The process of creating a prototype circuit board requires multiple phases and a large number of steps.
The process starts with the specification of the design, then proceeds through electrical design (often done with a schematic or
similar symbolic notation), into the physical design (layout), manufacture of the printed circuit boards themselves,
and culminates in the assembly of these boards. Errors can be induced at any one of these steps.
Specification— Electrical Design— Physical Design— Manufacture— Assembly
With the increase in the number of components available only in Surface Mount packages, assembly skills –at least for prototypes – will continue to move away from the realm of hand assembly by the design team.
If you’ve tried, then you know: it’s one thing to handsolder an 0804 component that’s tough enough.
Trying to work a soldering iron in and around anything smaller is difficult indeed.
Especially considering that the weight of the component can be so light that a mis-directed exhale would move the components around the board.
And, of course, hand‐soldering a Ball Grid Array (BGA) or other similar package is just not feasible.
The engineers who blog about soldering leadless packages overwhelmingly are doing nothing more than
creating breakout packages with the leadless component so as to facilitate bench testing of the component.
So, like it or not, machine‐based assembly is increasingly becomiing a requirement.
The trouble is that purchasing pick‐ and‐place machinery can be cost prohibitive.
Even if you have the pick‐and‐place equipment, you still need a stencil to
guide the application of solder paste prior to placing the components.
Where is the gap between hand assembly and outsourced assembly? And where does the purchase of a stencil fit in
bridging that gap?
The Board Assembly Process:
Apply Solder Paste—Pick‐and‐Place Components—Heat /reflow solder—Cool—Test