advent of readily available PCB layout software, but it is still challenging. Contents [hide] 1 Copper Thickness 2 Trace Width 3 footprints 4 Reference Handbook 5 Further reading [edit] Copper Thickness
preview: http://en.wikibooks.org

overview
Printed Circuit Board @ Wikipedia
In electronics, printed circuit boards, or PCBs, are used to mechanically support and electrically connect electronic components using conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate. Alternative names are printed wiring board (PWB), etched wiring board, and switchboard. After populating the board with electronic components, a printed circuit assembly (PCA) is formed. PCBs are rugged,...
preview: http://en.wikipedia.org

overview
The Printed Circuit Board (PCB) Layout
The connections on the PCB should be identical to the circuit diagram, but while the circuit diagram is arranged to be readable, the PCB layout is arranged to be functional, so there is rarely any visible correlation between the circuit and the layout.
preview: http://www.airborn.com.au

book
Complete PCB Design Using OrCad Capture and Layout
Most of the books for Orcad Layout and Capture software are many years out of date. This version covers version 10.5 (2006) and is essentially current for the newest version (15.7 for 2007) It is an excellent book to introduce new users to Orcad Capture and the Orcad Layout SW packages. It does NOT cover Orcad PCB Editor which is completely different from Orcad Layout. (Layout has a very similar user interface to Capture while PCB Editor...
preview: http://www.amazon.com date: 4/27/2007

book
Optimal Production Planning for PCB Assembly
Optimal Production Planning for PCB Assembly is the first book to focus on the optimization of the PCB assembly lines efficiency. This is done by: integrating the component sequencing and the feeder arrangement problems together for both the pick-and-place machine and the chip shooter machine; constructing mathematical models and developing an efficient and effective heuristic solution approach for the integrated problems for both...
preview: http://www.amazon.com date: 10/3/2006

book
Printed Circuit Boards
The printed circuit is the basic building block of the electronics hardware industry. This is a comprehensive single volume self-teaching guide to the art of printed circuit board design and fabrication -- covering the complete cycle of PCB creation, design, layout, fabrication, assembly, and testing. From the Back Cover THE MOST COMPREHENSIVE TUTORIAL ON THE COMPLETE CYCLE OF PCB CREATION Clear and [word missing], Printed Circuit... ictionary: circuit board
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n. Computer Science.
An insulated board on which interconnected circuits and components such as microchips are mounted or etched.


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How Products are Made: How is a printed circuit board made?
Background

A printed circuit board, or PCB, is a self-contained module of interconnected electronic components found in devices ranging from common beepers, or pagers, and radios to sophisticated radar and computer systems. The circuits are formed by a thin layer of conducting material deposited, or "printed," on the surface of an insulating board known as the substrate. Individual electronic components are placed on the surface of the substrate and soldered to the interconnecting circuits. Contact fingers along one or more edges of the substrate act as connectors to other PCBs or to external electrical devices such as on-off switches. A printed circuit board may have circuits that perform a single function, such as a signal amplifier, or multiple functions.

There are three major types of printed circuit board construction: single-sided, double-sided, and multi-layered. Single-sided boards have the components on one side of the substrate. When the number of components becomes too much for a single-sided board, a double-sided board may be used. Electrical connections between the circuits on each side are made by drilling holes through the substrate in appropriate locations and plating the inside of the holes with a conducting material. The third type, a multi-layered board, has a substrate made up of layers of printed circuits separated by layers of insulation. The components on the surface connect through plated holes drilled down to the appropriate circuit layer. This greatly simplifies the circuit pattern.

Components on a printed circuit board are electrically connected to the circuits by two different methods: the older "through hole technology" and the newer "surface mount technology." With through hole technology, each component has thin wires, or leads, which are pushed through small holes in the substrate and soldered to connection pads in the circuits on the opposite side. Gravity and friction between the leads and the sides of the holes keeps the components in place until they are soldered. With surface mount technology, stubby J-shaped or L-shaped legs on each component contact the printed circuits directly. A solder paste consisting of glue, flux, and solder are applied at the point of contact to hold the components in place until the solder is melted, or "reflowed," in an oven to make the final connection. Although surface mount technology requires greater care in the placement of the components, it eliminates the time-consuming drilling process and the space-consuming connection pads inherent with through hole technology. Both technologies are used today.

Two other types of circuit assemblies are related to the printed circuit board. An integrated circuit, sometimes called an IC or microchip, performs similar functions to a printed circuit board except the IC contains many more circuits and components that are electrochemically "grown" in place on the surface of a very small chip of silicon. A hybrid circuit, as the name implies, looks like a printed circuit board, but contains some components that are grown onto the surface of the substrate rather than being placed on the surface and soldered.Contact
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We buy all kinds of PCB, populated or non populated.

Your company's old / discarded PCB's contains heavy metals and hazardous materials and can not be disposed in a landfill, recycling of PCB is a very good way to help save our planet.

We are always ready to purchase all kinds of E scrap, PCB and plain PCB, we pick up everywhere, so if you have any, we will be glad to know about it and also have the chance to buy it from you, please contact us or just fill out this quick form and we will contact you shortly.

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Estimated weight of PCB for disposal? I do not know the weight Up to 100 lbs 100 to 200 lbs 200 to 300 lbs 300-500 lbs 500-1000 lbs 1000 to 1500 lbs 1500-3000 lbs more than 3000 lbs
Is it populated? Yes No Mixed

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Comment:


In electronics, printed circuit boards, or PCBs, are used to mechanically support and electrically connect electronic components using conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate. Alternative names are printed wiring board (PWB),and etched wiring board. Populating the board with electronic components forms a printed circuit assembly (PCA), also known as a printed circuit board assembly (PCBA).

PCBs are rugged, inexpensive, and can be highly reliable. They require much more layout effort and higher initial cost than either wire-wrapped or point-to-point constructed circuits, but are much cheaper, faster, and consistent in high volume production. Much of the electronics industry's PCB design, assembly, and quality control needs are set by standards that are published by the IPC organization.completion of the PCB, electronic components are attached to form the assembly. These components are attached by inserting them through holes, mounting them on the surface, and soldering. Afterwards, they are subject to tests again. If the tests fail, the components are going to be replaced.

Protection and packaging
To protect the printed circuit board against harsh environmental conditions, they should have a conformal coat that is applied by spraying or dipping them after attaching the components. The coat aids in preventing leakage currents, corrosion, and shortening. The coat is made of wax or a diluted solution of polyurethane, epoxy, acrylic, or silicone rubber.

Finally, when transporting PCBs, they should be in antistatic bags and the person handling them should be earthed to avoid static electricity from damaging them. Circuit board manufacturing companies like Almatron practice these safety measures to ensure high quality printed circuit boards.

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Abstract:According to at least one embodiment, a method comprises generating a data file having design parameters for an electrical design, and with a computer-executable program, accessing the data file and populating a computer-aided design (CAD) program's database with the design parameters. Quotables "The radio craze will die out in time."

Thomas Edison ; 1922
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Be the first to comment on this pageUS Patent 7069095 - System and method for populating a computer-aided design program's database with design parameters
US Patent Issued on June 27, 2006
Abstract Claims Description Full Text

Claims


What is claimed is:

1. A method comprising: generating a data file having design parameters for an electrical design, wherein the data file includes the design parameters in a CAD-independent
format; modifying said design parameters in said data file; and with a computer-executable program, accessing the modified data file and populating a computer-aided design (CAD) program's database with the modified design parameters.

2. The method of claim 1 wherein the design parameters include parameters for a plurality of layers of the electrical design.

3. The method of claim 1 wherein said generating comprises: receiving user input specifying the design parameters.

4. The method of claim 3 wherein said receiving user input comprises: receiving said user input via an interface of the CAD program.

5. The method of claim 4 wherein said generating further comprises: retrieving the design parameters input via the interface of the CAD program; and populating the data file with the design parameters.

6. The method of claim 1 wherein the electrical design comprises a design selected from the group consisting of: an integrated circuit design, a printed circuit board design, a microelectromechanical system (MEMS) design, and a
nanoelectromechanical system (NEMS) design.

7. The method of claim 1 wherein said generating comprises: retrieving the design parameters from the CAD program's database; and populating the data file with the design parameters.

8. A method comprising: generating a data file having design parameters for an electrical design, wherein the data file is a text file; and with a computer-executable program, accessing the data file and populating a computer-aided design
(CAD) program's database with the design parameters.

9. A system comprising: a database; a parameter entry program stored to computer-readable media and operable to access a data file and populate the database with design parameters included in the data file for an electrical design, wherein the
data file is in a CAD-independent format and is editable by an interface; and a computer-aided design (CAD) program stored to computer-readable media, wherein the CAD program is operable to communicatively access the database and retrieve the design Home | Electrical Engineering | Electrical Engineering | PCB Populating Challenge

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Jorrie
Guru


Join Date: May 2006
Location: 25.9S, 28.1E
Posts: 2183
Good Answers: 3 PCB Populating Challenge
03/15/2007 2:37 PM
I've got three identical prototype PCBs to be populated. Jim can populate one of these PCBs in three hours. Pam beats him by far and can populate one of these in two hours. Now, if I give the job to Pam and Jim as a team, what is the minimum time I'll have to wait for my three PCBs to be populated?

Jorrie

__________________

Let's see between them they can do 5 boards in 6 hours, right? So that means they can do 3 boards in 3/5*6 = 216 minutes.

Jorrie
Guru


Join Date: May 2006
Location: 25.9S, 28.1E
Posts: 2183
Good Answers: 3 #2
Re: PCB Populating Challenge
03/15/2007 11:49 PM
Oops, I forgot to also ask: since only one person at a time can work on any PCB, what will be their optimal work share plan?

Jorrie

__________________
"Curiosity has its own reason for existence" -- Albert Einstein

rcapper
Guru

In reply to #2
Re: PCB Populating Challenge
03/16/2007 8:55 AM
6 hours. Have Pam populate all the boards (3 boards x 2 hours) and task Jim with caring for Pam (gathering and providing water, food, etc) while she works.

Jim's labour is not compensated, so your production costs are materials, labour (Pam's only) and operational overhead.

That has been the model used in most capitalist countries the world over for the last 100 years.

 
 
 
 
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