1. What is fiberglass board
Glass fiber board alias: glass fiber insulation board, glass fiber board (FR-4), glass fiber composite board, which is composed of glass fiber material and high heat-resistant composite material, and does not contain asbestos harmful to human body. It has high mechanical properties and dielectric properties, good heat resistance and moisture resistance, and good processability. For plastic molds, injection molds, machinery manufacturing, molding machines, drilling machines, injection molding machines, motors, PCB.ICT fixtures, table grinding pads.
The glass fiber board is covered with fabric, leather, etc. to make beautiful wall and ceiling decoration, which is widely used. It has the characteristics of sound absorption, sound insulation, heat insulation, environmental protection, flame retardant and so on.
1. Advantages of glass fiber board
(1) It has high mechanical properties and electrical resistance properties, as well as good heat and moisture resistance, and good processability. Generally used for plastic molds and machinery manufacturing.
(2) Injection mold molding usually requires: high temperature material and low temperature mold. In the same machine condition, the heat insulation method must be adopted. Keep the injection molding temperature low without overheating the injection molding machine. This requirement can be met by installing an insulating heat shield between the injection mold and the injection machine. Shorten the production cycle, increase productivity, reduce energy consumption, and improve the quality of finished products, the continuous production process ensures stable product quality, prevents overheating of the machine, no electrical failure, and no oil leakage in the hydraulic system.
2, the use of glass fiber board
(1) Construction industry: It can be used for cooling towers, building structures, indoor equipment and decorative parts, glass fiber reinforced plastic panels, decorative panels, and solar energy utilization devices, etc.
(2) Chemical industry: It can be used as corrosion-resistant pipelines, corrosion-resistant delivery pumps and their accessories, as well as grilles, ventilation facilities, and wastewater and sewage treatment equipment.
(3) Automobile and railway transportation industry: it can be used as automobile shell and other parts, as well as the body shell, door, inner panel and instrument panel of large passenger cars; in the road construction part, there are road signs, isolation piers and highways Guardrails, etc.
(4) The performance of fiberglass board, fiberglass board can generally be used for soft-packed base, and then covered with fabric, leather, etc. on the outside, it can be made into beautiful wall and ceiling decoration.
(5) It has the advantages of sound absorption, sound insulation, heat insulation, environmental protection, flame retardant and so on. It has good insulation properties, so it has been used in radar casings, and it is also a good anti-corrosion material, and it has been widely used in the chemical industry. Fiberglass board has the advantage of strong plasticity.
Second, what is aluminum substrate
Aluminum substrate is a metal-based copper clad laminate with good heat dissipation function. Generally, a single-sided panel consists of three-layer structure, which are circuit layer (copper foil), insulating layer and metal base layer. For high-end use, there are also double-sided designs with a structure of circuit layer, insulating layer, aluminum base, insulating layer, and circuit layer. Very few applications are multi-layer boards, which can be made by laminating ordinary multi-layer boards with insulating layers and aluminum bases.
1. Advantages of aluminum substrates
(1) The heat dissipation is significantly better than the standard FR-4 structure.
(2) The thermal conductivity of the dielectric used is usually 5 to 10 times that of conventional epoxy glass, and the thickness is only one tenth.
(3) The heat transfer index is more efficient than the traditional rigid PCB.
(4) Lower copper weights than those shown in the IPC recommendations may be used.
2. The use of aluminum substrates
(1) Audio equipment: input, output amplifiers, balanced amplifiers, audio amplifiers, preamplifiers, power amplifiers, etc.
(2) Power supply equipment: switching regulators, DC/AC converters, SW regulators, etc.
(3) Communication electronic equipment: high-frequency amplifiers, filter appliances, and transmission circuits.
(4) Office automation equipment: motor drives, etc.
(5) Automobile: electronic regulator, igniter, power controller, etc.
(6) Computer: CPU board, floppy disk drive, power supply unit, etc.
(7) Power module: inverter, solid state relay, rectifier bridge, etc.
Aluminum substrates are widely used. Generally, aluminum substrates exist in audio equipment, power equipment, communication electronic equipment, office automation equipment, automobiles, computers, and power modules.
3. Design of aluminum substrate
The main technical requirements are:
Dimensional requirements, including board size and deviation, thickness and deviation, verticality and warpage; appearance, including cracks, scratches, burrs and delamination, aluminum oxide film, etc.; performance aspects, including peel strength, surface resistivity , minimum breakdown voltage, dielectric constant, flammability and thermal resistance requirements.
Special testing methods for aluminum-based copper clad laminates:
The first is the measurement method of dielectric constant and dielectric loss factor, which is a series resonance method with variable Q value, which connects the sample and the tuning capacitor in series to the high-frequency circuit, and measures the Q value of the series circuit;
The second is the thermal resistance measurement method, which is calculated by the ratio of the temperature difference between different temperature measurement points to the thermal conductivity.
4. Aluminum substrate circuit production
(1) Machining: The aluminum substrate can be drilled, but no burrs are allowed on the inside of the hole after drilling, which will affect the withstand voltage test. Milling profiles is very difficult. And punching the shape requires the use of advanced molds, and mold making is very skillful, which is one of the difficulties of aluminum substrates. After the shape is punched, the edges are required to be very neat, without any burrs, and without damaging the solder mask on the edge of the board. Usually, a soldier's die is used, the hole is punched from the circuit, the shape is punched from the aluminum surface, and the force when the circuit board is punched is cut up and down, etc. are all skills. After punching the shape, the warpage of the board should be less than 0.5%.
(2) The whole production process is not allowed to scratch the aluminum base surface: the aluminum base surface will be discolored and blackened by touching it by hand or by certain chemicals, which is absolutely unacceptable, and some customers who re-grind the aluminum base surface It is also not accepted, so the whole process does not bruise, does not touch the aluminum base surface is one of the difficulties in the production of aluminum substrates. Some companies use passivation technology, and some apply protective films before and after hot air leveling (tin spraying).
(3) Over-voltage test: The aluminum substrate of the communication power supply requires 100% high-voltage test, some customers require direct current, some require alternating current, the voltage requires 1500V, 1600V, the time is 5 seconds, 10 seconds, and 100% printed board is tested. Dirt on the board surface, holes and burrs on the edge of the aluminum base, line saw teeth, and bumps on any bit of the insulating layer will cause fire, leakage, and breakdown in the high-voltage test. The pressure test board is delaminated and blistered, all of which are rejected.
5. Specifications for aluminum substrate pcb production
(1) Aluminum substrates are often used in power devices, and the power density is high, so the copper foil is relatively thick. If more than 3oz copper foil is used, the etching process of thick copper foil requires engineering design line width compensation, otherwise, the line width after etching will be out of tolerance.
(2) The aluminum base surface of the aluminum substrate must be protected with a protective film in advance during the PCB processing process. Otherwise, some chemicals will erode the aluminum base surface and cause damage to the appearance. And the protective film is very easy to be bumped, resulting in gaps, which requires the entire PCB processing process to be inserted.
(3) The hardness of the milling cutter used for the glass fiber board gong plate is relatively small, while the hardness of the milling cutter used for the aluminum substrate is large. During the processing, the milling cutter for producing glass fiber board rotates fast, while the production of aluminum substrate is at least two-thirds slower.
(4) The computer edged fiberglass board can only use the heat dissipation system of the machine itself to dissipate heat, but when processing the aluminum substrate, it is necessary to add alcohol to the gong head to dissipate heat.
Three, three major differences between glass fiber board and aluminum substrate
1. In terms of price
Compared with the price of glass fiber board and aluminum substrate, the price of glass fiber board is obviously much cheaper.
2. Process
According to the different materials and production processes, the glass fiber board can be divided into three types: double-sided copper foil glass fiber board, perforated copper foil glass fiber board and single-sided copper foil glass fiber board. Of course, glass fiber boards made of different materials The price will also vary.
3. Performance
Since the aluminum substrate has good thermal conductivity, the heat dissipation performance of the aluminum substrate is much better than that of the glass fiber plate.
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