PCB Knowledge:
Welding defects caused by warpage
Circuit boards and components in the welding process emerge warpage, due to stress deformation caused virtual welding and short-circuit defects. Warpage is often caused by temperature imbalance between the upper and lower parts of the circuit board. The large PCB also warps due to the weight drop of the plate itself. The normal PBGA device is about 0.5 mm from the printed circuit board. If the device on the circuit board is large, the solder joint will be under stress for a long time as the circuit board is cooled down to its normal shape. If the device elevates the 0.1mm, it is sufficient to cause the virtual soldering open circuit.
The design of circuit board affects welding quality
In the layout, when the size of the circuit board is too large, the welding is easy to control, but the printing line is long, the impedance is increased, the ability of anti-noise is decreased, and the cost is increased. If it is too small, the heat dissipation will drop, the welding is difficult to control, and the adjacent lines will interfere with each other, such as the electromagnetic interference of the circuit board.
Therefore, the PCB board design must be optimized:
(1Shorten the connection between high frequency components and reduce EMI interference.
(2) Heavy (if more than 20 g) components shall be fixed with a bracket and then welded.
(3) Heat dissipation should be considered in order to prevent the defect and rework of Δ T on the surface of heating element, and the heat sensitive element should be far away from the heat source.
(4) The arrangement of components is as parallel as possible, so it is not only beautiful and easy to weld, but also suitable for mass production. The circuit board is designed for 4:3 rectangular optimum. Do not change the width of the wire to avoid discontinuity in wiring. When the circuit board is heated for a long time, copper foil is easy to expand and fall off. Therefore, large area copper foil should be avoided.
(pcb circuit board)
Process of pcb manufacturing:
PCB Capability:
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Max layers number: |
40 layers |
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Min line width/gap: |
3mil/3mil |
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Min hole size for mechanical drill: |
0.15mm |
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Min hole size for laser drill: |
0.1mm |
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Min annular ring: |
4 mil |
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Max copper thickness: |
12oz |
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Max size for single and double layers PCBs: |
600 x 1200mm |
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Max size for multi-layers PCBs: |
500 x 1200mm |
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Board thickness for 2 layers: |
0.2-8.0mm |
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Board thickness for multi-layers: |
0.4-8.0mm |
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Min solder mask bridge: |
0.08mm |
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Aspect raion: |
15:1 |
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Plugging vias capability: |
0.2-0.8mm |
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Impedance Control Tolerance: |
±10%(±5% for PCB Prototypes) |
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Thickness tolerance for PTH: |
+/- 3mil |
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Thickness tolerance for NPTH: |
+/- 2mil |
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Solder mask color: |
White, black, blue, green, yellow, red and so on |
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Character: |
White,yellow,black. |
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Finished surface: |
OSP(Entek), HASL no lead free, HASLLead Free,ENIG(Immersion Gold), Immersion Tin, Immersion Silver, Hard Gold, Platting Gold, Gold Finger, Enepig. |
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Month capability: |
6000 types/month, 30000 square meters/month |
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Normal board materials: |
SHENGYI,ITEQ,KB. |
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Special materials: |
ROGERS, ARLON,TACONIC,NELCO,ISOLA, HighTG:S1000-2.IT180 |
PCB Equipment:
Certifications:
Our Company is UL,ISO9001,ROHS and GJB9001B certified.
Packing and Shipping:
FAQ:
1. How to Get a quotation?
For PCBs,pls send us the Gerber File.For PCBA,pls send us the Gerber file and BOM(Bill of Materials)
2. What is the MOQ?
No MOQ.1 pcs is ok.
3.What is the lead time?
For PCB orders,the lead time is 2 to 10 days.For PCBA orders,the lead time will be 15 to 30 days.
4.Will the boards be tested before shippment?
Yes,all PCBs will be tested by Flying Probe or E-test.For PCBA,we will have AOI,X-ray,and functional test