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, too
In traditional THT printed circuit boards, both sides of the components and solder joints in plate respectively, and in SMT printed circuit boards, solder joints and components at the same surface of plate.
In SMT printed circuit boards, therefore, both sides of the hole is only used to connect to PCB conductor, the number of holes is much less, the diameter of the hole is much smaller, which can make the circuit board assembly density greatly improve.
Below small make up of SMT processing technique were introduced from the finishing assembly way.
The first is the single side mixed assembly, that is, 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.
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.
The second type is double mixing assembly, SMC/SMD and T.
HC can be mixed in with the side of the PCB, at the same time, the SMC/SMD may 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 assembly way.
SMC/SMD and 'FHC ipsilateral way, SMC/SMD with THC.
On one side of the PCB.
SMC/SMD and different modes of lateral iFHC, assemble the surface integrated chip (
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.
SMT processing and assembly process mainly depends on the surface of the assembly of components,
Type, use the types of components and assembly equipment conditions.
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.
Different types of SMA the assembly method is different, the same kinds of SMA the assembly method can also be different.
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