PCB aluminum substrate classification
1. Flexible aluminum substrate
One of the latest developments of IMS materials is flexible dielectrics. These materials can provide excellent electrical insulation, flexibility and thermal conductivity. When applied to flexible aluminum materials such as 5754 or similar, the product can be constructed to complete various shapes and angles, which can eliminate expensive fixing devices, cables and connectors. Although these materials are flexible, they are designed to bend in place and stay in place.
2. Mixed aluminum aluminum substrate
In the "hybrid" IMS structure, the "sub-components" of non-thermal substances are handled independently, and then AmitronHybridIMSPCBs are bonded to the aluminum substrate with thermal materials. The most common structure is a 2-layer or 4-layer subassembly made of traditional FR-4, which can be bonded to an aluminum substrate with a thermoelectric to help dissipate heat, improve rigidity, and act as a shield. Other benefits include:
1. The cost is lower than the construction of all heat-conducting materials.
2. Provide better thermal performance than standard FR-4 products.
3. It can eliminate expensive radiators and related assembly steps.
4. It can be used in RF applications that require the RF loss characteristics of the PTFE surface layer.
5. Use component windows in aluminum to accommodate through-hole components. This allows adapters and cables to pass the adapter through the substrate, while welding rounded corners to create a seal, without the need for special gaskets or other expensive adapters.
Three, multilayer aluminum substrate
In the high-performance power supply market, the multilayer IMSPCB is made of multilayer thermally conductive dielectrics. These structures have one or more layers of circuits buried in the dielectric, and blind vias are used as thermal vias or signal paths. Although single-layer designs are more expensive and less efficient to transfer heat, they provide a simple and effective heat dissipation solution for more complex designs.
Four, through-hole aluminum substrate
In the most complex structure, a layer of aluminum can form the "core" of a multilayer thermal structure. Before lamination, electroplating and dielectric filling of aluminum are stopped in advance. Thermal materials or sub-components can be laminated to both sides of the aluminum using thermal adhesive materials. Once laminated, the finished component is drilled similar to a traditional multilayer aluminum substrate. Plated through holes pass through gaps in the aluminum to maintain electrical insulation. Alternatively, the copper core may allow direct electrical connection and insulating vias.
The thermal conductivity of the aluminum substrate refers to the heat dissipation performance parameter of the aluminum substrate, which is one of the three major criteria for weighing the quality of the aluminum substrate (the other two standards are the thermal resistance value and the withstand voltage value). The thermal conductivity of aluminum substrates can be tested by testing instruments after the plates are pressed. At present, ceramics and copper are commonly used with high thermal conductivity. However, due to the cost problem, most of the aluminum substrates on the market are currently on the market. The thermal conductivity of the aluminum substrate is a parameter that everyone cares about. The higher the thermal conductivity, the better the performance.
Thermal conductivity of PCB aluminum substrate
Aluminum substrate is a common metal-based copper-clad aluminum substrate, which has good thermal conductivity, electrical insulation properties and mechanical processing properties. Under normal circumstances, in the LED design and PCB design, there will be the application of aluminum substrates, and the LED heat dissipation design is based on the fluid dynamics software to stop the simulation and basic design, which is very necessary for the consumption of aluminum substrates. .
The so-called resistance of fluid activity is due to the viscosity of the fluid and the influence of the solid border, which causes the fluid to encounter a certain resistance during the activity. This resistance is called the activity resistance, which can be divided into two types: along-the-path resistance and local resistance; The resistance along the way is the area where the border changes sharply, such as the sudden expansion or decrease of the cross-section, the local position of the elbow, it is the movement resistance produced by the sudden change of the fluid activity state.
Generally, the heat sink used in the LED aluminum substrate is natural heat dissipation. The design process of the heat sink is mainly divided into three steps:
1. Design the contour drawing of the radiator according to the relevant constraints
2. According to the relevant design criteria of the aluminum substrate radiator, optimize the tooth thickness, tooth shape, tooth spacing and the thickness of the aluminum substrate of the radiator
3. Suspend the check calculation to ensure the heat dissipation performance of the radiator.