A PCB consists of a nonconducting substrate (typically fiberglass with epoxy resin) upon which a conductive pattern or circuitry is formed. Copper is the most prevalent conductor, although nickel, silver, tin, tin-lead, and gold may also be used as etch-resists or top-level metal. There are three types of PCBs: single-sided, double-sided, and multilayer. Single-sided boards have a conductive pattern on one side only, double-sided boards have conductive patterns on both faces, and multilayer boards consist of alternating layers of conductor and insulating material bonded together. The conductive layers are connected by plated through-holes, which are also used to mount and electrically connect components. PCBs may also be either rigid, flexible, or a combination of the two (rigid-flex).
Three Types of PCBs
SINGLE-SIDED PCB
Several critical manufacturing steps are not included in the typical single-sided manufacturing sequence and no process is unique to single-sided productio
n. Therefore, any manufacturer of double-sided or multilayer PCBs can produce single-sided ones as well. Few shops produce single-sided panels exclusively, but instead include single-sided panels as part of their overall product mix. The most common sequence of single-sided production is drill, print-and-etch, surface finish, and final fabrication (all of these production processes are explained in Section 203). No inner-layer processing is required, and desmear is also eliminated. Furthermore, only in rare cases are plated through-holes required; therefore, all of the processes required to make the holes conductive are not applicable to single-sided manufactures. The holes instead provide mechanical stability for through-hole panels. Drilling may be completely eliminated on single-sided PCBs if the components are all surface-mounted.
DOUBLE-SIDED PCB
Not unlike single-sided, double-sided PCB manufacturing is al
so a subset of the multilayer process. The inner layer image transfer, lamination, and hole cleaning process are not performed. Therefore, any multilayer manufacturer can easily produce double-sided panels. Double-sided PCBs require electroless copper or other methods of making holes conductive, since the top and bottom sides of the board require interconnection.
MULTILAYER PCB
n. Therefore, any manufacturer of double-sided or multilayer PCBs can produce single-sided ones as well. Few shops produce single-sided panels exclusively, but instead include single-sided panels as part of their overall product mix. The most common sequence of single-sided production is drill, print-and-etch, surface finish, and final fabrication (all of these production processes are explained in Section 203). No inner-layer processing is required, and desmear is also eliminated. Furthermore, only in rare cases are plated through-holes required; therefore, all of the processes required to make the holes conductive are not applicable to single-sided manufactures. The holes instead provide mechanical stability for through-hole panels. Drilling may be completely eliminated on single-sided PCBs if the components are all surface-mounted.DOUBLE-SIDED PCB
Not unlike single-sided, double-sided PCB manufacturing is al
so a subset of the multilayer process. The inner layer image transfer, lamination, and hole cleaning process are not performed. Therefore, any multilayer manufacturer can easily produce double-sided panels. Double-sided PCBs require electroless copper or other methods of making holes conductive, since the top and bottom sides of the board require interconnection.MULTILAYER PCB
Single- and double-sided manufacturing proce
sses are
subsets of the multilayer process. Therefore the multilayer manufacturing process will be described in detail in Section 205. Multilayer boards represent two-thirds of the overall value of U.S. production dollars, even though they are produced in lower numbers
than single- or double-sided PCBs. The rigid multilayer process (rigid PCBs) represent about 95% of U.S. production.
More Information of PCBA at here: www.optimatech.net
sses aresubsets of the multilayer process. Therefore the multilayer manufacturing process will be described in detail in Section 205. Multilayer boards represent two-thirds of the overall value of U.S. production dollars, even though they are produced in lower numbers
than single- or double-sided PCBs. The rigid multilayer process (rigid PCBs) represent about 95% of U.S. production.
More Information of PCBA at here: www.optimatech.net
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