Automated optical inspection and verification during assembly was initially championed by the automotive and electronics industry, which often must assemble a large number of discrete components into a finished product.
For electronics assembly, machine vision plays a role in almost every step of the assembly process. Here the rule of 10 applies, where it costs 10 times more to correct an assembly error at each subsequent step of a manufacturing line. So, if a socket is placed on top of bad solder, but the problem isn''t found until ICT on the actual chip, then the correction will be 100 times more expensive than if the poor solder paste was detected at the very beginning. Also, by implementing machine vision into electronics assembly, you can test the components of a PCB that aren''t covered in ICT or Functional Test. Discovering that a capacitor is backwards on a PCB may not show up until a customer runs your product under certain conditions. This could result in a recall of the product, even if the issue is a one-time event.
National Instruments uses its Compact Vision System to test the assembly of Compact Vision Systems coming off its manufacturing line. The company uses ICT and functional test to ensure usability, but it also uses Vision to ensure that the gap pad (which transfers heat from the processor to the heat fins) is properly placed and that several transistors are applied correctly. If assembled incorrectly, the Compact Vision System would still perform well under normal conditions. However, we wanted to make sure that the Compact Vision System would not fail under critical conditions where ambient heat would affect the system''s performance.
In the automotive industry, product tracking plays a major role in assembly automation. By reading 2D barcodes etched into components, machine vision can ensure that the correct part is integrated into a product. In the Wheel ID System example, if the wrong wheel is placed into a lathe, $50,000 of damage to the machine and possible human injuries are possible.
Today, we''re finding machine vision in all sorts of new assembly and manufacturing applications. System costs and complexity have decreased drastically over the last few years while the speed has increased. From a short-term ROI perspective, it is economical to use machine vision during assembly to reduce scrap cost. From a long-term perspective, the benefits on final product quality and reliability are enough to position machine vision as a competitive advantage.