4 Technical Methods for Circuit Board Manufacturing Services2021-09-07
PCB role in circuit board manufacturing services
The printed circuit board (PCB) is a flat insulating base common in circuit board manufacturing services. On one or both sides of which, there are conductive metal strips (conductors) following the electrical circuit. In addition, printed circuit boards are common for mounting electrical radioelements (ERE) on them.
Furthermore, it is done using semi-automatic and automatic installations. Moreover, subsequent simultaneous soldering of all EREs by immersion in molten solder or on a wave of POS-60 liquid solder. Thus, holes on board, into which ERE leads are inserted during installation, are called mounting holes.
PCB methodologies for circuit board manufacturing service
Clearly, manual, semi-automated and automated methods carry out PCB design. Hence, the manual design method in circuit board manufacturing services ensures the optimal distribution of conductive patterns. Likewise, placement of electronic equipment (IET) on PCB and designer do tracing of printed conductors
In addition, the design begins with the development of a PCB sketch, which is performed on an enlarged scale (2: 1; 4: 1, etc.). And, for all elements included in the diagram (Figure 1, a), cardboard templates are made on the same scale and placed on the drawing field.
Procedure for PCB after conductor connection
After, choosing the best option for their location, connecting conductors are applied (Figure 1, b). Furthermore, printed wires located on other side of the circuit board manufacturing services are shown with dashed line. Also, at nodes of the coordinate grid, circles are:
- b) c) d)
a – First, electrical circuit diagram
b – second, a sketch of the PP
c- Also – PP drawing
d- Lastly- PP with hinged elements
Recommendations for circuit board manufacturing services
It is recommended to develop the design of the PP in the following main stages:
- First, the study of the technical task (TOR) for the product, which includes the designed software
- Secondly, determination of operating conditions and group of hardness
- Also, choice of type and class of accuracy of PP
- And the choice of sizes and configuration is considered in circuit board manufacturing services
- Additionally, choice of base material
- Likewise, choice of constructive coating
- Besides, placement of elements of a conducting pattern and tracing of printed conductors
- Furthermore, choice of marking method and its location
- Development of design documentation.
1 Method of manufacturing printed circuit boards
Manufacturing of printed circuit boards comes by chemical, electrochemical or combined methods. Moreover, recently new manufacturing methods have become widespread – additive. Below is a brief description of each of the methods (Table 1).
Table 1 – Brief description of PCB manufacturing methods
|PP manufacturing method||Raw material||Plated holes||Type of boards||Minimum conductor width, mm, up to||Advantages||Disadvantages|
|First, Chemical||Foil dielectric||No||OPP,
|0.2||Minimum labor intensity; high adhesion strength of conductors to the base||First and foremost, the need for metal bushings for double-sided mounting. Secondly, waste of copper|
|Second, Electrochemical||Non-foil dielectric||there is||OPP,
|0.15||Increased packing density in circuit board manufacturing services||Second, large unevenness of the conductors at the edges; low adhesion strength of conductors to the base|
|Also, Combined||Dielectric foiled on both sides||there is||OPP, DPP,
|0.2||Increased packing density||Also, significant labor intensity. Additionally has, rupture of the technological process due to the use of manual operations. And, drilling through varnish film|
|Additive||Non-foil dielectric||there is||Above all, OPP, DPP,
|0.1||Indeed, the high density of assembly; reduction in the cost of boards by 15-20%. Surely, reduction of production areas. Uniformity of the copper deposition layer. Not only, it can completely repair defective PCBs after copper etching but also work on re-metallization|
The chemical (subtractive) method
The chemical (subtractive) method in circuit board manufacturing services consists in applying a positive or negative pattern of a conductor circuit. Again, subsequent etching removes copper completely and creates a conductive pattern.
The combined approach is a combination of the first two methods. Etching copper obtains the conductive pattern.
Metallization process procedure for circuit board manufacturing services
Metallization of the holes is carried out through chemical copper plating, followed by electrochemical growth of the copper layer. Moreover, the additive method in circuit board manufacturing services creates a conductive pattern by metallization with a sufficiently thick layer of chemical copper.
In addition, cutting blanks for boards made of dielectric materials is carried out using roller or guillotine shears. Fixing and technological holes are obtained by drilling and in large-scale production – by stamping. Stamping operations in the manufacture of PCBs are common when cutting blanks.
Usage of PCB (Print Circuit Board) for circuit board manufacturing services
Also, it’s also commonin stamping holes of various shapes and cutting boards along the contour. The production of a metallic conductive pattern both in holes and on the surface of dielectric materials is usually carried out in two stages of chemical copper plating.
First, the dielectric commonin circuit board manufacturing services is metallized by the chemical (no-current) method. Then copper is electroplated onto the resulting thin layer of metal to the required thickness of the metal layer. And, in negative processes, the pattern protects conductive elements of PP from etching.
Significance of pattern in electrochemical deposition
Besides, in a positive process, the pattern is necessary to protect against electrochemical deposition of coatings on the gaps. And for instance, to areas from which copper is removed. Certainly, electroplate copper plating, a layer of copper vias and installation, and a conductive pattern in a semi-additive technology.
Considerations for PCB selection
When choosing the type of PCB for circuit board manufacturing services, you should consider
- Firstly, the ability to perform all switching connections
- Secondly, the technical and economic indicators
- Despite this, the cost of the primary material
- Also, the possibility of automation of manufacturing processes, control, and diagnostics
- Above all, the installation of mounted IET
An overview of circuit board manufacturing
Manufacturing of PCBs of a particular accuracy class (GOST 23751-86) is provided using various technical equipment and auxiliary materials.
- First and foremost, PPs of 1 and 2 accuracy classes are the simplest in execution
- Moreover, reliable in operation and have the lowest cost
- Additionally, three classes – require the use of high-quality materials
- Undoubtedly, more accurate tools and equipment
- 4 and 5 classes – precision equipment for circuit board manufacturing services
How to mitigate the negative effect of changing layers
According to typical wiring rules, there is at least one decoupling capacitor near each microcircuit. Thus, we can change the layer near the microcircuit. However, the total length of the segments that are not located in the “stripe” layer should be considered.
While the rough rule is that the total electrical length of these segments should not exceed one-eighth of the rise time. And, if too large, a change in Z 0 can occur on any of these segments.