PCB Mfg and Assembly

A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate.

The data presented here is the model. The user should consult with his cost engineers that these prices are in line with his particular industry.
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BOARD MATERIAL:
The PCB material here is FR4.

Material spec:

G10-FR4 (FR4) is a fire rated electrical-grade, dielectric fiberglass laminate epoxy resin system combined with a glass fabric substrate. The abbreviation "FR4" means: F (for flame) and R (for retardancies) and the 4 is a # 4 epoxy. FR4 grades offer excellent chemical resistance, flame ratings (UL94-VO) and electrical properties under dry and humid conditions. FR4 also features high flexural, impact, superior mechanical strength and bond strength at temperatures up to 130°C. G10-FR4 is suitable for structural, electronic, pc boards and electrical applications. The density of copper is 8.94 grams/cubic meter or .31498 lb/cubic inch. Density can vary depending on quality.

Board Material Prices came from JJ Orly, Inc.
Clark, NJ 07066

Other data from OnBoardCircuits.com

TECHNICAL DATA:
Density of Copper = 8.94 g/cm3
Density of Copper = .31498 lb/cu in

MATERIAL UNITS:
1 um = .001 mm
1 mil = .001 inches

1 oz = 1/16 lb

LAYERS:
The thickness of copper clad on a circuit board is usually given in ounces (oz). It is the weight of copper on one square foot of board. One ounce copper is 1.378mils (~35um) thick.

Normal PCB copper thicknesses are 1/4oz, 1/2oz, 1oz, and 2oz. Other thicknesses are possible, depending on the capabilities of the fabricator that makes your board. However, copper that is too thick creates lamination problems.

A typical board would use 1/2oz (.7mil or 18um) copper on inner layers, and 1oz (1.4mil or 35um) copper on planes and outside layers. If the board is thin and high density, thinner copper clad would be used to keep the weight and finished board thickness as small as possible.

A typical board would use 1/2oz (.7mil or 18um) copper on inner layers and 1oz (1.4mil or 35um) copper on planes and outside layers.

Copper Foil Thickness is based on 1 ounce per square foot of foil. This equates to the foil being .001378 (.0014") thick at one square foot.

Proof of this is multiply 12 x 12 x .001378 = .198432 cubic inches of copper per sheet.

Multiplying .1984 x .31498 (density of copper) = .0625 pounds of copper.

Multiplying .0625 lb x 16 = 1 ounce of copper per sheet (foil).

Foil can be anywhere from 1/2 to 3 ounces per square foot.

TRACE/SPACING:
Copper Trace Width/Spacing is the minimum air gap between any two adjacent copper features. Trace width is the minimum width of a copper feature, usually traces.

SOLDER MASK:
HAL
Acronym for Hot Air Level, which is the process of putting solder on exposed copper of the circuit board.

Also known as a SMOBC which is an acronym for Solder Mask Over Bare Copper.

SMOBC
Acronym for Solder Mask Over Bare Copper. After boards have been coated with solder mask, the process of Hot Air Leveling will distribute solder to all areas of copper that are not covered by mask.

Solder Mask (Artwork)
Generate your solder mask artwork with a swell of 0.008" to 0.010" larger than the component and solder side pads. An alternative method with Design Check: you may generate your mask layer with the same size pads as your component and solder layers. This is sometimes called a padmaster. Most cam departments at suppliers locations will then generate a mask swell based on the density of your board to give you trace coverage and minimal mask on pads (0.001" or less).

Please note: It is best to leave a mask dam between surface mounts, fine pitch areas will be relieved in strips. The manufacturing process needs at least 0.005" mask between pads in order to adhere to the board. Anything less than that has the potential for lifting and re-depositing on surface mounts that would then prevent solder coverage.

Info from: http://www.pcbpro.com

SILK SCREEN:
Silk Screen, Nomenclature, or Legend (Artwork) uses white marking ink to identify components during later assembly and troubleshooting processes. Can be placed on one or two sides, depending on the board design and application.

SURFACE MOUNT PITCH:
The pitch of the surface mount is defined as the dimension in inches from center to center of surface mount pads. Standard pitch is >0.025", fine pitch is 0.011"-0.025", and ultra fine pitch is <0.011". As boards contain finer pitch, processing and test fixture costs increase.

Tooling and test costs are influenced by the number of surface mount sides. If there is no surface mount, the same solder mask film can be used on both sides of the board. If there are surface mounts, it is required to produce different films for top and bottom side, as well as potentially requiring electrical testing on both sides.

If testing is required on a two-sided surface mount, then you will need a special test fixture that is not quoted here.

http://www.pcbpro.com

ELECTRICAL TEST:
Used to test for opens and shorts. Recommended for all surface mount boards and multi-layers. Testing is available for the Design Check and Plot & Go.

SOLDER PASTE:
Surface mount devices (SMDs) are mounted onto a printed circuit board (PCB) by soldering their external interconnection features (such as leads, bumps, or balls) to their corresponding mounting sites on the PCB. This is achieved by depositing a material known as solder paste on the PCB's device interconnection points, positioning the surface mount devices on the board, and subjecting the board to a process known as solder reflow to melt the solder and complete the board mount process.

Solder pastes are specially blended pastes that consist of a flux medium containing graded solder powder particles. The process of depositing solder paste on the board is known as Solder Paste Printing.

http://www.siliconfareast.com/solder-paste-print-pcb.htm