Before discussing the benefits of fixturing in Surface Mount Technology (SMT) it is worthwhile to clearly define some terms that relate to the concept of using fixtures in a manufacturing process. Fixturing and its similar concepts were originally used in woodworking. It then become commonplace in the world of engineering and manufacturing as a way to produce the exact same product multiple times.
Fixtures, Jigs and Templates have been used in woodworking and manufacturing for many years. The concepts are often confused, and are actually often used interchangeably. We are going to use the very simple example of replicating a housed or car key to explain the three components in the process and then zero in on how each of them are used in Surface Mount Process for Creating Printed Circuit Boards (PCB's)
A Jig is a tool custom designed for the express purpose of directing or controlling the location or motion of another tool. In our example, we clamp a master key into one side of a machine that will then trace the master and produce an exact replicate. Machine tool manufacturers have inventories of jigs they use when they need to create exact replicates of a product. Likewise, Printed Circuit Board Manufacturers now have libraries of PCB "jigs" they can reuse as required.
The Template in our rudimentary example, is the original key. A template may be the actual sample being replicated as in the case of our key. They may be also a model of something we want to create or a drawing that can be cut out like when installing a door knob. Templates can take many forms. In the case of a Printed Circuit Board, a template or schematic may be placed on a rectangular board and then cut into the desired shape using a template as show in this example. A typical PCB manufacturer also has libraries full of "templates" they refer to as footprints or schematics.
The Fixture in our example would be the clamping device that holds the key in exactly the right position every time without fail. (Well, maybe not every time because sometimes the key just does not work!) Fixtures also can take many different shapes and forms. Here is an example of a single board fixture being used to mount a board for soldering.
This brings us to fixturing in the world of Surface Mount Technology. Most mid volume Surface Mount companies today are use fixtures that hold multiple boards in place for picking and placing.
5 Benefits of Fixturing in Surface Mount Technology:
1. Flexibility - Boards can be mounted in many different ways
2. Ease of Replication - Once mounted, multiple iterations and processes may be performed
3. Quality Control - Because the processes are done exactly the same each time, the quality is dramatically improved
4. Reduced Waste - Once the process is defined, it works the same each time so there is minimal waste
5. Reduced Cost - All of the above result in lower costs to the electronics manufacturer and these cost savings can be passed on to the customers
Statement: This post is only the personal view of the author and does not represent the opinions of ALLPCB.com.