In electronics component interconnection technology, the most commonly used is the printed circuit board (
In the modern electronic and mechanical components encapsulation
And in order to achieve maximum production, cost minimization, shenzhen express more chopped think bond technology co. , LTD. , we are in the actual operation, consideration should be given to certain constraints.
And before embarking on PCB design work, should also consider the human factor.
These factors are described below: 1.
Wire spacing is less than 0.
1 mm will not be able to etch process, because if the etching liquid spread in the narrow space inside cannot effectively, it will cause metal can not be etched away.
If the conductor width less than 0.
1 mm, fracture and damage will occur in the etching process.
Bonding pad size than the size of the hole have thrown at least 0.
Listed in the following conditions determines the design method of the panel: 1.
For product size of reproductions of the original film camera performance;
The original TAB size;
The circuit board operation size of minimum or maximum;
Linear etching equipment.
In PCB design, from the Angle of printed circuit board assembly, to consider the following parameters: 1.
The diameter of the hole according to the maximum material condition (
And the minimum material conditions (
The situation to decide.
An unsupported components of the diameter of the hole should be selected, so that from the hole of the MMC minus the pin MMC, income difference at 0.
Between 5 mm.
And for ribbon pin, pin nominal diagonal and no-supporting hole diameter difference will not be more than 0.
5 mm, and no less than 0.
Reasonable to place small components, so that it will not be covered larger components.
The thickness of the resistance welding flux should not be greater than zero.
Silk screen printing logo can't intersect with any solder.
The upper half of the circuit board should be like the bottom half, in order to achieve the structure symmetry.
Because of the asymmetric circuit board can be bent.
Printed circuit board assembly point of view, we should pay more attention to an important factor to consider is before welding, due to insert components and its theoretical position tilt may be made in short circuit problem.
Based on experience, components pins allow maximum gradient should be kept within and location theory into a 15 degree Angle.
When the diameter of the hole and pin - difference is large gradient
Up to 20 & deg;
The components, slope of the vertical installation can be up to 25 or 30 degrees, but it leads to lower packing density.
Multiple circuit board assembly methods usually can make maintenance as well as pull out circuit board to replace on site is easy, of course, the premise condition that each individual can exercise its unique function of circuit board, such a circuit board to replace wouldn't have a lot of disassembly, guarantees the minimum number of welding/desoldering.
Therefore, the design of the printed circuit board must consider its maintainability.
Welding technology and equipment needed for the assembly, also make the circuit board design and layout of the increased a lot of limitations.
For example, in the wave soldering, the maximum size of the groove, the edge of the distance and space are the important factors of the operation.
At the same time, the PCB designer must be aware of as much as possible what should be the final finished product, and will try our best to protect the most sensitive part of it.
For example, any high voltage circuit should be protected to prevent contact with outside;
Products in the circuit board and circuit board components should be carefully placed, so that will bring damage to the minimum by external objects.
Turn-key Electronics Manufacturing Services for Printed Circuit Boards and Assembly