There are many kinds of electronic connectors, but the manufacturing process is basically the same. The general situation can be divided into four stages: Stamping, Plating, Molding and Assembly.
1 stamping
The manufacturing process of electronic connectors generally begins with a stamped pin. Through large-scale high-speed punches, electronic connectors (pins, terminals) are stamped from thin metal strips. One end of the large-volume metal belt is fed into the front end of the punching machine, and the other end is wound into the reeling belt through the hydraulic workbench of the punching press. The metal belt is pulled out by the reeling belt and rolled up to punch out the finished product.
2 Plating
Terminals and pins shall be sent to the plating section after stamping. At this stage, the connector's electronic contact surface will be plated with various metal coatings. The twisting, chipping or deformation of the pin occurs during the insertion of the punched pin into the plating apparatus. Through the detection techniques described in this article, such quality defects are easily detected.
However, for most machine vision system suppliers, many quality defects that occur in the electroplating process also belong to the “forbidden zone” of the inspection system. Electronic connector manufacturers want the inspection system to be able to detect various inconsistent defects such as fine scratches and pinholes on the plated surface of the connector pin. Although these deficiencies are easily identifiable with other products (eg, aluminum can bottom covers or other relatively flat surfaces), visual inspection systems are difficult to obtain due to the irregular and angular surface design of most electronic connectors. An image sufficient to identify these subtle defects.
Because some types of pins need to be plated with multiple layers of metal, manufacturers also want the inspection system to be able to distinguish the various metal coatings to verify that they are in place and in the right proportions. This is a very difficult task for a vision system using a black-and-white camera because the gray levels of the images of different metal coatings are virtually the same. Although the camera of the color vision system can successfully resolve these different metal coatings, the problem of lighting difficulties still exists due to the irregular angles and reflective effects of the coating surface.
3 Injection molding
The plastic connector of the electronic connector is made during the injection molding stage. The usual process is to inject the molten plastic into the metal film and then rapidly cool it. Short shots occur when molten plastic fails to completely fill the film, a typical defect that needs to be detected during the injection molding stage. Other defects include the filling or partial blockage of the receptacles (the receptacles must remain clear and clean for proper insertion with the pins during final assembly). Due to the fact that the use of backlight can easily identify the leakage of the cartridge holder and the jamming of the connector hub, a machine vision system for quality inspection after injection molding is relatively simple and easy to implement.
4 Assembly
The final stage in the manufacture of electronic connectors is assembly of finished products. There are two ways to connect the plated pins with the injection box seats: separate plug or combination plugs. Individual plugging refers to inserting one pin at a time; a combined plug inserts multiple pins at the same time with the cassette holder. Regardless of the type of patching method used, manufacturers are required to detect all pins in the assembly stage for missing and correct positioning. Another type of routine inspection task is related to the measurement of the spacing on the mating surface of the connector.