How to handle the thermal management during automotive PCB design?

Use CFD simulate PCB thermal design

Making sure that automotive electronics are reliable, safe, and properly designed begins at the component level. Heat must be addressed early in the design process for these goals to be achieved. The most important thermal resistance for heat, outside the IC package, is the PCB. Rich PCB manufacturing engineers use 3D computational fluid dynamics (CFD) to simulate and test a PCB’s thermal design. Modeling the main heat flow paths in detail is critical to ensure that generated heat in the component flows out to the ambient, either through convection, conduction, or radiation. Knowing the thermal junction resistance allows optimizing a design for more efficient and less costly heatsinks, materials, and ICs.

When building a model to use in simulation, different methods can be used to represent chip packages and PCB board. Chip packages are typically defined as four types. The simple cuboid is a lumped component with some material properties and a heat source applied to it. The 2-resistor model doesn’t include any thermal capacitance and is therefore not suitable for transient analysis of component temperatures. The Delphi model is comprised of several thermal resistances and capacitances and thus is more accurate and suitable for transient simulations. Finally, the detailed model is modeled explicitly and is the most accurate model; however, it also increases the simulation time and requirements for computing resources.

For the PCB, four detailing levels from simple to complex also are used in simulation: lumped approximation, individual layers’ representation, layers modeled with “patches,” and copper tracks and areas modeled in detail.

Top three ignore point during PCB manufacturing

This paper HTD PCB manufacturing experts will introduce three misunderstand.
If you have any questions about those Top three ignore point during PCB manufacturing, please feel free to contact us.
Our PCB manufacturing experts will reply ASAP.

1. Engineering design: the PCB design should note:
A. interlayer half curing chips, such as shall be symmetrical arrangement six layer board, 1 ~ 2 and 5 ~ 6 layer thickness and half between the number of curing pieces shall be consistent, otherwise layer after pressing warps easily.
B. produce multilayer prototypes core board and half curing piece should use the same supplier"s products.
C. outer A face and side B circuit patterns should be as close to the area. If A surface for big copper surface, but B surface walked several thread only, this kind of printed circuit board after the etching is very easy to warp. If both sides of the line are far too big, can the area in dilute side add some independent grid, make the balance.
2. Before blanking baked board:
Copper clad material before baking plate (150 degrees Celsius, time 8 + 2 hours) purpose is to remove the moisture in the plate and also make the plank to fully cure within the resin, further eliminate plank of stress, which left to prevent plate wrpping is helpful. At present, many two-sided and produce multilayer prototypes still insist on next makings before or after baking plate this step. But there are some board factory exception, currently the PCB board of the time regulation also baking inconsistent from 4 to 10 hours, according to the production, the suggestion to the class of the PCB and client requirements to decide the warping degrees. Baked or cut makeup; after block after baking feeding, two methods are feasible Suggestions after cutting materials, baking plate. Lining board should also be baking plate.
3. Half curing slice of weft to:
Half cured by slice layer after pressing zonally shrinkage to and material and, as must distinguish the stack layer to and a zonally. Otherwise, layer after pressing is very easy to create the finished product, even add pressure plate wrpping baking plate also hard to correct. Produce multilayer prototypes of reasons, many warping is laminated half curing chips when pyrocondensation, disorderly diego to didn"t distinguish caused by the release.
How to distinguish jinwei to? Volumes of half cured by the direction of tablet is up to, and width direction is a zonally; It long sides of copper foil board zonally, when the shorter edges is to cannot be determined by, such as producer or supplier to query.

HTD Group is professional gold finger PCB manufacturer from China.
This paper will discuss gold plate technology.
If you want to learn more, please mail to info@htdcircuits.com

Gold contact surfaces are often used on circuit boards with membrane switches which are a technology of choice for industrial, commercial and consumer products. When PCBs will be repeatedly installed and removed electroplated gold is used for edge-connector contacts or as they are more commonly known: Gold fingers.
It is difficult to hear the term Gold finger without remembering the villain Auric Goldfinger from the James Bond film of 1964.
However, the gold fingers (gold-plated contact pins) found on PCBs are quite unlike Auric’s stubby, fat digits.
To begin with, the plating thickness of a PCB gold finger is typically a mere 300 micro-inch. At this thickness the hard gold is expected to survive 1,000 cycles before wear through.

Warping degree standard and test methods

According to the American IPC - 6012 (1996 edition) rigid printed circuit board > > identification and performance specification for surface installation, PCB allowable maximum warping and distortion, and other various board for 0.75% allow 1.5%.
This is better than the IPC - RB - 276 (1992) improve the surface installation requirements.
Printed circuit board At present, various electronic potential manufacturing/remanufacturing curling degrees, whether permission or multilayer, 1.6 mm double thickness, usually 0.70 ~ 0.75%, many SMT, BGA board, the requirement is 0.5%.
Part of the electronic factory is inspired to raise the standard wrpping degrees 0.3%,
Test method of GB4677.5 wrpping degrees - 84 or in accordance with 650.2.4.22 B IPC - TM -.
The JingJian PCB on the platform, set the test needle is inserted into the warp degrees biggest place to test the needle diameter, divided by the PCB collaring length, just can calculate the PCB curling degrees.