If you’re looking to make your PCBs, you’ll love this company’s open-source hardware boards. You can make open-source hardware boards for the Arduino and IoT platforms or use their PCB assembly services to customize stencils. They even assemble everything sold at the Tindie store. Read on to find out more. But first, let’s discuss the PCB assembly process. There are a few things you need to know.
HASL finish
HASL is a standard surface finish used on many PCBs. It has long been a popular choice for its affordability and robustness. But its shortcomings have come to light, particularly with the advent of more complex surface mount technologies. Its disadvantages include leaving uneven surfaces, making it unsuitable for using fine pitch components. In addition, while it’s lead-free, other methods may be better suited for high-reliability products.
The HASL finish on Elecrow PCBS is a good choice for applications involving real current. Copper weight across all boards was within tolerance. In addition, all but one board had trace-net end solder mask witness marks that could be hazardous in real-current applications. The solder mask had scratched completely on one board, exposing a trace beneath, tested conducive to the pad at the trace net end. On another board, a via had significant scratches. Nevertheless, overall board quality is excellent.
HASL and ENIG finishes are similar, but HASL is less expensive. In addition, the ENIG finish has a flat surface that’s more conducive to soldering. ENIG is also preferred for high-pin-count and fine pitch components, as its flatness makes the placement of components more precise and enables controlled solder application. The latter finish also reduces the risk of shorts and opens.
HASL finish on Elecrow PCBA is a lead-free surface finish. HASL finish is an environmentally-friendly option, and its customers can select the color of the PCB. In addition to HASL finish, Elecrow PCB also offers fast shipping. The price of the HASL finish depends on the complexity of the design. However, the HASL finish makes a PCB more environmentally friendly than standard finishes.
Another option is immersion silver. This finish is more environmentally friendly and a good option for flat pack and fine pitch applications.
Green solder mask
The first thing that caught our attention about the Elecrow PCBs was the solder mask. As expected, it was green, but with some unusual features. The outlines of the XLR pins, for example, were not solid but rather had cuts in them. I noticed this problem even on the 4-layer board. Another strange feature we noticed is the solder mask color, which is inconsistent with other boards. In two cases, the solder mask color is red, while on the other, it’s orange. We speculated that these issues might be related to the PCBA process.
Another detail that we noticed was the size of the vias. While Elecrow’s website has a helpful illustration of the order process, this service does not include testing. This is because high-performance analog circuits are not easy to test. In addition, Elecrow’s PCBs are much smaller than a standard-sized PCB, and they have a minimum drill hole size of 0.3mm.
99% of all circuit boards have a green solder mask. However, you might opt for another color if you have special requirements depending on your needs. Solder masks can be printed or sprayed on the PCBs and are UV-exposed. Generally, green solder masks are more durable than others and lend themselves to visual inspection.
White and black PCBs are increasingly popular, although they’re not a perfect match for your product. For example, white PCBs tend to hide traces and are difficult to inspect without a bright overhead light. Moreover, a white solder mask does not look good with black silkscreens. However, if you’re looking for a professional-looking circuit board, you might consider using a white solder mask from Rayming PCB & Assembly.
Small vias
The Elecrow website shows how to order a custom PCB, but there is a catch. It does not provide testing services. Testing high-performance analog circuits is complex and requires a capable test kit. However, if you are a DIY designer or do-it-yourselfer who cannot buy or produce a prototype, then the Elecrow website will be your best bet.
When designing a PCB, it is essential to consider the layout. To choose the best layout for your PCB, you need to know the dimensions of the holes. The dimensions of the vias should be smaller than the thickness of the board. The corresponding hole size must also be bigger than the diameter of the hole itself. Choosing via size depends on the board’s size and purpose. The larger the PCB, the better, as older computing devices only accept bigger PCBs with through-hole components.
It is also crucial to choose a factory capable of manufacturing your PCB. The best factories can handle even the simplest PCB design, so choose a manufacturer with the requisite expertise and capability to manufacture your PCB. You should also know what to expect from Elecrow PCBs. You can order a prototype or a fully-completed board, depending on the complexity of your design.
The Gerber RS-274X file format is standard across manufacturers, making it easier to create high-quality prototypes. In addition, the rules of PCB design have become much tighter, with many manufacturers supporting 6/6 mil design rules, small vias, and a variety of PCB thicknesses. You can also use a low-cost $10 per ten-board-order price for the prototype. Finally, if you’re a beginner and want to experiment with PCB design, you can try TinySine.
Laser-cut stencils
The design and surface finish of laser-cut stencils are essential for a smooth solder paste transfer. The amount of paste deposited depends on the aperture size and design. An appropriate stencil will minimize the amount of solder paste deposited on the board, thereby maximizing solder joint strength and electrical functionality. Stencil printability is also dependent on the size of the aperture and the thickness of the foil.
A frameless laser-cut stencil is the most robust type of laser-cut stencil. It is suitable for high-volume screen-printing during a production run. It is permanently mounted within the stencil frame and features a mesh border to stretch the foil taut. This stencil type is ideal for components with an aperture wall smaller than 16 Mil, such as Micro BGAs. It also provides the highest level of positional accuracy and is suitable for use in temperature-controlled environments.
Laser-cut stencils for Elecrow are available in two sizes: one for the internal area of the board and another for the overall area. Laser-cut stencils should match the dimensions of a PCB’s ready-to-assemble state but should not be too small or too large for the board itself. Make sure that the PCB stencil’s internal area and the outer area are compatible with the parameters of your printer.
A laser-cut stencil is an excellent choice when solder paste is ideal for PCB panelizing. Its well-defined edges will make the placement of components easy and increase reflow rates. There are no other stencils that provide the same level of precision and accuracy. The design and thickness of the stencil are crucial in achieving the best results. The stencil is a product of polycarbonate and metal.
Conclusion
You should take the time to research and decide on the bare minimum requirements of a PCB manufacturer. A good PCB manufacturer will have expertise and experience and have the skills and equipment to manufacture your PCBs. A quality manufacturer will also provide testing services, a must for all high-performance devices. Elecrow’s website is an excellent resource for beginners looking to test their designs before making them commercially available.
