The following section will discuss best practices for selecting a PCB manufacturer to build your custom printed circuit board (PCB).
Choosing a Manufacturer of Printed Circuit Boards
Although this is not an attempt to provide a comprehensive list of PCB fabrication companies that you could consider hiring for a small-quantity order, that information is easily accessible using a search engine on the internet. Rather than that, I’d want to offer some of the thoughts and concepts that have developed due to my education and experience. Although I have never received a PCB that I would describe as poorly manufactured, I will refrain from commenting on the quality of the boards produced by a particular manufacturer because I have never received a PCB that I would describe as poorly manufactured (I’m not sure if this is because I’m fortunate or because I have a knack for identifying fab houses that take quality seriously).
Select an Assembly Method from the available choices
After investing significant time and effort in developing, verifying, and constructing a printed circuit board, it might be discouraging to discover that you have reached the most challenging part of the production process, assembly. Not always the case, but nowadays—that is, in the era of small (if not minuscule), densely packed surface-mount components with no protruding leads in some cases—the issue of physically attaching components to the board can present the most difficult challenge in low-volume printed circuit board manufacturing.
There are four methods available to you: professional assembly, do-it-yourself reflow, hot-air-gun soldering, or manual soldering. The most expensive option is to hire a professional assembly service (i.e., with a soldering iron). I’m not going to discuss manual soldering in PCB fabrication since it will be difficult, impractical, or just impossible (though the soldering iron can undoubtedly be helpful for minor rework tasks). The remaining three options will be examined further in the following sections.
The primary hurdle in this situation is financial. While automated assembly technology is well-established and exceedingly reliable, it is not economically feasible for small-quantity orders. Additionally, extra production data is required:
- Information on the Bill of Materials (BOM): This information is required by the assembly house in PCB manufacturer for them to order components or organize the parts that you have given.
- To submit a solder mask, you must offer Gerber files defining the board locations (for example, pads for IC pins) that must be soldered during the solder-paste deposition process. * Deposition of solder paste: Solder paste is the type of solder used in reflow assembly. Creating solder-mask divisions that divide a single large pad into multiple smaller rectangles of solder paste can be time-consuming and challenging in particular situations (for more details, please check this article).
- Positioning data: This section contains each component’s spatial coordinates and rotation on the board. * Rotational data: This contains the board’s rotation. Without knowledge of which components belong where and how they should be oriented, the machine will not install them.
Depending on your circumstances, you may decide that constructing the board yourself is less time-consuming than producing and verifying all supplementary information.
DIY Reflow (DIY)
Surprisingly, this procedure looks to be possible. The basic notion is that you apply solder paste, arrange the components, then bake the PCB in a customized toaster oven. You’ve finished your assignment. If manually dropping solder paste onto tiny, closely spaced pads proves challenging, consider using a stencil, a flat object with perforations matching the solder paste locations.
Using a Hot-Air-Gun to Solder
It’s worth noting that the only difference between DIY reflow and hot-air gun assembly is the heat source, which is an excellent incentive to practice solder paste deposit and component placement. Once those processes are mastered, you may select between reflow and hot air based on the other variables. Hot air is both practical and quite effective for smaller boards. While reflow requires a more elaborate setup, it uniformly heats the whole board and gives you better control over the temperature profile. A reflow profile is a visual representation of the temperature rise and decreases during the reflow procedure, and it is used to direct the operation.