Printed circuit board assembly is also known as PCBA. It is basically the process of assembling electronic components of a printed circuit board. Before the electronic components are assembled, the circuit board is known as a PCB (printed circuit board). Once these components are assembled or soldered, the board then becomes Printed Circuit Board Assembly (PCBA).
As technology is advancing, the gadgets we use are getting smaller. And as they get small in size, the PCB assembly needs to be small as well. There is no such thing as a standard PCB because each board is made according to a certain item.
The size of printed circuit board assembly depends on the design and the available space of the equipment or gadget. If it is a tiny gadget, then the printed circuit board will be as small as the gadget. However, when it comes to small PCB’s, it is important to remember that it will have small components as well. Because of that reason, soldering will be done with a solder that has a fine tip.
You should know that Printed Circuit Boards Assembly design is different from manufacturing it. The manufacturing process involves several different processes which includes creating and designing PCB prototype. Once the PCB is manufactured, then comes the time of assembling and designing it. For that, the electronic components need to be soldered onto it before it can be ready for use in an electronic gadget or equipment. Printed circuit board assembly design depends on the type of electronic components, circuit board and the reason for assembling and manufacturing the circuit board. If you look around, you will see that PCB assembly design has now become small and flexible.
For PCB assembly design, the following electronic components are required:
- A printed circuit board
- Soldering flux
- The type of electronic components required
- Soldering equipment which includes SMT equipment, soldering station, some inspection and testing equipment etc.
- Soldering material which includes solder bar, solder wire (this depends on the type of soldering that needs to be done)
When going for printed circuit board assembly design, there are a few things you should keep in mind so that the cost can remain low. These things are:
- The first thing is to make sure that the drawing package you are using is good so that it will be able to locate the components which you are using on the PCB.
- Start things off by placing the electronic components that needs to be placed on a specific location
- Leave a distance of at least 100 mils between each electronic component and the edge of the printed circuit board
- Try to space out the electronic components evenly vertically or horizontally. Position like/similar printed circuit board components in the same direction whenever it is possible. Make sure that the positioning of opposed parts is the same. Don’t place the electronic components at angles besides 0 or 90 degrees
- Another thing to keep in mind while doing printed circuit board assembly design is to try your best to minimize trace lengths when placing components.
Inner Layer Clearances
A minimum of 0.010″ inner layer clearance.
Printed Circuit Board
Minimum of 0.010″ (outer layers) and 0.015″ for inner layers (0.020″ preferred for inner layers). For scoring, minimum of .015 for outer layers and .020 for inner layers.
Pad Size/Annular Ring
Pad size should be at least + 0.010″ over finished hole size for vias and + 0.014″ over finished hole size for component holes. This means the annular ring (radius of the pad) should be at least .005″ for vias and a minimum of 0.007″ for component holes.
Hole Size
+/- 0.005″ Standard Spec (applies to holes up to .250″, larger holes will be routed, see Rout tolerances below)
+/- 0.005″ Custom Spec
+/- 0.003″ Custom Spec upon request 1 oz and 2 oz finished copper weight and 3 oz finished copper weight (when starting with 2 oz foil) only.
If your hole tolerances are zero (see below), then Advanced Circuits will assume that you are OK with our default hole tolerance. Our default hole tolerance is listed above.
A smaller that the minimum finished hole size; 0.004″ can be accommodated.
Printed Circuit Board Thickness:
Thickness tolerances may vary 10% (min.+/- 0.005″)
Minimum Board Thickness
Thickness Default File Review Req.
2-Layer .020″ .010″
4-Layer .020″ .015″
6-Layer .031″ .025″
8-Layer .047″ .031″
10-Layer .062″ .040″
Rout (Board Outline and Internal Cutouts)
The Outer Layer Tolerances on Standard Spec defined boards is +/- 0.010″
(+/- 0.005″ available for Custom Spec upon request)
Copper Trace Width/Spacing
Copper spacing is the minimum air gap between any two adjacent copper features. Trace width is the minimum width of a copper feature, usually traces.
For 1 oz. finished copper weight (inner layers), the minimum trace width/space is 0.005″
For 2 oz. finished copper weight (inner & outer), the minimum trace width/space is 0.006″
For 3 oz. finished copper weight (inner & outer), the minimum trace width/space is 0.010″
For 4 oz. finished copper weight (inner & outer), the minimum trace width/space is 0.012″
Trace Width/Air Gap
The greater of +/- 20% or +/- 0.002″
Soldermask Swell
This is the expansion of mask relief over pad area. Our minimum is 0.005″ over pad dimension or 0.0025″ each side. Advanced Circuits will modify files to meet the minimum dimension.
Slot Width
Minimum 0.031″ in width.
Minimum 0.031″ in width.
For smaller sizes, pricing and turn time, Contact Giltronics Associates today!