PCBA(プリント回路基板アセンブリ) stands at the heart of modern electronic devices, すべてがコンパクト, 効率的, 私たちが今日使用している信頼性の高い電子製品もそれに依存しています. しかし一部の初心者にとっては, 彼らはPCBAについてあまり知りません, so we decided to write an article like this to comprehensively introduce PCBA including its types, production process, PCBA testing methods, 等. その定義から始めましょう.
What Is PCBA?
PCBA refers to the finished board after all the electronic components are soldered onto a printed circuit board (PCB). And we call the process of assembling components on the circuit board as PCB Assembly, which plays a very significant role in the manufacturing of electronic devices. The main purpose of a PCBA is to act as a platform that supports the necessary electronic components to work harmoniously, so as to achieve the intended functions of the electronic device.
Types of PCBAs
According to the assembly techniques, we can divide PCBAs into 3 タイプ: SMT PCBAs, through-hole assembled PCBAs, and mixed-technology PCBAs.
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SMT PCBA
SMT PCBAs, 名前が示すように, 使用する 表面実装技術 where the components are mounted directly onto the PCB and connected to the traces through reflow soldering. SMT components are comparatively small and can be assembled on both sides of the PCB to achieve compact designs. PCBAs with surface mount assembled parts are used in most electronic products due to their enhanced performance and the ability to save space. And BGA assembly is particularly important for high-density connections in applications such as processors and memory chips.
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Through-hole assembled PCBAs
Through-hole assembled PCBAs refer to printed circuit boards where electronic components are mounted using the through-hole technology. In this assembly method, components have leads that are passed through holes drilled through the PCB and soldered on the other side. This assembly technique comes with benefits such as improved mechanical joints and fast prototyping. しかしながら, they are not suitable for small and dense PCB designs as スルーホール部品 are relatively larger in size than the Surface Mount Devices (SMD).
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Mixed-technology Printed Circuit Board Assembly
In mixed-technology printed circuit board assembly, through-hole and surface mount components are used on the same board. This kind of PCBA capitalizes on the benefits associated with both through-hole and surface mount techniques of assembly. It is usually applied where the design involves the usage of through hole connection which is mechanically secure and surface mount technology which affords density.
Differences between PCBA and PCB
PCB と PCBA は非常によく似た 2 つの用語です, 電子業界の初心者はよく混乱します。. では、PCBとPCBAの違いは何ですか?
PCB は基礎プラットフォームとして機能します, 非導電性基板と、さまざまなコンポーネントを電気的に接続する導電性経路で構成されます。, ただし、電子部品は取り付けられていません. 本質的には、コンポーネントの追加を待つ空白のボードです。. PCBA, 一方, 製造プロセスの次のステップを表します, 抵抗などの電子部品, コンデンサ, そして 集積回路(IC) are soldered onto the PCB, 電子機器ですぐに使用できる完全に組み立てられた機能的な回路基板を作成します。.
Below we have listed a table that lists the main differences between PCB and PCBA:
| 特徴 | PCB | PCBA |
| 意味 | Bare board with conductive tracks | Completed board with components |
| コンポーネント | No components attached | Components soldered onto the board |
| 機能性 | Cannot function on its own | Ready for use in electronic devices |
| 複雑 | Simpler | より複雑な |
| 料金 | より低い | より高い (includes components and assembly) |
| テスト | Basic electrical tests | Functional and quality tests |
| Time to produce | Shorter | Longer (includes assembly time) |
PCBA Process: ステップバイステップガイド
The PCBA process involves several crucial steps to assemble a functional printed circuit board:
- はんだペーストステンシル:The process starts with the deposition of solder paste on specific areas on the circuit board where components will be soldered. This paste is a composition of tin balls mostly but contains a little silver and copper together with the flux that aids in melting and fixing on the board.
- ピックアンドプレース: Electronic components and SMDs are placed onto the board using the manual tweezer and sometimes machines to place the components in the right position.
- リフローはんだ付け: During the リフローはんだ付け, the board is exposed to a conveyor belt of the oven which can reach up to 250°C where the solder paste melts and firms up the components on the board when it cools.
- 検査と品質管理: After reflow, inspection is performed to check if there are any connection defects or misconnections, making sure that all the leads are well and tightly soldered on the board.
- スルーホール部品の挿入: Some circuit boards also need to use through-hole components. These components require holes in the PCB to get signals from one layer to another. This step can be done by manual and by machine.
- 手動およびウェーブはんだ付け: 個々の PTH コンポーネントの挿入には手動はんだ付けが使用されます, which is a time-consuming process. Another method is wave soldering where the board is passed over the molten solder and the components are fixed. それにもかかわらず, wave soldering is not friendly to use with double-sided PCBAs.
参考文献: ウェーブはんだ付けvs. リフローはんだ付け: 違いは何ですか? - テストと最終検査: The last step involves a rigorous functional testing where a product is tested in real operating conditions: different options of Voltage, 信号, currents, 等, in order to identify any problems that might occur.
Popular PCBA Testing Methods
- インサーキットテスト (ICT):It is a commonly used testing technique involving the use of a bed of nail fixtures that contains multiple contact points to touch several points on the board all at once. This technique includes the identification of the presence, オリエンテーション, and basic operations of individual components. As much as ICT is fast and very efficient compared to others, it deals with the use of customized fixtures for each layout of the boards.
- Flying Probe Testing (FPT): に FPT, the probes are used in a movable manner to test various points on the board. Compared to ICT, it is more flexible because it doesn’t require custom fixtures. それにもかかわらず, FPT is relatively slower than ICT in mass-scale testing.
- 自動光学検査 (あおい): It is an equipment system that uses a high-resolution camera along with an image processor to look for defects in the circuit board like missing components, wrong component placements, and solder problems. あおい is an efficient and non-contact inspection, but sometimes it may miss internal or hidden flaws.
- Automated X-ray Inspection (AXI):In this testing method, X-rays are used in order to check internal aspects of components and solder joints. This method is particularly valuable in the assessment of BGAs (ボールグリッドアレイ) and other hidden connections. While AXI costs more than AOI, the range of inspection is much wider.
- 機能テスト (FCT): It is conducted in order to assess the functionality of the board by mimicking the actual operating environment. FCT can be a very time-consuming process, which has to be done with custom test equipment. Event though, it is necessary as it ascertain that the board is operating as was designed to.
How to Choose the Best PCBA Manufacturer?
Choosing the best PCBA manufacturer is crucial to ensuring the quality and reliability of the products. Below we list key factors that should be considered when finding your PCBA manufacturing partner:
- 品質保証
The quality is always the primary concern. In selecting a PCBA manufacturer, we must consider if they meet the standard, if they have complied with a certification like ISO9001, and if they have a strict quality control system.
- 技術的熟練度
In order to work on your project, a PCBA manufacturer must be capable of meeting the specifications of your project. This comprises their skill in handling various technologies of the PCBA such as through-hole and surface-mount technologies; their ability to handle the various components and materials, and their manufacturing capabilities as well.
- 価格設定
Though quality is crucial, one cannot overlook the cost factor in manufacturing the PCBA. It is always ideal for us to work with a PCBA manufacturer who provides affordable prices and quality products at the same time.
- 制作タイムライン
Another important consideration is the time that it takes to produce the PCBA. この点について, it is essential to choose a manufacturer that is well capable of working within your time frame to deliver high-quality boards.
PCBA プロジェクトの成功のために MOKO テクノロジーと協力してください
中国の大手PCBAメーカーとして, MOKO Technology は、競争力のある価格で高品質の回路基板を提供することに専念しています。, 透明性を重視し、隠れた手数料は一切かかりません. 私たちはさまざまな PCB アセンブリ技術に精通しています, 当社の最先端の施設は、お客様の多様なニーズに対応できるように設計されています。. We have a stringent quality control process to ensure the quality of each product. お問い合わせください to start your project now!
FAQs about Printed Circuit Board Assembly
What factors affect PCBA cost?
Major factors affecting PCBA cost include the size of the board, レイヤー数, 複雑, number of components, volume of production, type of tests that need to be done, and the time it takes to complete. Higher complexity and shorter turnaround time usually lead to the higher cost.
What’s the difference between SMT and through-hole assembly?
SMT is the process that places components on the surface of the PCB while through-hole involves insertion of the components through drilled holes on the PCB and soldering on the other side of the board. The SMT enables a higher component density and the technique is more widely used in modern PCBAs.
Can I use both through-hole and surface-mount components on the same PCBA?
はい, through-hole and surface-mount components can be used on the same PCBA, in this way, the PCBA benefits from the strong mechanical strength of through-hole and the high density of surface-mount technology.
What are common PCBA defects?
Some of the common defects are solder bridges, cold or dry solder joints, bad component position, 不足しているコンポーネント, wrong polarity, and components getting damaged due to heat during soldering.
How does MOKO Technology ensure the quality of Printed Circuit Board Assembly?
The quality control of MOKO Technology’s PCBA starts with careful designs. また, we have a standardized production process and implement a series of testing methods to ensure the utmost quality of each board.
Can PCBAs be repaired if they fail?
ほとんどの場合, はい, they can be repaired. しかしながら, some severely damaged PCBAs can not be repaired. 一般的に, repairing PCBAs involves replacing components, and fixing soldering issues or damaged traces.
