Once an alloy has been made it then needs to be fashioned into very small spherical particles, often referred to as solder powder. There are a number of different techniques for making solder powder, all of which require significant amounts of capital equipment and engineering expertise. The solder powder must then be sorted according to size, often referred to as “mesh size” or “type”. Here again a significant amount of equipment and labor is required. These sizes or types are defined in J-STD-006.
|
Type
|
Mesh
|
Particle Distribution (microns)
|
|
1
|
-100/+200
|
75 - 150
|
|
2
|
-200/+325
|
45 - 75
|
|
3
|
-325/+500
|
25 - 45
|
|
4
|
-400/+635
|
20 - 38
|
|
5
|
-500/N/A
|
15 - 25
|
|
6
|
N/A
|
5 - 15
|
The medium in which the powder is made must be inert to prevent oxidation. Similarly, powder must also be stored in an inert environment until its time of use.