JHDPCB specializes in rapid PCB prototyping and small-batch production. They can create inexpensive single-layer PCBs for beginners and enthusiasts and more complicated multi-layer PCBs for high-quality industrial applications.
JHDPCB pcb manufacturing has been working to decrease their pricing, improve their ordering process and increase their SMT lead time since 2006. Their bargaining power enables them to negotiate with component suppliers and cut their costs.
FR4 material properties
FR4 material is a type of glass epoxy laminate that’s used in circuit boards. It has favorable mechanical and electrical properties and good insulating and water resistance abilities.
FR4 is an inexpensive, lightweight, and generally, very stable base for printed circuit boards (PCBs) compared to other PCB materials. It also has a wide operating temperature range from 50 to 115 degrees Fahrenheit.
It has a low coefficient of thermal expansion, which means it doesn’t expand or contract a lot with temperature changes. This makes it a good choice for constructing electronic equipment cabinets and other applications that need to maintain their shape and size under extreme conditions.
However, fr4 material properties does not offer a uniform dielectric constant like high-speed board materials do. The Dk value varies as the frequency increases, and this presents challenges while maintaining impedance values.
For controlled impedance boards, FR4 may not be the best material option. The Dk variation could change the dielectric constant of adjacent layers, which could affect capacitance.
The PCB manufacturing process is a series of steps used to produce printed circuit boards. Each step is important and can affect the quality of the finished product.
The first step is to create an image of the board’s circuitry on a film, which is then exposed by a laser. This allows for more accurate and reliable results when it comes to producing the final board design.
Next, the boards are etched to remove excess copper. This can be done with a solution of ammonium hydroxide or another chemical.
In some cases, the etching can be automated to speed up the process. This is a great option for reducing costs and ensuring high quality the best smt asembly service.
The next step is to apply a surface finish that protects the remaining copper areas of the board from oxidation. This can be done by applying a coating of HASL or an alternative that is suitable for the PCB’s specifications, applications, and assembly process.
The QFN package is one of the most popular surface-mount IC packages used for consumer, industrial, automotive and power applications. Its small form factor makes it convenient to assemble on circuit boards.
It also features a bottom side with an exposed pad that provides a low thermal resistance path for heat transfer to the PCB. It enables ground connection as well.
Another variation of this QFN is a plastic-molded type, which lacks a lid. This type is suited for applications that use 2 to 3 GHz.
Among other common variations, some QFN packages feature wettable flanks that show the solder-wetting level of the pads. This helps a designer visually check that the pads are seated on the board correctly.
Solder mask dam
In PCB manufacturing, the solder mask dam ensures accurate assembly. In particular, it helps prevent accidental solder bridging between surface-mount pads and significantly reduces the rework required to remove shorts.
The design software will often set the solder mask dam to be a specific size. This is a good way to minimize risk and save rework during production, but the dam may be too small for SMD pads or for very fine-pitch components.
A narrow section can flake off the PCB when a mask is too small, leaving a path for shorts to be soldered between adjacent SMD pads. This condition is called slivers, and it can lead to errors in assembly.
When this happens, the designer should account for a minimum width of 100 microns (four miles) to avoid slivers in the finished board. This is the minimum recommended width for solder masks used in PCB fabrication.