Before going through the main PCB assembly, a PCB goes through so many stages. In this stage, the assembly requires sophisticated machines and good practices to finish the task and produce a PCB with minimal to zero errors. Below are the different machines and tools that manufacturers use in the assembly process. Depending on the assembly process done by these manufacturers, they might actually require everything listed below.
Pick and Place Equipment
This equipment aids in the automatic placing of components in the printed circuit boards. Manufacturers use two different types of pick and place machines, the surface mount equipment and through-the-hole mounting equipment.
Stencil Printing Machine
Usually, manufacturers use a stencil-printing machine in surface mount technology. This machine deposits solder paste on the surface pads of the boards. However, the process of stencil printing seems to create problems during the Quick turn PCB assembly process. As the printed circuit boards become smaller, the efficiency of stencil printing machine decreases, putting solder paste becomes more difficult. That’s probably the main reason why an innovation in solder paste stenciling has emerged.
Solder Paste Jet Printer
This is the newest technology in the assembly industry. It eliminates the use stencils in the printing of solder paste on the circuit boards. The machine uses an ejection process, whereby it deposits solder paste on the printed circuit boards through syringe-like cartridges. It can deposit 500 droplets per second, which makes the assembly process faster than the standard stencil printing. Furthermore, it is capable of squeezing solder pastes into the smallest board in the assembly line. Another major advantage of paste jet printer is the reduction of the total production cost.
Assembly companies use these machines to solder the printed circuit board in a matter of seconds. The solder joints are reliable despite the quick process. A certain temperature is kept during this phase of the PCB assembly.
The standard practice in this stage is to coat the boards with solder mask. This mask protects the boards during the soldering process. Aside from ensuring proper masking, the spacing between surface pads should be sufficient as well.
Although machines are obsolete, some manufacturers still use them especially for assembly units that are simple and are not densely populated with electronic components.
Dip soldering Tools
These tools are the manual equivalent of soldering machines. Manufacturers use these tools in the rework process and on soldering components that are too small for the placement equipment to handle. These tools are present on surface mount technology and through the hole-mounting method.
Automatic Wiring Machines
Assembly houses use these machines if the assembly process includes wiring of the PCB boards. Some assembly manufacturers include services where the final output aren’t mere boards but complete electronic devices. This means the service includes outer casing and other accessories.
This may not be a machine but it’s still an essential tool in keeping the boards in good condition. Using a storage rack to stack boards during transit from the PCB assembly house to the packaging department is standard procedure. It keeps surfaces of the boards safe from abrasion. Abrasion may cause short-circuits once the PCBs are connected to an external electric source.
The assembly process is the second of the three major stages of PCB production. The first one is the PCB fabrication and the last one is the final testing and inspecting of the boards for errors and defects. An assembly process is as important as the other two stages in the final output.
Thus, manufacturers have to exert effort in keeping the assembly line efficient and competitive. Efficiency refers to the keeping of the work area and equipment in top condition. On the other hand, competitiveness refers to the ability of a company to retain skillful workers to operate the machines necessary to complete the assembly. Surely, the very best manufacturing firms in the industry excel in maintaining both efficiency and competitiveness – in all possible aspects.
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