PCBA processing solder joints can become invalid due to issues like subpar electronic component pins, defects in flux quality, unqualified residues, and air oxidation. Furthermore, quality control involves submitting a manufacturability report (DFM) tailored to specific customer requirements. Next, I will provide further details.
1. What causes solder joints to be invalid in PCBA processing?
1. Inadequate positioning of electronic components: coating, environmental contamination, air oxidation, and shared issues.
2. Poor quality of the PCB welding layer: coating, environmental contamination, air oxidation, and thermal expansion.
3. Deficiencies in solder material quality: composition, unqualified residues, and air oxidation.
4. Limitations of flux quality: low flux performance, excessive erosion, and low SIR.
6. Disadvantages of other auxiliary materials: adhesives and detergents.
Second, how to ensure quality control in PCBA processing.
1. Holding a pre-production meeting after receiving a PCBA order is crucial. This meeting primarily involves analyzing the PCBGerber files and generating manufacturability reports (DFM) tailored to customer specifications. Many smaller manufacturers overlook this step, leading to quality issues from poor PCB design and resulting in significant rework and repairs.
2. Purchasing and inspecting electronic components provided by PCBA.
It’s essential to strictly control the procurement channels for electronic components, ensuring they come from reputable distributors and original manufacturers to prevent the use of second-hand or counterfeit materials. Additionally, establishing a dedicated PCBA incoming inspection station is necessary to rigorously check items for faults.
PCB: Verify the temperature calibration of the reflow oven, check for blockages or leaks in through holes without flying leads, and inspect for board warping.
IC: Ensure the screen printing matches the BOM and store components under controlled temperature and humidity conditions.
3. SMT assembly.
Solder paste printing and reflow oven temperature control are critical during assembly, necessitating high-quality laser templates and stringent processing standards. Depending on PCB requirements, adjustments to the stencil, such as adding or reducing mesh or U-shaped holes, may be needed. Temperature control in the reflow oven is vital for proper solder paste wetting and stencil integrity, following standard SOP guidelines. Moreover, rigorous implementation of AOI testing can significantly mitigate defects caused by human error.
4. Plug-in processing.
During the plug-in phase, mold design for wave soldering is pivotal. PE engineers should continuously refine their practices and insights on mold usage to enhance productivity.
5. PCBA processing board testing.
For orders that require PCBA testing, key assessments include ICT (In-Circuit Test), FCT (Functional Test), burn-in tests (aging tests), temperature and humidity tests, and drop tests.
This overview addresses “Why solder joints in PCBA processing fail and how to ensure quality control.” I hope this information is beneficial.
