Circuit board assembly is our specialty, along with cable and wire harness. The concept of Printed Circuit Board Assemply ("PCBA") may be simple: populating (placing and soldering) electronic components onto a circuit board as designed; the resulted quality of electronic assembly, however, can be different from manufacturer to manufacturer, depending on manufacturing techniques, workers skills, and quality assurance system in place.
Circuit board, or Printed Circuit Board ("PCB"), is a substrate ("support", in layman term; normally glass-epoxy material) with copper forming on surfaces, inner layers (for multi-layer board), and holes between layers. These copper formings serve as pads for components' leads to sit on and be soldered, and as paths and traces for components, as well as layers, to connect each other.
All electronic componenets can be grouped into two categories, i.e., THT and SMT. THT or Thru-hole stands for Through Hole Technology, while SMT Surface Mount Technology. The basic difference of these two is that THT components are those with leads coming through the circuit board, while SMT mounting on the surface of the board. The significance of SMT technology, however, is that it has revolutionized the electronic industry; simply put, it makes automation of assembling possible. In other words, while THT relies on traditional wave soldering and hand soldering techniques, SMT uses highly automated processing equipment for assembling so is more efficient and consistent in quality assurrance.
It is worth to mention that electronic, especially semiconductor, technology advances rapidly, resulting in components with higher and higher speed, smaller and smaller size, more and more functional, all of which, unfortunately, means more and more difficult in manufacturing. BGA (ball grid array) packages, for example, not only have many leads densely designed, but the mounting is required underneath the package. More sophisticated Equipment, higher accuracy, speed, and skills are required for this type of jobs. Building on years of experience, including continuous technology improving, GIC has established a capacity in meeting most of customer requirements.
GIC has established a Quality Management System which meets ISO 9001:2008 quality management standard and practice, including well-defined Quality Policy, Quality Objectives, and Plan for continual improvement. Upon request, a copy of Quality Manual can be provided to customer.
As for quality control, all of our products will go through several inspection check posts during production and are 100% inspected at the final inspection.
Our quality control process actually begins much earlier. Right after receiving customer POM or drawings, we first layout a process flow plan, which will include inspection check points, means, and cover areas such as materials, soldering, touch-up, visual check, optical, microscope, X-ray inspection, and final testing.
It may be easier to see how we assure your product quality by looking at our manufacturing process for a typical project.
Prior to placing components to a printed circuit board, solder paste needs to be added to those areas of the board where solder is required, typically component pads. This is achieved by our DEK Horizon 03iX or DEK Horizon 8 screen printer.
Solder paste is a paste of small grains of solder mixed with flux. It is deposited into place in a process that is very similar to a silkscreen printing process. The primary purpose of flux is to prevent the formation of metal oxides therefore help the solderability, while the adhesiveness of flux also helps components stick to the circuit board during placement and reflow processes.
Using a solder screen, called stencil, and a runner (squeegee, or roller) moving across the screen, solder paste is squeened and deposited directly onto the board and registered in the correct positions. As the screen of stencil is generated from the printed circuit board files, it has holes on the positions of the solder pads, and in this way solder is deposited only on the solder pads.
The solder paste that is deposited must be controlled to ensure the resulting joints have the right amount of solder and consistent all across, including thickness and covering pattern; this is the focal point for quality inspection. The other critical focal point is solder paste management.
We use three pick & place machines for this task, with the Essemtec CSM7100V mainly for prototyping, the state of the art Assembleon MG-1R and Yamaha YG100R Pick & Place machines handle the mass production needs, each runs up to twenty-four thousands components per hour.
During this stage of assembly process, the board with solder paste registered is then passed through the pick and place process, where the MG-1R or YG100R machine picks components from the reels or other dispensers then places them onto the correct positions of the board.
The components placed on the board are held in place by the tension of the solder paste. This should be sufficient to keep them in place provided that the board is not jolted.
The position and component information required to program the pick and place machine is derived from the printed circuit board design (placement files), enabling the pick and place programming to be considerably simple. Nevertheless, skills of the operators are important in assurance of quality, including correctly loading components and ability to spot operating errors.
This step seems simple but actually critical as soldering process requires certain thermal treatment, namely a four-stage thermal profiling (pre-heat, soak, reflow, and peak), each stage would require a combination of specific time and temperature depending on the nature of PCB board and solder paste used. We use the state of the-art KIC Explorer Profiler to help optimization therefore ensure soldering quality.
For those that hand soldering or touch-up is required, our skilled solderers would assure its quality.
If wave soldering is used, by the way, solder paste is not added to the board as the solder and flux are provided by the wave soldering machine separately.
Both manual and optical inspections will check for possible board and soldering errors including false soldering, insuficient soldering, poor joints, misplaced components, or wrong component.
If touch-up is employed, re-inspection is required and performed.
Tests including functional and electrical is usually done at client's site after the delivery of our assembled boards, for couple reasons. One is about security, meaning to minimize the exposure of customer's final design. The other reason is that customers usually have more sophisticated testing equipment setup, which makes it more convenient and precise for testing.
It doesn't mean, however, we can ignore this important step; just the opposite. For one, we do offer testing in our shop with fixture and necessary means customers may provide. For another, we would respond promptly or even participate in testing at client's site.
The other method and more important step is listening to customers, which includes getting feadbacks from clients and quick response.