PCB科技 - PCBA檢驗過程/檢驗科技 ∕ 流程概述

PCBA檢查流程/inspection technology∕process overview
The overall process of PCBA 檢查流程!
Note: The detection equipment and installation layout corresponding to various detection methods are generally divided into online (in series in the pipeline) and offline (independent of the pipeline). 在以下條件下, the online inspection process layout should be used first to improve the inspection efficiency and the efficiency of assembly line operations:
2 檢測科技/process overview
The inspection technology applicable to 電路板裝配產品 can be mainly divided into: solder paste coating inspection SPI, 自動光學檢測AOI, 自動X射線檢查AXI, 線上檢查集成電路T, 飛針檢查FP, 和功能檢查FT.
1 Automatic optical inspection
檢測原理: When the AOI detector automatically detects the 印刷電路板, 機器自動掃描 印刷電路板 通過攝像機, 收集影像, 將檢測到的焊點與資料庫中的合格參數進行比較, 圖像處理後, 檢測上的缺陷 印刷電路板, 並使用顯示器或自動標記顯示器/mark the defects for repair by maintenance personnel
Functions and characteristics of detection:

1) Automatic optical inspection (AOI) uses high-speed and high-precision visual processing technology to automatically detect various mounting errors and soldering defects on 印刷電路板 董事會. 印刷電路板 板的範圍從細間距高密度板到低密度大尺寸板, and can provide online inspection solutions to improve production efficiency and welding quality;
2) By using AOI as a tool to reduce defects, 在裝配過程的早期階段發現並消除錯誤，以實現良好的過程控制. 早期檢測缺陷將避免將不合格產品送至後續裝配階段. AOI將降低維修成本，避免無法修復的報廢 印刷電路板s.
2. AOI inspection content:
1) Check the top surface reflow soldering components;
2) Check the through-hole components before wave soldering;
3) Check the through holes and SMD/SMC after wave soldering;
4) Check the connector pins before press-fitting
5) Check the connector pins after press-fitting.
3. 檢查監測點的設定.
AOI可以應用於生產線上的多個檢查點, 但主要有3個檢查點, 即錫膏印刷後, 回流焊前, and after reflow soldering
1) After solder paste printing. 錫膏印刷工藝是否符合要求, 印刷缺陷引起的焊接缺陷將大大减少. Typical printing defects include the following:
Insufficient solder paste on the pad; too much solder paste on the pad; poor overlap of the solder paste on the pad; solder bridges between the pads.
該檢查點的檢查最直接地支持過程跟踪. The quantitative process control data at this stage includes printing offset and solder volume information and qualitative information about printed solder paste
2) Before reflow soldering. 該檢查點的檢查在部件放置完成後和 印刷電路板 送至回流爐. 這是一個典型的檢查點，在這裡可以發現錫膏印刷和機器放置的大多數缺陷. 在此位置生成的定量過程控制資訊提供了有關高速晶片機和精細間距元件放置設備校準的資訊.
該資訊可用於修改元件放置數據或訓示放置機器需要校準. 該檢查點的檢查符合過程跟踪的目標.
3) After reflow soldering. 該檢查點在SMT過程的最後一步進行檢查. 它是AOI最重要的檢查點, 並且可以找到所有裝配錯誤. 回流焊後檢查提供了高度的安全性，可以識別錫膏印刷引起的錯誤, 組件放置, 和回流過程.
儘管每個檢查點可以檢測出具有不同特徵的缺陷, AOI檢查設備應放置在能够儘快識別和糾正大多數缺陷的檢測位置.
3. Online Testing (ICT)
1. Detection principle.
ICT檢測主要是檢測開路, 短路, 和所有組件的焊接 PCBA通過接觸 印刷電路板 與檢測探頭組裝. 並且能够準確地識別 PCBA(（對部件的焊接檢測具有很高的識別能力）).
2. Testing functions and characteristics:
1) Within a few 證券交易委員會onds, 可以檢測組裝電路板上的所有組件：電阻器, 電容器, 電感器, 電晶體, FETs (field effect tubes), LEDs (light emitting diodes), 普通二極體, 齊納二極體, 光學蓮藕, IC, 等., whether they meet the design requirements;
2) Be able to find out the defects of the process in advance, 例如短路, 開路, 缺失零件, 顛倒, 錯誤的零件, 空焊, 等., and feedback to the improvement of the process;
3) The above detected fault or error information can be printed out through the printer. 該資訊主要包括故障位置, 零件的標準值, 以及檢測值，以供維護人員參攷. 它可以有效地减少人員對產品技術的依賴, 無需瞭解產品線, and also have the ability to maintain;
4) The defect information can be detected and statistically output, 生產管理人員可以對其進行分析，找出各種缺陷的原因, 包括人為因素, 這樣他們就可以解决, 改進, 並一一更正, 從而改善 PCBA 製造能力.
3. Flying probe detection (FP)
1. Detection principle:
1) The open circuit detection principle of flying probe detection is the same as that of ICT. 兩個探頭同時連接到網絡末端以通電, 將獲得的電阻與設定的開路電阻進行比較，以判斷電路是否開路. But the principle of short-circuit detection is different from that of ICT
2) Due to the limited detection probes (usually 40032 probes) and the number of points contacting the board surface at the same time is very small (corresponding to 40032 points), 如果使用電阻測量方法量測所有網絡之間的電阻, 然後有N個網絡用於 印刷電路板, 需要執行N2/2檢查, 探頭移動速度有限, 一般10分/秒至50分/sec, 囙此，飛行探針檢測的效率相對較低.