1. When PCB boards replaced the slow and cumbersome manual wiring systems of the past, they introduced a novel technology that allowed electronics engineers to assemble complex electronic systems relatively quickly, easily, and inexpensively.
2. As a result, the electronics industry has invested significant effort into making these boards as easy to manufacture as possible.
3. Substantial capital has been directed towards design software to aid in the design, manufacture, assembly, inspection, and testing of printed circuit boards.
4. These advancements enable design engineers to invest in improved processes that reduce part size, support surface mount (SM) and ball grid array (BGA) packages, and decrease PCB line width and size.
5. Other features include enhanced card inspection with X-ray imaging.
6. The gradual incorporation of artificial intelligence (AI) into design software means that some critical tasks, such as component placement on PCB boards, are still manually controlled by layout engineers.
7. As a design engineer, you need to understand part placement to ensure design stability.
8. The evolution of component placement throughout your design career has changed significantly.
9. I began by designing low-density, flexible circuit boards using the wire wrap method.
10. Later, I had the opportunity to work with printed circuit boards, starting with simple designs (through-hole parts, reasonably sparse layouts) and progressing to more complex SMT parts.
11. This means that the manual soldering process following the PCB board design was also relatively simple at the beginning.
12. However, as you advance in your career, you will work with high-density PCB boards featuring tiny SMT, BGA, and QFN parts in delicate design environments, with fine wires and components placed in small spaces.
13. This adds a new variable to the “assembly” process that design engineers must address.
14. For some, this might be an unpleasant surprise, but it’s important to be prepared.
15. Placing components on a PCB can be done in various ways.
16. Design engineers should consider specific assembly techniques, such as machine assembly, manual assembly, or hybrid assembly (manual and infrared oven), before starting the PCB design.
17. These choices often depend on cost, time, volume, and the nature of the design.
18. Several factors drive the process of placing parts on a PCB board, including signal length, ease of assembly, and ease of testing.
19. Below, we will explore the unique aspects of each assembly method.
20. **Conference Types and DFA Important Guidelines**
21. Throughout the electronics industry, you will encounter various assembly methods.
22. It is essential to understand each process, its benefits, typical uses, and how to optimize the DFA process to align with the final PCB production.
23. **PCB Board Component Placement in Machine Assembly**
24. Machines are often used for mass production assembly, and the component footprint on the PCB must adhere to design rules.
25. Machine assembly lacks the flexibility that human operators provide and relies on expensive industrial machines to complete the PCB assembly according to the rules.
26. This method is usually reserved for high-volume production due to its non-re-engineering requirement.
27. **Manual Assembly and Solder Bridge Issues**
28. Manual assembly is a slow technique, requiring significant human labor and is prone to errors.
29. Short circuits caused by solder bridges have derailed many engineers’ careers.
30. Consequently, most organizations employ two technicians: an assembler and a quality assurance (QA) technician, who reviews the assembler’s work to prevent solder bridges.
31. Assembly technicians must be highly skilled to handle design rule exceptions that machines and hybrid assemblers cannot accommodate.
32. For designs that violate design rules for compactness, hand soldering remains the appropriate choice.
33. **Infrared Oven or Wave Soldering in Hybrid Assemblies**
34. Hybrid assembly methods dominate the market, where technicians place components on boards and use an IR oven or wave soldering machine for the soldering process.
35. Hybrid assemblies typically involve using stencils and solder paste to prepare the PCB boards, where technicians place components on designated footprints and then place the boards in an oven to complete the reflow or soldering process.
36. If errors such as vertical lift occur during oven soldering, hybrid assemblers must ensure sufficient space between components for manual adjustment and rework.
37. QA technicians may also be involved in the line.
38. **Component Placement in High-Density PCB Board Design**
39. The demand for high-density PCB boards introduces new challenges not present in sparse designs.
40. In high-density design, it’s crucial to follow traditional design practices.
41. A common issue is discarding reference codes, which increases density but is necessary for assembly.
42. Engineers must create additional documentation to assist assembly technicians if these indicators are removed.
43. Remember, PCB boards, schematics, and programs require significant human effort to develop before becoming functional, so thorough documentation is essential for others to work with your design.
44. Always consider how your design choices will impact those who interact with your work after you.
45. The next person might not pay dearly for your mistakes, but someone on the design and assembly team will have to convert your PCB board into a fully operational electronic system, making your vision a reality.
2. As a result, the electronics industry has invested significant effort into making these boards as easy to manufacture as possible.
3. Substantial capital has been directed towards design software to aid in the design, manufacture, assembly, inspection, and testing of printed circuit boards.
4. These advancements enable design engineers to invest in improved processes that reduce part size, support surface mount (SM) and ball grid array (BGA) packages, and decrease PCB line width and size.
5. Other features include enhanced card inspection with X-ray imaging.
6. The gradual incorporation of artificial intelligence (AI) into design software means that some critical tasks, such as component placement on PCB boards, are still manually controlled by layout engineers.
7. As a design engineer, you need to understand part placement to ensure design stability.
8. The evolution of component placement throughout your design career has changed significantly.
9. I began by designing low-density, flexible circuit boards using the wire wrap method.
10. Later, I had the opportunity to work with printed circuit boards, starting with simple designs (through-hole parts, reasonably sparse layouts) and progressing to more complex SMT parts.
11. This means that the manual soldering process following the PCB board design was also relatively simple at the beginning.
12. However, as you advance in your career, you will work with high-density PCB boards featuring tiny SMT, BGA, and QFN parts in delicate design environments, with fine wires and components placed in small spaces.
13. This adds a new variable to the “assembly” process that design engineers must address.
14. For some, this might be an unpleasant surprise, but it’s important to be prepared.
15. Placing components on a PCB can be done in various ways.
16. Design engineers should consider specific assembly techniques, such as machine assembly, manual assembly, or hybrid assembly (manual and infrared oven), before starting the PCB design.
17. These choices often depend on cost, time, volume, and the nature of the design.
18. Several factors drive the process of placing parts on a PCB board, including signal length, ease of assembly, and ease of testing.
19. Below, we will explore the unique aspects of each assembly method.
20. **Conference Types and DFA Important Guidelines**
21. Throughout the electronics industry, you will encounter various assembly methods.
22. It is essential to understand each process, its benefits, typical uses, and how to optimize the DFA process to align with the final PCB production.
23. **PCB Board Component Placement in Machine Assembly**
24. Machines are often used for mass production assembly, and the component footprint on the PCB must adhere to design rules.
25. Machine assembly lacks the flexibility that human operators provide and relies on expensive industrial machines to complete the PCB assembly according to the rules.
26. This method is usually reserved for high-volume production due to its non-re-engineering requirement.
27. **Manual Assembly and Solder Bridge Issues**
28. Manual assembly is a slow technique, requiring significant human labor and is prone to errors.
29. Short circuits caused by solder bridges have derailed many engineers’ careers.
30. Consequently, most organizations employ two technicians: an assembler and a quality assurance (QA) technician, who reviews the assembler’s work to prevent solder bridges.
31. Assembly technicians must be highly skilled to handle design rule exceptions that machines and hybrid assemblers cannot accommodate.
32. For designs that violate design rules for compactness, hand soldering remains the appropriate choice.
33. **Infrared Oven or Wave Soldering in Hybrid Assemblies**
34. Hybrid assembly methods dominate the market, where technicians place components on boards and use an IR oven or wave soldering machine for the soldering process.
35. Hybrid assemblies typically involve using stencils and solder paste to prepare the PCB boards, where technicians place components on designated footprints and then place the boards in an oven to complete the reflow or soldering process.
36. If errors such as vertical lift occur during oven soldering, hybrid assemblers must ensure sufficient space between components for manual adjustment and rework.
37. QA technicians may also be involved in the line.
38. **Component Placement in High-Density PCB Board Design**
39. The demand for high-density PCB boards introduces new challenges not present in sparse designs.
40. In high-density design, it’s crucial to follow traditional design practices.
41. A common issue is discarding reference codes, which increases density but is necessary for assembly.
42. Engineers must create additional documentation to assist assembly technicians if these indicators are removed.
43. Remember, PCB boards, schematics, and programs require significant human effort to develop before becoming functional, so thorough documentation is essential for others to work with your design.
44. Always consider how your design choices will impact those who interact with your work after you.
45. The next person might not pay dearly for your mistakes, but someone on the design and assembly team will have to convert your PCB board into a fully operational electronic system, making your vision a reality.
