For a PCB Designer to come up with the best PCB design, s/he must carefully choose the right PCB Components for the board to be manufactured. If the PCB Components are not chosen wisely, problems might be encountered later that could greatly increase the cost of the whole project. For example, if the PCB Components used are rare to find, it will obviously result to a very expensive PCBA Exercise.For a PCB Designer to come up with the best PCB design, s/he must carefully choose the right PCB Components for the board to be manufactured. If the PCB Components are not chosen wisely, problems might be encountered later that could greatly increase the cost of the whole project. For example, if the PCB Components used are rare to find, it will obviously result to a very expensive PCBA Exercise.
As you make your PCB design schematic, you need to make use of the PCB Components that exist in the real world. Of course you could make a complete schematic with the virtual components and all will work fine but in simulation. As one of the steps to choosing the PCB Components, make sure that you have a complete Bill Of Material (BOM) for all your PCB Components that you intend to use. This will help you to figure out which PCB Components are virtual and work to ensure that all the PCB Components have the XYZ dimensions, they have a physical layout and that they are available for purchase at an affordable price.
When choosing the PCB Components, decide if they should be through-hole or if they will be surface-mounted. Here, the main aim should be to make all the PCB Components to be surface mounted since this is the cheapest and the most economical way of doing PCBA. In addition, it is better to go for the smallest PCB Component as possible. In such a case, the assumption is that the PCBA will be done by a machine. However, depending on the application, this target is rarely reached. If the PCB is meant for some hobby project, PCBA will majorly be done by hand, it is better to go for bigger SMT PCB Components that can be held by the hand PCB tools. If the PCBA involves lots of connectors, the board will have lots of through-hole PCB components and the soldering will be done by hand.
Some PCB Components require more clearance than others. For example, power components emit heat that needs to be dissipated quickly. This requires them to have a higher clearance between the board and the component itself. In some other extreme cases, it is required that you attach a heat sink on the PCB Component surface to assist in heat dissipation. When choosing the PCB Components, you need to put this into consideration since even the physical space occupied by the PCB Component and its heat sink can affect the shape of your final package, if this factor was not looked onto during the initial stages of PCB design.
When it comes to the final soldering exercise of the PCB Components, the first thing you want to do is to get datasheets for all the PCB Components involved. You must know their specifications before you set heat on them for soldering. After you have known their properties and possible extremes, you can go ahead and decide whether you shall do the hand or wave soldering or putt the PCBA in the reflow oven to get the job done. For hand soldering, start soldering the PCB Components that are bulky and through-hole, moving on to the lighter and the small-area PCB Components.