1. What’s Aluminium LED PCB?
Aluminum LED PCB substrate is a metal – based copper-clad sheet with good heat dissipation. A single panel is generally composed of three layers of structure, namely the circuit layer (copper foil), insulation layer and metal base layer. It is commonly found in LED lighting products. There are two sides, the white side is used to weld the LED pins, and the other side is the natural color of aluminum, which is usually coated with heat-conducting gel and then in contact with the heat-conducting part. Among all metal core PCBS, Aluminum LED PCB is the most common type. The base material consists of an aluminum core and standard FR4. It features a thermal cladding that dissipates heat in an efficient manner while cooling components and improving the overall performance of the product. Currently, aluminum-backed PCBS are considered solutions for high power and tight tolerance applications.
2. Aluminum LED PCB with Copper Layer, Dielectric Layer & Aluminum Layer
Aluminum LED PCB has a similar layout to any other printed circuit boards with copper layer(s), solder mask layer(s) and silkscreen(s). Instead of having a fiberglass or plastic substrate, Aluminum LED PCB is made from metal core substrate, which consists of copper layer, dielectric layer and aluminum layer. This substrate is called as Aluminum based copper clad laminate (CCL). The glass reinforced and ceramic filled dielectric layer in-between copper layer and aluminum layer is very thin, but plays a very important role of electric insulation and thermal conductivity (because of minimum thermal resistance) from copper layer to aluminum base. The copper is etched into conductors and metal base is to withdraw thermal (/heat). The superior heat transfer capacity of Aluminum-based PCB helps cooling components while eliminating problems associated with managing fragile ceramics.
3. Thermal conductivity of Aluminium LED PCB
The general thermal conductivity of Aluminum LED PCB is 0.3, 0.6, 1.0, 1.5, 2.0, 3.0, 5.0, 122W/m.k, etc., among which 0.3-1.0w /m.k is the general conductive Aluminum LED PCB, 1.5W/m.k is the middle conductive Aluminum LED PCB, 2.0-3.0w /m.k is the high conductive Aluminum LED PCB. 5.0W/m.k is thin abasal substrate, and 122W/m.k is ultra-high conductivity Aluminum LED PCB, also known as ALC Aluminum LED PCB.
At present, the common Aluminum LED PCB on the market has a thermal conductivity of 1.0, 1.5, 2.0W/m.k high conductivity type Aluminium LED, wherein the thermal conductivity of 1.0W/m.k Aluminum LED PCB is called general Aluminum LED PCB, its insulation layer is composed of epoxy glass cloth bonded sheet; Aluminum LED PCB with thermal conductivity of 1.5W/m.k is called high heat dissipation Aluminum LED PCB, and its insulation layer is composed of epoxy resin or other resins with high thermal conductivity; The Aluminum LED PCB with a thermal conductivity of 2.0W/m.k is called the Aluminum LED PCB for high-frequency circuit, and the insulating layer is composed of polyolefin resin or Polyimide resin glass cloth bonded sheet. The thermal conductivity of Aluminum LED PCB varies according to the copper layer in the circuit. Different processes produce different levels of thermal conductivity.
We currently support Aluminum based CCLs from Ventec, GDM and BoYu with thermal conductivity from 1.0 ~ 7 W/m•K. The Aluminum LED PCB prices of Ventec is much higher than that with GDM and BOYU since material cost, and the prices of high thermal conductivity is higher than low thermal conductivity. Hitechpcb provides a wide range of electrical and thermally conductive interface pads, thermally conductive gap filler, thermal phase change materials and thermally conductive electrically insulating materials, as well as specialized equipment for high volume Aluminum LED PCB manufacturing. Choosing Hitech Circuits PCB as your Aluminum LED PCB supplier, just send your Gerber files and fabrication notes to us, we will deliver qualitied PCB boards to you on time.
4. Dielectric constant of Aluminium LED PCB
The dielectric constant of Aluminum LED PCB substrate is a special detection method for Aluminum LED PCB. It is a variable Q value series resonance method through the measurement of dielectric constant and dielectric loss factor. The sample and tuning capacitor are connected in series to the high frequency circuit to measure the series circuit The principle of Q value.
The performance of Aluminum LED PCB includes requirements such as peel strength, surface resistivity, minimum breakdown voltage, dielectric constant, flammability and thermal resistance.
5. Aluminum LED PCB with White Solder Mask
The retail price of Aluminum LED lights has dropped dramatically in recent years, while the energy efficiency and brightness of LED lights have improved. These technological advances have led some to predict annual growth of 45% over the next five years. With the development of the LED industry, the demand for LED PCBS and solder masks is also increasing. Solder shield is a protective coating applied to exposed printed circuit boards. The exposed PCB board is covered with a mask to prevent accidental solder bridging during PCB assembly and to protect the PCB from the environment. Solder masks are traditionally green, and are expected to withstand the high temperatures that occur in reflow soldering, as different colors such as blue, red, or black will occasionally appear. Increased production of Hitch Aluminum LED PCB requires increased whiteness and color stability of the mask. Aluminum LED PCB commonly used LPI welding color is white and black, of which white welding color is the most commonly used to achieve high brightness and perfect light reflection. White Aluminum LED PCB ensures no darkening and will not affect the color temperature of LED smd. At the same time, it also helps to increase the life of LED applications. Looking for reliable Aluminum LED PCB suppliers, Hitech is a good choice.
6. Classification of Aluminum LED PCB substrate
Aluminum LED PCB-based copper clad plates are divided into three categories:
The first is the universal aluminum-based copper clad plate, the insulation layer is composed of epoxy glass cloth bonded sheet;
The second is the high heat dissipation aluminum-based copper-clad plate, the insulation layer is composed of high thermal conductivity epoxy resin or other resins;
Third, high frequency circuit aluminum base copper plate, insulation layer by polyolefin resin or Polyimide resin glass cloth bonded sheet.
The biggest difference between aluminum clad copper plate and conventional FR-4 clad copper plate is heat dissipation. Compared with 1.5mm thickness of FR-4 clad copper plate and aluminum clad copper plate, the former thermal resistance of 20 ~ 22 ℃, the latter thermal resistance of 1.0 ~ 2.0℃, the latter is much smaller.
7. Aluminum LED PCB Performance:
(1) Heat dissipation
Many double panel, multi – layer plate high density, power, heat distribution is difficult. Conventional printed board substrates such as FR4, CEM3 are bad conductors of heat, insulation between layers, heat does not escape. Local heating of electronic equipment is not excluded, leading to high temperature failure of electronic components, and Aluminum LED PCB can solve this problem of heat dissipation.
(2) Thermal Expansibility
Thermal expansion and cold contraction is the common nature of substances, and the coefficient of thermal expansion of different substances is different. Aluminum based printed board can effectively solve the problem of heat dissipation, so that the printed board components of different substances on the thermal expansion and contraction problem, improve the durability and reliability of the whole machine and electronic equipment. Especially solve SMT (surface mount technology) thermal expansion and shrinkage problems.
(3) Dimensional stability
Aluminum-based printed boards are obviously much more stable in size than those made of insulating materials. Aluminum base printed board, aluminum sandwich board, heating from 30℃ to 140~150℃, the size change is 2.5~3.0%.
(4) Other reasons
Aluminum based printed board, with shielding effect; Instead of brittle ceramic substrate; Safe use of surface mounting technology; Reducing the real effective area of the printed board; Instead of radiator and other components, improve the heat resistance and physical properties of products; Reduce production costs and labor.
8. Why choose Aluminum LED PCB from Hitechpcb? What are the advantages of Aluminum LED PCB?
(1) Good heat dissipation performance: Aluminum LED PCB can reduce the thermal resistance to the minimum, has a smaller thermal resistance, thermal expansion coefficient is closer to copper foil, so that Aluminum LED PCB has excellent thermal conductivity and heat dissipation performance, reduce the module operating temperature, prolong the service life.
High current load: Using the same thickness, the same line width, Aluminum LED PCB substrate can carry higher current.
(2) Good machinability: can replace ceramic substrate, better mechanical endurance. At the same time, high strength and toughness, can realize large area printed board manufacturing and component mounting.
(3) Good electromagnetic shielding: In order to ensure the performance of electronic circuits, some components of electronic products need to prevent electromagnetic radiation and interference. Aluminum LED PCB can act as a shield plate, play the role of shielding electromagnetic wave
(4) Environmental protection: The Aluminum LED PCB used in the raw material is non-toxic and can be recycled. Meet RoHs requirements.
(5)Light weight: Aluminum LED PCB has a surprisingly light weight with excellent strength and elasticity, which is very convenient.
Hitech Circuits can provide high quality and affordable Aluminum LED PCB products for you.
9. Technical requirements for Aluminum LED PCB
The main technical requirements are:
1. Dimensional requirements: including panel size and deviation, thickness and deviation, perpendicularity and warpage; Appearance, including cracks, scratches, burrs and delimitation, aluminum oxide film, etc.
2. Performance requirements, including peel strength, surface resistively, minimum breakdown voltage, dielectric constant, combustion and thermal resistance requirements.
10. Special test method for Aluminum-based copper clad plates
One is the measurement method of dielectric constant and dielectric loss factor. It is the series resonance method with variable Q value. The sample and tuned capacitor are connected to the high-frequency circuit in series to measure the Q value of the series circuit.
The other is the measurement method of thermal resistance, which is calculated by the ratio of temperature difference and heat conduction between different temperature measurement points.
11. The Aluminum LED PCB manufacturing process in Hitechpcb
(1)Substrate cutting
a. cutting process: material → cutting
b. Note: ① Check the size of the first piece; ② Pay attention to Aluminum surface scratching and copper surface scratching; ③ Pay attention to the layering of the board edge and the tip.
(2)Plate drilling
a, drilling process: pin → drilling → inspection plate
b, matters needing attention: ① check the number of drilling holes, the size of the empty chestnut chain; ② Check the plate burr, hole deviation; ③ Avoid scratching the substrate; ④ Check and replace the drill nozzle.
(3) Imaging transfer
a, graphic imaging process: grinding plate → film → exposure → development
b, precautions: ① Check whether there is an open circuit after development; ② Pay attention to the poor line caused by the board wipe; ③ There can be no air residual exposure to prevent poor exposure; ④ Whether there is deviation in developing counterpoint; ⑤ After exposure, the development should be done at rest for more than 15 minutes.
(4)Solder mask and Silkscreen process
a, kill row silk printing resistance welding, character process: screen printing → pre-baking → exposure → development → character
b, matters needing attention: ① Check whether there is foreign body on the board; ② Pay attention to the cleaning of the net board; ③ Pre-bake for more than 30 minutes after screen printing, to avoid bubbles in the line; ④ Pay attention to the thickness and uniformity of screen printing; ⑤ After the pre-baked plate to completely mutual cooling, avoid touching film or damage to the ink surface gloss.
(5)E-test or flying probe test
a, test process: line test → withstand voltage test
b, precautions: ① How to distinguish after the test how to store qualified and unqualified products.
(6)FQC, FQA, packaging, shipping
a. Process: FQC→FQA→ Packaging → shipping
b. Note: ① FQC should pay attention to the confirmation of the appearance of the finished Aluminum LED PCB in the process of eye inspection and make a reasonable distinction; ② FQA does spot check and verify the inspection standards of FQC; ③ We should confirm the number of packages to avoid mixed plates, wrong plates and package
12. Application of Aluminum LED PCB
1. Audio devices: input, output amplifier, balance amplifier, audio amplifier, preamplifier, power amplifier.
2. Power Supply: switching voltage regulator, DC/AC converter, SW voltage regulator, etc.
3. Communication electronic equipment: high frequency amplifier, filter, transmitter circuit
4. Office automation equipment: motor drive, etc
5. Automobile: electronic regulator, ignition device, power controller, etc.
6. Computer :CPU board, floppy disk drive, power equipment, etc.
7. Power module: converter, solid relay, rectifier bridge, etc
8. Lamps and lighting: A variety of colorful LED energy-saving lamps are well received by the market, and Aluminum LED PCB used in LED lights has also begun to be applied on a large scale.
13. Aluminum LED PCB Storage Conditions
Aluminum LED PCB are generally stored in a dark and dry environment. Most Aluminum LED tube lighting metal core pcb are prone to dampness, yellowing, and blackening. Generally, they should be used within 48 hours after opening the vacuum package.
14. Specification for the manufacture of Aluminum LED PCB
a. Aluminum LED PCB is often used in power devices, power density is high, so the copper foil is thicker. If copper foils over 3oz are used, the etching of thick copper foils requires engineered line width compensation, otherwise the line width will be out of tolerance after etching.
b. The aluminum base surface of aluminum substrate must be protected by protective film in advance during PCB processing, otherwise, some chemicals will etch the aluminum base surface, resulting in appearance damage. And the protective film is easy to be hurt, resulting in gaps, which requires the whole PCB processing process must be inserted.
c. The hardness of the milling cutter used by the glass fiber board gong board is relatively small, and the hardness of the milling cutter used by the aluminum substrate is large. In the process of manufacturing glass fiber board milling cutter speed, while the production of aluminum substrate is at least two thirds slower.
d, computer milling glass fiber board is just the use of the machine’s own cooling system, but the processing of aluminum substrate must be in addition to alcohol heat dissipation for the gong head.
15. Aluminum LED PCB circuit fabrication
(1) Mechanical processing: Drilling of aluminum substrate can be done, but no burr is allowed on the edge of the inner hole after drilling, which will affect the pressure test. Milling the shape is very difficult. And punching shape, need to use advanced mold, mold production is very skilled, as one of the difficulties of aluminum substrate. After shape punching, the edge should be very neat, without any burr, and do not hurt the welding resistance layer on the edge of the plate. Usually the use of soldier die, hole from the line, shape from the aluminum surface, circuit board punching force is cut down, and so on are 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 wipe the aluminum base surface: aluminum base touch, or by a certain chemical will produce surface discoloration, blackening, which is absolutely unacceptable, re-polishing aluminum base some customers do not receive, so the whole process does not touch the aluminum base surface is one of the difficulties in the production of aluminum base plate. Some enterprises use passivation process, some in hot air leveling (spray tin) before and after each pasted protective film.
(3) Over-high voltage test: the aluminum base board of the communication power supply shall be tested at 100% high voltage. Some customers require direct current or alternating current. The voltage shall be 1500V or 1600V, and the time shall be 5 seconds or 10 seconds. Dirt on the board, holes and aluminum edge burr, line saw tooth, damage to any little insulation layer will lead to high voltage test fire, leakage, breakdown. Pressure test board stratification, foaming, are rejected.
Learn more: https://www.hitechpcba.com/aluminium-led-pcb
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