Hot Air Rework BGA Reballing Kit
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Automatic Hot Air Rework BGA Reballing Kit
1.Application Of Automatic Hot Air Rework BGA Reballing Kit
Work with all kinds of motherboards or PCBA.
Solder, reball, desoldering different kind of chips: BGA,PGA,POP,BQFP,QFN,SOT223,PLCC,TQFP,TDFN,TSOP, PBGA,CPGA,LED chip.
2.Product Features of Automatic Hot Air Rework BGA Reballing Kit
3.Specification of Automatic Hot Air Rework BGA Reballing Kit
4.Details of Automatic Hot Air Rework BGA Reballing Kit
5.Why Choose Our Automatic Hot Air Rework BGA Reballing Kit?
6.Certificate of Automatic Hot Air Rework BGA Reballing Kit
UL, E-MARK, CCC, FCC, CE ROHS certificates. Meanwhile, to improve and perfect the quality system, Dinghua has passed ISO, GMP, FCCA, C-TPAT on-site audit certification.
7.Packing & Shipment of Automatic Hot Air Rework BGA Reballing Kit
8.Shipment for Automatic Hot Air Rework BGA Reballing Kit
DHL/TNT/FEDEX. If you want other shipping term, please tell us. We will support you.
9. Terms of Payment
Bank transfer, Western Union, Credit Card.
Please tell us if you need other support.
10. How DH-A2 Semi Automatic Hot Air Rework BGA Reballing Kit work?
11. Related knowledge
Cause Analysis and Prevention of PCBA Assembly Explosion--Analysis of Causes of Explosion
1 What is the explosion?
Explosion is the common name for delamination or foaming of printed boards.
Layering is the phenomenon of separation between layers and layers within the substrate, between the substrate and the conductive copper foil, or in any other layer of the printed board.
Foaming is a layering that manifests as local expansion and separation between any layers of a laminate substrate or between a substrate and a conductive copper foil or protective coating layer. Foaming is also a manifestation of stratification.
2 Analysis of the cause of the explosion
The customer's products are used in industrial-controlled inverters. The design requirements are PCBs with CTI values. This 4-layer PCB has special requirements in the production and application process. Due to the special nature of CTI>600 copper clad material, it can't be directly pressed with the inner layer. This type of plate must be pressed with different types of interlayer insulating prepreg materials to meet CTI and lamination bonding force. Process requirements.
Due to the use of two kinds of prepreg insulation materials, the two materials have different resin types, and the bonding strength of the fusion interface of the two insulation materials is relatively small compared with the single insulation material of the conventional four-layer board. When the printed board absorbs moisture to a certain extent in the natural state, when the wave soldering or manual plug-in soldering, the PCB rises from normal temperature to 240 degrees Celsius or more, and the moisture absorbed in the board is instantaneously heated and vaporized, and the internal pressure is generated. When the pressure is greater than the bonding strength of the insulating layer in 2, a burst is generated.
In general, the explosion is caused by a congenital deficiency in materials or processes. For the material, it is a copper clad laminate or a PCB. The process includes the production process of the copper clad laminate and the PCBA board, the PCB production process, and the PCBA assembly process.
(1) Moisture absorption during PCB manufacturing
The raw materials of the PCB have a good affinity for water, and it is easy to absorb moisture. The existence of water in the PCB, the way of water vapor diffusion, and the pressure change of water vapor pressure with temperature to reveal the existence of water vapor is the primary cause of PCB explosion.
The moisture in the PCB mainly exists in the resin molecules and the physical structure defects existing inside the PCB. The water absorption rate and the equilibrium water absorption of the epoxy resin are mainly determined by the free volume and the concentration of the polar groups. The larger the free volume, the faster the initial water absorption rate, and the polar group has affinity for water, which is also the main reason for the epoxy resin to have higher moisture absorption capacity. The higher the content of polar groups, the more balanced water absorption The greater the amount. On the one hand, when the PCB is reflow soldered or wave soldered, as the temperature rises, the water in the volume and the water in which the limit group forms hydrogen bonds can obtain sufficient energy to perform diffusion motion in the resin. The water spreads outward and accumulates at physical structural defects, and whose molar volume increases. On the other hand, as the welding temperature increases, the saturated vapor pressure of water also increases.
According to the data, as the temperature rises, the saturated vapor pressure of the person also rises sharply, reaching 400 P/kPa at 250 degrees Celsius. When the adhesion between the layers of the material is lower than the saturated vapor pressure generated by the water vapor, the material is blasted by delamination or foaming. Therefore, moisture absorption before soldering is the main cause of PCB explosion.
(2) Moisture absorption during PCB storage
PCBs with CTI>600 should be listed as moisture sensitive devices. The presence of moisture in the PCB has an extremely important influence on its assembly and performance. If the PCB with high CTI value is stored without moisture or moisture, it will agree to cause moisture absorption. Obviously, under static conditions, the water content of the PCB will gradually increase with the promotion of time. The difference between the water absorption rate of vacuum packaging and the water absorption rate of vacuum packaging without the temporary storage time is shown in the figure below.
(3) Long-term moisture absorption during PCBA production
In the production process, due to materials or other factors affecting the PCBA in a long period of time in the production process, it may also cause PCBA moisture absorption of CTI>600. If welding is carried out after moisture absorption, there is also a risk of bursting.
(4) PCBA lead-free process production welding curve is not good
For PCBA lead-free process, Sn53/Pb87 solder has been replaced by SnAg-Cu lead-free solder, its melting point has risen from 183 degrees Celsius to above 217 degrees Celsius, reflow soldering, wave soldering temperature increased from 230 to 235 degrees Celsius to 250 ~255 degrees Celsius, the peak temperature may be higher. In the welding process, if the welding time is long, the rapid increase of the welding heat will increase the factor of poor PCB production, and the possibility of bursting will increase.