Surface mount technology, refers to the lamellar structure of the miniaturization of components or suitable for surface mount components, in accordance with the requirements of the circuit
SMT assembly way depend on the type of surface mount components, use the types of components and assembly equipment conditions.
Different types of SMA the assembly method is different, the same type of SMA the assembly method can also be different.
According to the specific requirements of product assembly and assembly equipment conditions to choose the right means of assembly, is the basis of high efficiency and low cost of assembly production, also is the main content of the SMT process design.
Generally SMA can be divided into single-sided, double-sided pack 2 mixed assemble and the whole surface on a total of 6 three types of assembly way.
One, SMT single mixed assembly way: single mixed assembly, namely SMC/SMD and hole instrumentation components (
Conventional distribution on one side of the PCB is different, but the welding surface is only single.
This way of assembly adopts single sided PCB and wave soldering (
Now generally adopts double wave soldering)
There are two kinds of process, the specific way of assembly.
Stick method: first the first assembly style known as the first method, namely the PCB surface (B
Mount SMC/SMD first, and then the a-side instrumentation THC.
After the method.
Stick method after the second mode of assembly is called, is first in A PCB surface instrumentation THC, B side after SMT SMD.
Second, double mixed assembly way: double mixing assembly that SMC/SMD and THC distribution can be mixed on the same side of PCB, at the same time, the SMC/SMD can also be distributed in double sided PCB.
Double mixed assembly using double-sided PCB, double wave soldering or reflow soldering.
In the way of assembly also has to post of SMC/SMD or after the difference, generally according to the size of the type of SMC/SMD and PCB reasonable choice, usually USES the first method is more.
The commonly used two kinds of assembly method of assembly: 1, SMC/SMD and FHC ipsilateral way: SMC/SMD with THC side of PCB.
2, SMC/SMD and lateral iFHC different ways: the surface integrated chip assembly (
And THC on the PCB of A surface, but the SMC and small outline transistor (
On the B side.
This kind of assembly due to the way in which the single side or double side PCB SMT SMC/SMD, and inserted the surface has a lead of assembly components hard to assemble, so very high density assembly.
Three, the whole surface assembly way all mean surface mount on the PCB only SMC/SMD and no THC.
The current components has not been fully implemented in SMT, the assembly in the actual application form.
This kind of PCB assembly method is generally in the thin line graphics or ceramic substrate, using fine pitch components and reflow welding process for assembly.
It also has two assembly method: 1, single surface assembly method: using single sided PCB in a single assembly SMC/SMD.
2, double-sided surface assembly method: using double-sided PCB assemble at two sides, SMC/SMD, higher density assembly.
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