2017, the new year
Is your dream more "chicken"?
Must insist, maybe it will be realized.
I still can’t remember the introduction of the last class’s sister to the classmates.
PCB design basic process
Many students in the background have reflected the urgent need for deeper literacy.
Don't worry, there will be
Slightly, slightly, oh~
An excellent PCB design engineer
First, master the basics of PCB manufacturing.
PCB designers are a subdivision of hardware design. From the perspective of hardware development process, upstream customer docking hardware schematic design engineers and downstream customers docking PCB/PCBA processing plants, so PCB designers need to understand the basic knowledge of upstream and downstream processes. .
(1) PCB manufacturing process
Single/double-sided PCB manufacturing process diagram
Multi-layer PCB manufacturing process diagram
(2) PCB board types
1. CCL classification
The rigid CCL is divided into a paper substrate, a ring fiber cloth substrate, a composite material, a material substrate, and a special type.
2, substrate material
(1) Main raw materials
a, usually use electronic grade alkali-free glass cloth, commonly used models are 1080, 2116, 7826 and so on.
b, impregnated fiber paper
c, copper foil
Classified according to the method of copper foil: rolled copper foil and electrolytic copper foil
The standard thickness of copper foil is: 18um (HOZ), 35 um (1OZ) and 70 um (2OZ)
Other specifications: 12 um (1/3OZ) and high thickness copper foil
(2) Paper substrate
Commonly used models such as FR-1, FR-2, FR-3
(3) Glass cloth base
The most commonly used is FR-4 fiberglass cloth based CCL. Its basic formula is low bromine epoxy resin (bisphenol A type) as the main resin, dicyandiamide as epoxy curing agent, and polyamines as the promotion. The agent is the largest raw material used in PCB production.
The commonly used reinforcing materials for FR-4 are E-type fiberglass cloth. The commonly used grades are 7628, 2116, 1080, etc. The commonly used electrolytic roughened copper foil is 0.18 um, 0.35 um, 0.70 um.
FR-4 is generally divided into:
FR-4 rigid plate, common plate thickness 0.8-3.2mm; FR-4 thin plate, common plate thickness is less than 0.78mm.
The general technical specifications of FR-4 sheets are:
Bending strength, peel strength, thermal shock resistance, flame retardancy, volume resistivity, surface resistance, dielectric constant, dielectric loss tangent, glass transition temperature Tg, dimensional stability, maximum use temperature, warpage, and the like.
(4) Composite CCL
Mainly divided into CEM-1 (epoxy paper base material) and CEM-3 (epoxy glass fiber non-woven core). The main difference from FR-4 is that the specific core material is sandwiched between the substrates. The various performances are similar to those of FR-4. Each has its own advantages and disadvantages, mainly in terms of CEM in terms of processability and heat resistance. -4 strong.
The general technical specifications of CEM materials are roughly the same as those of FR-4.
(5) Prepreg (Prepreg or PP)
PP is a prepreg composed of a resin and a reinforcing material. Among them, the resin is a "B-stage" resin which is in a semi-cured state. The commonly used PP for circuit boards generally uses FR-4 prepreg.
FR-4 type PP is a polymer which is made of an alkali-free glass cloth as a reinforcing material, impregnated with an epoxy resin, and has a resin structure as a branch.
The commonly used FR-4 type PP is divided into 106, 1080, 2116, 1500 and 7628 according to the reinforcing materials, which correspond to different fiberglass cloth characteristics, resin content and PP thickness.
The technical indicators of PP are as follows:
Glue content, fluidity, gel time, volatile content
New PP varieties: Tg PP, low dielectric constant PP, high resistance to CAF PP, high dimensional stability PP, low CTE PP, bubble free PP, green PP, resin coated copper foil (RCC), etc.
(6) Flexible CCL (FCCL)
classification
According to the media substrate: PI and PET
According to flame retardant properties: flame retardant and non-flame retardant
According to the manufacturing process: two-layer method and three-layer method
Raw material
a, dielectric substrate: PI, PET film film, generally required to have good flexibility;
b. Metal conductor foil: ordinary ED, high elongation ED, RA, copper beryllium alloy foil and aluminum foil, generally required to have good ductility, commonly used are high elongation ED and RA. Common thicknesses are 18um, 35um and 70um;
c. Adhesive: PET, EP/modified EP, acrylic, phenolic/butyral, PI, generally required to have good resin adhesion and low Z-axis thermal expansion coefficient, commonly used acrylic Class and EP/modified PP adhesives.
(3) PCB plate type
PCB sheet type list
Car Phone Holder,Mobile Holder For Cars,Mobile Phone Holder For Dashboard,Mobile Phone Holder For Car Dashboard
Ningbo Luke Automotive Supplies Ltd. , https://www.nbluke.com