PCB board design inspection
The following checklist covers all aspects of the design cycle, with additional items for special applications.
General PCB board design drawing inspection items:
1) Has the circuit been analyzed, and has it been divided into basic units to ensure smooth signal flow?
2) Does the circuit allow for the use of short or isolated key leads?
3) Have areas requiring shielding been identified, and has effective shielding been implemented?
4) Have the basic grid graphics been fully utilized?
5) Is the size of the printed board appropriate for its intended use?
6) Have the selected wire widths and spacing been utilized to the fullest extent possible?
7) Are the preferred pad sizes and hole sizes being used?
8) Are the photographic plates and sketches suitable for the design?
9) Are there minimal jumper wires being used, and have they been appropriately routed through components and accessories?
10) Are the labels legible after assembly, and are their sizes and models correct?
11) Have large areas of copper foil been opened to prevent blistering?
12) Are tool positioning holes present?
PCB board electrical characteristics inspection items
1) Analyze the influence of wire resistance, inductance and capacitance; especially the impact of key voltage drop to grounding;
2) Ensure that spacing and shape of wire accessories meet insulation requirements;
3) Control and specify insulation resistance value at key points;
4) Ensure adequate polarity identification;
5) Measure the influence of wire spacing on leakage resistance and voltage from a geometrical perspective;
6) Identify any medium that alters surface coating.
PCB board physical characteristics inspection items
1) Ensure all pads and positions are suitable for final assembly;
2) Confirm assembled printed board can withstand shock and vibration power conditions;
3) Determine spacing of specified standard components;
4) Verify proper installation of components and secure heavier parts;
5) Ensure correct heat dissipation and cooling of heating element;
6) Confirm correct positioning of voltage divider and multi-lead components;
7) Arrange components for easy inspection;
8) Eliminate all potential interference on printed board and assembly;
9) Verify correct size of positioning holes;
10) Ensure complete and reasonable tolerance;
11) Control and approve physical properties of all coatings;
12) Ensure hole diameter to lead wire ratio is within acceptable range.
PCB board mechanical design factors
Although the printed board mechanically supports components, it should not be used as a structural part of the device. Support points should be placed at least every 5 inches on the edge of the board. Considerations for selecting and designing printed boards include:
1) Size and shape of the printed board;
2) Type of mechanical accessories and plugs required;
3) Adaptability of the circuit to other circuits and environmental conditions;
4) Mounting orientation depending on factors such as heat and dust;
5) Special attention to environmental factors such as heat dissipation, vibration, humidity, etc.;
6) Degree of support needed;
7) Secure mounting and fixing;
8) Ease of removal.
Installation requirements for printed circuit boards
Printed boards should be supported within 1 inch of the three edge edges. Spacing of support points should be at least 4 inches for boards with thickness of 0.031-0.062 inches, and 5 inches for boards with thickness over 0.093 inches. Factors to consider before deciding on mounting technology include:
1) Size and shape of the board;
2) Number of input and output terminals;
3) Available equipment space;
4) Desired ease of loading and unloading;
5) Type of installation accessories;
6) Required heat dissipation;
7) Shieldability needed;
8) Relationship of the circuit with other circuits.
Dial-out requirements for printed boards
1) No printed board area should be used for mounting components;
2) Consideration of plugging tools on installation distance between boards;
3) Design of mounting holes and slots;
4) Size consideration of plug-in tools;
5) Use of rivets to secure plug-in devices to the board;
6) Inclusion of load bearing flanges in the mounting frame;
7) Adapting plugging tools to board size, shape, and thickness;
8) Consideration of costs involved in using plugging tools;
9) Accessibility to inside of equipment for tool tightening and usage.
PCB board mechanical considerations
Substrate properties such as water absorption, coefficient of thermal expansion, flexural strength, impact strength, and more, impact the functionality and productivity of printed board structures. Dielectric backing materials include phenolic impregnated paper, acrylic-polyester impregnated glass mats, epoxy impregnated paper, and epoxy impregnated glass cloth. Considerations for mounting printed boards include dimensional stability and ability to reduce cracks in metallized holes.
PCB wire spacing
Conductors must be spaced to prevent voltage breakdown or arcing. Spacing depends on factors such as peak voltage, atmospheric pressure, coating layer, and capacitive coupling parameters. Components with critical impedance or high frequency should be close together to reduce delays, while transformers and inductive components should be isolated to prevent coupling and noise.
PCB board wire pattern inspection
1) Ensure wire is short and straight without compromising function;
2) Adhere to limitations on wire width;
3) Maintain proper distances between wires, mounting holes, and pads;
4) Avoid parallel arrangement of wires and close proximity with component leads;
5) Avoid acute angles in wire patterns on the PCB board.
The following checklist covers all aspects of the design cycle, with additional items for special applications.
General PCB board design drawing inspection items:
1) Has the circuit been analyzed, and has it been divided into basic units to ensure smooth signal flow?
2) Does the circuit allow for the use of short or isolated key leads?
3) Have areas requiring shielding been identified, and has effective shielding been implemented?
4) Have the basic grid graphics been fully utilized?
5) Is the size of the printed board appropriate for its intended use?
6) Have the selected wire widths and spacing been utilized to the fullest extent possible?
7) Are the preferred pad sizes and hole sizes being used?
8) Are the photographic plates and sketches suitable for the design?
9) Are there minimal jumper wires being used, and have they been appropriately routed through components and accessories?
10) Are the labels legible after assembly, and are their sizes and models correct?
11) Have large areas of copper foil been opened to prevent blistering?
12) Are tool positioning holes present?
PCB board electrical characteristics inspection items
1) Analyze the influence of wire resistance, inductance and capacitance; especially the impact of key voltage drop to grounding;
2) Ensure that spacing and shape of wire accessories meet insulation requirements;
3) Control and specify insulation resistance value at key points;
4) Ensure adequate polarity identification;
5) Measure the influence of wire spacing on leakage resistance and voltage from a geometrical perspective;
6) Identify any medium that alters surface coating.
PCB board physical characteristics inspection items
1) Ensure all pads and positions are suitable for final assembly;
2) Confirm assembled printed board can withstand shock and vibration power conditions;
3) Determine spacing of specified standard components;
4) Verify proper installation of components and secure heavier parts;
5) Ensure correct heat dissipation and cooling of heating element;
6) Confirm correct positioning of voltage divider and multi-lead components;
7) Arrange components for easy inspection;
8) Eliminate all potential interference on printed board and assembly;
9) Verify correct size of positioning holes;
10) Ensure complete and reasonable tolerance;
11) Control and approve physical properties of all coatings;
12) Ensure hole diameter to lead wire ratio is within acceptable range.
PCB board mechanical design factors
Although the printed board mechanically supports components, it should not be used as a structural part of the device. Support points should be placed at least every 5 inches on the edge of the board. Considerations for selecting and designing printed boards include:
1) Size and shape of the printed board;
2) Type of mechanical accessories and plugs required;
3) Adaptability of the circuit to other circuits and environmental conditions;
4) Mounting orientation depending on factors such as heat and dust;
5) Special attention to environmental factors such as heat dissipation, vibration, humidity, etc.;
6) Degree of support needed;
7) Secure mounting and fixing;
8) Ease of removal.
Installation requirements for printed circuit boards
Printed boards should be supported within 1 inch of the three edge edges. Spacing of support points should be at least 4 inches for boards with thickness of 0.031-0.062 inches, and 5 inches for boards with thickness over 0.093 inches. Factors to consider before deciding on mounting technology include:
1) Size and shape of the board;
2) Number of input and output terminals;
3) Available equipment space;
4) Desired ease of loading and unloading;
5) Type of installation accessories;
6) Required heat dissipation;
7) Shieldability needed;
8) Relationship of the circuit with other circuits.
Dial-out requirements for printed boards
1) No printed board area should be used for mounting components;
2) Consideration of plugging tools on installation distance between boards;
3) Design of mounting holes and slots;
4) Size consideration of plug-in tools;
5) Use of rivets to secure plug-in devices to the board;
6) Inclusion of load bearing flanges in the mounting frame;
7) Adapting plugging tools to board size, shape, and thickness;
8) Consideration of costs involved in using plugging tools;
9) Accessibility to inside of equipment for tool tightening and usage.
PCB board mechanical considerations
Substrate properties such as water absorption, coefficient of thermal expansion, flexural strength, impact strength, and more, impact the functionality and productivity of printed board structures. Dielectric backing materials include phenolic impregnated paper, acrylic-polyester impregnated glass mats, epoxy impregnated paper, and epoxy impregnated glass cloth. Considerations for mounting printed boards include dimensional stability and ability to reduce cracks in metallized holes.
PCB wire spacing
Conductors must be spaced to prevent voltage breakdown or arcing. Spacing depends on factors such as peak voltage, atmospheric pressure, coating layer, and capacitive coupling parameters. Components with critical impedance or high frequency should be close together to reduce delays, while transformers and inductive components should be isolated to prevent coupling and noise.
PCB board wire pattern inspection
1) Ensure wire is short and straight without compromising function;
2) Adhere to limitations on wire width;
3) Maintain proper distances between wires, mounting holes, and pads;
4) Avoid parallel arrangement of wires and close proximity with component leads;
5) Avoid acute angles in wire patterns on the PCB board.
