PCB Tech - OSP process operation method for PCB manufacturing

PCB manufacturing process operation method

1.0 Purpose:

Formulate OSP PCB on-line production operation procedures to reduce the occurrence of empty soldering, cold soldering, poor tin eating and even PCBA scrapping during the PCB manufacturing process.

2.0 Scope:

All OSP PCB products produced by our company.

3.0 Operation authority:

3.1 Purchasing Department (PUR):

Responsible for PCB procurement and PCB rework arrangements

3.2 Product Engineering Department (PED):

Formulate OSP PCB operating procedures and PCB board factory approval operations

Formulate the production flow chart of OSP PCB products.

3.3 Manufacturing Department (MFD):

According to the OSP PCB process operation method for production operations

3.4 Operation Department (OP):

Responsible for scheduling control

3.5 Incoming Quality Management Department (IQC)

Responsible for PCB incoming inspection and solderability judgment

3.6 Storage Department (SM)

Responsible for warehouse management and inventory PCB Date code check.

4.0 Definition:

without

5.0 Homework content:

5.1 PC part

5.1.1 OSP PCB production must complete all welding operations within 24Hrs after the PCB is unpacked. When scheduling a work order, adjust the number of work orders according to the time required in the table below. When the same work order is calculated based on standard working hours, it cannot be When the production is completed within the time specified in the table below, please open the work order and put it online in batches.

Process time limit table

5.1.2 Before going online, please confirm whether the SMT&PTH material is Ready. If there is a shortage of materials, the online cannot be arranged.

5.2 SMT part

5.2.1 Because OSP PCB is prone to oxidation, it is forbidden to unpack and bake the PCB before it is online.

5.2.2 During production, if the number of work orders cannot be completed within two hours, please unpack the PCB vacuum packaging in batches. It is forbidden to unpack it all at once (the unpacking quantity is based on the required quantity of production per hour). When unpacking at the SMT site, if the incoming material has a humidity display card, it must be confirmed that the humidity display card meets the specifications, and the production will be completed within the specified time. It is necessary to confirm whether the PCB OSP production date exceeds 3 months. If it exceeds 3 months, it needs to be returned to the warehouse or find the engineering department and SQE for experimentation.

5.2.3 Before going online, check whether the PCB PAD surface has oxidation and discoloration (as shown in appendix 1). If the discoloration needs to be returned to the warehouse, please purchase and send it back to the PCB factory for the heavy industry OSP process.

5.2.4 Before going online, please confirm that all materials are ready for SMT materials. If there is a shortage of materials and SMT cannot be produced online, please do not unpack the PCB.

5.2.5 Please fill in the PCB unpacking time on the "Product Identification Card" in order to control the production time of each process section.

5.2.6 When IPQC is judged to return, the production shift at the time of the judgment shall be dealt with immediately, and it cannot be placed on the shift that produces the PCBA bad for processing, so as not to delay the time limit.

5.2.7 When designing the solder paste printing steel plate, as far as possible, the solder should be completely covered on the solder pad, and the coverage rate after melting should reach at least 90% of the area of the solder pad.

5.2.8 Used for PAD or through holes for ICT/MDA testing. When the solder paste printed steel plate is designed, the size of the steel plate opening is more than 50% of the area of the tested PAD or through holes, and it is covered with solder paste to avoid subsequent testing. There are cases of poor probe contact.

5.2.9 When the PCB printing solder paste is bad, it cannot be soaked or cleaned with a high volatile solvent. You can wipe the solder paste with a non-woven cloth dipped in 75% alcohol, and complete the SMT soldering operation on the PCB surface within 2 hours.

5.2.10 If it is necessary to produce on-line production due to lack of material due to shipping requirements, the steel plate still needs to be printed with solder paste on the part of the lack of material when printing solder paste. It is necessary to paste the lack of material and not print the solder paste to avoid PAD. The parts cannot be welded after oxidation.

5.3 IPQC section

5.3.1 Due to timeliness issues, IPQC was changed to on-line inspection.

5.4 PTH section

5.4.1 PCBA cannot be baked.

5.4.2 After SMT transfer, please follow the standard production in Table 1. The production time is calculated from the SMT unpacking and all welding production actions must be completed within 24Hrs.

5.4.3 There is no requirement for the tin degree in the empty PTH hole without parts. If there are parts in the hole, if the customer does not provide special instructions, it will be implemented in accordance with the IPC standard.

5.5 PCB storage conditions & shelf life

5.5.1 The storage environment before unopening the PCB is: temperature 20～30  degree Celsius relative humidity: ≤60%.

5.5.2 It is unopened and vacuum packaged in accordance with the above storage conditions. The OSP film has a shelf life of 3 months. The shelf life is one month before it must be returned to the manufacturer for rework. After the rework is OK, it can be used for another 3 months. Validity period of PCB quality assurance It is 6 months and cannot be baked.

5.5.3 OSP PCB incoming materials should be vacuum packaged (non-sea shipping may not require humidity test paper)

5.5.4 The warehouse needs to collect the PCB Date code to IQC, material control, purchase, and material control need to notify PM&purchasing within one month before the OSP film expires and send it back to the PCB board factory for heavy industry (re-OSP processing); otherwise, more than 3 If it is not used, it will be discarded.

5.5.5 OSP PCB is only allowed to be reworked once. After rework, the service life can be extended for another 3 months. At this time, it must be calculated based on the rework date, not the PCB Date Code. The supplier must mark the completion date of the heavy work on the outer packaging as the basis for the judgement of incoming inspection and SMT online. If the PCB is re-inspected by IQC and found to be oxidized or blackened after heavy work, it shall be returned. After heavy work, the PCB must be put online for use within 3 months. If it is not used, it will be discarded.

5.6 Requirements for process control

5.6.1 When opening the vacuum packaging of OSP PCB in SMT, please record the unsealing time on the "Product Identification Card" and check whether the copper foil on the PCB surface is oxidized. If you please inform the purchase immediately and notify the PCB board factory to deal with it. Please start production immediately after unpacking without discoloration.

5.6.2 OSP PCB shall not be baked in the whole process, so as to prevent the organic anti-oxidation film from being destroyed and dissolved at high temperature, resulting in oxidation of the copper foil surface and poor tin eating.

5.6.3 All welding operations must be completed within 24 hours after the vacuum packaging is unpacked, so as to avoid oxidation of the copper foil and lead to poor tin eating.

5.6.4 If the unused PCB is unpacked, please purchase and inform the PCB manufacturer of the heavy industry OSP process and put it into the warehouse in vacuum packaging. If it cannot be processed, it will be discarded.

5.6.5 When producing OSP PCB, please help the production manager to help arrange the production in time, try to complete the production from SMT to PTH in the shortest time, and not exceed the specified time limit, otherwise the copper foil will be oxidized and lead to poor tinning.

5.6.6 If the PCB board is FR1, please note that the copper foil of the board is very easy to fall off (compared to FR-4) when soldering and repairing. Please refer to the "Soldering Iron Operating Standard (D103-009002) for the soldering iron temperature during soldering". set up. When soldering, pay attention to the soldering iron not to poke hard on the copper foil so as not to cause the copper foil to fall off.

5.6.7 During the production process, please wear gloves and do not touch the surface of the PCB copper foil with your hands, so as to avoid PAD pollution and oxidation solder rejection problems.

5.6.8 Once all PCBs are unpacked, all soldering operations must be completed within 24 hours. If material problems are found in the middle of the production (for example: wrong material, lack of material...), the unpacked part must still be unpacked within 24 hours Complete the production of SMT and PTH processes to avoid PCBA scrapping.

5.6.9 All exposed copper parts of OSP PCB must be tinned (screw holes (including screw torx holes) are tinned in a torx hole by the SMT repair steel mesh, and the degree of tinning is: covering the screw holes by 50% ~ 65%). To prevent the copper platinum from being oxidized when exposed to the air for a long time.

5.6.10 In the case of dual PAD layout, the PAD under Chip is not allowed

5.6.11 The minimum safety distance allowed by the transistor is 1.0mm, and the empty PAD beyond the distance must be tinned in the form of "Tian" or all.

5.6.12 The antenna part is not allowed to be tinted.

5.6.13 The heat dissipating PAD is tinned with more than 75% of the area in the shape of "Tian".

5.6.14 Switch product Stack interface screw holes and optical points are not allowed to be tinned.

5.7 PDE section

5.7.2 When PED formulates the production flow chart of OSP PCB products, it must fully consider the prerequisite requirements of "24-hour production to complete all welding actions".

5.7.2 When changing to the OSP process, it is necessary to review whether the product flow chart of the product flow chart meets the prerequisite requirements of "24-hour production to complete all welding actions" for all applications of the material number PCB.

5.8 Chemical silver board

Please refer to OSP PCB for the production of the board. However, it must be ensured that the silver plate is isolated from sulfur-containing substances during the production process.