Generally speaking, the PCB assembly can be divided into two kinds: manual assembly and auto assembly. We all know that manual assembly is not less expensive than auto assembly sometimes. Actually, there exit many controlling factors such as labor expense, time, volume, etc. Thus, in order to make a wise decision, we’d better learn some key determinants.
Above all, the most restrictive one is space. Provided that space is so small that surface mount component must be used, then manual assembly becomes fairly difficult. In other words, when component spacing becomes extremely tight and manual assembly seems impossible, then auto assembly should be a better option.
Apart from space, quantities should be another determinant for manual assembly and auto assembly. When the large production quantities are required within a very limited time, auto assembly becomes a necessity. Nevertheless, it does not mean that the small quantities will be always suitable for manual assembly. Take thru-hole component for example, auto assembly tends to be more proper when the component is of low volume but high density.
As mentioned above, the determination between manual assembly and auto assembly is generally related to these factors: space, quantities as well as components used. Perhaps you may be clearer about the final decision now, right?