Gadgets and technology are now considered a daily necessity and most of us find it hard to live without these. However, despite the wide usage of devices only a few people know that phones, tablets, televisions and computer shave one vial thing in common, that is having a printed circuit board. So we at www.pcbnet.com would like to give you an overview of how PCB assembly is done.
What is PCB Assembly?
Printed Circuit Boards or PCB are engraved plastic or metal sheets inside gadgets which serve as paths for electronic signals. When the electronic parts of a single sheet are glued or soldered into, then it becomes a printed circuit assembly (PCA).
Essential Items for Printed Circuit Board Assembly
Putting together a circuit board depends on the material requested by the client and the purpose of the item. There suppliers who offer board assembly customization like pcbnet.
Here are the basic necessities:
- Plain printed circuit board
- Soldering tools (wave soldering and SMT machines, soldering
- station, quality control and testing gear)
- Soldering materials (solder wire, bar, paste, preforms)
- Soldering flux
- Electronic pieces
Methods of Assembling Circuit Boards
- Procedure –
- Placing the electronic parts
- Applying flux
- Preheat preparation
- Removing debris and excess
- Testing the PCBA
The wave welding process is used when the electronic parts to be put contain tin or lead which can be melted. A high-temperature soak is prepared to liquefy a solder bar. The electronic items, also known as thru-hole electronics,are run through the molten solder bar via a conveyor belt to thaw the tin or lead inside. Once the process is done the PCB will be tested.
Hand soldering is a form polishing for the products of the wave soldering method. If the PCB Assembly did not pass the initial quality control tests, they are sent to the soldering station to be redone manually. This means is only used for retouch purposes or light welding requirements.
Surface Mount Technology (SMT)
Surface Mount Technology is used commonly for electronic pieces with little or no lead content. The technique utilizes a Surface Mount Device (SMD) to heat and melt the parts directly on to the printed circuit board.The metal parts without holes also known as solder pads, include lead-tin, silver and gold plated copper. Instead of solder bar, solder paste is more appropriate for SMT. Surface mount is favored by customers compared to thru-hole welding as it is cheaper, efficient, convenient and high quality. Another reason for the preference is that SMT uses lead-free soldering and is therefore safer to our health.
Things to Consider During Assembly
A lot of people don’t really pay attention to circuit board assembly but these tips might be useful when you become a customer.
Here are a few things to double check:
- Avoid excessive heat while soldering as it can cause damage or destroy the PCB and its parts. Prior to beginning, make sure that you know or the assembler knows the suitable temperature needed for the kind of materials and method of welding. The board’s endurance to heat depends on with of its cross-section
- Ensure the proper spacing of the electronic components so that they can properly transmit signals with each other. Poorly spaced components may cause problems during quality control and might delay production schedule. Also check if the items are arranged in similar direction.
- Provide a space on the top of your printed circuit board for the assembly name, revision name (optional) and parts numerals.
- Make sure that the electronic parts are soldered in accessible manner. Awkward positioning may result in uneven welding and might not pass standards.
- Surface mounted sockets are for sample use only as it will increase production cost if mass produced.
- Never work with a live circuit board. Always make sure that it is unplugged to prevent electrocution.
- Make sure that your supplier uses high-grade soldering materials and heat-resistant equipment. Cost-cutting is one of the reasons why many assemblers downgrade however it might greatly affect the output.