PCB Blogu - PCB işleme tamamlandıktan sonra kontrol edilecek öğeler

1. PCB tahtası design inspection
The following checklist covers all aspects of the design cycle, özel için eklenen öğelerle: uygulamalar. General PCB tahtası design drawing inspection items:
1) The circuit is analyzed or not, and the circuit is divided into basic units in order to smooth the signal;
2) Whether the circuit allows the use of short or isolated key leads;
3) Where must be shielded, whether it is effectively shielded;
4) Make full use of the basic grid graphics without;
5) Whether the size of the printed board is the size;
6) Whether to use the selected wire width and spacing as much as possible;
7) Whether the preferred pad size and hole size are used;
8) Whether the photographic plate and sketch are suitable;
9) Whether there are few jumper wires used; whether the jumper wires should pass through components and accessories;
10) Whether the letters are visible after assembly; whether their size and model are correct;
11) In order to prevent blistering, büyük bir bölge bakır yağmuru açılmıştır.?
12) Whether there is a tool positioning hole;

2. PCB tahtası electrical characteristics inspection items
1) Whether the influence of wire resistance, inductance and capacitance has been analyzed; especially the influence of the key voltage drop to grounding;
2) Whether the spacing and shape of the wire accessories meet the insulation requirements;
3) Whether the insulation resistance value is controlled and specified at key points;
4) Whether the polarity is adequately identified;
5) The influence of wire spacing on leakage resistance and voltage was measured from the geometrical point of view;
6) Whether the medium that changes the surface coating has been identified;

3. PCB tahtası physical characteristics inspection items
1) Whether all pads and their positions are suitable for final assembly;
2) Whether the assembled printed board can meet the Şok and vibrasyon power conditions;
3) What is the spacing of the specified standard components;
4) Whether the components that are not firmly installed or the heavier parts are fixed well;
5) Whether the heat dissipation and cooling of the heating element are correct; or whether it is isolated from the printed board and other thermal elements;
6) Whether the voltage divider and other multi-lead components are positioned correctly;
7) Component arrangement and orientation for easy inspection;
8) Whether all possible interference on the printed board and the entire printed board assembly has been eliminated;
9) Whether the size of the positioning hole is correct;
10) Whether the tolerance is complete and reasonable;
11) Control and sign off the physical properties of all coatings;
12) Whether the ratio of the diameter of the hole to the lead wire is within the acceptable range;

4. PCB tahtası mechanical design factors
Although the printed board supports components mechanically, tüm cihazın yapısal bir parças ı olarak kullanılamaz. Bastırma tabağının kenarında, en azından her 5 santim belirli destek için. The factors that must be considered in the selection and design of printed boards are as follows;
1) The structure of the printed board - size and shape.
2) The type of mechanical accessories and plugs (seats) required.
3) The adaptability of the circuit to other circuits and environmental conditions.
4) Consider mounting the printed board vertically or horizontally depending on factors such as heat and dust.
5) Some environmental factors that need special attention, sıcaklık patlaması gibi, ventilasyon, shock, vibration, aşağılık. Dust, tuz spray ve radyasyon.
6) Degree of support.
7) Hold and fix.
8) Easy to take off.

5. Installation requirements for printed circuit boards
It should be supported at least within 1 inch of the three edge edges of the printed board. Pratik deneyimlere göre, 0'nın kalınlığıyla basılmış tahtaların destek noktalarının yer alanı.031-0.062 inç en azından 4 inç olmalı; 0'dan fazla kalınlığıyla yazılmış tahtalar için.093 santim, destek noktaları en az 4 santim olmalı.. 5 inç. Bu ölçü almak basılı tahtın güçlüğünü arttırır ve basılı tahtın mümkün kaynaklarını yok eder.. Bastırılmış bir tahta genelde yükleme teknolojisini karar vermeden önce bu faktörleri düşünmeli..
1) The size and shape of the printed board.
2) Number of input and output terminals.
3) The available equipment space.
4) Desired ease of loading and unloading.
5) The type of installation accessories.
6) The required heat dissipation.
7) Required shieldability.
8) The type of circuit and its relationship with other circuits.

6. Dial-out requirements for printed boards
1) No printed board area for mounting components.
2) The influence of plugging tools on the installation distance between two printed boards.
3) The mounting holes and slots should be specially prepared in the design of the printed board.
4) When the plug-in tool is to be used in the equipment, Özellikle büyüklüğü.
5) A plug-in device is required, Genelde nehirlerle yazılmış tahta toplantısına.
6) In the mounting frame of the printed board, Özel tasarımlar, yükleyen ışıklar gibi.
7) The adaptability of the plugging tools used to the size, Bastırılmış tahtın şekli ve kalınlığı.
8) The cost involved in using plugging and unplugging tools includes both the price of the tool and the increased expenditure.
9) In order to tighten and use plug-in tools, ekipmanın içerisine belirlenmesi gerekiyor..

7. PCB tahtası mechanical considerations
Substrate properties that have a significant impact on printed circuit assemblies are: water absorption, sıcaklık genişlemenin koefiksiyonu, sıcak özellikleri, fleksik gücü, etkisi gücü, tensile strength, Güçlü ve sertlik. Bütün bu özellikler de basılı tahta yapısının ve basılı tahta yapısının üretimliliğine etkiler.. Çoğu uygulamalar için, the printed circuit board's dielectric backing is one of the following:
1) Phenolic impregnated paper.
2) Acrylic-polyester impregnated glass mats with random arrangement.
3) Epoxy impregnated paper.
4) Epoxy impregnated glass cloth.
Her substrat yangın geri çekici veya yakıcı olabilir.. Yukarıdaki 1, 2, 3 vurulabilir.. Metalize delik için genelde kullanılan materyal, basılmış tahtalar epoksi camlı elbisedir.. Onun boyutlu stabillik yüksek yoğunluk devreleri için uygun., metal deliklerinde kırıkların oluşturduğunu. Bir epoksi-cam laminatların zorluğu sıradan basılmış tahtaların kalınlık alanına vurmak zordur., Bu nedenle tüm delikler genelde boğulmuş ve bir kopya mili operasyonu basılı tahta şeklini oluşturmak için kullanılır.

8. PCB wire spacing
The conductors must be spaced to eliminate voltage breakdown or arcing between adjacent conductors. Spacing is variable and depends primarily on the following factors:
1) Peak voltage between adjacent wires.
2) Atmospheric pressure (working height).
3) Coating layer used.
4) Capacitive coupling parameters.
Kritik impedans komponentleri veya yüksek frekans komponentleri genellikle kritik fazla gecikmelerini azaltmak için birbirine yaklaştırılır.. Birleşmeyi engellemek için değiştirme ve etkileyici komponentler ayrılmalıdır; İşletici sinyal kabloları doğru açılarda doğru şekilde çalışmalı; Manyetik alan hareketi yüzünden elektrik gürültü üreten komponentler fazla vibraciya engellemek için ayrılmalı veya sert yüklenmeli.

9. PCB tahtası kablo örneki inspection
1) Whether the wire is short and straight without sacrificing function;
2) Whether the limitation of wire width is complied with;
3) Check whether the distance between wires, kablolar ve delikler arasında, and between wires and pads must be guaranteed;
4) Whether the parallel arrangement of all wires (including component leads) is relatively close is avoided;
5) Whether acute angles (90°C or less) are avoided in the PCB tahtası wire pattern.