How Are Components Assembled onto a PCB During Fabrication?

Components Assembled onto a PCB During Fabrication

Whether you’ve ever disassembled your cellphone or opened up your TV remote, you’ve seen the green-looking circuit board that connects all of the components together. smt circuit board are the heart of electronic devices, ensuring they communicate with each other, and providing an electrical outlet for all of the device’s functions. The assembly process for PCBs consists of several stages, each of which contributes to the final product’s functionality and reliability.

The first step is designing the PCB. This is typically done by a client’s in-house engineering team, but if they don’t have the capacity to do this, they can consult with the engineers at their PCB fabrication company. This is where Altest comes in, as we offer a full range of design services.

After a thorough inspection, the PCB is ready for the next stage in the assembly process. During this phase, we use a machine to apply solder paste to designated areas of the board. This is followed by a component placement process, using machines that are able to place up to 80,000 individual parts per hour. Once the component has been placed, it is transferred to the reflow soldering oven. This process heats the solder paste, allowing it to melt and fuse with the leads of the component. This makes strong, durable mechanical and electrical connections between the component and the PCB.

How Are Components Assembled onto a PCB During Fabrication?

Some components require a more delicate touch, so they’re manually inserted by hand. This is known as through-hole technology (THT), and it involves passing the conductive ‘legs’ of the component through small apertures that have been machined into the PCB at specified points. Once the legs have been inserted, they are soldered to pads on the reverse side of the PCB.

The SMT assembly process was developed to provide a more efficient way of mounting components onto PCBs. Rather than having to pass the component’s conductive ‘legs’ through drilled holes, SMT allows for components to be mounted directly to the PCB surface. This makes for a more compact and lightweight device, as well as a faster assembly time.

However, not every part is able to be soldered by this method. Some parts are too sensitive to heat, or they can experience thermal stress if moved through the soldering oven. Other issues that might make them unsuitable for SMT are their size or weight, and a low mass-to-adherence ratio. In these cases, they can be attached using a manual insertion process or by using through-hole soldering techniques.

This is why it’s so important that the component names, polarities, and orientations are clearly marked in the PCB’s assembly drawing before manufacturing begins. These details will be used to guide the automated insertion and soldering processes. Moreover, these details are also used by the inspection machines during the SMT assembly process to assess the quality of the printed solder paste. This is a crucial step in ensuring the quality of SMT boards. If the printed solder paste is found to be substandard, it will be replaced.

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